INTRODUCTION: Prison-based drug and alcohol group treatment programs operate in all Australian jurisdictions. With more than two-thirds of people in prison having a history of substance use prior to incarceration, such programs are needed. There have been few published papers on the impact of attending group treatment programs in Australian prisons, and the research published to date has been predominately quantitative. We aim to report the experiences of males in prison who completed and those who did not complete a group-based drug and alcohol program, to gain insight into their strategies for reducing harm from drug and alcohol post-release.

METHODS: Qualitative thematic analysis of in-depth interviews with 12 males who completed or were about to complete and 10 males who discontinued a prison-based group drug and alcohol treatment program.

RESULTS: Program completers were more likely to have well-developed plans to reduce drug and alcohol harms and maintain abstinence upon return to the community, which included creating healthier social networks. They also showed stronger insights into the factors that led to offending. Those who did not complete the drug and alcohol program appeared to rely on self-will as the main way to reduce drug and alcohol harms, with less awareness of options for support services to reduce or stop drug and alcohol use.

DISCUSSION AND CONCLUSIONS: Prison-based drug and alcohol program engagement imparted useful information for program completers. Controlled trials are needed to examine whether such differences equate to improved outcomes after release.