Objective
War profoundly impacts people's lives, causing death, displacement and psychological trauma but limited research has investigated adolescents’ suicidality in this context. We compared suicidality or self-harm behavior among adolescents in regions that were, and were not, affected by Russia’s initial invasion of Ukraine in 2014.

Method
This cross-sectional study comprised 2,752 school students aged 11-17 years from war-affected Donetsk region and non-war Kirovograd region. Data collection occurred from 2016-17 using self-report tools to assess suicidality or self-harm behavior, psychopathology including post-traumatic stress disorder (PTSD), depression and anxiety, and war trauma exposure.

Results
Adolescent girls in war-affected region reported more suicide attempts (9.5% vs 5.1%, adjusted odds ratio [aOR] 1.8, 95% confidence interval [CI] 1.2-2.8), suicidal ideation (39.3% vs 19.6%, aOR 2.6, 95% CI 2.01-3.3) or self-harm behavior (19.6% vs 13.1%, aOR 1.6, 95% CI 1.2-2.1) and boys reported more suicidal ideation (17.0% vs 9.8%, aOR 1.7, 95% CI 1.2-2.4). Boys and girls with PTSD, depression or anxiety showed increased risks for any suicidality or self-harm. A dose-effect relationship was observed in the relationship between war trauma exposure and suicidality or self-harm. The association was strongest for those who had been exposed to 5 or more different war trauma exposures (aOR 3.2, 95% CI 2.2-4.8).

Conclusion
War trauma exposure and psychopathology were strongly associated with suicidality or self-harm behavior, with a greater impact in girls than boys. The high prevalence of suicidality found in this study emphasizes the need for intervention at large scale for adolescents living in war situations. Keywords: suicide attempts, suicidal ideation, self-harm, war, adolescents