Empirically derived subtypes of opioid use and related behaviors

Aims To identify and validate homogeneous subtypes of opioid use and related behaviors. Design Family-based and case-control genetic studies of opioid and/or cocaine dependence. Settings Clinical and general community samples from Connecticut, Massachusetts, Pennsylvania and South Carolina. Participants A total of 4061 individuals (2003 individuals from 835 families and 2058 unrelated individuals) recruited to participate in genetic studies. Measurements The computer-assisted Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA) was used to assess participants' demographics, medical history, substance use behaviors and disorders and other psychiatric disorders. Findings Five homogeneous subtypes were identified, which differed on opioid-related measures, demographics and prevalence rates of substance use and psychiatric disorders. Heritability estimates for the two most severely affected subtypes exceeded 0.60. Conclusions An empirical approach based on opioid use and related behaviors can yield homogeneous subtypes that could be of value in gene finding for opioid dependence.