Background The Community Mental Health Initiative (CMHI) is mandated to assist offenders with serious mental disorders in their transition from institutions to the community, but this incorporates different styles of service. An important unanswered question is whether these are equivalent. Aims/hypotheses Our aim was to compare outcomes for different intervention styles within the CMHI, a programme for serious offenders in prison who also have at least one major mental disorder. Our specific research questions were as follows: do outcomes differ according to whether offenders with mental health difficulties receive (1) clinical discharge planning only; (2) community mental health services only; (3) the combined services or (4) none, although meeting criteria for any CMHI service? Methods Survival analyses, controlling for variables with a significant effect on recidivism or return to prison, were used to test for differences in recidivism or return to prison rates between the intervention and no‐intervention groups during a fixed follow‐up period. Results Men receiving only community mental health services had a significantly lower risk of returning to custody and of recidivism than men receiving discharge planning alone or no community mental health service at all, even after controlling for potential confounders including age, number of previous imprisonments and number of previous community failures. The advantages were apparent within 3–6 months and sustained for up to 4 years. Conclusions/implications for practice Provision of specialised community mental health services for higher‐risk male offenders with a mental disorder may reduce recidivism in the short and longer term – within 3 months and up to 4 years respectively. Statistical modelling also pointed to the need to include treatment for substance abuse and assistance in identifying stable accommodation and brokerage of community services among the interventions and services. Copyright © 2016 John Wiley & Sons, Ltd.