Background: Some questionnaire studies have shown increased mental health problems, including probable post-traumatic stress disorder (PTSD), in soldiers deployed to Iraq.
Aims: To test prospectively whether such problems change over time and whether questionnaires provide accurate estimates of deployment-related PTSD compared with a clinical interview.
Methods: Dutch infantry troops from three cohorts completed questionnaires before deployment to Iraq (n=479), and about 5 months (n=382, 80%) and 15 months (n=331, 69%) thereafter. Post-traumatic stress disorder was evaluated by questionnaire and clinical interview.
Results: There were no group changes for general distress symptoms. The rates of PTSD for each cohort were 21, 4 and 6% based on questionnaires at 5 months. The deployment-related rates of PTSD based on the clinical interview were 4, 3 and 3%.
Conclusions: There was a specific effect of deployment on mental health for a small minority. Questionnaires eliciting stress symptoms gave substantial overestimations of the rate of PTSD.