Key Substance Use and Mental Health Indicators in the United States:
Results from the 2015 National Survey on Drug Use and Health

Summary

This national report summarizes key findings from the 2015 National Survey on Drug Use and Health (NSDUH) for indicators of substance use and mental health among people aged 12 years old or older in the civilian, noninstitutionalized population of the United States. Results are provided for the overall category of individuals aged 12 or older as well as by age subgroups. The NSDUH questionnaire underwent a partial redesign in 2015 to improve the quality of the NSDUH data and to address the changing needs of policymakers and researchers with regard to substance use and mental health issues. Trends continue to be presented for estimates that are assumed to have remained comparable with those in earlier years (e.g., marijuana and heroin use trends for 2002 to 2015 and mental health trends typically for 2008 to 2015).

Illicit Drug Use

Changes in measurement for 7 of the 10 illicit drug categories—hallucinogens, inhalants, methamphetamine, and the misuse of prescription pain relievers, tranquilizers, stimulants, and sedatives—may have affected the comparability of the measurement of these illicit drugs.¹ Therefore, only 2015 estimates are presented for these seven illicit drug categories and for the use of any illicit drug. In 2015, 27.1 million people aged 12 or older used an illicit drug in the past 30 days, which corresponds to about 1 in 10 Americans (10.1 percent). The illicit drug use estimate for 2015 continues to be driven primarily by marijuana use and the misuse of prescription pain relievers, with 22.2 million current marijuana users aged 12 or older (i.e., users in the past 30 days) and 3.8 million people aged 12 or older who reported current misuse of prescription pain relievers. The 2015 estimate of current marijuana users was similar to the estimate in 2014, but it was higher than the estimates from 2002 to 2013. This increase in marijuana use among people aged 12 or older reflects the increase in marijuana use by adults aged 26 or older and, to a lesser extent, the increase in marijuana use among young adults aged 18 to 25.

In 2015, NSDUH adopted a revised definition of prescription drug misuse, which defined misuse as use in any way not directed by a doctor, including use without a prescription of one's own; use in greater amounts, more often, or longer than told to take a drug; or use in any other way not directed by a doctor. The estimated 3.8 million people aged 12 or older who were current misusers of pain relievers represent 1.4 percent of the population aged 12 or older.

The estimate of current heroin use in 2015 among people aged 12 or older was higher than the estimates in most years between 2002 and 2009, but it was similar to the estimates between 2010 and 2014. Current cocaine use in 2015 was similar to the estimates in most years between 2007 and 2013, but it was higher than the estimate in 2014. The 2015 estimate of crack use was similar to the estimates in most years from 2008 to 2014. There were new baselines in 2015 for hallucinogen, inhalant, and methamphetamine use (0.5, 0.2, and 0.3 percent, respectively, for current use among people aged 12 or older).

Tobacco Use

In 2015, an estimated 52.0 million people aged 12 or older were current cigarette smokers. Although about 1 in 5 people aged 12 or older were current cigarette smokers, cigarette use generally declined between 2002 and 2015 across all age groups. Among the 52.0 million current cigarette smokers in 2015, 30.2 million were daily cigarette smokers, including 12.4 million daily smokers who smoked approximately a pack or more of cigarettes per day.

Alcohol Use

NSDUH collects information on past month alcohol use, binge alcohol use, and heavy alcohol use. For men, binge alcohol use is defined in NSDUH as drinking five or more drinks on the same occasion on at least 1 day in the past 30 days. For women, binge drinking is defined as drinking four or more drinks on the same occasion on at least 1 day in the past 30 days. Heavy alcohol use is defined as binge drinking on 5 or more days in the past 30 days. In 2015, there were 138.3 million Americans aged 12 or older who reported current use of alcohol, including 66.7 million who reported binge alcohol use in the past month and 17.3 million who reported heavy alcohol use in the past month. Past month binge drinkers and heavy alcohol users represented 24.9 and 6.5 percent of people aged 12 or older, respectively.

Underage alcohol use (i.e., among people aged 12 to 20) and binge and heavy use among young adults aged 18 to 25 are a concern. In 2015, about 7.7 million people aged 12 to 20 reported drinking alcohol in the past month, including 5.1 million who reported binge alcohol use and 1.3 million who reported heavy alcohol use. Among all people aged 12 to 20 in 2015, 13.4 percent were binge drinkers, and 3.3 percent were heavy drinkers. About 2 out of 5 young adults aged 18 to 25 were current binge alcohol users, and 1 out of every 10 young adults were heavy alcohol users.

Substance Use Disorders

In 2015, approximately 20.8 million people aged 12 or older had a substance use disorder (SUD) related to their use of alcohol or illicit drugs in the past year,² including 15.7 million people who had an alcohol use disorder and 7.7 million people who had an illicit drug use disorder. The percentage of people aged 12 or older with an alcohol use disorder (5.9 percent) in 2015 was lower than the percentages in 2002 to 2014. Due to revisions to the NSDUH illicit drug questions, estimates in 2015 for any illicit drug use disorder are not compared with estimates from previous years.

Substance Use Treatment

In 2015, an estimated 21.7 million people aged 12 or older needed substance use treatment (i.e., treatment for problems related to the use of alcohol or illicit drugs), or about 1 in 12 people (8.1 percent). For NSDUH, people are defined as needing substance use treatment if they had an SUD in the past year or if they received substance use treatment at a specialty facility in the past year.³

In 2015, 10.8 percent of people aged 12 or older (2.3 million people) who needed substance use treatment received treatment at a specialty facility in the past year.

Mental Health Issues among Adults

In 2015, an estimated 43.4 million adults aged 18 or older (17.9 percent) had any mental illness (AMI) in the past year. An estimated 9.8 million adults in the nation had a serious mental illness (SMI) in the past year, representing 4.0 percent of all U.S. adults in 2015.⁴ The percentage of adults with AMI and the percentage of adults with SMI remained stable from 2008 to 2015. In 2015, 6.7 percent of adults aged 18 or older (16.1 million adults) had at least one major depressive episode (MDE) in the past year, and 4.3 percent (10.3 million adults) had an MDE with severe impairment in the past year.⁵ The percentage of adults who had a past year MDE remained stable between 2005 and 2015.

Mental Health Service Use among Adults

In 2015, an estimated 34.2 million adults (14.2 percent of adults) received mental health care during the past 12 months. Among the 43.4 million adults with AMI, 18.6 million (43.1 percent) received mental health services in the past year. About 6.4 million of the 9.8 million adults with past year SMI (65.3 percent) received mental health services in the past year. The percentage of adults with AMI who received mental health care in 2015 was similar to the percentages in most years from 2008 to 2014.

Co-Occurring Mental Illness and Substance Use Disorders among Adults

An estimated 8.1 million adults (3.3 percent of all adults) had both AMI and SUDs in the past year, and 2.3 million adults (1.0 percent of all adults) had co-occurring SMI and SUDs in the past year. Among the 8.1 million adults with co-occurring AMI and an SUD in the past year, 48.0 percent received either substance use treatment at a specialty facility or mental health care in the past year. Among the 2.3 million adults who had co-occurring SMI and an SUD in the past year, 62.6 percent received either substance use treatment at a specialty facility or mental health care in the past year.

Mental Health Issues among Adolescents

In 2015, 12.5 percent of adolescents aged 12 to 17 (3.0 million adolescents) had an MDE during the past year, and 8.8 percent of adolescents (2.1 million adolescents) had a past year MDE with severe impairment.⁵ The percentage of adolescents in 2015 who had a past year MDE was higher than the percentages in 2004 to 2014. Among the 3.0 million adolescents in 2015 who had a past year MDE, 1.2 million (39.3 percent) received treatment for depression. This 2015 percentage was similar to the percentages in most years from 2004 to 2014.

Co-Occurring MDE and Substance Use among Adolescents

In 2015, the percentage of adolescents who used illicit drugs in the past year was higher among those with a past year MDE than it was among those without a past year MDE (31.5 vs. 15.3 percent). An estimated 350,000 adolescents in 2015 had an SUD and an MDE in the past year. This number represents 1.4 percent of all adolescents in the United States. Among adolescents who had a co-occurring MDE and an SUD in the past year, 63.1 percent received either substance use treatment at a specialty facility or mental health services in the past year.

Introduction

Substance use and mental health issues affect millions of adolescents and adults in the United States and contribute heavily to the burden of disease.^1,2,3 The National Survey on Drug Use and Health (NSDUH) is the primary source for statistical information on illicit drug use, alcohol use, substance use disorders (SUDs), and mental health issues for the civilian, noninstitutionalized population of the United States. Information on mental health and substance use allows the Substance Abuse and Mental Health Services Administration (SAMHSA) and other policymakers to gauge progress toward improving the health of the nation.

The benefit of using NSDUH data to assess trends across time has to be balanced with the periodic need to revise NSDUH content to address changes in society and emerging issues. Although minor changes may sometimes be made annually, the 2015 NSDUH included a wide array of changes that affected the reporting of trends for many NSDUH estimates.

This report contains one of the first sets of findings from the 2015 NSDUH for key substance use and mental health indicators in the United States. Comprehensive 2015 NSDUH detailed tables that show additional substance use and mental health-related outcomes, including data for various subpopulations covered in NSDUH, are available separately at https://www.samhsa.gov/data/.⁴

Survey Background

NSDUH is an annual survey of the civilian, noninstitutionalized population of the United States aged 12 years old or older.⁵ The survey is sponsored by SAMHSA within the U.S. Department of Health and Human Services (HHS). The survey covers residents of households and individuals in noninstitutional group quarters (e.g., shelters, boarding houses, college dormitories, migratory workers' camps, halfway houses). The survey excludes people with no fixed address (e.g., homeless people not in shelters), military personnel on active duty, and residents of institutional group quarters, such as jails, nursing homes, mental institutions, and long-term care hospitals.

NSDUH employs a stratified multistage area probability sample that is designed to be representative of both the nation as a whole and for each of the 50 states and the District of Columbia. The 2015 NSDUH annual target sample size of 67,500 interviews was distributed across three age groups, with 25 percent allocated to adolescents aged 12 to 17, 25 percent allocated to young adults aged 18 to 25, and 50 percent allocated to adults aged 26 or older. From 2002 through 2013, the NSDUH sample was allocated equally across these three age groups. Although the sample design changed in 2014, NSDUH had the same total target sample size per year of 67,500 interviews between 2002 and 2015.⁶

NSDUH is a face-to-face household interview survey that is conducted in two phases: the screening phase and the interview phase. The interviewer conducts a screening of the eligible household with an adult resident (aged 18 or older) in order to determine whether zero, one, or two residents aged 12 or older should be selected for the interview.⁷ NSDUH collects data using audio computer-assisted self interviewing (ACASI) in which respondents read or listen to the questions on headphones, then enter their answers directly into a NSDUH laptop computer. ACASI is designed for accurate reporting of information by providing respondents with a highly private and confidential mode for responding to questions about illicit drug use, mental health, and other sensitive behaviors. NSDUH also uses computer-assisted personal interviewing (CAPI) in which interviewers read less sensitive questions to respondents and enter the respondents' answers into a NSDUH laptop computer.

In 2015, screening was completed at 132,210 addresses, and 68,073 completed interviews were obtained, including 16,955 interviews from adolescents aged 12 to 17 and 51,118 interviews from adults aged 18 or older. Weighted response rates for household screening and for interviewing were 79.7 and 69.3 percent, respectively, for an overall response rate of 55.2 percent for people aged 12 or older. The weighted interview response rates were 77.7 percent for adolescents and 68.4 percent for adults.⁸ Further details about the 2015 NSDUH design and methods can be found on the web at https://www.samhsa.gov/data/.⁹

Notable 2015 NSDUH Questionnaire Changes

The NSDUH questionnaire underwent a partial redesign in 2015 to improve the quality of the NSDUH data and to address the changing needs of policymakers and researchers with regard to substance use and mental health issues. The prescription drug questions were redesigned to shift the focus from lifetime misuse to past year misuse. Additionally, questions were added about any past year prescription drug use rather than just misuse. New methamphetamine questions were added, replacing the methamphetamine questions that were previously asked within the context of prescription stimulants. Substantial changes were also made to questions about smokeless tobacco, binge alcohol use, inhalants, and hallucinogens. These changes led to potential breaks in the comparability of 2015 estimates with estimates from prior years. Consequently, these changes potentially affected overall summary measures, such as illicit drug use, and other measures, such as initiation, SUD, and substance use treatment. Additionally, certain demographic items were changed as part of the partial redesign. Education questions were updated, and new questions were added on disability, English-language proficiency, sexual orientation of adults, and military families.

Due to these changes, only 2015 data are presented for certain estimates until comparability with prior years can be established. Trends will continue to be presented for items that are assumed to have remained comparable with earlier years. Details on the 2015 NSDUH questionnaire changes, reasons for the changes, and implications of the changes for NSDUH data users are included in a brief report on these questionnaire changes, in a report on the design changes for the 2014 and 2015 NSDUHs, and in the methodological summary and definitions report for 2015.^10,11,12

Data Presentation and Interpretation

This report focuses on substance use and mental health in the United States based on NSDUH data from 2015 and earlier years.¹³ Estimates of substance use and substance use treatment are presented for individuals aged 12 or older, adolescents, and adults.¹⁴ However, estimates of mental health issues and mental health service use are not presented jointly for individuals aged 12 or older. Rather, these estimates are presented separately for adolescents aged 12 to 17 and adults aged 18 or older because adolescents and adults completed different sets of questions regarding mental health and mental health service utilization.

All estimates (e.g., percentages and numbers) presented in the report are derived from NSDUH survey data that are subject to sampling errors. The estimates have met the criteria for statistical precision. Estimates that do not meet these criteria have been suppressed and are not shown.¹⁵ Trend analyses in this report focus on percentages because the percentages take into account any change in the size of the total population and facilitate the comparison of estimates across years.¹⁶ This report focuses on long-term trends by comparing percentages in 2015 with percentages in each of the years from 2002 to 2014. Statistical tests also have been conducted for comparisons that appear in the text of the report. Statistically significant differences are described using terms such as "higher," "lower," "increased," or "decreased." Statements use terms such as "similar," "remained steady," or "stable" when a difference is not statistically significant. Analyses of long-term trends in this report summarize whether the 2015 estimates are different from or similar to estimates in most or all previous years,¹⁷ while minimizing discussion of anomalous differences between any 2 years that can occur due to these estimates being based on samples.¹⁸ Graphics and tables contain estimates that support the statements in this report, and supplementary tables of estimates (including standard errors) are included in Appendix A. Also, Appendix B provides a list of contributors, reviewers, and report production staff who worked on this report.

Illicit Drug Use

NSDUH obtains information on 10 categories of illicit drugs: marijuana, cocaine (including crack), heroin, hallucinogens, inhalants, and methamphetamine, as well as the misuse of prescription pain relievers, tranquilizers, stimulants, and sedatives; see the section on the misuse of psychotherapeutic drugs for the definition of misuse. Estimates of "illicit drug use" reported from NSDUH reflect the data from these 10 drug categories. Changes in measurement for 7 of the 10 illicit drug categories—hallucinogens, inhalants, methamphetamine, and the misuse of prescription pain relievers, tranquilizers, stimulants, and sedatives—may have affected the comparability of the measurement of these illicit drugs between 2015 and prior years. Therefore, only 2015 estimates are presented for these seven illicit drug categories. Also, only 2015 estimates are presented for the use of any illicit drug.

In 2015, an estimated 27.1 million Americans aged 12 or older were current (past month) illicit drug users, meaning that they had used an illicit drug during the month prior to the survey interview (Figure 1). The most commonly used illicit drug in the past month was marijuana, which was used by 22.2 million people aged 12 or older. An estimated 6.4 million people reported misusing psychotherapeutic drugs in the past month, including 3.8 million people who were misusers of prescription pain relievers. Thus, the number of current misusers of pain relievers was second to marijuana among specific illicit drugs. Smaller numbers of people in 2015 were current users of the other illicit drugs shown in Figure 1.¹⁹

Aged 12 to 17

In 2015, 7.0 percent of adolescents aged 12 to 17 were current users of marijuana (Figure 3). This means that approximately 1.8 million adolescents used marijuana in the past month. The percentage of adolescents in 2015 who were current marijuana users was similar to the percentages in most years between 2004 and 2014.

Aged 18 to 25

In 2015, about 1 in 5 young adults aged 18 to 25 (19.8 percent) were current users of marijuana (Figure 3). This means that 6.9 million young adults used marijuana in the past month. The percentage of young adults who were current marijuana users in 2015 was stable compared with the percentages between 2011 and 2014. However, the 2015 estimate was higher than the estimates in 2002 through 2010.

Aged 26 or Older

In 2015, 6.5 percent of adults aged 26 or older were current users of marijuana (Figure 3), which represents about 13.6 million adults in this age group. The percentage of adults aged 26 or older who were current marijuana users in 2015 was similar to the percentage in 2014, but it was higher than the percentages in 2002 to 2013.

Misuse of Psychotherapeutic Drugs

Because of the changes that were made to the prescription drug questions in 2015, a new baseline started in 2015 for all prescription drug measures. The four categories of prescription drugs (pain relievers, tranquilizers, stimulants, and sedatives) cover numerous medications that currently are or have been available by prescription. NSDUH respondents are asked to report misuse of these drugs, defined as use in any way not directed by a doctor, including use without a prescription of one's own; use in greater amounts, more often, or longer than told to take a drug; or use in any other way not directed by a doctor. Misuse of over-the-counter drugs is not included. NSDUH reports combine the four prescription drug groups into a category referred to as "psychotherapeutics." Additional information on the revisions to the NSDUH prescription drug questions are documented in a separate 2015 NSDUH report on prescription drugs.²⁰ The report for prescription drugs also includes new content, such as estimates of any use of prescription drugs (i.e., not just misuse), and motivations for misusing prescription drugs.

In this section, a summary of current misuse of any prescription psychotherapeutic drug is presented first, followed by sections on the current misuse of pain relievers, tranquilizers, stimulants, and sedatives. In 2015, an estimated 6.4 million Americans aged 12 or older were current misusers of psychotherapeutic drugs, which represent 2.4 percent of the population aged 12 or older (Figure 4). An estimated 492,000 adolescents aged 12 to 17 misused psychotherapeutic drugs in the past month. Stated another way, about 1 in 50 adolescents (2.0 percent) were current misusers of psychotherapeutic drugs. An estimated 1.8 million young adults aged 18 to 25 were current misusers of psychotherapeutic drugs, which corresponds to 5.1 percent of young adults. There were 4.1 million adults aged 26 or older who were current misusers of psychotherapeutic drugs, or 2.0 percent of adults in this age group.

An estimated 3.8 million people aged 12 or older in 2015 were current misusers of pain relievers, which represents 1.4 percent of the population aged 12 or older (Figures 5 and 6). In 2015, an estimated 276,000 adolescents aged 12 to 17 were current misusers of pain relievers, which corresponds to 1.1 percent of adolescents (Figure 6). An estimated 829,000 young adults aged 18 to 25 misused pain relievers in the past month, which represents 2.4 percent of young adults. An estimated 2.7 million adults aged 26 or older were current misusers of pain relievers, which corresponds to 1.3 percent of adults aged 26 or older.

Aged 12 to 17

There were 53,000 adolescents aged 12 to 17 who were current users of cocaine in 2015. This number who used cocaine represents 0.2 percent of adolescents (Figure 7). The 2015 estimate for current cocaine use among adolescents was similar to the estimates between 2009 and 2014, but the 2015 estimate was lower than the estimates in the years from 2002 to 2008. Where estimates had sufficient precision to be reported, estimates of crack use among adolescents in 2002 to 2015 ranged from less than 0.1 percent to 0.1 percent (Table A.2B in Appendix A).

Aged 18 to 25

An estimated 1.7 percent of young adults aged 18 to 25 were current users of cocaine in 2015 (Figure 7), and 0.1 percent used crack in the past month (Table A.3B in Appendix A). These percentages represent 580,000 young adults who used cocaine, including 39,000 who used crack. The 2015 percentage of young adults who were current cocaine users was lower than the percentages in 2002 through 2006, and it was similar to the percentages in most years between 2007 and 2014. The estimate of current crack use among young adults in 2015 was similar to estimates between 2007 and 2014.

Aged 26 or Older

In 2014, 0.6 percent of adults aged 26 or older were current users of cocaine (Figure 7), and 0.2 percent used crack in the past month (Table A.4B in Appendix A). These percentages represent 1.2 million adults aged 26 or older who currently used cocaine, including 354,000 who currently used crack. The 2015 estimate of current cocaine use among adults aged 26 or older was similar to the estimates from most years between 2002 and 2014. Current use of crack was stable between 2008 and 2015, but the 2015 estimate was lower than the estimates in most years from 2002 to 2007.

Tobacco Use

Tobacco use continues to be the leading cause of preventable death in the United States. Tobacco use, particularly cigarette smoking, imposes substantial health and financial costs on our nation.^22,23 NSDUH data can be used to estimate the percentage of individuals who used tobacco products and, in turn, can be used to monitor changes in use over time. NSDUH asks respondents aged 12 or older about their tobacco use in the 30 days before the interview. Tobacco products include cigarettes, smokeless tobacco (such as snuff, dip, chewing tobacco, or "snus"), cigars, and pipe tobacco. Cigarette use is defined as smoking "part or all of a cigarette." A discussion of the estimates for daily cigarette smoking follows a presentation of the estimates for any current cigarette smoking. Finally, this section presents estimates for current use of cigars, pipe tobacco, and smokeless tobacco.

In 2015, respondents were asked about their use of any smokeless tobacco product (i.e., instead of being asked separately about their use of snuff and chewing tobacco) because data from prior years indicated that respondents had difficulty distinguishing between these types of smokeless tobacco. Due to these changes, estimates of smokeless tobacco use in 2015 are not compared with estimates in prior years.

The majority of current (i.e., past month) tobacco users in 2015 were current cigarette smokers (Figure 13), as has been the case historically.²⁴ Among current users of any tobacco product aged 12 or older in 2015, 66.3 percent smoked cigarettes but did not use other tobacco products, 15.0 percent smoked cigarettes and used some other type of tobacco product, and 18.8 percent used only tobacco products other than cigarettes (Figure 14). This same pattern was observed across the three age groups in 2015 (adolescents aged 12 to 17, young adults aged 18 to 25, and adults aged 26 or older), with most current tobacco use consisting only of cigarette smoking, followed by the use of tobacco products other than cigarettes or the use of both cigarettes and other tobacco products. Among young adults and adults aged 26 or older who were current users of tobacco products, about 20 percent did not smoke cigarettes (19.0 and 18.4 percent, respectively). In contrast, among adolescents who were current tobacco users, 30.3 percent used tobacco products other than cigarettes but did not smoke cigarettes. In addition, about one fourth of adolescents and young adults who were current tobacco users smoked cigarettes and used other tobacco products (26.0 and 23.6 percent, respectively). Among adults aged 26 or older who were current tobacco users, about 1 in 8 (12.7 percent) were current cigarette smokers and current users of other tobacco products.

Aged 12 to 17

Among adolescents aged 12 to 17 in 2015, 1.0 million smoked cigarettes in the past month. This number represents 4.2 percent adolescents who were current cigarette smokers (Figure 15). The percentage of adolescents who were past month cigarette smokers declined from 13.0 percent in 2002 (or about 1 in 8 adolescents) to 4.2 percent in 2015 (or fewer than 1 in 20). The percentage of adolescents who were current cigarette smokers in 2015 also was lower than the percentages in each year from 2002 to 2014.

Aged 18 to 25

Among young adults aged 18 to 25 in 2015, 9.3 million smoked cigarettes in the past month. This number of young adults who were current cigarette smokers represents about one quarter of young adults (26.7 percent) (Figure 15). The percentage of young adults who were current cigarette smokers in 2015 was lower than the percentages in 2002 to 2014.

Aged 26 or Older

In 2015, 41.6 million adults aged 26 or older smoked cigarettes in the past month. Stated another way, 1 out of 5 adults aged 26 or older (20.0 percent) were current cigarette smokers in 2015 (Figure 15). The 2015 estimate for current cigarette smoking among adults in this age group was lower than the estimates from 2002 to 2014.

Alcohol Use

NSDUH asks respondents aged 12 or older about their alcohol use in the 30 days before the interview. Current alcohol use is defined as any use of alcohol in the past 30 days. In addition to asking about any alcohol use, NSDUH collects information on binge alcohol use and heavy alcohol use.²⁶ Consistent with federal definitions²⁷ and other federal data collections, the NSDUH definition for binge alcohol use varies for males and females. Binge drinking for males is defined as drinking five or more drinks on the same occasion on at least 1 day in the past 30 days, which is the same as the definition of binge alcohol use that was applied to males in prior years. For females, binge alcohol use is defined in 2015 as drinking four or more drinks on the same occasion on at least 1 day in the past 30 days. The threshold of four or more drinks for females differs from the threshold of five or more drinks that was used in prior years. Heavy alcohol use is defined as binge drinking on 5 or more days in the past 30 days based on the thresholds that were described previously for males and females. Any alcohol use, binge drinking, and heavy drinking are not mutually exclusive categories of use; heavy use is included in estimates of binge and current use, and binge use is included in estimates of current use (Figure 21). Because of these changes to the definition of binge alcohol use in NSDUH, estimates of binge and heavy alcohol use in 2015 are presented in this report, but these 2015 estimates are not compared with estimates from prior years.²⁸

In 2015, 138.3 million Americans aged 12 or older reported current use of alcohol, 66.7 million reported binge alcohol use in the past month, and 17.3 million reported heavy alcohol use in the past month (Figure 21). Thus, nearly half of current alcohol users reported binge alcohol use (48.2 percent), and about 1 in 8 current alcohol users reported heavy alcohol use (12.5 percent). Among binge alcohol users, about 1 in 4 (26.0 percent) were heavy users.

Aged 12 to 17

The percentage of adolescents aged 12 to 17 who were current alcohol users was 9.6 percent in 2015 (Figure 22), which corresponds to 2.4 million adolescents in 2015 who drank alcohol in the past month. The percentage of adolescents who were current alcohol users in 2015 was lower than the percentages in 2002 through 2014. Although the estimate of current alcohol use among adolescents decreased between 2002 and 2015, about 1 in 10 adolescents aged 12 to 17 were current alcohol users in 2015.

Aged 18 to 25

In 2015, 58.3 percent of young adults aged 18 to 25 were current alcohol users (Figure 22), which corresponds to about 20.4 million young adults. The percentage of young adults in 2015 who drank alcohol in the past month was similar to the percentages in 2013 and 2014. Although the 2015 estimate was lower than the estimates in 2002 through 2012, about three fifths of young adults were current alcohol users in each year between 2002 and 2015 (ranging from 58.3 to 62.0 percent).

Aged 26 or Older

More than half (55.6 percent) of adults aged 26 or older in 2015 were current alcohol users (Figure 22). This percentage corresponds to about 115.6 million adults in this age group who drank alcohol in the past month. The percentage of adults aged 26 or older in 2015 who were current alcohol users was higher than the percentages in most years from 2002 to 2007, but it was similar to the percentages in 2008 to 2014. In each year between 2002 and 2015, however, more than half of adults aged 26 or older were current alcohol users (ranging from 52.5 to 56.5 percent).

The estimate of 7.7 million underage people in 2015 who reported current alcohol use represents 20.3 percent of 12 to 20 year olds (Figure 25). Among all people aged 12 to 20 in 2015, 13.4 percent were binge drinkers, and 3.3 percent were heavy drinkers. The percentage of underage individuals who reported current alcohol use in 2015 was lower than the percentages in 2002 through 2014 (Figure 26). Despite these declines over time, about 1 in 5 individuals aged 12 to 20 in 2015 drank alcohol in the past month.

Substance Use Disorders in the Past Year

Substance use disorders (SUDs) represent clinically significant impairment caused by the recurrent use of alcohol or other drugs (or both), including health problems, disability, and failure to meet major responsibilities at work, school, or home. NSDUH includes a series of questions to estimate the percentage of the population aged 12 or older who had SUDs in the past 12 months. Respondents were asked questions about SUDs if they previously reported use in the past 12 months of alcohol or illicit drugs. Illicit drugs include marijuana, cocaine, heroin, hallucinogens, inhalants, methamphetamine, and the misuse of prescription psychotherapeutic drugs (i.e., pain relievers, tranquilizers, stimulants, and sedatives). These SUD questions classify people as having an SUD in the past 12 months and are based on criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM IV).^30,31

Because of changes that were described previously to the questions for the use of hallucinogens, inhalants, and methamphetamine and the misuse of prescription drugs, the sets of respondents who were asked the SUD questions for those drugs in 2015 could have differed from the corresponding sets of respondents who were asked these SUD questions in prior years. Consequently, the 2015 SUD estimates for those drugs are not comparable with the estimates from prior years. Also, questions were added in 2015 about SUD symptoms that respondents attributed specifically to their use of methamphetamine; prior to 2015, past year methamphetamine users were asked about SUD symptoms for the misuse of prescription stimulants. In addition, these changes are assumed to have affected the comparability of the overall SUD measures in 2015 with those prior to 2015 for illicit drugs and for any substance (i.e., illicit drugs or alcohol). Thus for these measures, the 2015 estimates are not compared with estimates from prior years. Because the questions did not change for alcohol, marijuana, cocaine, and heroin, estimates of SUDs for these substances in 2015 are assumed to have remained comparable with estimates from earlier years.

This section presents estimates for the most common SUDs among the population aged 12 or older. Estimates of less common SUDs are not discussed in this report (e.g., inhalant use disorder) but are available in Table A.12B in Appendix A.

Need for Substance Use Treatment

NSDUH includes questions that are used to identify people who needed substance use treatment (i.e., treatment for problems related to the use of alcohol or illicit drugs) in the past year. For NSDUH, people are defined as needing substance use treatment if they had an SUD in the past year or if they received substance use treatment at a specialty facility³³ in the past year.^34,35 Because of the previously described effects of the questionnaire changes on the comparability of SUD estimates between 2015 and prior years, the 2015 estimates of the need for substance use treatment are not compared with estimates from prior years.

In 2015, an estimated 21.7 million people aged 12 or older needed substance use treatment, which means that about 1 in 12 people (8.1 percent) needed substance use treatment (Figure 36).³⁵ About 1.3 million adolescents aged 12 to 17 in 2015 needed treatment for a substance use problem in the past year, representing 5.1 percent of adolescents. About 5.4 million young adults aged 18 to 25 in 2015 needed treatment for a substance use problem in the past year, representing 15.5 percent of young adults. Stated another way, about 1 in 6 young adults needed substance use treatment. In 2015, about 15.0 million adults aged 26 or older needed substance use treatment in the past year. This number represents 7.2 percent of adults in this age group.

Receipt of Substance Use Treatment

NSDUH respondents who used alcohol or illicit drugs in their lifetime are asked whether they ever received substance use treatment, and those who received substance use treatment in their lifetime are asked whether they received treatment in the 12 months prior to the survey interview (i.e., the past year). Substance use treatment refers to treatment or counseling received for illicit drug or alcohol use or for medical problems associated with the use of illicit drugs or alcohol. NSDUH collects information on the receipt of substance use treatment at a specialty facility. Receipt of substance use treatment at a specialty facility is defined as substance use treatment a respondent received at a hospital (only as an inpatient), a drug or alcohol rehabilitation facility (as an inpatient or outpatient), or a mental health center. People could report receiving treatment at more than one location.

As previously described, the changes to the questions for the use of hallucinogens, inhalants, and methamphetamine and the misuse of prescription drugs also had the potential to affect the group of respondents in 2015 who answered questions about their receipt of substance use treatment. Investigations with future years of NSDUH data will help to assess whether these changes ultimately affected the comparability of NSDUH estimates for the receipt of substance use treatment between 2015 and prior years. For this report, however, the 2015 estimates of the receipt of substance use treatment are not compared with estimates from prior years.

In 2015, 10.8 percent of people aged 12 or older (2.3 million people) who needed substance use treatment received treatment at a specialty facility in the past year (Figure 38). Among people in specific age groups in 2015 who needed substance use treatment, 6.3 percent of adolescents aged 12 to 17, 7.7 percent of young adults aged 18 to 25, and 12.3 percent of adults aged 26 or older received substance use treatment at a specialty facility in the past year. These percentages represent 80,000 adolescents, 417,000 young adults, and 1.8 million adults aged 26 or older who needed substance use treatment and received treatment at a specialty facility in the past year.

Mental Health Issues and Mental Health Service Use

Mental disorders are generally characterized by changes in mood, thought, or behavior. They can make carrying out daily activities difficult and can impair an individual's ability to work or function in school, interact with family, and fulfill other major life functions. As noted in this report's survey background section, unlike what is done in the substance use questions, NSDUH uses different age-adapted questions to collect mental health information for adults and adolescents. Therefore, this section presents mental health estimates separately for adults and adolescents.

Mental Illness among Adults

NSDUH provides estimates of any mental illness (AMI) and serious mental illness (SMI) for adults aged 18 or older.³⁶ An adult with AMI was defined as having any mental, behavioral, or emotional disorder in the past year that met DSM-IV criteria (excluding developmental disorders and SUDs).³⁰ Adults with AMI were defined as having SMI if they had any mental, behavioral, or emotional disorder that substantially interfered with or limited one or more major life activities. AMI and SMI are not mutually exclusive categories; adults with SMI are included in estimates of adults with AMI. Adults with AMI who do not meet the criteria for having SMI are categorized as having AMI excluding SMI. This section includes past year estimates of adults with AMI, SMI, and AMI excluding SMI.³⁷

In 2015, an estimated 43.4 million adults aged 18 or older had AMI in the United States (Figure 39). This number represents 17.9 percent of all adults in the United States. An estimated 9.8 million adults in the nation had SMI in the past year, and 33.7 million adults had AMI excluding SMI in the past year. The number of adults with SMI represents 4.0 percent of all U.S. adults in 2015, and the number of adults with AMI excluding SMI represents 13.9 percent of all adults. Among adults with AMI in the past year, 22.5 percent had SMI and 77.5 percent did not have SMI.^38,39 In 2015, the percentages of adults with AMI, adults with SMI, and adults who had AMI excluding SMI were similar to the percentages from 2008 to 2014 (Figures 40, 41, and 42).

Aged 18 to 25

In 2015, an estimated 7.6 million young adults aged 18 to 25 (21.7 percent) had AMI in the past year (Figure 40), and an estimated 1.8 million young adults (5.0 percent) had SMI in the past year (Figure 41). An estimated 5.8 million young adults (16.7 percent) had AMI excluding SMI in the past year (Figure 42). With one exception, the percentages of young adults in 2015 who had AMI, SMI, and AMI excluding SMI were greater than the percentages from 2008 to 2014. However, similar percentages of young adults had SMI in 2014 and 2015.

Aged 26 to 49

In 2015, 20.6 million adults aged 26 to 49 (20.9 percent) had AMI in the past year (Figure 40), and an estimated 4.9 million adults aged 26 to 49 (5.0 percent) had SMI in the past year (Figure 41). An estimated 15.7 million adults aged 26 to 49 (15.9 percent) had AMI excluding SMI in the past year (Figure 42). Estimates of AMI, SMI, and AMI excluding SMI among adults aged 26 to 49 in 2015 were similar to the estimates in all years between 2008 and 2014.

Aged 50 or Older

In 2015, an estimated 15.3 million adults aged 50 or older (14.0 percent) had AMI in the past year (Figure 40), and an estimated 3.1 million adults aged 50 or older (2.8 percent) had SMI in the past year (Figure 41). An estimated 12.1 million adults aged 50 or older (11.1 percent) had AMI excluding SMI in the past year (Figure 42).

The estimate of AMI among adults aged 50 or older was lower in 2015 than the estimates between 2012 and 2014, but it was similar to the estimates between 2008 and 2011. The percentage of adults aged 50 or older with past year SMI in 2015 was similar to the percentages in 2008 to 2014. Although the percentage of adults aged 50 or older with past year AMI excluding SMI was lower in 2015 than in 2012 or 2014, the 2015 estimate was similar to the percentages in most years since 2008.

Mental Health Service Use among Adults

Adults are asked whether they received treatment or counseling for any problem with emotions, "nerves," or mental health in the past year in any inpatient or outpatient setting or if they used prescription medication in the past year for a mental or emotional condition. All adults are asked these questions about their use of mental health services (i.e., not just those with mental illness). Respondents are asked not to include treatment for their use of alcohol or illicit drugs. The questions about the receipt of treatment or counseling for mental health issues do not ask specifically about treatment for a particular mental disorder. Consequently, references to treatment or counseling for any problem with emotions, nerves, or mental health are described broadly as "mental health service use."

Although the collection of data for making estimates of AMI and SMI began in 2008, NSDUH has included questions on mental health service use among adults since 2002. Therefore, this section compares the 2015 estimates of mental health service use with estimates from 2002 to 2014 for the entire adult population. This section also compares the 2015 estimates of mental health service use with estimates from 2008 to 2014 for adults with AMI and adults with SMI.

In 2015, an estimated 34.2 million adults aged 18 or older (14.2 percent of adults) received mental health care during the past 12 months (Figure 43). Among the 43.4 million adults with AMI, 18.6 million (43.1 percent) received mental health services in the past year (Figure 44). About 6.4 million of the 9.8 million adults with past year SMI (65.3 percent) received mental health services in the past year (Figure 45).

The estimate of 14.2 percent of adults aged 18 or older in 2015 who received mental health care in the past 12 months was similar to the estimates in most years from 2010 to 2014, but it was greater than the estimates in most years between 2002 and 2009 (Figure 43). The percentage of adults with AMI who received mental health care in 2015 (43.1 percent) was similar to the percentages in most years from 2008 to 2014 (Figure 44). However, higher percentages of adults with AMI received mental health services in the past year in 2013 and 2014 (44.7 percent in each year) compared with the corresponding percentages of adults in most years from 2008 to 2011. The percentage of adults with SMI who received mental health services in the past year remained relatively steady across years between 2008 and 2015 (Figure 45).

Aged 18 to 25

In 2015, 4.0 million young adults aged 18 to 25 used mental health services in the past year, including 2.4 million young adults with AMI. The 2.4 million young adults with AMI who used mental health services include 887,000 young adults with SMI. Among all adults aged 18 to 25 in 2015, 11.7 percent used mental health services in the past year. Among young adults with AMI in the past year, 32.0 percent used mental health services (Table A.18B in Appendix A). Among young adults with SMI, 50.7 percent used mental health services.

Aged 26 to 49

In 2015, 15.1 million adults aged 26 to 49 used mental health services in the past year, including 8.9 million adults aged 26 to 49 with AMI. The 8.9 million adults aged 26 to 49 with AMI who used mental health services include 3.2 million adults aged 26 to 49 with SMI. In 2015, 15.3 percent of all adults aged 26 to 49 used mental health services in the past year. Among adults in this age group, 43.3 percent of those with AMI and 66.1 percent with SMI used mental health services in the past year (Table A.18B in Appendix A).

Aged 50 or Older

In 2015, 15.1 million adults aged 50 or older used mental health services in the past year, including 7.3 million adults aged 50 or older with AMI. The 7.3 million adults aged 50 or older with AMI who used mental health services include 2.2 million adults aged 50 or older with SMI. In 2015, 13.9 percent of all adults aged 50 or older used mental health services in the past year. Nearly half (48.3 percent) of adults aged 50 or older with AMI used mental health services (Table A.18B in Appendix A). Nearly three fourths (72.2 percent) of adults aged 50 or older with SMI used mental health services in the past year.

Co-Occurring Mental Health Issues and Substance Use Disorders among Adults

The coexistence of both a mental disorder and an SUD is referred to as co-occurring disorders. Because NSDUH data allow estimates to be made for the presence of a mental disorder (as defined by AMI and SMI) and SUDs, it is possible to estimate the percentages of adults with co-occurring disorders. This section presents findings on mental disorders (i.e., AMI, SMI, and major depressive episode [MDE]) co-occurring with SUDs (i.e., illicit drug use disorder or alcohol use disorder) among adults aged 18 or older in the United States. Because of the potential effects of the 2015 questionnaire changes on SUD estimates that were described previously, the 2015 estimates of co-occurring mental disorders and SUDs among adults are not compared with estimates from prior years.

Mental Illness and Substance Use Disorders among Adults with a Disorder

In 2015, among the 19.6 million adults with a past year SUD, 8.1 million (41.2 percent) had AMI in the past year (Figure 46). In contrast, among adults without a past year SUD, 15.8 percent (35.4 million adults) had AMI in the past year. The 8.1 million adults with AMI who met the criteria for an SUD in the past year represent 18.6 percent of the 43.4 million adults with AMI (Figure 47). In contrast, 5.8 percent of adults who did not have past year AMI (11.5 million adults) met the criteria for an SUD (Table A.23B in Appendix A).

Among the 19.6 million adults aged 18 or older in 2015 who had a past year SUD, 2.3 million (11.9 percent) also had SMI in the past year (Figure 48). The 2.3 million adults with SMI who met the criteria for an SUD in the past year represent 23.8 percent of the 9.8 million adults with SMI (Figure 49).

Aged 18 to 25

In 2015, among the 5.3 million young adults aged 18 to 25 with a past year SUD, 2.1 million (38.7 percent) had AMI in the past year (Table A.22B in Appendix A). In contrast, among young adults without a past year SUD, 18.6 percent (5.5 million adults) had AMI in the past year.

In 2015, among the 5.3 million adults aged 18 to 25 with a past year SUD, 593,000 (11.1 percent) had SMI in the past year. In contrast, among young adults without a past year SUD, 3.9 percent (1.2 million adults) had SMI in the past year.

Aged 26 to 49

Among the 9.7 million adults aged 26 to 49 with a past year SUD, 4.3 million (44.1 percent) had AMI in the past year (Table A.22B). Among adults aged 26 to 49 without a past year SUD, 18.3 percent (16.3 million adults) had AMI in the past year.

Among the 9.7 million adults aged 26 to 49 with a past year SUD, 1.3 million (13.5 percent) had SMI in the past year. Among adults aged 26 to 49 without a past year SUD, 4.0 percent (3.6 million adults) had SMI in the past year.

Aged 50 or Older

Among the 4.5 million adults aged 50 or older with a past year SUD, 1.7 million (38.0 percent) had AMI in the past year (Table A.22B). Among adults aged 50 or older without a past year SUD, 12.9 percent (13.5 million adults) had AMI in the past year.

Among the 4.5 million adults aged 50 or older with a past year SUD, 422,000 (9.3 percent) had SMI in the past year. Among adults aged 50 or older without a past year SUD, 2.6 percent (2.7 million adults) had SMI in the past year.

Co-Occurring Mental Illness and Substance Use Disorders among Adults in the General Population

Prior sections described the percentage of adults with mental illness among the subpopulation of adults who had a past year SUD or described the percentage of adults with an SUD among the subpopulation of adults with mental illness. This section presents findings on the percentages of adults who had co-occurring SUDs and mental illness among all adults in the United States. This type of presentation helps to provide further context for discussions of co-occurring disorders. Although the numbers of adults in the population who had co-occurring disorders are the same as those that were presented in previous sections, the percentages presented in this section are based on the total population of adults.

In 2015, the estimate of 8.1 million adults aged 18 or older who had both mental illness and SUDs in the past year corresponds to 3.3 percent of all adults (Table A.24B in Appendix A). The estimate of 2.3 million adults aged 18 or older in 2015 who had co-occurring SMI and SUDs in the past year corresponds to 1.0 percent of all adults.

Aged 18 to 25

In 2015, the estimate of 2.1 million adults aged 18 to 25 who had both mental illness and SUDs in the past year corresponds to 5.9 percent of all young adults (Table A.24B). The estimate of 593,000 adults aged 18 to 25 in 2015 who had co-occurring SMI and SUDs in the past year corresponds to 1.7 percent of all young adults.

Aged 26 to 49

In 2015, the estimate of 4.3 million adults aged 26 to 49 who had both mental illness and SUDs in the past year corresponds to 4.3 percent of all adults aged 26 to 49 (Table A.24B). The estimate of 1.3 million adults aged 26 to 49 in 2015 who had co-occurring SMI and SUDs in the past year corresponds to 1.3 percent of all adults aged 26 to 49.

Aged 50 or Older

In 2015, the estimate of 1.7 million adults aged 50 or older who had both mental illness and SUDs in the past year corresponds to 1.6 percent of all adults aged 50 or older (Table A.24B). The estimate of 422,000 adults aged 50 or older in 2015 who had co-occurring SMI and SUDs in the past year corresponds to 0.4 percent of all adults aged 50 or older.

Receipt of Services among Adults with Co-Occurring Mental Illness and a Substance Use Disorder

This section presents data on the receipt of mental health care or specialty substance use treatment among adults with an SUD who have co-occurring AMI and co-occurring SMI.³³ The 2015 NSDUH estimates of the receipt of services among adults with co-occurring mental disorders and SUDs are not compared with estimates from prior years because of the potential effects of the 2015 questionnaire changes on SUD estimates that were described previously.

Among the 8.1 million adults with co-occurring AMI and an SUD in the past year, approximately 48.0 percent received either mental health care or substance use treatment at a specialty facility in the past year (Figure 50). In other words, about half of the adults with co-occurring AMI and an SUD in the past year did not receive either type of service.⁴⁰ An estimated 6.8 percent of adults with co-occurring disorders received both mental health care and specialty substance use treatment, 36.7 percent received only mental health care, and 4.4 percent received only specialty substance use treatment.

Among the 2.3 million adults who had co-occurring SMI and an SUD in the past year, 62.6 percent received either substance use treatment at a specialty facility or mental health care in the past year (Figure 51). Stated another way, about 1 in 3 adults with co-occurring SMI and an SUD did not receive either type of care in the past year. Among adults with co-occurring SMI and an SUD, 11.0 percent received both mental health care and specialty substance use treatment, 47.4 percent received only mental health care, and 4.2 percent received only specialty substance use treatment.

Aged 18 to 25

Among young adults aged 18 to 25 in 2015 who had co-occurring AMI and an SUD in the past year, 35.2 percent received mental health care or substance use treatment at a specialty facility in the past year (Table A.25B in Appendix A). Among young adults who had co-occurring AMI and an SUD, 26.5 percent received only mental health care, 5.4 percent received both mental health care and specialty substance use treatment, and 3.1 percent received only specialty substance use treatment in the past year. Among young adults with co-occurring SMI and an SUD in 2015, 53.1 percent received either mental health care or specialty substance treatment, 9.3 percent received both mental health care and specialty substance use treatment, 41.6 percent received only mental health care, and 2.2 percent received only specialty substance use treatment in the past year.

Aged 26 to 49

Among adults aged 26 to 49 in 2015 who had co-occurring AMI and an SUD in the past year, 50.5 percent received mental health care or substance use treatment at a specialty facility in the past year (Table A.25B). Among adults 26 to 49 who had co-occurring AMI and an SUD, 37.6 percent received only mental health care, 7.6 percent received both mental health care and specialty substance use treatment, and 5.3 percent received only specialty substance use treatment in the past year. Among adults aged 26 to 49 with co-occurring SMI and an SUD in 2015, 68.0 percent received either mental health care or specialty substance treatment, 12.4 percent received both mental health care and specialty substance use treatment, 49.0 percent received only mental health care, and 6.6 percent received only specialty substance use treatment in the past year.

Aged 50 or Older

Among adults aged 50 or older in 2015 who had co-occurring AMI and an SUD in the past year, 57.1 percent received mental health care or substance use treatment at a specialty facility in the past year (Table A.25B). Among adults aged 50 or older who had co-occurring AMI and an SUD, 46.8 percent received only mental health care, 6.6 percent received both mental health care and specialty substance use treatment, and 3.6 percent received only specialty substance use treatment in the past year. Estimates for the receipt of services among adults aged 50 or older with co-occurring SMI and an SUD were not reported because of low precision.¹⁵

Major Depressive Episode (MDE) and MDE with Severe Impairment among Adults

NSDUH also provides estimates of having a past year MDE among adults. MDE is defined using the diagnostic criteria from the DSM-IV.³⁰ Adults were defined as having an MDE if they had a period of 2 weeks or longer in the past 12 months when they experienced a depressed mood or loss of interest or pleasure in daily activities, and they had at least some additional symptoms, such as problems with sleep, eating, energy, concentration, and self-worth.⁴¹ Adults were defined as having an MDE with severe impairment if their depression caused severe problems with their ability to manage at home, manage well at work, have relationships with others, or have a social life.⁴²

In 2015, 6.7 percent of adults aged 18 or older (16.1 million adults) had at least one MDE in the past year, and 4.3 percent of adults (10.3 million adults) had an MDE with severe impairment in the past year (Figure 52). Adults in 2015 who had an MDE with severe impairment represent nearly two thirds (64.0 percent) of adults who had a past year MDE.⁴³

The percentage of adults who had a past year MDE remained stable between 2005 and 2015 (Figure 53). The percentage of adults with a past year MDE with severe impairment also remained stable between 2009 and 2015 (Figure 54).

Aged 18 to 25

In 2015, an estimated 3.6 million young adults aged 18 to 25 had a past year MDE, or 10.3 percent of young adults (Figure 53). The percentage of young adults with a past year MDE was greater in 2015 than in 2005 to 2014.

In 2015, an estimated 2.2 million young adults aged 18 to 25 had a past year MDE with severe impairment, or 6.5 percent of young adults (Figure 54). The percentage of young adults with a past year MDE with severe impairment was greater in 2015 than in 2009 to 2013, but it was similar to the percentage in 2014.

Aged 26 to 49

In 2015, an estimated 7.3 million adults aged 26 to 49 had a past year MDE, or 7.5 percent of adults in this age group (Figure 53). The percentage of adults aged 26 to 49 in 2015 who had a past year MDE was similar to the corresponding percentages in 2005 to 2014.

In 2015, an estimated 4.8 million adults aged 26 to 49 had a past year MDE with severe impairment, or 4.9 percent of adults in this age group (Figure 54). The percentage of adults aged 26 to 49 in 2015 who had a past year MDE with severe impairment was similar to the percentages in 2009 to 2014.

Aged 50 or Older

In 2015, an estimated 5.2 million adults aged 50 or older had a past year MDE, or 4.8 percent of adults in this age group (Figure 53). The percentage of adults aged 50 or older in 2015 who had a past year MDE was similar to the corresponding percentages in 2005 to 2014.

In 2015, an estimated 3.2 million adults aged 50 or older had a past year MDE with severe impairment, or 3.0 percent of adults in this age group (Figure 54). The percentage of adults aged 50 or older in 2015 who had a past year MDE with severe impairment was similar to the percentages in 2009 to 2014.

Treatment for Depression among Adults

Adults who had met the criteria for having a past year MDE were asked whether they had received treatment for their depression in the past year. Treatment for depression in adults is defined as seeing or talking to a health professional or other professional or using prescription medication for depression in the past year.⁴⁴

In 2015, an estimated 67.2 percent of adults aged 18 or older who had a past year MDE received treatment for depression (Figure 55). This percentage represents 10.8 million adults with a past year MDE who received treatment for depression. The percentage of adults with a past year MDE who received treatment for depression remained stable between 2009 and 2015. Among adults who had a past year MDE with severe impairment, 7.5 million, or 72.7 percent, received treatment for depression. The percentage of adults with an MDE with severe impairment in 2015 who received treatment for depression was similar to the percentages in most years from 2009 to 2014.

Aged 18 to 25

In 2015, 1.7 million young adults aged 18 to 25 with a past year MDE received treatment for depression in the past year. Among young adults, the percentage of adults with MDE in 2015 who received treatment for depression (46.8 percent) was similar to the percentages in 2009 to 2014 (Table A.20B in Appendix A).

In 2015, 1.2 million young adults aged 18 to 25 with a past year MDE with severe impairment received treatment for depression in the past year. Among young adults, the percentage of adults with MDE with severe impairment in 2015 who received treatment for depression (52.0 percent) was similar to the percentages in 2009 to 2014.

Aged 26 to 49

In 2015, 4.9 million adults aged 26 to 49 with a past year MDE received treatment for depression in the past year. Among adults aged 26 to 49, the percentage of adults with MDE in 2015 who received treatment for depression (67.4 percent) was similar to the percentages in 2009 to 2014 (Table A.20B).

In 2015, 3.4 million adults aged 26 to 49 with a past year MDE with severe impairment received treatment for depression in the past year. Among adults aged 26 to 49, the percentage of adults with MDE with severe impairment in 2015 who received treatment for depression (72.0 percent) was similar to the percentages in 2009 to 2014.

Aged 50 or Older

In 2015, 4.2 million adults aged 50 or older with a past year MDE received treatment for depression in the past year. Among adults aged 50 or older, the percentage of adults with MDE in 2015 who received treatment for depression (80.9 percent) was similar to the percentages in 2009 to 2014 (Table A.20B).

In 2015, 2.8 million adults aged 50 or older with a past year MDE with severe impairment received treatment for depression in the past year. Among adults aged 50 or older, the percentage of adults with MDE with severe impairment in 2015 who received treatment for depression (87.9 percent) was similar to the percentages in 2009 to 2014.

Mental Health Service Use among Adolescents

In addition to asking youths about substance use, NSDUH includes questions for adolescents aged 12 to 17 that ask about the receipt of services for emotional and behavioral problems that were not caused by substance use. As discussed earlier, these questions differ for adolescents and adults. The youth mental health service utilization section of the interview asks respondents aged 12 to 17 whether they received any treatment or counseling within the 12 months prior to the interview for problems with emotions or behavior in several settings: (a) the specialty mental health setting (inpatient or outpatient care); (b) the education setting (talked with a school social worker, psychologist, or counselor about an emotional or behavioral problem; participated in a program for students with emotional or behavioral problems while in a regular school; or attended a school for students with emotional or behavioral problems); (c) the general medical setting (care from a pediatrician or family physician for emotional or behavioral problems); (d) the juvenile justice setting (services for an emotional or behavioral problem in a detention center, prison, or jail); or (e) the child welfare setting (foster care or therapeutic foster care).

The NSDUH interview currently does not include questions or methods for estimating the occurrence of mental disorders among adolescents other than whether adolescents had an MDE. Therefore, a NSDUH measure of any mental disorder does not exist for adolescents. Consequently, this section focuses on mental health care among all adolescents. Some estimates of mental health service use among youths in this report may differ from estimates in reports prior to the 2014 NSDUH due to changes in the definition of mental health service use.⁴⁵

Mental Health Service Use among All Adolescents

In 2015, the following numbers of adolescents aged 12 to 17 received mental health services in the past 12 months in specific settings for problems with emotions or behaviors (Figure 56):

• 3.3 million received mental health services in a specialty mental health setting (inpatient or outpatient care),
• 3.2 million received mental health services in an education setting,
• 668,000 received mental health services in a general medical setting,
• 79,000 received mental health services in a child welfare setting, and
• 53,000 received mental health services in a juvenile justice setting.

In addition, 1.4 million youths aged 12 to 17 received mental health services in both specialty and nonspecialty settings (i.e., an education, general medical, or child welfare setting).

These numbers correspond to the following percentages of all adolescents aged 12 to 17 (Figure 56):

• 13.3 percent who received mental health services in a specialty mental health setting,
• 13.2 percent who received mental health services in an education setting,
• 2.7 percent who received mental health services in a general medical setting,
• 0.3 percent who received mental health services in a child welfare setting,
• 0.2 percent who received mental health services in a juvenile justice setting, and
• 5.7 percent who received mental health services in both specialty and nonspecialty settings.

The percentage of adolescents in 2015 who received mental health services in a specialty mental health setting in the past 12 months (13.3 percent) was higher than the percentages in 2002, 2003, 2009, and 2010, which ranged from 11.8 to 12.4 percent (Table A.30B in Appendix A). However, the 2015 estimate was similar to the estimates in all other years. The percentage of youths aged 12 to 17 in 2015 who received mental health services in an education setting (13.2 percent) was similar to the percentages in most years from 2009 to 2014. The percentage of youths in 2015 who received mental health services in a general medical setting (2.7 percent) was similar to the percentages in most years from 2002 to 2014. The percentage of youths in 2015 who received mental health services in a juvenile justice setting (0.2 percent) was similar to the percentages in most years from 2009 to 2014.

MDE and MDE with Severe Impairment among Adolescents

Although NSDUH does not have an overall measure of mental illness among adolescents aged 12 to 17, the survey provides estimates of having a past year MDE for this age group. MDE is defined using the diagnostic criteria from DSM-IV.³⁰ Similar to adults, adolescents were defined as having an MDE if they had a period of 2 weeks or longer in the past 12 months when they experienced a depressed mood or loss of interest or pleasure in daily activities, and they had at least some additional symptoms, such as problems with sleep, eating, energy, concentration, and self-worth. However, some wordings to the questions for adolescents were designed to make them more developmentally appropriate for youths.⁴⁶ Adolescents were defined as having an MDE with severe impairment if their depression caused severe problems with their ability to do chores at home, do well at work or school, get along with their family, or have a social life.⁴⁷

In 2015, 12.5 percent of adolescents aged 12 to 17 (3.0 million adolescents) had an MDE during the past year, and 8.8 percent of adolescents (2.1 million adolescents) had a past year MDE with severe impairment (Figure 57). Adolescents in 2015 who had an MDE with severe impairment represent more than two thirds (70.7 percent) of adolescents who had a past year MDE.⁴³

The percentage of adolescents aged 12 to 17 in 2015 who had a past year MDE was higher than the percentages in 2004 to 2014 (Figure 58). The percentage of adolescents in 2015 who had a past year MDE with severe impairment was higher than the percentages in 2006 to 2013, which ranged from 5.5 to 7.7 percent. However, the 2015 estimate was similar to the estimate in 2014.

Co-Occurring MDE and Substance Use among Adolescents

This section describes co-occurring MDE and substance use and co-occurring MDE and SUDs among adolescents aged 12 to 17. Specifically, estimates of substance use and SUDs are presented among adolescents with an MDE, and estimates of having a past year MDE are presented among those with SUDs. Estimates of co-occurring MDE and SUDs also are presented among all adolescents. Because of the potential effects of the 2015 questionnaire changes on SUD estimates that were described previously, the 2015 estimates of co-occurring MDE and SUD are not compared with estimates from prior years.

Among adolescents aged 12 to 17 in 2015, 1.8 percent of those with a past year MDE were daily cigarette smokers in the past month compared with 0.7 percent of those without a past year MDE (Table A.33B in Appendix A). In addition, 1.7 percent of adolescents aged 12 to 17 with a past year MDE and 0.8 percent of those without a past year MDE were heavy alcohol drinkers in the past month.

Among the 3.0 million adolescents aged 12 to 17 in 2015 who had a past year MDE, a total of 350,000 adolescents (11.6 percent) had a past year SUD. In contrast, among adolescents without a past year MDE, 854,000 (4.0 percent) had an SUD in the past year (Figure 61 and Table A.28B in Appendix A).

Receipt of Services among Adolescents with Co-Occurring MDE and a Substance Use Disorder

This section presents data from NSDUH on the receipt of mental health care or specialty substance use treatment among adolescents aged 12 to 17 who had a co-occurring MDE and an SUD. Among the 350,000 adolescents who had a co-occurring MDE and an SUD in the past year, 63.1 percent received either substance use treatment at a specialty facility or mental health services in the past year (Table A.29B in Appendix A). Stated another way, more than one third of adolescents with both an MDE and an SUD in the past year did not receive either type of treatment. Among adolescents with a co-occurring MDE and an SUD, 3.8 percent received both mental health care and specialty substance use treatment, and 59.4 percent received only mental health care. The percentage of adolescents with a co-occurring MDE and an SUD who received only specialty substance use treatment is not reported because of low precision.¹⁵

Appendix A: Supplemental Tables of Estimates for Key Substance Use and Mental Health Indicators in the United States