History of regular nonmedical sedative and/or alcohol use differentiates substance-use patterns and consequences among chronic heroin users

Background: Concurrent use of sedating substances (e.g. alcohol or benzodiazepines) with opioids is associated with increased negative consequences of opioid use; however, few studies have attempted to differentiate effects of using sedating substances on heroin-use outcomes. This study examines differences between heroin users who use alcohol or misuse sedatives regularly and those who do not. Methods: Substance-use data were collected from 367 non-treatment seeking, chronic heroin-using, 18-to- 55 year-old participants. We created 4 groups based on self-reported lifetime history of regular (at least weekly) substance use: heroin only (n = 95), heroin and sedatives (n = 21), heroin and alcohol (n = 151), and heroin, sedative, and alcohol (n = 100). Chi-square analyses and ANOVAs with Bonferroni post hoc tests were used to explore differences between these groups. Results: Heroin users who denied lifetime alcohol or nonmedical sedative use regularly endorsed fewer consequences associated with any substance they had used. Total adverse consequences of heroin use (e.g. health problems) were significantly higher among those who misused sedatives regularly, irrespective of alcohol use history (F(3,361) = 10.21; p <.001). Regular alcohol use did not independently impact heroin consequences but was associated with increased use of other substances. Conclusions: Although polysubstance use is normative among heroin users, the risks depend on the substances used. Regular sedative use is associated with increased heroin consequences whereas regular alcohol use is not. This study refines the investigation of polysubstance use and highlights subgroup differences depending on types of substances used regularly. This knowledge is critical for understanding substance-use motivations and creating avenues for harm reduction.