ObjectiveThis study was to evaluate the effect of an assertive community treatment (ACT) program on psychiatric symptoms, global functioning, life satisfaction, and recovery-promoting relationships among individuals with mental illness.MethodsThirty-two patients were part of the ACT program and 32 patients matched for age, sex, and mental illness were in a standard case-management program and served as a control group. Follow-up with patients occurred every 3 months during the 15 months after a baseline interview. Participants completed the Brief Psychiatric Rating Scale (BPRS), Global Assessment of Functioning (GAF) Scale, Life Satisfaction Scale, and Recovery-Promoting Relationship Scale (RPRS).ResultsAccording to the BPRS, the ACT group showed a significant reduction in symptom severity, but the ACT program was not significantly more effective at reducing psychiatric symptoms from baseline to the 15-month follow-up compared to the case-management approach. The ACT group showed more significant improvement than the control group in terms of the GAF Scale. Both groups showed no significant differences in the change of life satisfaction and in the change of recovery-promoting relationships. We observed a significant increase in recovery-promoting relationships in the control group, but the group × time interactions between groups were not statistically significant.ConclusionsIn this study, we observed that ACT was significantly better at improving the GAF than case management. However, ACT did not demonstrate an absolute superiority over the standard case-management approach in terms of the BPRS and the measures of life satisfaction and recovery-promoting relationships. ACT, however, may have some advantages over a standard-case management approach.Disclosure of interestThe authors have not supplied their declaration of competing interest.