To analyze nationally representative data on the lifetime and 12-month prevalences of use of and dependence on illegal drugs (marijuana/hashish, cocaine/crack, heroin, hallucinogens), nonmedical prescription psychotropic drugs (sedatives, tranquilizers, stimulants, analgesics), and inhalants; and to examine data on the sociodemographic correlates of use and dependence.
The data come from the National Comorbidity Survey, a structured diagnostic interview administered to persons aged 15 to 54 years that generates reliable diagnoses according to the definitions and criteria of DSM-III-R.
Of the respondents, 51.0% used one of the above drugs at some time in their lives, and 15.4% did so in the past 12 months. These estimates are similar to those obtained in the 1991 National Household Survey of Drug Abuse, where lifetime prevalence was 45.2% and 12month prevalence was 16.7% among respondents in the age range 15 to 54 years. Of National Comorbidity Survey respondents, 7.5% (14.7% of lifetime users) were dependent at some time in their lives and 1.8% were dependent in the past 12 months. The prevalence estimate for lifetime dependence was reduced to 5.3% when calculated the percentage of respondents in the age range of 28 to 54 years who reported an onset of dependence as of 10 years earlier (ie, when they were 18 to 44 years old) was computed. This is similar to the Epidemiologic Catchment Area Study estimate of 5.1% among respondents in the age range 18 to 44 years, a comparison that matches the two studies on year of assessment, age of risk, and cohort. Males were significantly more likely to report both lifetime and 12-month use and dependence. Use and dependence were found to be more common in cohorts born after World War II than those born before the end of the war. The demographic predictors of lifetime use differed from the predictors of lifetime dependence among users, and these, in turn, differed from the predictors of recent dependence among people with a lifetime history of dependence.
Drug use and dependence are highly prevalent in the general population. The fact that there are differences in the correlates of first use, dependence among users, and persistence of dependence means that future research aimed at pinpointing modifiable risk factors must be based on disaggregated analyses of separate stages of progression.