The active ingredients in a treatment for justice-involved persons with mental illness: The importance of addressing mental illness and criminal risk.

[Correction Notice: An Erratum for this article was reported online in Psychological Services on Oct 8 2020 (see record 2020-75253-001). In the article, the authors listed the wrong version of a measure in the Method section of Study 2. The article should have listed PICTS-Layperson-Short Form (PICTS-L-SF) instead of the PICTS-Short Form (PICTS-SF) as the measure used. The correct citation for the measure appears in the erratum.] Corrections research literature is replete with treatment and intervention outcome studies but lacking empirical examinations of the process of change in justice-involved populations. The current studies expand upon previous outcome evaluations of Changing Lives and Changing Outcomes (CLCO), a treatment program for justice-involved persons with mental illness, by using process research designs to examine therapeutic mechanisms of change. Study 1 used CLCO participants' (n = 264) pre and post module quizzes to examine differences in content retention between Mental Illness, Criminalness, and Both mental illness and criminalness domains to determine if participants differentially learn treatment content. In Study 2, 1 CLCO module was administered to 9 groups of adult men on probation in a residential treatment facility (n = 4 to 8 per group) in 3 iterations: (a) Mental Illness-only content (n = 16), (b) Criminalness-only content (n = 20), (c) Full module (mental illness and criminalness content; n = 22). Results for both studies indicated significant treatment gains across outcome measures of interest (namely content retention and symptomology). Contrary to expectations in Study 1, effect sizes of Mental Illness and Criminalness content retention were similar, suggesting there are not differential effects in the magnitude of content retained between the 2 domains. In Study 2, the integration of mental illness and criminalness content produced greater global improvement than focusing on mental illness or criminalness alone. These results underscore the necessity and effectiveness of integrating mental illness and criminalness in the treatment of justice-involved persons with mental illness. (PsycInfo Database Record (c) 2021 APA, all rights reserved).