Prevalence and correlates of mental health problems in Canadian Forces personnel who deployed in support of the mission in Afghanistan: findings from postdeployment screenings, 2009-2012.

OBJECTIVE: An important minority of military personnel will experience mental health problems after overseas deployments. Our study sought to describe the prevalence and correlates of postdeployment mental health problems in Canadian Forces personnel.
METHOD: Subjects were 16 193 personnel who completed postdeployment screening after return from deployment in support of the mission in Afghanistan. Screening involved a detailed questionnaire and a 40-minute, semi-structured interview with a mental health clinician. Mental health problems were assessed using the Patient Health Questionnaire and the Posttraumatic Stress Disorder Checklist-Civilian Version. Logistic regression was used to explore independent risk factors for 1 or more of 6 postdeployment mental health problems.
RESULTS: Symptoms of 1 or more of 6 mental health problems were seen in 10.2% of people screened; the most prevalent symptoms were those of major depressive disorder (3.2%), minor depression (3.3%), and posttraumatic stress disorder (2.8%). The strongest risk factors for postdeployment mental health problems were past mental health care (adjusted odds ratio [AOR] 2.89) and heavy combat exposure (AOR 2.57 for third tertile, compared with first tertile). These risk groups might be targeted in prevention and control efforts. In contrast to findings from elsewhere, Reservist status, deployment duration, and number of previous deployments had no relation with mental health problems.
CONCLUSIONS: An important minority of personnel will disclose symptoms of mental health problems during postdeployment screening. Differences in risk factors seen in different nations highlight the need for caution in applying the results of research in one population to another.