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

ABSTRACT

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.

Antecedentes: El impacto a largo plazo de los ataques violentos masivos es prácticamente desconocido, especialmente en niños y adolescentes. Recientemente hemos encontrado que 8,5 años después de un ataque terrorista dirigido principalmente a adolescentes, casi la mitad de los sobrevivientes cumplían criterios diagnósticos de insomnio.

Objetivos: El objetivo de este estudio fue investigar: (1) si la exposición a un único evento de violencia masiva durante la adolescencia aumenta el riesgo de insomnio casi una década después por encima de lo esperado para una población no expuesta y (2) si la exposición previa a la violencia interpersonal y las reacciones postraumáticas tempranas predicen el insomnio posterior.

Método: Los participantes fueron supervivientes del ataque terrorista de la isla de Utøya de 2011 (n = 279), y controles del estudio de población general noruego HUNT (n = 35.664). El insomnio en la edad adulta temprana se evaluó utilizando 4 ítems del Cuestionario Karolinska del Sueño 8,5 años después del ataque. Los participantes que también habían completado oleadas anteriores de recogida de datos para ambos estudios (n = 116 y 2.382 respectivamente) se incluyeron en modelos de regresión logística que probaban las asociaciones entre los predictores durante la adolescencia y el insomnio posterior.

Resultados: Casi 10 años después del atentado de Utøya, el 38,4% (n = 56) de los sobrevivientes declararon síntomas de insomnio indicativos de insomnio probable, en comparación con el 20,5% (n = 5771) de los controles. La exposición al terror durante la adolescencia fue un predictor significativo de insomnio posterior (OR = 3,18, CI = 2,05–4,87, p < ,001). Los síntomas postraumáticos tempranos de ansiedad y depresión (OR = 1,34; IC = 1,02–1,76; p = ,033) y las cefaleas semanales (OR = 1,64; IC = 1,08–2,47; p = ,018) también fueron predictores significativos al controlar los factores de fondo y otros predictores.

Conclusiones: La evaluación y el tratamiento a largo plazo son necesarios para los sobrevivientes de violencia masiva para mejorar la resiliencia y la recuperación.

KEYWORDS:

• Sleep disturbance
• trauma
• young people
• longitudinal
• mass shooting

PALABRAS CLAVE:

• Alteración del sueño
• trauma
• jóvenes
• longitudinal
• tiroteo masivo

Acknowledgements

We wish to thank all the participants for taking part in the study. We also thank Ingebjørg Lingaas, Andrea Undset, and Hilde Michelsen for their coordination of the Utøya study at T4.

Disclosure statement

No potential conflict of interest was reported by the authors.

Authors’ contributions

K. P. formulated the research questions, created the analytical plan, analysed the data, and drafted the article. G. D. and S. S. designed the Utøya study and collected data for all four time-points. G. D. , T. W.-L., and S. S. contributed to formulating the research questions and analytical plan for this paper and editing the article. T. W.-L. additionally contributed to the data analysis. All authors approved the final version of the manuscript.

Data availability statement

The data that support the findings of this study can be made available upon reasonable request to the corresponding author (Kate Porcheret). The data are not publicly available as they contain information that could compromise the privacy of the research participants.

Additional information

Funding

This work was supported by the Norwegian Centre for Violence and Traumatic Stress Studies, the Norwegian Directorate of Health and Kate Porcheret was supported by the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 801133.].