Underreporting in the military: perceived sensitivity of trauma-related and comorbid disorders among soldiers and civilian employees of the Austrian Armed Forces

<b>Background:</b> Underreporting is a potential source of bias. In the context of the military, the underreporting of mental health symptoms may be linked to inconsistent performance of mental health measures and heterogenous prevalence estimates. However, few studies systematically investigated the potential underreporting of mental health symptoms among military personnel.<b>Objective:</b> The present study systematically examined indications of underreporting symptoms of trauma-related and comorbid mental health disorders among three comparative samples of the Austrian Armed Forces.<b>Methods:</b> In a cross-sectional survey, 576 active duty soldiers, 764 conscripts, and 164 civilian employees rated the perceived sensitivity of items of the International Trauma Questionnaire (ITQ), several other commonly used self-report mental health measures, and the Effort-Reward Imbalance Questionnaire/short version as a control measure. Applying multilevel modelling, we tested whether mental health measures/ITQ symptom clusters would be perceived as more sensitive than the control measure across the three samples and investigated associations of demographic variables, trust in data protection and item order with sensitivity ratings.<b>Results:</b> All mental health measures, particularly items on alcohol use disorder and the negative self-concept symptom cluster of complex posttraumatic stress disorder (CPTSD), distrust in data protection and item order predicted perceived sensitivity. Active duty soldiers gave similar ratings as civilian employees while recruits rated the sensitivity of mental health measures lower than civilian employees in relation to the control measure.<b>Conclusions:</b> Although it remains unclear whether this is a specific characteristic of military populations, we conclude that military personnel may underreport mental health disorders, particularly symptoms of alcohol use disorder and CPTSD. In order to avoid biased results, strategies to reduce underreporting may be of particular importance in the field of military mental health. Further research is needed on predictors and effects of sensitivity perceptions as well as corresponding differences between civilian and military populations.<b>Trial registration:</b> German Clinical Trials Register identifier: DRKS00026627.