2021 National Survey of Drug Use and Health (NSDUH) Releases
Conducted annually, the National Survey on Drug Use and Health (NSDUH) provides nationally representative data on the use of tobacco, alcohol, and drugs; substance use disorders; receipt of substance use treatment; mental health issues; and the use of mental health services among the civilian, noninstitutionalized population aged 12 or older in the United States. NSDUH estimates allow researchers, clinicians, policymakers, and the general public to better understand and improve the nation’s behavioral health. These reports and detailed tables present estimates from the 2021 National Survey on Drug Use and Health (NSDUH). Because of methodological changes in 2021, estimates from this year should not be compared with previous years.
2021 NSDUH Highlights
2021 NSDUH Frequently Asked Questions
1. How did the coronavirus disease 2019 (COVID-19) pandemic continue to affect data collection for the 2021 NSDUH?
- SAMHSA decided to continue with multimode data collection moving forward, meaning that the 2021 NSDUH is based on both in-person and web interviews. In-person data collection remained limited to areas with low COVID-19 infection rates. As COVID-19 infection rates dropped in most areas of the country over the course of the year, the proportion of web interviews decreased. More than three quarters of interviews in Quarter 1 were completed via the web (76.6 percent). By Quarter 4, fewer than half of the interviews (41.5 percent) were completed that way. Altogether, 54.6 percent of the 2021 interviews were completed via the web.
2. Why is it not appropriate to compare estimates from 2021 with estimates from 2019 and earlier years?
- In order to assess comparability, we first tested, “Did the mode of data collection (i.e. whether a respondent completed the survey on the web or in-person) influence the estimates?” In other words, “Were there differences between responses from the two modes of collection, and were those differences significant enough to affect whether or not the data from each mode was comparable?”
- We found that estimates based on web interviews are different from estimates based on in-person interviews. First, we found that the demographics of each mode differed significantly. That is to say, the composition of the people answering by web differed from the composition of the people answering in-person (i.e. by gender, race, education, etc.). Secondly, in addition to demographic differences, we also found that in-person respondents were more likely to be users of certain substances and were more likely to have experienced mental health issues. These differences are often called a mode effect because the differences are observed between the two modes of data collection.
- We then asked, “Given that we know there are differences between modes of data collection which make them incomparable, can we use demographics to weight the data in such a way that they ARE comparable?” In other words, “Can we make both groups of respondents similar enough in demographic composition to control for the differences in mode that we observe, and therefore allow us to compare estimates between the two modes?”
- We know that while weighting (adjusting) the data to account for the differing demographics between respondents who responded via the web and in person helps to lessen the mode effect impact, it doesn’t completely eliminate the effect enough so that we can fairly compare the two modes statistically. Because of this, estimates based on both web and in-person interviews are not comparable to estimates based on either mode alone.
- Therefore, because 2021 estimates are based on multimode data collection and estimates from 2019 or earlier are based on in-person data collection alone, 2021 estimates are not comparable with estimates from 2019 or earlier. Estimates of change from 2019 or earlier to 2021 would be too greatly influenced by the mode effect.
3. This year’s annual National Report and Detailed Tables do not contain data from previous years. Why not?
- Methodological investigations conducted in 2022 concluded that estimates based on multimode data collection in 2021 are not comparable with estimates from prior years. Thus, it was decided that presenting NSDUH estimates from prior years alongside 2021 estimates could be misleading because differences in estimates could be due to a change in the population’s behavior, the method used to ask the questions (i.e., web vs. in-person), or both.
4. If more in-person respondents report substance use than web respondents, does that mean that web-based respondents are not accurately reporting their experience?
- Differences in substance use between web respondents and in-person respondents could be due to variability in COVID-19 infection rates in different areas. For example, many respondents could complete the interview only on the web (i.e., those living in areas with high COVID-19 infection rates where in-person data collection was not permissible). If individuals living in these areas are less likely to use substances, overall estimates of substance use in 2021 would be affected given the large proportion of interviews completed on the web (54.6 percent).
- There could be differences between web respondents and in-person respondents for reasons other than underreporting of substance use among web respondents. For example, some people prefer to complete an interview via web, while others prefer to complete an interview in person. Adult web respondents in NSDUH have completed higher levels of education, on average, than their in-person counterparts; people with higher educational levels are less likely to smoke cigarettes and are more likely to have access to the Internet. Weighting the data to match the demographic characteristics of the population controls helped to account for educational differences between web and in-person respondents.
5. What are the benefits of multimode data collection?
- Offering a web mode enables collecting data from individuals who may not have otherwise completed an interview. For example, some individuals will complete an interview only on the web because they will not allow strangers in their homes. Some individuals’ only option is to complete the interview on the web because they live in areas inaccessible to field interviewers, such as gated communities, or they live in areas where in-person data collection is not permissible due to high COVID-19 infection rates.
- Likewise, offering an in-person mode enables collecting data from individuals who would not otherwise complete an interview. For example, some individuals’ only option is to complete an interview in person because they do not have a computer, a Smart phone, or a tablet or do not have Internet or a cellular data plan. Some individuals choose to complete an interview only in person due to a lack of computer proficiency or discomfort with entering personal information online.
6. Why should estimates from 2021 not be compared with estimates from 2020?
- The 2020 NSDUH included only 2 quarters (Quarters 1 and 4) of data collection unlike the four quarters of data collected in 2021. Comparisons of 2-quarter and 4-quarter estimates using data from years prior to 2020 show significant differences in key measures of substance use and mental health (see Chapter 6 of the 2021 Methodological Summary and Definitions for detailed description); thus, using only 2 quarters of data may yield a different trend than use of 4 quarters of data. Therefore, the 2020 NSDUH, which collected only 2 quarters of data, should not be compared with any other year.
7. Is it appropriate to combine 2021 data with previous years’ data?
- Data from 2021 data should not be combined with data prior to 2019 due to differences in estimates based on mode of survey administration (as explained in Question 2).
- Combining 2021 data with 2020 data is not advisable because 2-quarter estimates and 4-quarter estimates differ (as explained in Question 6).
8. Do the methodological issues for 2021 mean that 2021 will represent a trend break from previous years?
- Yes. See Questions 2,6 and 7.
9. Is SAMHSA still planning to release state- and substate-level estimates using 2021 data?
- Currently, we are planning to produce state estimates. These estimates are tentatively scheduled for release in early 2023. We plan to produce substate estimates using combined 2021 and 2022 data in late 2023 or early 2024.
10. What is meant by the phrase “the use but not misuse” of prescription drugs?
- Respondents in the 2021 NSDUH were asked about the following categories of prescription drugs: pain relievers, tranquilizers, stimulants, and sedatives. Respondents first were asked if they used prescription drugs for any reason in the past 12 months or lifetime. Respondents who reported any use of prescription drugs in the past 12 months or lifetime were asked if they used prescription drugs in any way a doctor did not direct them to. Use in any way not directed by a doctor was defined as misuse. Examples of misuse were presented to respondents and included (1) use without a prescription of the respondent’s own; (2) use in greater amounts, more often, or longer than told to take a drug; or (3) use in any other way a doctor did not direct the respondent to use a drug.
- Respondents were classified as having used but not misused prescription drugs if they reported any use of prescription drugs in the past 12 months or lifetime, but they did not report misuse of prescription drugs.
11. Why did the 2021 NSDUH ask substance use disorder (SUD) questions of all past year users of prescription drugs?
- SUDs are characterized by 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. SUD questions in the 2021 NSDUH assessed the presence of an SUD in the past 12 months based on criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM 5).* NSDUH respondents were classified as having an SUD if they met 2 or more of up to 11 applicable criteria in a 12-month period.
- DSM-5 SUD criteria apply to any use of prescription drugs, not just misuse. People who use but do not misuse prescription drugs could nevertheless meet SUD criteria. It is important for individuals who are using prescription drugs to receive ongoing medical monitoring, even if individuals are not misusing the prescription drugs. For these reasons, respondents in the 2021 NSDUH who reported any use of prescription pain relievers, tranquilizers, stimulants, or sedatives in the past 12 months were asked corresponding SUD questions.
12. Are there differences in SUD criteria for misusers of prescription drugs and for users but not misusers of prescription drugs?
- The number of applicable DSM-5 criteria for classifying respondents as having a prescription drug use disorder depends on whether respondents misused prescription drugs or whether they used prescription drugs in the past year but did not misuse them. Respondents who misused prescription drugs in the past year were classified as having a prescription drug use disorder if they met 2 or more of 11 DSM-5 SUD criteria. Respondents who used prescription drugs in the past year but did not misuse them were classified as having a prescription drug use disorder if they met two or more of nine criteria. Two criteria (tolerance and withdrawal) do not apply to respondents who used but did not misuse these prescription drugs in the past year; tolerance and withdrawal can occur as normal physiological adaptations when people use these prescription drugs appropriately under medical supervision.˚
13. How did asking SUD questions of all past year users of prescription drugs affect SUD estimates?
- Asking SUD questions in 2021 of all past year users of prescription drugs more than doubled the estimated numbers of people who had prescription drug use disorders, compared with the estimated numbers based only on people who misused prescription drugs in the past year.
- Asking SUD questions of all past year users of prescription drugs also tended to capture data from people with mild SUDs, defined as having two or three SUD criteria for a given substance.
- In contrast, asking SUD questions of all past year users of prescription drugs had less effect on SUD estimates for aggregate SUD measures that included substances other than prescription drugs. For example, 20.0 million people aged 12 or older in 2021 were estimated to have an illicit drug use disorder in the past year (including use of marijuana, cocaine, heroin, hallucinogens, inhalants, or methamphetamine and misuse of prescription drugs). The estimate increased for any drug use disorder to 24.0 million people when data included past year users of prescription drugs, or an increase of about 20 percent.
Annual National Report
Key Substance Use and Mental Health Indicators in the United States
NSDUH’s latest annual report shows indicators of substance use and mental health in the United States based on 2021 NSDUH data. Because of methodological changes in 2021, estimates from this year should not be compared with previous years. All reported indicators meet rigorous criteria for statistical precision. The 2021 Key Substance Use and Mental Health Indicators report summarizes the following:
- Substance use (tobacco, alcohol, vaping, marijuana and other illicit drug use, as well as the use and misuse of prescription drugs)
- Initiation of substance use by type
- Substance use disorders (SUDs)
- Major depressive episode (MDE), any mental illness, and serious mental illness
- Mental illness and MDE co-occurring with substance use and SUDs
- Suicidal thoughts, plans, and non-fatal attempts
- Substance use treatment and mental health service use
- Perceived impact of the COVID-19 pandemic on substance use, mental health issues, and treatment
Estimates are presented by age group and by race/ethnicity for selected measures.
The 2021 NSDUH Detailed Tables present national estimates of substance use and mental health. Because of methodological changes in 2021, estimates from this year should not be compared with previous years. The tables still include information for many different populations in 2021. They present indicators for youths aged 12 to 17 and adults aged 18 or older (separately or combined) on drug, alcohol, and tobacco use, risk and availability of substance use, substance initiation, substance use disorder (SUD), mental illness and major depressive episodes, suicidality, treatment, and the perceived effects of the Coronavirus Disease 2019 (COVID-19) pandemic, along with some other miscellaneous health topics. Please refer to the Methodological Summary and Definitions report for more information on the NSDUH survey.
Sections of the 2021 Detailed Tables:
Please refer to the related README file for instructions on how to use the Table of Contents and download files for faster viewing.
- Clickable Table of Contents
- Section 1: Illicit Drug Use/Misuse Tables - 1.1 to 1.131
- Section 2: Tobacco Product Use, Nicotine Vaping, and Alcohol Use Tables - 2.1 to 2.47
- Section 3: Risk and Protective Factor Tables - 3.1 to 3.18
- Section 4: Incidence Tables - 4.1 to 4.10
- Section 5: Substance Use Disorder and Treatment Tables - 5.1 to 5.44
- Section 6: Adult Mental Health Tables - 6.1 to 6.89
- Section 7: Youth Mental Health Tables - 7.1 to 7.19
- Section 8: Miscellaneous Tables - 8.1 to 8.42
- Section 9: Sample Size and Population Tables - 9.1 to 9.8
- Section 10: Perceived Effects of Coronavirus Disease 2019 (COVID-19) Tables - 10.1 to 10.17
- Appendix A: Glossary
- Appendix B: List of Tables
- Appendix C: List of Contributors
The 2021 Methodological Summary and Definitions report summarizes the information users need to properly interpret NSDUH estimates of substance use and mental health issues. This report accompanies the annual detailed tables and provides information on overall methodology, key definitions for measures and terms used in 2021 NSDUH reports and tables, along with some analysis of these measures and of the survey as a whole. The report is organized into six chapters:
- Chapter 1 is an introduction to the report.
- Chapter 2 describes the survey, including information about the sample design; data collection procedures; and key aspects of data processing, such as development of analysis weights.
- Chapter 3 presents technical details on the statistical methods and measurement, such as suppression criteria for unreliable estimates, statistical testing procedures, and measurement issues for selected substance use and mental health measures.
- Chapter 4 covers special methodological topics related to prescription psychotherapeutic drugs.
- Chapter 5 describes other sources of data on substance use and mental health issues, including data sources for populations outside the NSDUH target population.
- Chapter 6 covers Special Methodological Issues for the 2021 NSDUH, including issues of comparability with previous NSDUH surveys.
- Appendix A is a glossary that covers key definitions for use as a resource with the 2021 NSDUH reports and detailed tables.
- Appendix B provides a list of contributors to the report.
Additional methodological reports and materials are available from the 2021 Methodological Resource Book.