Methods: A total of 106 (Pittsburgh: n = 54; Boston: n = 52) early course schizophrenia outpatients were randomized to either 18 months of CET (n = 61) or an Enriched Supportive Therapy (EST; n = 45) comparison intervention. Participants completed functioning measures and MRI scans at baseline, 9, and 18 months. MRI data were prepared for analysis using the longitudinal normalization preprocessing pipeline in the Computational Anatomy Toolbox (CAT12). Intent-to-treat linear and quadratic mixed-effects models were used to investigate differential change trajectories in functional outcome and gray matter volume between CET and EST. Mediation models examined the indirect effect of CET-related gray matter volume changes on the relationship between treatment assignment and functional outcome changes.
Results: Results indicated that CET had a significant beneficial impact on functional performance (B = 2.78, p = 0.027, d = 1.11) and social functioning (B = 3.25, p = 0.047, d =1.30) relative to EST. A significant neuroprotective effect of CET was observed on an accelerated rate (i.e., quadratic effect) of increasing left posterior cingulate cortex (PCC) gray matter volume, relative to an accelerated decline in EST (B = 0.07, p = 0.051, d = 0.47). A significant longitudinal relationship was observed between accelerated left PCC gray matter volume increases and accelerated improvements in social functioning (B = 4.58, p = 0.012), along with functional performance (B = 3.56, p = 0.068). Differential effects between CET and EST on social functioning were partially mediated by CET-related accelerated increases in left PCC gray matter volume (z' = 1.56, p = 0.043).
Conclusions and Implications: These results establish a new understanding of how brain changes during CET, a social work-developed intervention, contribute to meaningful changes in functioning in individuals with early course schizophrenia. CET had a large social functioning effect, which occurred, in part, through a CET-related accelerated rate of gain in left PCC gray matter volume. Such neuroprotective effects of CET on gray matter volume continue to underscore the impact of this treatment on reducing disability when provided in the early course of schizophrenia. Overall, this research reflects the progression and utility of social work research rooted in the person-in-environment perspective by connecting the brain to community outcomes.