BACKGROUND:War-affected youth often suffer from multiple co-occurring mental health problems. These youth often live in low-resource settings where it may be infeasible to provide mental health services that simultaneously address all of these co-occurring mental health issues. It is therefore important to identify the areas where targeted interventions would do the most good.METHODS:This analysis uses observational data from 3 waves of a longitudinal study on mental health in a sample of 529 war-affected youth (24.2% female; ages 10–17 at T1, 2002) in Sierra Leone. We regressed 4 mental health outcomes at T3 (2008) on internalizing (depression/anxiety) and externalizing (hostility/aggression) problems and prosocial attitudes/behaviors and community variables at T2 (2004) controlling for demographics, war exposures, and previous mental health scores at T1, allowing us to assess the relative impact of potential mental health intervention targets in shaping mental health outcomes over time.RESULTS:Controlling for baseline covariates at T1 and all other exposures/potential intervention targets at T2, we observed a significant association between internalizing problems at T2 and 3 of the 4 outcomes at T3: internalizing (β = 0.27, 95% confidence interval [CI]: 0.11–0.42), prosocial attitudes (β = –0.20, 95% CI: –0.33 to –0.07) and posttraumatic stress symptoms (β = 0.22, 95% CI: 0.02–0.43). No other potential intervention target had similar substantial effects.CONCLUSIONS:Reductions in internalizing may have multiple benefits for other mental health outcomes at a later point in time, even after controlling for confounding variables.