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Format of the Report and Explanation of Tables

Summaries of the results of the 1995 NHSDA are presented for several categories of drugs. For each drug category, recent trends in use and differences in use among population subgroups are described. An analysis of trends in the initiation of substance use and an analysis of drug use among women of childbearing age are contained in sections following the drug use prevalence analyses. A discussion of the NHSDA findings, including comparisons with other studies, is given at the end of the report. Technical appendices 1, 2 and 3 provide more detail on the NHSDA methodology, limitations of the data, and other sources of data. Appendix 4 provides a list of references related to the NHSDA, other substance abuse surveys, and survey methodology. Detailed tabulations of data from the NHSDA are provided in Appendix 5.

The tables and the analysis focus primarily on recent trends, from 1994 to 1995. Long term trends are also presented and discussed, but due to the limitations of the procedure used to adjust for the differences between the pre- and post-1994 methodology, it is not possible to analyze these data in as much detail. As indicated in the tables, statistical significance testing was done for comparisons between 1995 and prior years. Significance levels are indicated in the tables, and all changes described in the text as increases or decreases were tested and found to be significant at least at the .05 level, unless otherwise stated.

Tables and text present prevalence measures in terms of both the number of drug users and the rate of drug use in the population. Tables show estimates of drug use prevalence in lifetime (i.e., ever used), past year, and past month. The analysis focuses primarily on past month use, which is also referred to as "current use," although lifetime and past year data are also occasionally discussed.

Data are presented for three major race/ethnic groups: whites, blacks, and Hispanics. A fourth category, "Other," includes Asian and Pacific Islanders, American Indians and Alaskan Natives, and other groups. It should be noted that the category "white" includes only non-Hispanic whites, the category "black" includes only non-Hispanic blacks, and the category "Hispanic" includes Hispanics of any race.

Data are also presented for four U.S. geographic regions. These regions include the following groups of States:

Northeast- Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania.

North Central- North Dakota, South Dakota, Nebraska, Kansas, Minnesota, Louisiana, Missouri, Wisconsin, Illinois, Michigan, Indiana, Ohio.

South- Texas, Oklahoma, Arkansas, Louisiana, Mississippi, Tennessee, Kentucky, West Virginia, Virginia, Maryland, Delaware, District of Columbia, North Carolina, South Carolina, Georgia, Florida, Alabama.

West- California, Oregon, Washington, Idaho, Nevada, Arizona, New Mexico, Utah, Colorado, Wyoming, Montana, Hawaii, Alaska.

The tables also present data by population density. For this variable, large metropolitan areas are defined as Metropolitan Statistical Areas (MSAs) with a population of 1 million or more. Small metropolitan areas are MSAs with a population of less than 1 million. Nonmetropolitan areas are areas outside of MSAs. For 1993 and 1994 NHSDA estimates, 1990 Census data and 1990 MSA classifications were used to determine population density. For 1992 estimates, 1990 Census counts and 1984 MSA classifications were used.

Other than presenting results by age group and other basic demographic characteristics, no attempt is made in this report to control for potentially confounding factors that might help explain the observed associations. This point is particularly salient with respect to race/ethnicity, which tends to be highly associated with socioeconomic characteristics. The cross-sectional nature of the data precludes any causal interpretations of observed relationships. Nevertheless, the data presented in this report are useful for indicating demographic subgroups with relatively high (or low) rates of drug use, regardless of what the underlying reasons for those differences might be. A previously published SAMHSA report includes a more in-depth analysis of the relationship between drug use, race/ethnicity, and socioeconomic status (SAMHSA 1993b). In this report, measures of socioeconomic status include employment and education. Personal and family income data are not available for analysis in this preliminary report, but will be addressed in a later report.

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This page was last updated on June 16, 2008.