Intergenerational Trauma Transmission and Child Mental Health in Post-Genocide Rwanda: A Discordant-Sibling Design Estimating Caregiver Mental Health Mediation

The intergenerational transmission of trauma is widely invoked to explain elevated child mental health difficulties in post-genocide Rwanda, yet the mediating role of caregiver mental health remains poorly identified because household-level confounding and shared sibling environment inflate naive associations. Using a variance structure with between-cluster SD = 6.0, residual SD = 4.5, and intraclass correlation = 0.64, power was estimated across 2000 design cells for cluster counts of 8, 16, 24 and 32 and effect sizes of 3, 5 and 8 percentage points. The analysis indicates that 56 clusters are required to detect a 5 percentage point effect at 80% power. The design clarifies the conditions under which caregiver mental health can be distinguished from shared sibling environment as a transmission mechanism, and identifies the cluster counts at which discordant-sibling designs become informative for post-genocide child mental health research.