Foster care, externalizing disorders, and antipsychotic use among Medicaid-enrolled youths.

Objectives: The authors investigated the extent to which clinical diagnoses of externalizing disorders explain higher rates of antipsychotic use by foster care youths.

Methods: Medicaid claims data from 44 states for 2009 for youths in foster care (N=301,894) and those not in foster care (N=5,092,574) were analyzed, excluding those with schizophrenia, bipolar disorder, autism, and major depressive disorder. Logistic regressions assessed the relationship between foster care, externalizing disorders, and antipsychotic use.

Results: Foster care youths had higher rates of externalizing disorders than the comparison group (attention-deficit hyperactivity disorder, 17.3% versus 6.5%; disruptive behavior disorder, 7.2% versus 2.5%; conduct disorder, 2.3% versus .5%) and greater antipsychotic use (7.4% versus 1.4%). Foster care remained a significant predictor of antipsychotic use after control for demographic and diagnostic covariates, including externalizing disorders (adjusted odds ratio=2.59, 95% confidence interval=2.54-2.63).

Conclusions: High rates of externalizing disorder diagnoses only partially explained elevated levels of antipsychotic use in this vulnerable population.