A Comparison of Opioid and Nonopioid Substance Users in Residential Treatment for Co-Occurring Substance Use and Mental Disorders

The past decade has seen a marked increase in the illicit use of opioids, as well as a doubling of the percentage of individuals seeking treatment for opioid use disorders. However, little is known about the differences between opioid users and nonopioid users in residential treatment. Further, no studies have been published that compare opioid users and nonopioid users in treatment for co-occurring substance use and mental disorders. To address this gap, this study examined differences between opioid and nonopioid substance users in residential treatment for co-occurring disorders. Data was drawn from 1,972 individuals treated between 2009 and 2011 at one of three private residential treatment centers that provide integrated treatment for co-occurring substance use and mental disorders. Data was collected at program intake, and 1- and 6-month postdischarge using the Addiction Severity Index and the University of Rhode Island Change Assessment. To examine within-group changes in substance use, addiction severity, and mental health across time, linear mixed-model analyses were conducted with facility, year, age, gender, and race included as covariates. The authors found more similarities than differences between the two groups on baseline characteristics, treatment motivation, length of stay, and outcomes on measures of substance use, addiction severity, and mental health. The results demonstrate that though opioid users entered treatment with higher levels of substance use–related impairment, they were just as successful in treatment outcomes as their non-opioid-using peers.