Objective: This study examines sociodemographic and clinical characteristics, as a function of primary substance of abuse, among clients approached, screened, and assessed for eligibility in a 10-site effectiveness trial of a Web-based psychosocial intervention for substance use disorders. Consistent with the design of effectiveness trials, eligibility criteria were broad and exclusion criteria minimal; thus, the recruited sample may be viewed as relatively representative of patients seeking treatment throughout the United States.
Methods: χ2 tests for categorical variables and F tests for continuous variables were used to analyze demographic, substance use, physical and mental health, and sexual risk data collected at screening and baseline; pairwise comparisons between primary substance subgroups for baseline data were conducted if the test statistic P value was 0.01 or less.
Results: Few participants expressed disinterest in the study at screening because of the computer-assisted intervention. A diverse sample of substance users completed baseline and were enrolled: 22.9% marijuana; 21.7% opiates; 20.9% alcohol; 20.5% cocaine; and 13.9% stimulants users. Marijuana users demonstrated the greatest differences across primary substances: they were younger, less likely to be married or attend 12-step meetings, and more likely to be in treatment as a result of criminal justice involvement. All patients, even marijuana users, reported comparable rates of co-occurring mental health disorders and sexual risk and substantial rates of polysubstance use disorders.
Conclusions: Primary substance of abuse may be a less important indicator of overall severity compared with co-occurring disorders and other factors common across treatment seekers, further demonstrating the need for integrated treatment services and care and comprehensive pretreatment assessment.