Course of drug use from early adulthood to mid-life among Vietnam-era veterans

There is limited study of drug use trajectories over the life-course and limited examination of drug versus alcohol use trajectories. The purpose of this study was to identify differences in drug use trajectories from early adulthood to mid-life and to compare and contrast these with trajectories based on the course of alcohol abuse. The sample consisted of male veterans from the Vietnam-era study, a 25-year follow-up of the Vietnam Drug User Returns project that assessed medical and psychiatric consequences of substance use disorders. Retrospective structured interviews covered the 25 years since an original 1972 survey; measures of alcohol and drug use were obtained for each year of the follow-up interval. Individuals with a lifetime diagnosis of a drug use disorder (DUD) (n = 319) were selected for further analysis. A four-class model was identified with trajectories parallel to those identified in previous studies examining alcohol use. However, the covariates that differentiated the alcohol use trajectories did not differentiate the drug use trajectories. The limited overlap between the alcohol and drug use trajectories and the nature of alcohol use disorders (AUD)–DUD comorbidity are discussed. Application of this research will aid in development of early intervention and long-term treatment programs for similar populations with AUD–DUD diagnoses.