Prevalence of psychiatric disorders in foster care adolescent populations.

BACKGROUND: Children in foster care and institutional settings experience disproportionately high rates of mental health disorders, yet large-scale data on psychiatric comorbidities in this population remain limited.

OBJECTIVE: To examine the prevalence and patterns of psychiatric diagnoses within one year of placement in foster care or institutional care, with attention to demographic disparities and comorbidity burden.

METHODS: This retrospective cohort study used de-identified electronic health record data from the TriNetX network, identifying U.S. children placed in foster or institutional care between 2003 and 2023 via ICD-10-CM codes. The final sample included 95,764 children after exclusions. Demographic characteristics and psychiatric diagnoses were analyzed descriptively, and comorbidity patterns were assessed by co-occurrence of two or more disorders.

RESULTS: The mean age at placement was 6.62 years; 47,911 (50.02%) were male, 46,484 (48.57%) female, and 1369 (1.41%) of unknown gender. Black or African American children comprised 28,876 (30.16%) of the cohort, exceeding their proportion in the general U.S. child population. Within one year of placement, 53,627 (56%) had at least one psychiatric diagnosis, and 28,729 (30%) had two or more. Behavioral and emotional disorders were most prevalent (31,602; 33%), with attention-deficit/hyperactivity disorder affecting 20,110 (21%) and conduct disorder 7661 (8%). Anxiety disorders occurred in 23,941 (25%), including post-traumatic stress disorder in 11,492 (12%) and generalized anxiety disorder in 5746 (6%). Mood disorders affected 14,365 (15%), developmental disorders 13,407 (14%), and substance use disorders 5746 (6%), primarily nicotine dependence (2873; 3%) and cannabis use disorder (1915; 2%). Common co-occurrences included ADHD with anxiety disorders in 11,492 (12%) and PTSD with mood disorders in 7661 (8%).

CONCLUSIONS: Psychiatric morbidity is common and complex among children entering foster or institutional care, underscoring the need for early, trauma-informed, and culturally responsive mental health interventions. High co-occurrences rates and persistent racial disparities highlight the urgency of coordinated, equity-focused approaches to assessment and treatment in child welfare systems.