Schizophrenia, co-occurring substance use disorders and quality of care: the differential effect of a managed behavioral health care carve-out.

This study explores the differential effect of a managed behavioral health Carve-Out (CO) on outpatient treatment quality for persons with schizophrenia (SCHZ) alone and co-occurring substance use disorders (SUD) (SCHZ+SUD). We used claims data from a state Medicaid program and employed a retrospective, quasi-experimental design with logit and difference in difference formula regression models. The results show the CO was associated with greater changes in treatment quality for the SCHZ population, compared to the SCHZ+SUD population. Most pronounced across both populations were decrements in receiving the psychosocial treatments for enrollees in the CO arrangement.