Adverse Childhood Experiences and One-year Outcomes of Child and Adolescent Psychiatric Inpatient Treatment in Japan.

Adverse childhood experiences (ACEs) are highly prevalent among youth requiring psychiatric hospitalization and are associated with complex clinical presentations. However, evidence regarding how cumulative ACE burden influences inpatient treatment processes and post-discharge outcomes remains limited, particularly in non-Western settings. This retrospective cohort study included 76 consecutive children and adolescents discharged from a psychiatric inpatient unit in Japan. ACE exposure was retrospectively assessed at discharge using clinician-integrated multidisciplinary evaluations based on the original 10-item ACE framework. Global functioning was measured using the Children's Global Assessment Scale (CGAS) at admission, discharge, and at 6 and 12 months post-discharge. Multivariable regression and linear mixed-effects models were used to examine associations between ACE burden and length of stay, use of seclusion and physical restraint, longitudinal CGAS trajectories, treatment discontinuation, and re-hospitalization, after adjusting for sex, neurodevelopmental disorder status, and age at admission. Higher ACE scores were independently associated with longer hospital stays and greater odds of seclusion and physical restraint use. CGAS scores improved substantially from admission to discharge and remained above baseline at 6 and 12 months. In the primary analysis, ACE burden was not significantly associated with longitudinal CGAS scores. ACE burden was also not significantly associated with treatment discontinuation or re-hospitalization within 12 months. Cumulative ACE burden is associated with greater inpatient clinical complexity but was not significantly related to short-term functional trajectories or post-discharge outcomes in this study. These findings highlight the importance of trauma-informed inpatient care and continued post-discharge support for youth exposed to adversity.