Course and Predictors of Posttraumatic Stress Disorder in the Canadian Armed Forces: A Nationally Representative, 16-Year Follow-up Study: Cours et prédicteurs du trouble de stress post-traumatique dans les Forces armées canadiennes: une étude de suivi de 16 ans nationalement représentative.

Objective: This study examined baseline risk and protective predictors and interim correlates of the persistence/recurrence, remission, and onset of posttraumatic stress disorder (PTSD) in a 16-year prospective, nationally representative sample of Canadian Forces members and veterans.

Methods: The 2018 Canadian Armed Forces Members and Veterans Mental Health Follow-up Survey is a prospective study of 2,941 regular force service members and veterans who participated in the 2002 Canadian Community Health Survey on Mental Health and Wellbeing: Canadian Forces Supplement ( = 5,155; ages 15 to 64 years; response rate 68%). PTSD diagnoses in 2002 and 2018 were used to create 4 groups: (1) , (2) , (3) , and (4) PTSD. Multinomial regressions were conducted to identify predictors of PTSD courses.

Results: Female sex, being a junior noncommissioned member (vs. officer), and land (vs. air) operations in 2002 were associated with all PTSD courses relative to no lifetime PTSD (relative risk ratio [RRR] range: 1.28 to 3.65). After adjusting for sociodemographic variables, baseline predictors of all PTSD courses included lifetime mental disorder, history of mental health care utilization, all trauma type categories (deployment-associated, sexual, "other"), and the number of lifetime traumatic events (RRR range: 1.14 to 8.95). New ("since 2002") traumas, transitioning to veteran status, and alcohol dependence were mostly associated with the new onset and persistent/recurrent PTSD courses (RRR range: 1.79 to 4.31), while mental health care utilization and greater avoidance coping were associated with all PTSD courses (RRR range: 1.10 to 17.87). Protective factors for several PTSD courses at one or both time points included social support, social network size, and problem-focused coping (RRR range: 0.71 to 0.98).

Conclusions: This is the first population-based survey to examine the longitudinal course of PTSD in Canadian Forces members. Prevention and intervention programs focused on bolstering social support and active coping strategies as possible protective factors/correlates may help mitigate the development and persistence of PTSD.