National Survey on Drug Use and Health (NSDUH)
Population Data

The questionnaire was significantly redesigned in 1994. The 1994 survey included, for the first time, a rural population supplement to allow separate estimates to be calculated for this population.

Additional modules were added to NSDUH over the years, covering the following new topics and questions:

• Mental health and access to care (1994-B)
• Risk and availability of drugs (1996)
• Cigar smoking, plus new questions on marijuana and cocaine use (1997)
• Question series asked only of respondents aged 12 to 17 (1997)
• Tobacco brands (1999)
• Marijuana purchase (2001)
• Prior marijuana and cigarette use; additional questions on drug treatment, adult mental health services, and social environment (2003)
• Adult and adolescent depression (questions derived from the National Comorbidity Survey, Replication [NCS-R] and National Comorbidity Survey, Adolescent [NCS-A]) (2004)

The survey administration and sample design were improved with the implementation of the 1999 survey, and additional improvements were made in 2002. Since 1999, the survey sample has employed a 50-state design with an independent, multistage area probability sample for each of the 50 states and the District of Columbia. The collection mode of the survey changed from personal interviews and self-enumerated answer sheets to computer-assisted personal interviews and audio computer-assisted self-interviews.

In 2020, NSDUH began using web data collection in addition to in-person interviews. In 2002, the survey’s title was officially changed to the National Survey on Drug Use and Health.

As of 2002, participants receive $30 for participating in the study. As a result, participation rates increased starting in 2002.

Also, in 2002 and 2011, the new population data from the 2000 and 2010 decennial Censuses, respectively, became available for use in the sample weighting procedures. For these reasons, data gathered for 2002 and beyond cannot validly be compared to data prior to 2002.

NSDUH underwent a partial redesign in 2015, so there are several measures that “broke trends” in 2015, meaning that estimates from 2015 and later are no longer comparable to their 2014 and earlier counterparts. This also means that you cannot pool data across incomparable years. For affected measures, you will likely only be able to look at the 2002−2014 timeframe to pool enough years of comparable data to get a sufficient sample size at the county level. Measures that were not affected can be pooled through 2015. The SAMHSA Data Website has more information on the partial 2015 redesign and its effects on estimates.

Although NSDUH is useful for many purposes, it has certain limitations. First, the data are based on self-reports of drug use, and their value depends on respondents’ truthfulness and memory. Although some experimental studies have established the validity of self-reported data in similar contexts and NSDUH procedures were designed to encourage honesty and recall, some underreporting and overreporting may take place.

To aid respondent recall, the prescription drug questions in 2018 allowed respondents to report any use or misuse in the past 12 months of specific related medications (e.g., the tranquilizers Xanax®, Xanax® XR, generic alprazolam, and generic extended-release alprazolam). These self-reports capture information on the use or misuse of prescription drugs that contain a given active ingredient.

However, these self-reports may not accurately identify the exact drugs that respondents took, especially when respondents identify certain drugs by their brand names. For example, a respondent might have used the generic drug alprazolam but reported use or misuse of the brand name tranquilizer Xanax® because of name recognition. For this reason, the public-use file includes recoded variables for subtypes of related prescription drugs (for example, alprazolam products) but with few exceptions does not include variables for individual prescription drugs.

Second, the survey is cross-sectional rather than longitudinal. That is, individuals were interviewed only once and were not followed for additional interviews in subsequent years. Each year’s survey, therefore, provides an overview of the prevalence of drug use at a specific point in time rather than a view of how drug use changes over time for specific individuals.

Third, because the target population of the survey is defined as the civilian, noninstitutionalized population of the United States, a small proportion (approximately 3 percent) of the population is excluded. The subpopulations excluded are active-duty members of the military and individuals in institutional group quarters (such as hospitals, prisons, nursing homes, and treatment centers). If the drug use of these groups differs from that of the civilian, noninstitutionalized population, NSDUH may provide slightly inaccurate estimates of substance use and mental health in the total population. This may be particularly true for prevalence estimates for less commonly used drugs, such as heroin.

The estimates yielded by NSDUH are based on sample survey data rather than on complete data for the entire population. This means that the data must be weighted to obtain unbiased estimates for survey outcomes in the population represented by the survey.

For methodological information for a particular year or date range, please check the codebook for a specific data set from the sidebar to the right.