Prevalence and Treatment of Maternal Substance Use Disorder in Child Welfare.

Importance: Parental substance use is a primary driver of child welfare system involvement, and child welfare services primarily seek to address caregiver challenges, including connecting parents to treatment. Although research highlights that formal child welfare services connect children to health care professionals, less is known about how the system affects caregivers' substance use treatment. Objective: To examine the prevalence of maternal substance use disorder (SUD) in the Pennsylvania child welfare system and the association between formal child welfare system response and mothers' take-up of SUD treatment. Design, Setting, and Participants: This cohort study used linked Medicaid claims and child welfare system records for mothers enrolled in Medicaid and involved in the Pennsylvania child welfare system between 2015 and 2018, followed by 12 months postsystem contact. The study applied a difference-in-differences framework to estimate associations between child welfare system intervention and maternal SUD treatment utilization. Data were analyzed from January to September 2024. Exposure: Child welfare system intervention was defined in 3 categories: no formal services, in-home services, and foster care services. Main Outcomes and Measures: Maternal SUD was defined by International Classification of Diseases, Ninth Revision or Tenth Revision diagnosis codes. Dependent variables were mothers' monthly and cumulative use of inpatient and outpatient SUD treatment, defined by procedure and service location codes. Results: Among 46 484 mothers, the prevalence of maternal SUD was estimated at 62% within the child welfare system population, predominantly involving opioid and polysubstance use. Compared with mothers who did not receive a formal child welfare system response, those who received a formal intervention had a statistically significant higher probability of monthly outpatient (in-home services: 24%; 95% CI, 18%-28%; foster care: 63%; 95% CI, 55%-75%) and inpatient (in-home services: 36%; 95% CI, 23%-48%; foster care: 130%; 95% CI, 103%-156%) SUD treatment in the 12 months after referral. Conclusions and Relevance: This cohort study demonstrates that formal child welfare services can facilitate substance use treatment for caregivers. As states seek to reduce the role of formal child welfare system responses in responding to parental substance use, alternative strategies to engage and retain parents in treatment are needed.