National Household Survey on Drug Abuse (NHSDA-1999)

Parent Series Details:

Background

The National Survey on Drug Use and Health (NSDUH) series, formerly titled National Household Survey on Drug Abuse, is a major source of statistical information on the use of illicit drugs, alcohol, and tobacco and on mental health issues among members of the U.S. civilian, non-institutional population aged 12 or older. The survey tracks trends in specific substance use and mental illness measures and assesses the consequences of these conditions by examining mental and/or substance use disorders and treatment for these disorders.

Examples of uses of NSDUH data include the identification of groups at high risk for initiation of substance use and issues among those with co-occurring substance use disorders and mental illness.

NSDUH public-use data files are available for download in SAS, SPSS, STATA and ASCII formats, and online analysis with SDA. NSDUH restricted-use data files are available for online analysis with the R-DAS.

The NSDUH is sponsored by the Center for Behavioral Health Statistics and Quality (formerly Office of Applied Studies), Substance Abuse and Mental Health Services Administration. For more information, visit the NSDUH website.

NSDUH Questionnaire Details

The population of the NSDUH series is the general civilian population aged 12 and older in the United States. Questions include age at first use, as well as lifetime, annual, and past-month usage for the following drugs: alcohol, marijuana, cocaine (including crack), hallucinogens, heroin, inhalants, tobacco, pain relievers, tranquilizers, stimulants, and sedatives. The survey covers substance abuse treatment history and perceived need for treatment, and includes questions from the Diagnostic and Statistical Manual (DSM) of Mental Disorders that allow diagnostic criteria to be applied.

Respondents were also asked about personal and family income sources and amounts, health care access and coverage, illegal activities and arrest record, problems resulting from the use of drugs, perceptions of risks, and needle-sharing. Demographic data include gender, race, age, ethnicity, educational level, job status, income level, veteran status, household composition, and population density.

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. Other modules have been added each year and retained in subsequent years: mental health and access to care (1994-B); risk/availability of drugs (1996); cigar smoking and new questions on marijuana and cocaine use (1997); question series asked only of respondents aged 12 to 17 (1997); questions on tobacco brand (1999); marijuana purchase questions (2001); prior marijuana and cigarette use, additional questions on drug treatment, adult mental health services, and social environment (2003); and adult and adolescent depression questions derived from the National Comorbidity Survey, Replication (NCS-R) and National Comorbidity Survey, Adolescent (NCS-A) (2004).

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. At this time, the collection mode of the survey changed from personal interviews and self-enumerated answer sheets to using computer-assisted personal interviews and audio computer-assisted self-interviews. In 2002, the survey’s title was officially changed to the National Survey on Drug Use and Health (NSDUH).

Since 2002, participants are given $30 for participating in the study. This resulted in an increase in participation rates from the years prior to 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.


Study Details:
The National Household Survey on Drug Abuse (NHSDA) series measures the prevalence and correlates of drug use in the United States. The surveys are designed to provide quarterly, as well as annual, estimates. Information is provided on the use of illicit drugs, alcohol, and tobacco among members of United States households aged 12 and older. Questions include age at first use as well as lifetime, annual, and past-month usage for the following drug classes: marijuana, cocaine (and crack), hallucinogens, heroin, inhalants, alcohol, tobacco, and nonmedical use of prescription drugs, including pain relievers, tranquilizers, stimulants, and sedatives. The survey covers substance abuse treatment history and perceived need for treatment, and includes questions from the Diagnostic and Statistical Manual (DSM) of Mental Disorders that allow diagnostic criteria to be applied. Respondents are also asked about personal and family income sources and amounts, health care access and coverage, illegal activities and arrest record, problems resulting from the use of drugs, and needle-sharing. Questions introduced in previous NHSDA administrations were retained in the 1999 survey, including questions asked only of respondents aged 12 to 17. These "youth experiences" items covered a variety of topics, such as neighborhood environment, illegal activities, gang involvement, drug use by friends, social support, extracurricular activities, exposure to substance abuse prevention and education programs, and perceived adult attitudes toward drug use and activities such as school work. Also retained were questions on mental health and access to care, perceived risk of using drugs, perceived availability of drugs, driving behavior and personal behavior, and cigar smoking. Questions on the tobacco brand used most often were introduced with the 1999 survey. Demographic data include gender, race, age, ethnicity, marital status, educational level, job status, veteran status, and current household composition.

Study Scope

Time period: 
1999
Collection date: 
1999
Geographic coverage : 
United States
Unit of observation: 
individual
Data types: 
survey data
Universe: 
The civilian, noninstitutionalized population of the United States aged 12 and older, including residents of noninstitutional group quarters such as college dormitories, group homes, shelters, rooming houses, and civilians dwelling on military installatio
Notes: 
Data were collected and prepared for release by Research Triangle Institute, Research Triangle Park, NC.
The National Household Survey on Drug Abuse survey administration and sample design changed with the implementation of the 1999 survey. Starting in 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. Therefore, estimates produced from the 1999, 2000, and 2001 surveys are not comparable to those produced from the 1998 and earlier surveys.
For selected variables, statistical imputation was performed following logical inference to replace missing responses. These variables are identified in the codebook as "...LOGICALLY ASSIGNED" for the logical procedure, or by the designation "IMPUTATION-REVISED" in the variable label when the statistical procedure was also performed. The names of statistically imputed variables begin with the letters "IR". For each imputation-revised variable there is a corresponding imputation indicator variable that indicates whether a case's value on the variable resulted from an interview response or was imputed. Missing values for some demographic variables were imputed by the unweighted hot-deck technique used in previous NHSDAs. Beginning in 1999, imputation of missing values for many other variables was accomplished using predictive mean neighborhoods (PMN), a new procedure developed specifically for the NHSDA. Both the hot-deck and PMN imputation procedures are described in the codebook.
To protect the privacy of respondents, all variables that could be used to identify individuals have been encrypted or collapsed in the public use file. To further ensure respondent confidentiality, the data producer used data substitution and deletion of state identifiers and a subsample of records in the creation of the public use file.
Previously published estimates may not be exactly reproducible from the variables in the public use file due to the disclosure protection procedures that were implemented.
The data definition and dictionary files for Stata are designed to be compatible with StataSE, Version 8. This is a large data file requiring that approximately 250 megabytes of Random Access Memory be allocated to Stata. Operations within Stata, including conversion of the ASCII data to Stata format, are likely to be slow. Analysts may wish to download subsets of data from the SAMHDA Data Analysis System (DAS) for use with Stata.
Subject Terms: 
  • alcohol abuse
  • alcohol consumption
  • amphetamines
  • barbiturates
  • cocaine
  • drug abuse
  • drug use
  • drugs
  • hallucinogens
  • heroin
  • households
  • inhalants
  • marijuana
  • mental health
  • mental health services
  • methamphetamine
  • prescriptions drugs
  • smoking
  • substance abuse
  • substance abuse treatment
  • tranquilizers

Study Methodology

Mode of data collection: 
audio computer-assisted self interview (ACASI)
Sample: 
A multistage area probability sample for each of the 50 states and the District of Columbia was used. A coordinated five-year sample design was developed for 1999 through 2003. Although there is no overlap with the 1998 sample, the design facilitated an overlap in first-stage units (area segments) between each two successive years in the five-year design. This design was intended to increase the precision of estimates in year-to-year trend analyses because of the expected positive correlation resulting from the overlapping sample. To obtain the required precision at the state level and to improve the precision of cigarette brand data for youths at the national level, youths and young adults were oversampled. The result was that each state's sample was approximately equally distributed among three major age groups: 12 to 17 years, 18 to 25 years, and 26 years or older. The achieved sample for the 1999 computer-assisted interview (CAI) sample was 66,706 persons. The public use file has 53,560 records due to the subsampling step used in the disclosure protection procedures. Minimum item response requirements were defined for cases to be retained for weighting and further analysis (i.e., "usable" cases). These requirements, as well as full sampling methodology, are detailed in the codebook.
Weight: 
Due to unequal selection probabilities at multiple stages of sample selection and the coverage bias, the 1999 NHSDA sample is not self-weighting. Analysts are advised to use the sample weight when attempting to use the NHSDA data to draw inferences about the target population or any subdomain of the target population. All estimates published in SAMHSA reports (such as the Summary of Findings from the 1999 NHSDA) are weighted. The appropriate and final sample weight is called ANALWT_C on this data file. This sample weight represents the total number of target population persons each record on the file represents. Note that the sum of ANALWT_C, over all records on the data file, represents an estimate of the total number of people in the target population.
Response rates: 
  • The study yielded a weighted screening response rate of 90 percent and a weighted interview response rate for the CAI of 69 percent.
Versions: 
  • 2013-06-25: Released Methodological Resources documentation and updated xml file to include variable groupings.
  • 2006-12-07: On May 18, 2006, the data producer resupplied the data file and codebook documentation. In this new data file, 10 variables were modified, 106 variables were dropped, and 10 new variables were added. Some of these changes were to correct for data errors, but most of these changes were done to provide consistency with the 2004 NSDUH study. Of these changes, the most important change to note is that two study design variables (VEREP and VESTR) were revised to provide consistency with the 2004 study, which collapsed the strata in order to maximize the number of people in each replicate.
  • 2004-03-24: Corrected coding errors in the following variables: IISDRC, II2LSDRC, IIPCPRC, II2PCPRC, IIMTHRC, II2MTHRC, NRCH17_2, MTHYR, MTHMON.
  • 2003-04-18: The data file has been updated. The variables NRCH017 and IIEDUC were removed and the variables JBSTATR2, EMPSTAT4, IIEMPST4, NRCH17_2, and IIEDUC2 were added.
  • 2002-06-07: The data producer made minor changes to the documentation text and added an appendix with a variable map.
Extent of processing: 
  • Performed consistency checks.
  • Created online analysis version with question text.
  • Checked for undocumented or out-of-range codes.

Study Bibliography