The National Survey on Drug Use and Health

Formerly called the National Household Survey on Drug Abuse (NHSDA) Report
February 7, 2003

The National Survey on Drug Use and Health (NSDUH)


In Brief

  • The National Survey on Drug Use and Health (NSDUH) is the primary source of information on the use of illegal drugs by the U.S. population

  • Each year, about 70,000 individuals aged 12 or older are surveyed across the 50 States and the District of Columbia

  • NSDUH public use files for 1990 to 2001 and selected earlier years are available for on–line analysis through the Substance Abuse and Mental Health Data Archive (SAMHDA)
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The National Survey on Drug Use and Health (NSDUH) is sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA). The survey has been conducted since 1971 and serves as the primary source of information on the prevalence and incidence of illicit drug, alcohol, and tobacco use in the civilian, noninstitutionalized population aged 12 or older in the United States. Information about substance abuse and dependence, mental health problems, and receipt of substance abuse and mental health treatment also is included. Since 1999, about 70,000 interviews are conducted each year using a computer–assisted interviewing (CAI) methodology. Before 2002, the name of the survey was the National Household Survey on Drug Abuse (NHSDA).

Sample Design
The NSDUH collects information from residents of households, noninstitutional group quarters (e.g., shelters, rooming houses, dormitories), and civilians living on miliary bases. Persons excluded from the survey include homeless persons who do not use shelters, active–duty military personnel, and residents of institutional group quarters, such as prisons and long–term hospitals. The sample employs a 50–State design with an independent, multistage area probability sample for each State and the District of Columbia. The design provides a sample large enough to yield direct estimates of substance use in eight States with the largest populations (California, Florida, Illinois, Michigan, New York, Ohio, Pennsylvania, and Texas). Small area estimation techniques are used to develop estimates for the remaining 42 States and the District of Columbia.

The design also oversamples youths and young adults, so that each State's sample is distributed equally among three age groups (12 to 17 years, 18 to 25 years, and 26 years or older).

Data Collection
The data collection method is in–person interviews conducted with a sample of individuals at their place of residence. Prior to 1999, the NSDUH used a paper–and–pencil interviewing (PAPI) methodology. Since 1999, the interview has been carried out with CAI methodology. The survey uses a combination of computer–assisted personal–interviewing (CAPI) conducted by the interviewer for some basic demographic information and audio computer–assisted self–interviewing (ACASI) for most of the questions. ACASI provides a highly private and confidential means of responding to questions to increase the level of honest reporting of illicit drug use and other sensitive behavior.

Information is collected continuously from January 1 through December 31. A total of 157,471 addresses were screened for the 2001 survey, and 68,929 persons were interviewed. In 2001, the weighted response rate for screening was 92 percent, and the weighted response rate for interviewing was 73 percent.

Key Terms
A number of key measures of substance use and mental health are reported from the NSDUH data (Table 1). For illicit drug use, alcohol use, and tobacco use, information is presented about use in the lifetime, past year, and past month. Use in the past month also is referred to as "current use." The survey also produces measures of abuse, dependence, treatment, and mental health problems, generally for the past year.

Measures for nine specific classes of drugs are presented in analyses. These include the use of marijuana/hashish, cocaine (including crack), inhalants, hallucinogens, heroin, and prescription–type drugs used nonmedically (pain relievers, tranquilizers, stimulants, and sedatives). Non–prescription medications and legitimate uses under a doctor's supervision are not included in the survey. Summary measures such as "any illicit drug use" and "any illicit drug use other than marijuana" are produced.

In addition to a measure of any alcohol use, measures of "binge" alcohol use and heavy use in the past 30 days have been developed. "Binge" alcohol use is defined as having five or more drinks on the same occasion at least once in the 30 days prior to the survey, and "heavy" use is defined as having five or more drinks on the same occasion on at least 5 different days in the past 30 days.

The measure of tobacco use includes use of cigarettes, chewing tobacco, snuff, cigars, and pipe tobacco.

Measures of the perceived risk of harm from use of a number of illicit drugs, alcohol, and cigarettes at varying levels of use also are included. Measures of substance abuse and dependence and serious mental illness are based on criteria described in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM–IV).1

In addition to these key substantive terms, a number of demographic and geographic characteristics are used in many analyses of the NSDUH data (Table 2).

Table 1. Key Measures of Substance Use and Mental Health

Table 2. Demographic and Geographic Characteristics

Table 1. Key Measures of Substance Use and Mental Health Table 2. Demographic and Geographic Characteristics

Data Processing
Even though significant editing and consistency checking occurs automatically during the interview, more complex edits and consistency checks are performed during the processing of the data. For some key variables with missing or ambiguous values after editing, statistical imputation is used to replace the missing data. The general approach for developing analysis weights involves development of design–based weights and application of adjustment factors to adjust for nonresponse, to poststratify to known population control totals, and control for extreme weights, when necessary.

Sampling Error and Statistical Significance
National estimates, along with the associated measures of precision, are computed using a multiprocedure software package, Survey Data Analysis (SUDAAN) Software for Statistical Analysis of Correlated Data, which was designed for the statistical analysis of sample survey data from stratified, multistage cluster samples.2 The sampling error of an estimate is the error caused by the selection of a sample rather than conducting a census of the population. Sampling errors are used to identify unreliable estimates and test for the statistical significance of differences between estimates.

Survey estimates considered to be unreliable due to unacceptably large sampling errors are omitted from publications and denoted by an asterisk (*).

The statistical significance of observed differences in the NSDUH is generally reported at the 0.05 and 0.01 levels. In reports on NSDUH data, differences between groups or years of the survey are generally noted only if they are statistically significant.

Availability of Data and Reports
The report titled Results from the 2001 NHSDA provides an overview of key findings and methodological procedures for the survey. The report is published annually.

Recent analytic monographs published by SAMHSA using NSDUH data include: Substance Dependence, Abuse, and Treatment; Initiation of Marijuana Use: Trends, Patterns, and Implications; and State Estimates of Substance Use from the 2000 NHSDA.

Several reports on methodological issues are also available. The Methodological Resource Book (MRB) is produced annually. It includes the questionnaire and information on data collection and data analysis procedures and is available on the SAMHSA website. Development of Computer–Assisted Interviewing Procedures for the National Household Survey on Drug Abuse3 documents field testing and pretesting of the CAI instrument, and Redesigning an Ongoing National Household Survey: Methodological Issues4 discusses statistical and methodological issues concerning the 1999 redesign of the NSDUH.

A complete listing of previously published NSDUH reports is available from SAMHSA's Office of Applied Studies. Many of these reports are available on the SAMHSA website.

The NSDUH Report, published approximately twice a month, presents key findings from the NSDUH. These reports are available by mail and are posted on the SAMHSA website.

Associated with the release of the annual survey findings are detailed tables presenting analyses of substance use and other measures by demographic and geographic characteristics. These are also posted on the SAMHSA website.

Public use data files for 1979, 1982, 1985, 1988, and annually from 1990 to 2001 are currently available through the Substance Abuse and Mental Health Data Archive (SAMHDA) and the archive's on–line data analysis system (http://www.icpsr.umich.edu/SAMHDA).

End Notes
  1. American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.

  2. RTI. (2001). SUDAAN user's manual: Release 8.0. Research Triangle Park, NC: Author.

  3. Substance Abuse and Mental Health Services Administration (2001). Development of Computer–Assisted Interviewing Procedures for the National Household Survey on Drug Abuse (DHHS Publication No. SMA 01–3514, Methodology Series: M–3). Rockville, MD: Author.

  4. Gfroerer, J., Eyerman, J., and Chromy, J., Eds. (2002). Redesigning an ongoing national household survey: Methodological issues. DHHS Publication No. SMA 03–3768. Rockville, MD: Substance Abuse and Mental Health Services Administration, Office of Applied Studies.

The National Survey on Drug Use and Health (NSDUH) is an annual survey sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA).

The NSDUH Report is prepared by the Office of Applied Studies (OAS), SAMHSA, and by RTI in Research Triangle Park, North Carolina.
Information and data for this issue are based on the following publications:

Substance Abuse and Mental Health Services Administration. (2000). Summary of findings from the 1999 National Household Survey on Drug Abuse (DHHS Publication No. SMA 00–3466, NHSDA Series: H–12). Rockville, MD: Author.

Substance Abuse and Mental Health Services Administration. (2001). Summary of findings from the 2000 National Household Survey on Drug Abuse (DHHS Publication No. SMA 01–3549, NHSDA Series: H–13). Rockville, MD: Author.

Substance Abuse and Mental Health Services Administration. (2002). Results from the 2001 National Household Survey on Drug Abuse: Volume I. Summary of national findings (DHHS Publication No. SMA 02–3758, NHSDA Series: H–17). Rockville, MD: Author.

Also available on–line:

http://www.oas.samhsa.gov.

Additional tables available on request.
The NSDUH Report (formerly The NHSDA Report) is published periodically by the Office of Applied Studies, Substance Abuse and Mental Health Services Administration (SAMHSA). All material appearing in this report is in the public domain and may be reproduced or copied without permission from SAMHSA. Additional copies of this fact sheet may be downloaded from Other reports from the Office of Applied Studies are also available on-line on the OAS home page: http://www.oas.samhsa.gov

This page was last updated on December 31, 2008.