OBJECTIVE: To investigate associations between minimally adequate treatment and clinical outcomes among youth with bipolar disorder. METHODS: This study utilized a retrospective cohort of publicly-insured (Medicaid) youth aged 10-18 years with a new bipolar disorder episode between 2009 and 2013 from 15 geographically diverse states. Four minimally adequate treatment measures were evaluated during a 180-day treatment period: 1) Minimally Adequate Pharmacotherapy: medication (mood stabilizer and/or atypical antipsychotic) possession ratio ≥80%
2) Minimally Adequate Psychotherapy: ≥8 psychotherapy visits
3) Minimally Adequate Pharmacotherapy and Psychotherapy, and 4) Recommended Pharmacotherapy with No Antidepressant Monotherapy: no antidepressant prescription without a mood stabilizer and/or atypical antipsychotic. Cox proportional hazards models examined associations between minimally adequate care and time to four clinical outcomes: bipolar disorder-related psychiatric hospitalization or emergency room (ER) visits, deliberate self-harm, and all-cause mortality. We estimated average treatment effects (ATE) using propensity score weighting with stabilized ATE weights to control for confounding. RESULTS: Hazard of hospitalization was increased among youth receiving minimally adequate psychotherapy (HR = 1.23 [95% CI: 1.04-1.44]) and both minimally adequate pharmacotherapy and psychotherapy (HR = 1.48 [95% CI: 1.12-1.96]) and decreased among youth receiving no antidepressant monotherapy (HR = 0.74 [95% CI: 0.62-0.88]). Hazard of ER visits was increased among youth receiving minimally adequate pharmacotherapy (HR = 1.38 [95% CI: 1.14-1.68]), minimally adequate psychotherapy (HR = 1.35 [95% CI: 1.13-1.61]), and both minimally adequate pharmacotherapy and psychotherapy (HR = 1.66 [95% CI: 1.24-2.24]). CONCLUSIONS: Further research is needed to understand why receipt of minimally adequate care is positively associated with increased mental healthcare utilization among youth with new bipolar disorder episodes.