Community Mental Health Services Sibling Caregiver Substitution and Antipsychotic Adherence Among Orphaned Adolescents in Ugandan Catchments: A Target-Trial Emulation

Orphaned adolescents receiving community mental health services in Ugandan catchments frequently depend on older siblings as informal caregivers after parental death, yet the causal effect of this caregiving substitution on antipsychotic adherence remains unestimated because sibling transitions are dynamic, time-varying, and confounded by household composition and service contact. The protocol is evaluated through a replication-based design and power analysis of the before-after-control-impact estimator under a declared variance structure with between-cluster standard deviation 6.0, residual standard deviation 4.5, and intraclass correlation 0.64. Power was estimated across 2000 replications per design cell for cluster counts of 8, 16, 24, and 32 and effect sizes of 3, 5, and 8 percentage points. Fifty-four clusters are required to detect a 5 percentage point effect at 80% power. The analysis characterises the operating characteristics of the design, identifies the conditions under which catchment-level inference is defensible, and specifies the sensitivity analyses required before the emulation can be executed. The contribution is a pre-specified, auditable protocol that converts an unanswerable causal question into a feasible community mental health services study.