Young Adults Advancing Through the Stages of Change: A Mediational Analysis of Cannabis Use Disorder Treatment

The Stages of Change (SoC) model explains addictive behavior change through 5 stages: precontemplation, contemplation, preparation, action, and maintenance. Limited evidence exists from randomized controlled trials testing the SoC model in Cannabis Use Disorder (CUD) treatments. The aim of this study was to test the indirect effects of Peer Network Counseling- text (PNC-txt), a text-message delivered motivational interviewing informed treatment for cannabis use disorder, advancing participants through the SoC. Design was a two-arm randomized clinical trial CUD treatment with 1078 U.S. young adults. Participants were allocated to 4 wk of PNC-txt or a wait-list control condition and followed for 6 months. Urine drug tests for the presence of THC metabolites and self-reported days used cannabis in the past 30 days were outcome variables. Stages of change was measured with the Marijuana Ladder, used as a dichotomized mediator variable representing Cognitive change stage (precontemplation, contemplation, preparation = 0) or Behavioral change stage (action, maintenance = 1). Mediation analysis showed PNC-txt participants in the Action/Maintenance stage at 1-month post baseline had 50% lower odds of the highest measured level of THC metabolite (300 ng/ml) test result and reported using cannabis 4 fewer days in the past 30 days compared to controls at 6 months. Results suggest that PNC-txt increased motivation to change resulting in participants advancing through the SoC, explaining decreases in cannabis use. Findings provide novel biological support for SoC as a modifiable clinical mechanism when treating CUD in young adults.