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DEPARTMENT OF HEALTH AND HUMAN SERVICES
Substance Abuse and Mental Health Services Administration
Office of Applied Studies
This report was prepared by the Division of Population Surveys, Office of Applied Studies, SAMHSA, and by RTI International, a trade name of Research Triangle Institute, Research Triangle Park, North Carolina. Work by RTI was performed under Contract No. 283989008. Contributors and reviewers at RTI listed alphabetically include Jeremy Aldworth, Kortnee Barnett-Walker, Katherine R. Bowman, Janice M. Brown, Patrick Chen, James R. Chromy, Andrew Clarke, Elizabeth Copello, David B. Cunningham, Teresa R. Davis, Jessica E. Duncan, Steven L. Emrich, Joe D. Eyerman, Ralph E. Folsom, Jr., G. G. Frick, Eric A. Grau, Jennie L. Harris, David C. Heller, Laurel Hourani, Larry A. Kroutil, Amy Licata, Bing Liu, Mary Ellen Marsden, Christine Murtha, Dawn Odom, Lisa E. Packer, Michael R. Pemberton, Michael A. Penne, Kristine L. Rae, Avinash C. Singh, Thomas G. Virag (Project Director), Michael Vorburger, Jill Webster, Matt Westlake, and Li-Tzy Wu. Contributors at SAMHSA listed alphabetically include Peggy Barker, Joan Epstein, Joseph Gfroerer, Joe Gustin, Arthur Hughes, Joel Kennet, Dicy Painter, Ken Petronis, and Doug Wright. At RTI, Richard S. Straw edited the report with assistance from K. Scott Chestnut and Kathleen B. Mohar. Also at RTI, Diane G. Caudill prepared the graphics; Brenda K. Porter and Keri V. Kennedy formatted the tables; Joyce Clay-Brooks and Danny Occoquan formatted and word processed the report; and Pamela Couch Prevatt, Teresa F. Gurley, Kim Cone, David Belton, and Shari B. Lambert prepared its press and Web versions. Final report production was provided by Beatrice A. Rouse, Coleen Sanderson, and Jane Feldmann at SAMHSA.
All material appearing in this report is in the public domain and may be reproduced or copied without permission from the Substance Abuse and Mental Health Services Administration. However, this publication may not be reproduced or distributed for a fee without specific, written authorization of the Office of Communications, SAMHSA, U.S. Department of Health and Human Services. Citation of the source is appreciated. Suggested citation:
Substance Abuse and Mental Health Services Administration. (2003). Overview of Findings from the 2002 National Survey on Drug Use and Health (Office of Applied Studies, NHSDA Series H-21, DHHS Publication No. SMA 033774). Rockville, MD.
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Highlights of Findings
2. Illicit Drug Use
3. Alcohol Use
4. Tobacco Use
5. Trends in Lifetime Prevalence of Substance Use
6. Trends in Initiation of Substance Use
7. Youth Prevention-Related Measures
8. Substance Dependence, Abuse, and Treatment
9. Prevalence and Treatment of Mental Health Problems
Appendix: Prevalence Estimate Tables
Full Results from the 2002 NSDUH
Detailed Tables from the 2002 NSDUH
Current and prior national surveys are available at SAMHSA's website:
This report presents the first information from the 2002 National Survey on Drug Use and Health (NSDUH), an annual survey of the civilian, noninstitutionalized population of the United States aged 12 years old or older. Prior to 2002, the survey was called the National Household Survey on Drug Abuse (NHSDA). This brief Overview report provides a concise summary of the main results from the 2002 NSDUH. A more complete presentation of the initial results of the survey is given in the full report, Results from the 2002 National Survey on Drug Use and Health: National Findings (Office of Applied Studies [OAS], 2003). Both reports present national estimates of rates of use, numbers of users, and other measures related to illicit drugs, alcohol, and tobacco products. Measures related to mental health problems also are included. State-level estimates from NSDUH will be presented in other reports to be released separately.
Several improvements to the survey were implemented in 2002. In addition to the name change, respondents were offered a $30 incentive payment for participation in the survey starting in 2002, and quality control procedures for data collection were enhanced in 2001 and 2002. Because of these improvements and modifications, estimates from the 2002 NSDUH should not be compared with estimates from the 2001 or earlier versions of the survey to examine changes over time. The data collected in 2002 represent a new baseline for tracking trends in substance use and other measures. A discussion of the changes in survey methodology, some of the reasons for these changes, and their impact on survey estimates is outlined in Section 1.2.
NSDUH is the primary source of statistical information on substance use and abuse by the U.S. population. This survey was initiated in 1971 in response to the growing concern over drug abuse. Over the years, the frequency, size, sample design, methods of administration, and content have changed. The current survey collects information from a representative sample of the population through face-to-face interviews at their place of residence. The survey is sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA) and is planned and managed by SAMHSA's Office of Applied Studies (OAS). The fieldwork is conducted by RTI International, Research Triangle Park, North Carolina.1 A more complete description of the survey is provided in Appendix A in the full "National Findings" report (OAS, 2003).
NSDUH collects information from residents of households, noninstitutional group quarters (e.g., shelters, rooming houses, dormitories), and civilians living on military bases. Persons excluded from the survey include homeless persons who do not use shelters, military personnel on active duty, and residents of institutional group quarters, such as jails and hospitals. The NSDUH sample is representative of almost 98 percent of the U.S. population aged 12 years old or older.
Since 1999, the NSDUH interview has been carried out using "computer-assisted interviewing" (CAI). The survey uses a combination of "computer-assisted personal interviewing" (CAPI) conducted by the interviewer and "audio computer-assisted self-interviewing" (ACASI), where a laptop computer provides both visual and audio versions of the questionnaire. Use of ACASI provides respondents with a highly private and confidential way to record answers to questions. Research shows that the approach results in more honest reporting of illicit drug use and other sensitive behaviors compared with paper-and-pencil methods of data collection.
The 2002 NSDUH employed a 50State sample design with an independent, multistage area probability sample for each of the 50 States and the District of Columbia. This design will support the development of both national and State-level estimates. Approximately one third of the total sample was dedicated to youths aged 12 to 17 years, one third to young adults aged 18 to 25 years, and one third to adults aged 26 years or older.
Nationally, 136,349 addresses were screened for the 2002 survey, and 68,126 completed interviews were obtained. The survey was conducted from January through December 2002. Weighted response rates for household screening and for interviewing were 90.7 and 78.9 percent, respectively.
All periodic surveys change over time. The content of the questionnaire changes as new issues arise and priorities are modified. Because of increased interest in the problem of the co-occurrence of mental illness and substance abuse, for example, a new module to measure serious mental illness (SMI) was introduced in 2001. There may be greater resistance to responding to surveys requiring new strategies to encourage participation. There may be innovations in survey technology that can provide more complete and accurate data. Several different problems resulted in the changes made in NSDUH in 2002. The most consequential changes are discussed below.
Name Change. In 2000, the Secretary of the Department of Health and Human Services (DHHS) instructed SAMHSA to change the name of the National Household Survey on Drug Abuse to make it more representative of the topic and content of the survey. There was concern that the term "drug abuse" might be misleading or threatening to potential respondents. A change of this nature, given the size of the survey, requires extensive preparation because all written materials, computer programs, training and field manuals, respondent letters, and the like must be modified. The 2002 survey was the first to carry the new name.
Incentive Payments. Declining response rates in the NHSDA, a problem observed in many recent Federal surveys, were a growing concern because they could threaten the integrity of the estimates. Of particular concern was the variation in response rates among the States. To address this problem, many Federal surveys have in the past few years introduced incentive payments to encourage participation. In 2001, a field experiment was conducted in the context of the national survey to assess the benefits and problems that might derive from this strategy. Initial analyses of the experiment showed substantial improvement in response rates, lower data collection costs, and little impact on substance use prevalence rates. Based on these results, a $30 incentive payment was offered to respondents beginning with the 2002 NSDUH.
Improved Data Collection Quality Control. Analyses conducted in conjunction with the 1999 survey in an effort to understand some anomalous findings revealed that the interviews completed by newer field staff yielded slightly higher prevalence rates than those completed by more experienced staff. Anecdotal evidence suggested that the newer interviewers were following the survey protocol more closely than the veteran staff, resulting in higher self-reports of substance use by respondents. To address this problem, a series of changes in field procedures were implemented during 2001, and they were institutionalized in the 2002 survey.
Analyses to date of the impact of the methodological improvements made in the 2002 NSDUH have provided important insights, but a number of questions still remain. Comparisons of the changes in lifetime prevalence with trends based on retrospective reporting by respondents in the 2002 survey demonstrate that increases in lifetime substance use rates reported in 2002 are not due to an increase in new initiates or the aging of a particular group of users. The 2002 data are simply not comparable with data from previous surveys. With no other basis for explaining these and other results, it would appear this problem is a consequence of changes in the survey process. A complete discussion of the analyses done to date is contained in Appendix C of the full report. The conclusion from the results of these analyses is that 2002 data should not be compared with data collected in 2001 or earlier to assess changes over time. Therefore, this report presents data only from the 2002 NSDUH.
Using only the 2002 data, limited trend assessment can be carried out using information collected in the survey on prior substance use. Specifically, questions on age at first use of substances, in conjunction with respondents' ages and interview dates, provide data that can be used to estimate the rates of first-time use (incidence), as well as the rates of lifetime prevalence (the percentage of the population that has ever used each substance) for years prior to 2002. Trends in these measures for youths and young adults are discussed in Chapters 5 and 6. Additional discussion of trends, including results from the Monitoring the Future (MTF) study, is included in the final discussion in Chapter 10.
This Overview report is intended to provide a concise summary of the key results from the 2002 NSDUH. It contains a subset of the results given in the full report, Results from the 2002 National Survey on Drug Use and Health: National Findings (OAS, 2003). Both reports present the results in separate chapters that discuss the national findings on eight topics: use of illicit drugs; use of alcohol; use of tobacco products; trends in lifetime use of substances; trends in initiation of substance use; prevention-related issues; substance dependence, abuse, and treatment; and mental health. A final chapter summarizes the results and discusses key findings in relation to other research and survey results. The full report also includes technical appendices that provide technical details on the survey methodology, discuss the effects of survey protocol changes on trend measurement, offer key NSDUH definitions, discuss other sources of data, list the references cited in the report (as well as other relevant references), and present selected tabulations of estimates. This Overview report includes two tables showing the prevalence of substance use by age in an appendix.
An extensive set of tables, including standard errors, is available upon request from OAS or through the Internet at http://www.oas.samhsa.gov. Additional methodological information on NSDUH, including the questionnaire, is available electronically at the same web address. Brief descriptive reports and in-depth analytic reports focusing on specific issues or population groups also are produced by OAS. A complete listing of previously published reports from NSDUH and other data sources is available from OAS. Most of these reports also are available through the Internet (http://www.oas.samhsa.gov). In addition, OAS makes public use data files available to researchers through the Substance Abuse and Mental Health Data Archive (SAMHDA, 2003). Currently, files are available from the 1979 to 2001 NHSDAs at http://www.icpsr.umich.edu/SAMHDA. The NSDUH 2002 public use file will be available by the end of 2003.
This overview report includes a summary of the key findings that are discussed in the full report. Highlights of these findings are given below:
The National Survey on Drug Use and Health (NSDUH) obtains information on nine different categories of illicit drug use: marijuana, cocaine, heroin, hallucinogens, inhalants, and nonmedical use of prescription-type pain relievers, tranquilizers, stimulants, and sedatives. In these categories, hashish is included with marijuana, and crack is considered a form of cocaine. Several drugs are grouped under the hallucinogens category, including LSD, PCP, peyote, mescaline, mushrooms, and "Ecstasy" (MDMA). Inhalants include a variety of substances, such as amyl nitrite, cleaning fluids, gasoline, paint, and glue. The four categories of prescription-type drugs (pain relievers, tranquilizers, stimulants, and sedatives) cover numerous drugs available through prescriptions and sometimes illegally "on the street." Methamphetamine is included under stimulants. Over-the-counter drugs and legitimate uses of prescription drugs are not included. Respondents are asked to report only uses of drugs that were not prescribed for them or drugs they took only for the experience or feeling they caused. NSDUH reports combine the four prescription-type drug groups into a category referred to as "any psychotherapeutics."
Estimates of "any illicit drug use" reported from NSDUH reflect use of any of the nine substance categories listed above. Use of alcohol and tobacco products, while illegal for youths, are not included in these estimates, but are discussed in Chapters 3 and 4. Findings from the 2002 NSDUH on illicit drug use are summarized below.
Prevalence, by Type of Drug. In 2002, an estimated 19.5 million Americans aged 12 or older were current illicit drug users, meaning they had used an illicit drug during the month prior to the survey interview. This estimate represents 8.3 percent of the population aged 12 years old or older (Figure 1). Marijuana was the most commonly used illicit drug, with 14.6 million current users (6.2 percent of the population). About one third of these marijuana users (4.8 million persons) used the drug on 20 or more days in the past month.
An estimated 2.0 million persons (0.9 percent) were current cocaine users, 567,000 of whom used crack during the same time period. Hallucinogens were used by 1.2 million persons (0.5 percent), including 676,000 users of Ecstasy. There were an estimated 166,000 current heroin users (0.1 percent).
An estimated 6.2 million persons were current users of prescription-type drugs (referred to as psychotherapeutics) nonmedically. This represents 2.6 percent of the population aged 12 or older. This includes 4.4 million using pain relievers, 1.8 million using tranquilizers, 1.2 million using stimulants, and 0.4 million using sedatives.
In 2002, approximately 1.9 million persons aged 12 or older had used OxyContin nonmedically at least once in their lifetime. OxyContin is a controlled-release tablet form of the narcotic oxycodone that can have severe health consequences if the tablet is crushed and then ingested.
Age. Rates of drug use showed substantial variation by age (Figure 2). For example, 4.2 percent of youths aged 12 or 13 reported current illicit drug use in 2002. As in other years, illicit drug use in 2002 tended to increase with age among young persons. It peaked among 18 to 20 year olds (22.5 percent) and declined steadily after that point with increasing age. Among youths aged 12 to 17, 11.6 percent were current illicit drug users. Rates were 20.2 percent for the young adult age group (18 to 25 years) and 5.8 percent for adults aged 26 or older.
Race/Ethnicity. Rates of current illicit drug use varied significantly among the major racial/ethnic groups in 2002. The rate was highest among American Indians/Alaska Natives (10.1 percent) and persons reporting two or more races (11.4 percent). Rates were 8.5 percent for whites, 7.2 percent for Hispanics, and 9.7 percent for blacks. Asians had the lowest rate at 3.5 percent. There were variations in rates of past month illicit drug use among Hispanic subgroups. Rates were 10.0 percent for Puerto Ricans, 7.3 percent for Mexicans, 6.5 percent for Cubans, and 5.0 percent for Central or South Americans.
Rates of use also varied by race/ethnicity among youths aged 12 to 17 (Figure 3). The rate of current illicit drug use among American Indians/Alaska Natives (20.9 percent) was significantly higher than the rate among all youths (11.6 percent), and the rate among Asian youths (4.8 percent) was significantly lower compared with the overall rate for all youths.
Employment Status. Current employment status was highly correlated with rates of illicit drug use in 2002. An estimated 17.4 percent of unemployed adults aged 18 or older were current illicit drug users compared with 8.2 percent of those employed full time and 10.5 percent of those employed part time. Although the rate of drug use was higher among unemployed persons compared with those from other employment groups, most drug users were employed. Of the 16.6 million illicit drug users aged 18 or older in 2002, 12.4 million (74.6 percent) were employed either full or part time.
Pregnant Women. Among pregnant women aged 15 to 44 years, 3.3 percent reported using illicit drugs in the month prior to their interview. This rate was significantly lower than the rate among women aged 15 to 44 who were not pregnant (10.3 percent).
Criminal Justice Populations. Illicit drug use was prevalent among persons who were either on parole or probation. In 2002, among the estimated 1.8 million adults aged 18 or older on parole or other supervised release from prison during the past year, 29.1 percent were current illicit drug users compared with 7.7 percent among adults not on parole or supervised release. Among the estimated 4.8 million adults on probation at some time in the past year, 28.7 percent reported current illicit drug use in 2002. This compares with a rate of 7.4 percent among adults not on probation in 2002.
Driving Under the Influence of Illicit Drugs. In 2002, an estimated 11.0 million persons reported driving under the influence of an illicit drug during the past year. This corresponds to 4.7 percent of the population aged 12 or older. The rate was 10 percent or greater for each age from 17 to 25, with 21 year olds reporting the highest rate of any age (18.0 percent). Among adults aged 26 or older, the rate was 3.0 percent.
Association with Cigarette and Alcohol Use. In 2002, the rate of current illicit drug use was approximately 8 times higher among youths who smoked cigarettes (48.1 percent) than it was among youths who did not smoke cigarettes (6.2 percent). Among youths who were heavy drinkers, 67.0 percent also were current illicit drug users, whereas among nondrinkers, the rate was only 5.6 percent.
How Marijuana Is Obtained. NSDUH includes questions asking marijuana users how, from whom, and where they obtained the marijuana they used most recently. In 2002, most users (56.7 percent) got the drug for free or shared someone else's marijuana. Almost 40 percent of marijuana users bought it. Most marijuana users obtained the drug from a friend; 79.0 percent who bought their marijuana and 81.8 percent who obtained the drug for free had obtained it from a friend.
The National Survey on Drug Use and Health (NSDUH) includes a set of questions asking about the recency and frequency of the consumption of alcoholic beverages, such as beer, wine, whiskey, brandy, and mixed drinks. An extensive list of examples of the kinds of beverages covered is given to respondents prior to the question administration. A "drink" is defined as a can or bottle of beer, a glass of wine or a wine cooler, a shot of liquor, or a mixed drink with liquor in it. Times when the respondent only had a sip or two from a drink are not considered as consumption. For this report, estimates for the prevalence of alcohol use are reported primarily at three levels defined for both males and females and for all ages as follows:
Current use - At least one drink in the past 30 days (includes binge and heavy use).
Binge use - Five or more drinks on the same occasion at least once in the past 30 days (includes heavy use).
Heavy use - Five or more drinks on the same occasion on at least 5 different days in the past 30 days.
Prevalence, by Level of Use. About half of Americans aged 12 or older reported being current drinkers of alcohol in the 2002 survey (51.0 percent). This translates to an estimated 120 million people. About 54 million persons (22.9 percent) participated in binge drinking, and 15.9 million (6.7 percent) were heavy drinkers.
Age. The prevalence of current alcohol use increased with increasing age in 2002, from 2.0 percent at age 12 to 6.5 percent at age 13, 13.4 percent at age 14, 19.9 percent at age 15, 29.0 percent at age 16, and 36.2 percent at age 17 (Figure 4). The rate reached a peak of 70.9 percent for persons 21 years old. Rates of binge alcohol use were 0.8 percent at age 12, 2.8 percent at age 13, 7.0 percent at age 14, 11.6 percent at age 15, 17.9 percent at age 16, and 25.0 percent at age 17. The rate peaked at age 21 (50.2 percent). Among youths aged 12 to 17, an estimated 17.6 percent used alcohol in the month prior to the survey interview. Of all youths, 10.7 percent were binge drinkers, and 2.5 percent were heavy drinkers.
Underage Alcohol Use. About 10.7 million persons aged 12 to 20 reported drinking alcohol in the month prior to the survey interview in 2002 (28.8 percent of this age group). Alcohol is an illicit substance for this group of users. Of these, nearly 7.2 million (19.3 percent) were binge drinkers, and 2.3 million (6.2 percent) were heavy drinkers. Among persons aged 12 to 20, past month alcohol use rates in 2002 ranged from 15.5 percent for Asians and 19.3 percent among blacks to 32.8 percent for whites. Binge drinking was reported by 22.7 percent of underage whites, 22.6 percent of underage American Indians or Alaska Natives, and 16.8 percent of underage Hispanics, but only by 8.6 percent of underage Asians and 9.8 percent of underage blacks.
Pregnant Women. Among pregnant women aged 15 to 44 in 2002, 9.1 percent used alcohol and 3.1 percent reported binge drinking in the month prior to the survey. These rates were significantly lower than the rates for nonpregnant women of that age (53.4 and 23.4 percent, respectively). Heavy alcohol use was relatively rare (0.7 percent) among pregnant women.
College Attendance. Among persons aged 18 to 22, full-time college students were more likely to be heavy drinkers than others (18.8 and 13.4 percent, respectively). However, at later ages (26 or older), those who had attended college were less likely to drink heavily than those who had not attended college (5.2 and 6.7 percent, respectively).
Driving Under the Influence of Alcohol. About 1 in 7 Americans aged 12 or older in 2002 (14.2 percent, or 33.5 million persons) drove under the influence of alcohol at least once in the 12 months prior to the interview. Among young adults aged 18 to 25, the rate was 26.6 percent.
The National Survey on Drug Use and Health (NSDUH) includes a series of questions asking about the use of several tobacco products, including cigarettes, chewing tobacco, snuff, cigars, and pipe tobacco. For analysis purposes, data for chewing tobacco and snuff are combined and referred to as "smokeless tobacco." Cigarette use is defined as smoking "part or all of a cigarette." Findings from the 2002 NSDUH are summarized below.
Prevalence for Different Tobacco Products. An estimated 71.5 million Americans reported current use (past month use) of a tobacco product in 2002, a prevalence rate of 30.4 percent for the population aged 12 or older. About 61.1 million (26.0 percent) smoked cigarettes, 12.8 million (5.4 percent) smoked cigars, 7.8 million (3.3 percent) used smokeless tobacco, and 1.8 million (0.8 percent) smoked tobacco in pipes.
Cigarette Use, by Age and Gender. Current cigarette smoking rates increased steadily by year of age up to age 21, from 1.7 percent at age 12 to 4.7 percent at age 13, 8.5 percent at age 14, 14.1 percent at age 15, 21.9 percent at age 16, and 28.1 percent at age 17. The rate peaked at 46.2 percent at age 21. After age 21, rates generally declined, reaching 19.9 percent for persons aged 60 to 64 years and 10.3 percent for persons aged 65 or older. By age group, the prevalence of cigarette use was 13.0 percent among 12 to 17 year olds, 40.8 percent among young adults aged 18 to 25 years, and 25.2 percent among adults aged 26 or older.
A higher proportion of males than females aged 12 or older smoked cigarettes in 2002 (28.7 vs. 23.4 percent). However, among youths aged 12 to 17, girls were slightly more likely than boys to smoke (13.6 vs. 12.3 percent) (Figure 5).
Cigarette Use, by Race/Ethnicity. Current cigarette smoking rates among persons aged 12 or older were 37.1 percent among American Indians/Alaska Natives, 35.0 percent among persons reporting two or more races, 26.9 percent among whites, 25.3 percent among blacks, 23.0 percent for Hispanics, and 17.7 percent for Asians.
Cigarette Use, by Population Density. Rates of current cigarette use among persons aged 12 or older were higher in less densely populated areas. In large metropolitan areas, 24.6 percent smoked in the past month compared with 27.1 percent in small metropolitan areas and 27.9 percent in nonmetropolitan areas. The rate of smoking was 30.6 percent in completely rural nonmetropolitan areas. For youths aged 12 to 17 in large metropolitan areas, 11.0 percent smoked in the past month compared with 20.7 percent of youths in completely rural nonmetropolitan areas.
Cigarette Use among Pregnant Women. In 2002, 17.3 percent of pregnant women aged 15 to 44 smoked cigarettes in the past month compared with 31.1 percent of nonpregnant women of the same age group.
Cigarette Use, by Level of Education. The prevalence of cigarette smoking decreased with increasing levels of education. Among adults aged 18 or older in 2002, college graduates were the least likely to report smoking cigarettes (14.5 percent) compared with 35.2 percent of adults who lacked a high school diploma. Young adults aged 18 to 22 enrolled full time in college in 2002 were less likely to use cigarettes than their peers not enrolled full time. Past month cigarette use was reported by 32.6 percent of full-time college students compared with 45.8 percent of their peers who were not enrolled full time.
Frequency of Cigarette Use among Smokers. Among smokers, the frequency of cigarette use increases with age. Of the 61.1 million past month cigarette smokers, 63.4 percent (38.7 million) reported smoking every day in the past 30 days. However, among youths aged 12 to 17 who smoked in the past month, 31.8 percent were daily smokers. This translates to about 1 million daily smokers aged 12 to 17. The percentage of smokers who were daily smokers was 51.8 percent for 18 to 25year-old smokers and 68.8 percent for smokers aged 26 or older.
This chapter discusses trends in the lifetime prevalence of the use of various substances based on data from the 2002 National Survey on Drug Use and Health (NSDUH). These trends are based on estimates of the percentage of the population each year who had used a substance at least one time in their life. Estimates for youths aged 12 to 17 and young adults aged 18 to 25, by gender, from 1965 to 2002 have been produced. Selected findings are discussed.
Because of the changes in NSDUH in 2002 and the effect of these changes on estimates of substance use prevalence, this report does not compare estimates from the 2002 survey to estimates from prior surveys. However, analysis of trends in substance use can be done using just the 2002 NSDUH data based on survey questions asking about prior use. NSDUH includes questions asking about age at first use of various substances, including month and year of first use for recent new users. Using this information along with the respondent's date of birth, the interview date, and editing and imputation when necessary, an exact date of first use is determined for each substance used by each respondent. This makes it possible to construct estimates of lifetime prevalence as well as incidence (number of new users) for years prior to 2002. Details of the methods used are provided in Section B.4 of Appendix B of the complete report of "National Findings" (OAS, 2003). Estimates of incidence are discussed Chapter 6.
Because the lifetime prevalence estimates reported are based on retrospective reports of age at first substance use by survey respondents interviewed during 2002, they may be subject to several sources of bias. These include bias due to differential mortality of users and nonusers of each substance, bias due to memory errors (recall decay and telescoping), and underreporting bias due to social acceptability and fear of disclosure.
Marijuana. The percentage of youths aged 12 to 17 who had ever used marijuana declined slightly from 2001 to 2002 (21.9 to 20.6 percent). Among young adults aged 18 to 25, the rate increased slightly from 53.0 percent in 2001 to 53.8 percent in 2002.
Long-term trends show increases in marijuana use during the 1960s and 1970s, declines in the 1980s, and increases in the 1990s (Figure 6). In 1965 and 1966, only 1.8 percent of youths had ever used marijuana. Beginning in 1967, use increased until it reached a peak at 19.6 percent in 1979. A period of decline followed until 1991, when the rate was 11.5 percent, after which the trend reversed, reaching a peak at 21.9 percent in 2001.
The percentage of young adults aged 18 to 25 who had ever used marijuana was 5.1 percent in 1965, but increased steadily to 54.4 percent in 1982. Although the rate for young adults declined somewhat from 1982 to 1993, it did not drop below 43 percent and actually increased to 53.8 percent by 2002.
Cocaine. The percentage of youths aged 12 to 17 who had ever used cocaine increased slightly from 2001 to 2002 (2.3 to 2.7 percent). Among young adults aged 18 to 25, the rate increased slightly from 14.9 percent in 2001 to 15.4 percent in 2002.
From 1965 to 1967, only 0.1 percent of youths had ever used cocaine, but rates rose throughout the 1970s and 1980s, reaching 2.2 percent in 1987. A period of decline followed in the early 1990s, after which the trend reversed, reaching a peak at 2.7 percent in 2002. The percentage of young adults aged 18 to 25 who had ever used cocaine was below 1 percent during the mid-1960s, but rose steadily throughout the 1970s and early 1980s, reaching 17.9 percent in 1984. By 1996, the rate had dropped to 10.1 percent, but climbed to 15.4 percent in 2002.
Heroin. Since the mid-1990s, the prevalence of lifetime heroin use increased for both youths and young adults. From 1995 to 2002, the rate among youths aged 12 to 17 increased from 0.1 to 0.4 percent; among young adults aged 18 to 25, the rate rose from 0.8 to 1.6 percent.
Hallucinogens. The prevalence of lifetime hallucinogen use among youths aged 12 to 17 was at its highest level in 2001 (6.1 percent) but declined to 5.7 percent in 2002. Among young adults aged 18 to 25, use increased from 14.3 percent in 1992 to 24.2 percent in 2002. The increase in hallucinogen use in the 1990s appears to have been driven by the use of Ecstasy (i.e., MDMA).
Nonmedical Use of Pain Relievers. Lifetime nonmedical pain reliever prevalence among youths aged 12 to 17 increased from 2001 (9.6 percent) to 2002 (11.2 percent), continuing an increasing trend from 1989 (1.2 percent). Among young adults aged 18 to 25, the rate increased from 19.4 percent in 2001 to 22.1 percent in 2002. The young adult rate had been 6.8 percent in 1992.
Nonmedical Use of Stimulants. Lifetime nonmedical use of stimulants increased steadily from 1990 to 2002 for youths aged 12 to 17 (0.7 to 4.3 percent). For young adults aged 18 to 25, rates declined from 1981 to 1994 (from 10.9 to 5.9 percent), then increased to 10.8 percent in 2002. Rates increased between 2001 and 2002 for both youths (3.8 to 4.3 percent) and young adults (10.2 to 10.8 percent).
Cigarettes. The rate of lifetime cigarette use among youths aged 12 to 17 has remained between 29 and 39 percent in every year since 1965. Although the rate increased during the 1990s from 30.3 percent in 1990 to 37.8 percent in 1999, there was a significant decline from 2001 to 2002 (from 37.3 to 33.3 percent).
From 1965 to 1980, there was little change in the rate of lifetime cigarette use among boys aged 12 to 17. Rates were 37.9 percent in 1965 and 37.8 percent in 1980. However, during that period, the rate among adolescent girls increased from 21.7 to 36.2 percent. Since 1980, rates for girls have been nearly the same as the rates for boys (Figure 7).
The rate of lifetime daily cigarette use among youths aged 12 to 17 declined from 10.6 percent in 2001 to 8.2 percent in 2002. There also was a small decline in lifetime prevalence among young adults (37.7 to 37.1 percent) from 2001 to 2002. Since 1965, the rate of lifetime cigarette use among young adults aged 18 to 25 has been between 65 and 72 percent.
Estimates of substance use incidence, or initiation, concern the number of new users of illicit drugs, alcohol, or tobacco during a given year. These estimates supplement prevalence estimates as measures of the Nation's substance use problem. Where prevalence estimates describe the extent of use of substances over some period of time, incidence data describe emerging patterns of use, particularly among young people. In the past, increases and decreases in incidence usually have been followed by corresponding changes in the prevalence of use, particularly among youths.
The incidence estimates are based on 2002 National Survey on Drug Use and Health (NSDUH) questions on age at first use, year and month of first use for recent initiates, the respondent's date of birth, and the interview date. Using this information along with editing and imputation when necessary, an exact date of first use is determined for each substance used by each respondent. By applying sample weights to incidents of first use, estimates of the number of new users of each substance are developed for each year. These estimates include the number of new users at any age (including those younger than age 12) and also are shown for two specific age groupspersons younger than 18 and adults aged 18 or older. In addition, the average age of new users in each year and age-specific rates of first use are estimated.
Because the incidence estimates are based on retrospective reports of age at first use, the most recent year available for these estimates is 2001, based on the 2002 NSDUH. For two of the measures, first alcohol use and first cigarette use, initiation before age 12 is common. A 2year lag in reporting for "all ages" estimates is applied for these measures because the NSDUH sample does not cover youths under age 12. The 2year lag ensures that initiation at ages 10 and 11 is captured in the estimation.
Marijuana. There were an estimated 2.6 million new marijuana users in 2001. This number is similar to the numbers of new users each year since 1995, but above the number in 1990 (1.6 million).
In 1965, there were an estimated 0.8 million new users of marijuana. The annual number of marijuana initiates generally increased until about 1973. From 1973 to 1978, the annual number of marijuana initiates remained level at approximately 3.5 million per year. After that, the number of initiates declined to 1.6 million in 1990, then rose to 2.8 million in 1995. From 1995 to 2001, there was no consistent trend, with estimates varying between 2.5 and 3.0 million per year.
Cocaine. Incidence of cocaine use generally rose throughout the 1970s to a peak in 1980 (1.7 million new users) and subsequently declined until 1991 (0.7 million new users). Cocaine initiation steadily increased during the 1990s, reaching 1.2 million in 2001.
Heroin. During the latter half of the 1990s, the annual number of heroin initiates rose to a level not reached since the late 1970s. In 1974, there were an estimated 246,000 heroin initiates. Between 1988 and 1994, the annual number of new users ranged from 28,000 to 80,000. Between 1995 and 2001, the number of new heroin users was consistently greater than 100,000.
Hallucinogens. The incidence of hallucinogen use has exhibited two notable periods of increase (Figure 8). Between 1966 and 1970, the annual number of initiates rose almost sixfold, from 168,000 to 956,000. This increase was driven primarily by use of LSD. The second period of increase, driven by Ecstasy (MDMA), began in 1992 when there were approximately 706,000 new hallucinogen users. By 2000, the number of initiates rose to 1.7 million, which is similar to the number for 2001 (1.6 million). Initiation of Ecstasy use has been rising since 1993, when there were 168,000 new users. There were 1.9 million initiates in 2000 and 1.8 million in 2001 (not a statistically significant decline). LSD incidence dropped from 958,000 new users in 2000 to 606,000 in 2001.
Nonmedical Use of Pain Relievers. Pain reliever incidence increased from 1990, when there were 628,000 initiates, to 2000, when there were 2.7 million. In 2001, the number was 2.4 million, not significantly different from 2000.
Cigarettes. Cigarette initiation increased from 2.6 million initiates in 1990 to 3.6 million in 1996, then decreased to 3.0 million in 2000. Initiation of cigarette use among youths under 18 significantly decreased from 2.8 million new users in 1996 to 2.2 million in 2000. The number of new daily smokers decreased from 2.1 million in 1998 to 1.4 million in 2001. Among youths under 18, the number of new daily smokers decreased from 1.1 million per year (3,000 per day) between 1997 and 2000 to 757,000 (2,000 per day) in 2001.
The National Survey on Drug Use and Health (NSDUH) includes an extensive set of questions about risk and protective factors directed at youths aged 12 to 17. Risk factors include those individual characteristics or social environments associated with an increased likelihood of substance use, while protective factors are related to a decreased likelihood of substance use. These factors derive from circumstances, influences, and perceptions at many levels, such as the individual, peer, family, school, and community levels (Hawkins, Catalano, & Miller, 1992). One goal of research on preventing substance use has been to identify both risk factors and protective factors, and, subsequently, design programs that might decrease substance use.
Perceived Risk. Youths were asked how much they thought people risk harming themselves physically and in other ways when they use various substances. Response choices in the survey were "great risk," "moderate risk," "slight risk," or "no risk." Only 32.4 percent of youths indicated that smoking marijuana once a month was a great risk. A higher percentage of youths perceived a great risk in using cocaine once a month (50.5 percent). Smoking one or more packs of cigarettes per day was cited as a great risk by 63.1 percent of youths. About three fifths of all youths (62.2 percent) thought that having four or five drinks of an alcoholic beverage nearly every day was a great risk.
Among youths indicating that "smoking marijuana once a month" was a "great risk," only 1.9 percent indicated that they had used marijuana in the past month. However, among youths who indicated "moderate, slight, or no risk," the prevalence rate was 11.3 percent-almost 6 times larger.
Perceived Availability of Drugs. Slightly more than half of youths aged 12 to 17 indicated that it would be fairly or very easy to obtain marijuana if they wanted some (55.0 percent). The percentages of youths reporting that it was fairly or very easy to obtain specific drugs were 25.0 percent for cocaine, 19.4 percent for LSD, and 15.8 percent for heroin.
The percentage of youths who reported that it would be fairly or very easy to obtain marijuana was similar for youths who lived in large metropolitan areas, small metropolitan areas, and nonmetropolitan areas (Figure 9). The percentages of youths reporting it would be easy to get LSD and cocaine was slightly less in nonmetropolitan areas than in large metropolitan areas.
Parental Disapproval of Substance Use. Youths were less likely to use substances if they perceived that their parents would disapprove of it. Most youths (89.1 percent) reported that their parents would strongly disapprove of their trying marijuana once or twice. Among these youths, only 5.5 percent had used marijuana in the past month. However, among youths who perceived that their parents would only somewhat disapprove or neither approve nor disapprove of their trying marijuana, 30.2 percent reported past month use of marijuana.
Delinquent Behavior. Youths who self-reported delinquent behavior during the past year were more likely to use illicit drugs in the past month than other youths. Specifically, youths reported the following levels of using an illicit drug in the past month depending on whether or not they had engaged in the delinquent behavior: getting into a serious fight at school or work (20.7 vs. 9.3 percent); carrying a handgun (34.6 vs. 10.8 percent); selling illegal drugs (68.8 vs. 9.0 percent); and stealing or trying to steal something worth $50 or more (43.8 vs. 9.9 percent).
Participation in Religious Activities. Youths who were involved in religious activities were less likely to use substances. Among youths who attended religious services 25 times or more in the past year (33.0 percent of youths), 7.1 percent had used an illicit drug in the past month. Among youths attending less often or not at all, 13.9 percent reported past month use. Among youths who agreed or strongly agreed that religious beliefs are a very important part of their life (78.2 percent of all youths), 9.2 percent had used an illicit drug in the past month. In contrast, among youths who "disagreed or strongly disagreed" with the statement, 20.5 percent had used an illicit drug.
The National Survey on Drug Use and Health (NSDUH) includes a series of questions to assess dependence on and abuse of substances, including alcohol and illicit drugs, which include nonmedical use of prescription-type drugs. These questions are designed to measure dependence and abuse based on criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) (American Psychiatric Association [APA], 1994). The questions on dependence ask about health, emotional problems, attempts to cut down on use, tolerance, withdrawal, and other symptoms associated with substances used. The questions on abuse ask about problems at work, home, and school; problems with family or friends; physical danger; and trouble with the law due to substances used.
Dependence or Abuse, by Type of Drug. An estimated 22.0 million Americans aged 12 or older in 2002 were classified with substance dependence or abuse (9.4 percent of the total population). Of these, 3.2 million were classified with dependence on or abuse of both alcohol and illicit drugs, 3.9 million were dependent on or abused illicit drugs but not alcohol, and 14.9 million were dependent on or abused alcohol but not illicit drugs. Of the 7.1 million Americans classified with dependence on or abuse of illicit drugs, 4.3 million were dependent on or abused marijuana. Cocaine accounted for 1.5 million persons, and nonmedical use of pain relievers accounted for 1.5 million persons.
Dependence or Abuse, by Age. The rate of substance dependence or abuse was 8.9 percent for youths aged 12 to 17; it was 21.7 percent for persons aged 18 to 25 and 7.3 percent for persons aged 26 or older. Illicit drugs accounted for 62 percent of youths with substance dependence or abuse, 38 percent of persons aged 18 to 25, and 24 percent of persons aged 26 or older (Figure 10).
Dependence or Abuse, by Race/Ethnicity. Among persons aged 12 or older in 2002, the rate of substance dependence or abuse was highest among American Indians/Alaska Natives (14.1 percent). The next highest rate was among persons reporting two or more races (13.0 percent). Asians had the lowest rate (4.2 percent). The rate was similar among blacks and whites (9.5 and 9.3 percent, respectively). Among Hispanics, the rate was 10.4 percent.
Dependence or Abuse, by Employment Status. Rates of substance dependence or abuse varied with current employment status. In 2002, an estimated 19.7 percent of unemployed adults aged 18 or older were classified with dependence or abuse, while 10.6 percent of full-time employed adults and 10.5 percent of part-time employed adults were classified as such. Most adults with substance dependence or abuse were employed either full or part time. Of the 19.8 million adults classified with dependence or abuse, 15.3 million (77.1 percent) were employed.
Dependence or Abuse among Parolees. More than a third (36.2 percent) of adults aged 18 or older who were on parole or a supervised release from jail during the past year were classified with dependence on or abuse of a substance. This compares with a rate of 9.2 percent among other adults.
Substance Treatment, by Location. An estimated 3.5 million people aged 12 or older (1.5 percent of the population) received some kind of treatment for a problem related to the use of alcohol or illicit drugs in the 12 months prior to being interviewed in 2002. More than half (2.0 million) received treatment at a self-help group. There were 1.5 million people who received treatment at a rehabilitation facility as an outpatient, 1.1 million who received treatment at a rehabilitation facility as an inpatient, 1.0 million at a mental health center as an outpatient, 859,000 at a hospital as an inpatient, 523,000 at a private doctor's office, 469,000 at an emergency room, and 259,000 at a prison or jail. (Note that the estimates of treatment by location include persons reporting more than one location.)
Substance Treatment, by Type of Substance. More than half (2.2 million) of the 3.5 million persons who received treatment in the past year received treatment for alcohol during their most recent treatment (Figure 11). An estimated 974,000 persons received treatment for marijuana, 796,000 persons for cocaine, 360,000 for pain relievers, and 277,000 for heroin. (Note that the estimates of treatment by substance include persons reporting more than one substance.)
Source of Payment for Illicit Drug Specialty Treatment. Specialty treatment is treatment received at drug or alcohol rehabilitation facilities (inpatient or outpatient), hospitals (inpatient only), or mental health centers. It excludes treatment at an emergency room, private doctor's office, self-help group, prison or jail, or hospital as an outpatient. Among the 1.4 million persons who received specialty treatment for an illicit drug problem in the past year, 33.9 percent reported "own savings or earnings" as a source of payment for their most recent specialty treatment. An estimated 30.0 percent reported private health insurance, 26.1 percent reported Medicaid, and 23.3 percent reported public assistance other than Medicaid as a source of payment. An estimated 20.3 percent reported Medicare, and 16.2 percent reported family members. (Note that the estimates of treatment by source of payment include persons reporting more than one source.)
Source of Payment for Specialty Alcohol Treatment. Among the 1.5 million persons who received specialty treatment for an alcohol problem in the past year, 46.3 percent reported "own savings or earnings" as a source of payment for their most recent specialty treatment. An estimated 31.7 percent reported using private health insurance, 21.5 percent reported public assistance other than Medicaid, and 21.4 percent reported Medicaid. An estimated 19.0 percent reported using Medicare, and 15.2 percent reported family members.
Needing and Receiving Specialty Treatment. An individual is defined as needing treatment for an alcohol problem if he or she was dependent on or abused alcohol or received specialty treatment for alcohol or drugs in the past 12 months. Similarly, an individual is defined as needing treatment for a drug problem if he or she was dependent on or abused a drug or received specialty treatment for drugs in the past 12 months. In 2002, the estimated number of persons aged 12 or older needing treatment for an alcohol or illicit drug problem was 22.8 million (9.7 percent of the total population). Of these, 2.3 million persons (1.0 percent of the total population aged 12 or older and 10.3 percent of those who needed treatment) received treatment at a specialty substance abuse facility in the past 12 months (Figure 12).
Illicit Drug Treatment Need. In 2002, the estimated number of persons aged 12 or older needing treatment for an illicit drug problem was 7.7 million (3.3 percent of the total population). Of these persons, 1.4 million (18.2 percent) received treatment for drug abuse at a specialty substance abuse facility in the past 12 months (Figure 12). Of the 6.3 million people aged 12 or older who needed drug treatment but did not receive treatment at a specialty facility in 2002, an estimated 362,000 (5.7 percent) reported that they felt they needed treatment for their drug problem. This included an estimated 88,000 (24.4 percent) who reported that they made an effort but were unable to get treatment.
Alcohol Treatment Need. In 2002, the estimated number of persons aged 12 or older needing treatment for an alcohol problem was 18.6 million (7.9 percent of the total population). Of these, 8.3 percent (1.5 million) received alcohol treatment at a specialty substance abuse facility in the past 12 months (Figure 12). Of the 17.1 million people who needed but did not receive alcohol treatment for their alcohol problem in 2002, an estimated 761,000 (4.5 percent) reported that they felt they needed treatment for their alcohol problem. Of the 761,000 persons, 266,000 (35 percent) reported that they made an effort but were unable to get treatment.
The 2002 National Survey on Drug Use and Health (NSDUH) includes a series of questions designed to assess serious mental illness (SMI) among adults aged 18 or older. The survey also includes questions on mental health treatment and counseling. Separate questions are asked for adults and for youths aged 12 to 17, and different definitions are applied. Because the survey represents the civilian, noninstitutionalized population, persons who reside in long-term psychiatric or other institutions at the time of interview are excluded from the sample and from the estimates presented in this chapter.
Serious Mental Illness. SMI is defined for this report as having at some time during the past year a diagnosable mental, behavioral, or emotional disorder that met the criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) (American Psychiatric Association [APA], 1994) and resulted in functional impairment that substantially interfered with or limited one or more major life activities. A scale consisting of six NSDUH questions is used to measure SMI. Use of this scale to estimate SMI is supported by methodological research that determined the scale to be a good predictor of SMI, based on clinical assessments done on survey respondents (Kessler et al., 2003). The six questions and further discussion of this scale are given in Section B.5 of Appendix B of the full "National Findings" report (OAS, 2003).
Prevalence of Serious Mental Illness, by Demographic Characteristics. In 2002, there were an estimated 17.5 million adults aged 18 or older with SMI. This represents 8.3 percent of all adults. Rates of SMI were highest for persons aged 18 to 25 (13.2 percent) and lowest for persons aged 50 or older (4.9 percent). Among adults, the percentage of females with SMI was higher than the percentage of males (10.5 vs. 6.0 percent). Rates were higher for women than men in all age groups (Figure 13). Among adults aged 18 or older in 2002, the rate of SMI was highest among persons reporting two or more races (13.6 percent) and American Indian/Alaska Natives (12.5 percent) and lowest among Native Hawaiian or other Pacific Islanders (5.4 percent).
Serious Mental Illness and Substance Use. SMI was highly correlated with illicit drug use in 2002. Among adults who used an illicit drug in the past year, 17.1 percent had SMI in that year, while the rate of SMI was 6.9 percent among adults who did not use an illicit drug. Among adults with SMI, 28.9 percent used an illicit drug in the past year, while the rate of illicit drug use was 12.7 percent among those without SMI. SMI was not strongly correlated with alcohol use. The rate of past year alcohol use among adults with SMI was almost the same as the rate among adults without SMI (71.1 vs. 69.7 percent, respectively, in 2002). However, SMI was correlated with binge alcohol use, defined as drinking five or more drinks on the same occasion on at least 1 day in the past 30 days. Among adults with SMI, 28.8 percent were binge drinkers, while 23.9 percent of adults without SMI were binge drinkers.
Co-Occurrence of Serious Mental Illness with Substance Dependence/Abuse. SMI was highly correlated with substance dependence or abuse (Figure 14). Among adults with SMI in 2002, 23.2 percent (4.0 million) were dependent on or abused alcohol or illicit drugs, while the rate among adults without SMI was only 8.2 percent. Adults with SMI were more likely than those without SMI to be dependent on or abuse illicit drugs (9.6 vs. 2.1 percent) and more likely to be dependent on or abuse alcohol (18.0 vs. 7.0 percent). Among adults with substance dependence or abuse, 20.4 percent had SMI. The rate of SMI was 7.0 percent among adults who did not have substance abuse or dependence.
Mental Health Treatment among Adults. For adults, treatment is defined as the receipt of treatment or counseling for any problem with emotions, "nerves," or mental health in the 12 months prior to the interview in any inpatient or outpatient setting; it also includes the use of prescription medication for treatment of a mental or emotional condition.
In 2002, an estimated 27.3 million adults received mental health treatment in the 12 months prior to the interview. This estimate represents 13.0 percent of the population 18 years old or older. The most prevalent type of treatment in the adult population was prescription medication (10.5 percent), followed by outpatient treatment (7.4 percent). An estimated 1.5 million adults (0.7 percent) were hospitalized for mental health problems at some time within the past 12 months. Among the 17.5 million adults with SMI in 2002, 8.4 million (47.9 percent of those with SMI) received treatment.
Unmet Need for Treatment among Adults with Serious Mental Illness. Unmet need is defined as a perceived need for mental health treatment at any time in the 12 months prior to the interview that was not received. Among adults with SMI, 30.5 percent perceived an unmet need for mental health treatment. The rate of perceived unmet need among persons with SMI was 37.8 percent among those who had received treatment and 23.8 percent among those who did not receive any treatment in the past 12 months. The most common reasons for not getting needed treatment that were reported by with any unmet need were "could not afford the cost" (44.3 percent) and "did not know where to go for services" (20.5 percent).
Mental Health Treatment among Youths. For youths, treatment is defined as receiving treatment or counseling for emotional or behavioral problems from specific mental health or other health professionals in school, home, outpatient, or inpatient settings within the 12 months prior to the interview. In 2002, an estimated 4.8 million youths aged 12 to 17 received treatment in the year prior to the interview. This represents 19.3 percent of this population. The reason cited most often for receiving mental health treatment was "felt depressed" (49.5 percent of youths receiving treatment) (Figure 15). The rate of mental health treatment among youths who used illicit drugs in the past year (26.7 percent) was higher than the rate among youths who did not use illicit drugs (17.2 percent).
This report presents findings from the 2002 National Survey on Drug Use and Health (NSDUH). Conducted since 1971 and previously named the National Household Survey on Drug Abuse (NHSDA), the survey underwent several methodological improvements in 2002 that have affected prevalence estimates. As a result, the 2002 estimates are not comparable with estimates from 2001 and earlier surveys. The primary focus of the report is on the numbers of persons and rates for a variety of measures related to substance use and mental health in 2002, including comparisons across sociodemographic and geographic subgroups of the U.S. population. Some of the most important findings for 2002 are presented in the Highlights section of this report.
The prevalence estimates from the 2002 NSDUH are uniformly higher than the corresponding estimates from the 2001 NHSDA. Analyses to date of the effects of the methodological changes in 2002 (see Appendix C of the full report [OAS, 2003]) indicate that the higher prevalences in 2002 mostly reflect an increase in the reporting of these behaviors by survey respondents due to the $30 incentive payment and other survey improvements, not actual increases in the prevalence of these behaviors and problems. The results of these analyses were presented to a panel of survey methodology experts, who concluded that 2002 estimates should not be compared with 2001 and earlier estimates. The panel also concluded that it would not be possible to develop a method of "adjusting" pre-2002 data to make them comparable for trend assessment.
Although traditional comparisons of estimates across years cannot be used to examine recent trends, it is possible to study trends by constructing "retrospective" estimates of lifetime prevalence and incidence produced from the 2002 NSDUH data alone (see Chapters 5 and 6). These trends can be compared with the results from Monitoring the Future (MTF), a study sponsored by the National Institute on Drug Abuse (NIDA). Figure 16 shows the trends in lifetime marijuana use based on the 2002 NSDUH retrospective estimates for youths aged 16 to 20, as well as trends in lifetime marijuana use and past month marijuana use among the MTF 12th graders. The two data sources produce similar trends in lifetime prevalence, and the MTF trend in past month use also is similar to the trend for lifetime use. These trends also are consistent with trends for youths aged 12 to 17 and young adults aged 18 to 25 discussed in Chapter 5. They show very low rates of illicit drug use in the mid-1960s. In 1965, only 1.8 percent of youths had ever used marijuana. There were dramatic increases in use during the late 1960s and 1970s, and by 1979, 19.6 percent of youths had ever used marijuana. After that, use declined until 1991, when 11.5 percent of youths had ever used marijuana. The trend reversed during the 1990s, reaching 21.9 percent in 2001 before dropping slightly in 2002 to 20.6 percent.
Retrospective estimates based on 2002 NSDUH data are presented in Table 10.1 for selected substances along with related estimates from the 2002 MTF for youths and young adults. The NSDUH data show decreases from 2001 to 2002 in lifetime use of marijuana, LSD, and cigarettes among youths, but an increase for cocaine among youths. For young adults aged 18 to 25 during this time period, there was a slight increase in lifetime cocaine and Ecstasy use and a decrease in lifetime LSD use. These NSDUH results are generally consistent with MTF trends, with a few exceptions. MTF shows no change in lifetime cocaine use among youths, and it shows decreases in youth Ecstasy and alcohol use not found in the NSDUH estimates.
Estimates of incidence, or first-time use, also suggest that illicit drug use prevalence had been very low during the early 1960s, but began to increase during the mid-1960s as substantial numbers of young people initiated the use of marijuana. As discussed in Chapter 6, annual marijuana incidence increased from about 0.8 million new users in 1965 until it reached a peak of 3.5 million initiates per year during 1973 to 1978, just before the prevalence rates peaked. Interestingly, the annual number of marijuana initiates reached a low point in 1990 (1.6 million), then increased, 2 years before the increase in youth prevalence occurred. This finding demonstrates the value of analyzing the incidence data and using it to forecast future trends in prevalence. Assuming this relationship between incidence and prevalence continues to hold, the continuing high levels (between 2.5 and 3.0 million initiates per year) of marijuana incidence between 1995 and 2001 indicate that substantial declines in youth prevalence may not occur in the near future. However, the NSDUH incidence estimates for youths under age 18 indicate a decline from 2000 to 2001 (from 2.1 million to 1.7 million), which suggests that youth prevalence may decline. The NSDUH youth lifetime prevalence and MTF past month prevalence estimates do show decreases from 2001 to 2002. High rates of marijuana initiation during the 1970s among the cohort identified as the "baby boomers" has resulted in an increase in the numbers needing treatment for substance abuse problems. The increase in marijuana initiation rates during the 1990s may have the same result.
Table 10.1 Comparison of NSDUH and MTF Prevalence Rates
8th and 10th
-- Not available.
Note: NSDUH data in this table are retrospective estimates from the 2002 data. MTF data for 8th and 10th graders are simple averages of estimates for those two grades reported in Johnston, O'Malley, and Bachman (2003a). MTF data for youths aged 19 to 24 are simple averages of estimates for youths aged 1920, 2122, and 2324 reported in Johnston et al. (2003b).
Sources: SAMHSA, Office of Applied Studies, National Survey on Drug Use and Health, 2002.
The Monitoring the Future Study, University of Michigan, 2001 and 2002.
American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: American Psychiatric Association.
Hawkins, J. D., Catalano, R. F., & Miller, J. Y. (1992). Risk and protective factors for alcohol and other drug problems in adolescence and early adulthood: Implications for substance abuse prevention. Psychological Bulletin, 112(1), 64105.
Johnston, L. D., O'Malley, P. M., & Bachman, J. G. (2003a). Monitoring the Future national results on adolescent drug use: Overview of key findings, 2002 (NIH Publication No. 035374). Bethesda, MD: National Institute on Drug Abuse. [Also available at http://www.monitoringthefuture.org/pubs.html and http://www.monitoringthefuture.org/pubs/monographs/overview2002.pdf]
Johnston, L.D., O'Malley, P.M., & Bachman, J.G. (2003b). Monitoring the Future national survey results on drug use, 19752002: College students and adults ages 1940 (NIH Publication No. 035376, Vol. II). Bethesda, MD: National Institute on Drug Abuse. [Also available at http://www.monitoringthefuture.org/pubs.html and http://www.monitoringthefuture.org/pubs/monographs/vol2_2002.pdf]
Kessler, R. C., Barker, P. R., Colpe, L. J., Epstein, J. F., Gfroerer, J. C., Hiripi, E., Howes, M. J., Normand, S.-L. T., Manderscheid, R. W., Walters, E. E., & Zaslavsky, A. M. (2003). Screening for serious mental illness in the general population. Archives of General Psychiatry, 60, 184189.
Office of Applied Studies, Substance Abuse and Mental Health Services Administration. (2003). Results from the 2002 National Survey on Drug Use and Health: National Findings (DHHS Publication No. SMA 033836, NHSDA Series H-22). Rockville, MD: Substance Abuse and Mental Health Services Administration, Office of Applied Studies. [Also available at http://www.oas.samhsa.gov/p0000016.htm#standard]
Substance Abuse and Mental Health Data Archive. (2003). National Household Survey on Drug Abuse (NHSDA) series. Retrieved July 14, 2003, from http://www.icpsr.umich.edu/SAMHDA/ and http://webapp.icpsr.umich.edu/cocoon/SAMHDA-SERIES/00064.xml
Table A.1 Illicit Drug, Tobacco, and Alcohol Use in the Past Month among Persons Aged 12 or Older, by Age Group: Numbers in Thousands and Percentages, 2002
|Past Month Use||Number of Users in Thousands||PERCENTAGES|
|Total||AGE GROUP (Years)|
|1217||1825||26 or Older|
|Any Illicit Drug1||19,522||8.3||11.6||20.2||5.8|
|Marijuana and Hashish||14,584||6.2||8.2||17.3||4.0|
| Nonmedical Use of
| Any Illicit Drug Other
|Binge Alcohol Use4||53,787||22.9||10.7||40.9||21.4|
|Heavy Alcohol Use4||15,860||6.7||2.5||14.9||5.9|
*Low precision; no estimate reported.
1 Any Illicit Drug includes marijuana/hashish, cocaine (including crack), heroin, hallucinogens, inhalants, or any prescription-type psychotherapeutic used nonmedically. Any Illicit Drug Other Than Marijuana includes cocaine (including crack), heroin, hallucinogens, inhalants, or any prescription-type psychotherapeutic used nonmedically.
2 Nonmedical use of any prescription-type pain reliever, tranquilizer, stimulant, or sedative; does not include over-the-counter drugs.
3 Any Tobacco product includes cigarettes, smokeless tobacco (i.e., chewing tobacco or snuff), cigars, or pipe tobacco.
4 Binge Alcohol Use is defined as drinking five or more drinks on the same occasion (i.e., at the same time or within a couple of hours of each other) on at least 1 day in the past 30 days. Heavy Alcohol Use is defined as drinking five or more drinks on the same occasion on each of 5 or more days in the past 30 days; all Heavy Alcohol Users are also Binge Alcohol Users.
Source: SAMHSA, Office of Applied Studies, National Survey on Drug Use and Health, 2002.
Table A.2 Substance Dependence or Abuse for Specific Substances in the Past Year among Persons Aged 12 or Older, by Age Group: Numbers in Thousands and Percentages, 2002
Dependence or Abuse
|Number with Dependence or Abuse in Thousands||PERCENTAGES|
|Total||AGE GROUP (Years)|
|1217||1825||26 or Older|
|Any Illicit Drug1||7,116||3.0||5.6||8.2||1.8|
|Marijuana and Hashish||4,294||1.8||4.3||6.0||0.8|
|Nonmedical Use of Any Psychotherapeutic2||2,018||0.9||1.3||1.9||0.6|
|Any Illicit Drug or Alcohol1||22,006||9.4||8.9||21.7||7.3|
|Any Illicit Drug and Alcohol1||3,210||1.4||2.5||4.2||0.7|
*Low precision; no estimate reported.
NOTE: Dependence or abuse is based on definitions found in the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).
1 Any Illicit Drug includes marijuana/hashish, cocaine (including crack), heroin, hallucinogens, inhalants, or any prescription-type psychotherapeutic used nonmedically.
2 Nonmedical use of any prescription-type pain reliever, tranquilizer, stimulant, or sedative; does not include over-the-counter drugs.
Source: SAMHSA, Office of Applied Studies, National Survey on Drug Use and Health, 2002.
1 RTI International is a trade name of Research Triangle Institute.
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