Abstract
This study aimed to identify trajectories of substance use from adolescence to young adulthood among 166 females with dual child welfare and juvenile justice system involvement, and to explore the influence of adolescent child custody status and substance use treatment on substance use trajectories. Results identified four substance use trajectory groups (stable moderate substance use, decreasing substance use, increasing substance use, stable high substance use). Custody loss during adolescence predicted membership in the stable high substance use trajectory group (log odds estimate = 2.99, p = < 0.01). No significant associations were found with adolescent substance use treatment. The findings can inform policymakers, foster care professionals, and law enforcement officers to promote the delivery of timely and appropriate substance use services that respond to the unique needs of females across the child welfare and juvenile justice system populations.