Predictors of early adulthood insomnia following exposure to a single mass violence attack during adolescence : 7–13 year follow-up from the Utøya and HUNT studies

Background: The long-term impact of mass violence attacks is practically unknown, especially in children and adolescents. In a previous study, we found that 8.5 years after a terror attack targeting mainly adolescents, nearly half of the survivors met diagnostic criteria for insomnia.

Objectives: The aims of this study were to investigate: (1) whether exposure to a single mass violence event during adolescence increases the risk of insomnia almost a decade later above that expected for a non-exposed population; and (2) whether prior interpersonal violence exposure and early post-traumatic reactions predict later insomnia.

Method: Participants were survivors of the 2011 Utøya Island terrorist attack (n = 279) and controls from the HUNT Norwegian general population study (n = 35,664). Early adulthood insomnia was assessed using four items from the Karolinska Sleep Questionnaire 8.5 years after the attack. Participants who had also completed earlier data collection waves for both studies (n = 116 and 2382, respectively) were included in logistic regression models testing the associations between predictors during adolescence and later insomnia.

Results: Nearly a decade after the Utøya attack, 38.4% (n = 56) of the survivors reported symptoms of insomnia indicative of probable insomnia compared to 20.5% (n = 5771) of controls. Terror exposure during adolescence was a significant predictor of later insomnia [odds ratio (OR) = 3.18, 95% confidence interval (CI) = 2.05–4.87, p < .001]. Early post-trauma symptoms of anxiety and depression (OR = 1.34, 95% CI = 1.02–1.76, p = .033) and weekly headaches (OR = 1.64, 95% CI = 1.08–2.47, p = .018) were also significant predictors while controlling for background factors and other predictors.

Conclusion: Long-term assessment and treatment are needed for survivors of mass violence to improve resilience and recovery.

HIGHLIGHTS

• Nearly twice as many young adults exposed to a terror attack during adolescence report insomnia compared to a general population sample.
• Exposure to the attack and early post-trauma symptoms of anxiety, depression, and weekly headaches were significant predictors of insomnia around a decade later.
• Long-term assessment and treatment is needed for survivors of mass violence attacks.