Remission from post-traumatic stress disorder in adults: a systematic review and meta-analysis of long term outcome studies.

Posttraumatic stress disorder (PTSD) is a frequent mental disorder associated with significant distress and high costs. We conducted the first systematic review and meta-analysis on spontaneous long-term remission rates, i. e., without specific treatment. Data sources were searches of databases, hand searches, and contact with authors. Remission estimates were obtained from observational prospective studies of PTSD without specific treatment. Remission was defined as the actual percentage of PTSD cases at baseline who are non-cases after a minimum of ten months. Forty-two studies with a total of 81,642 participants were included. The mean observation period was 40 months. Across all studies, an average of 44.0% of individuals with PTSD at baseline were non-cases at follow-up. Remission varied between 8 and 89%. In studies with the baseline within the first five months following trauma the remission rate was 51.7% as compared to 36.9% in studies with the baseline later than five months following trauma. Publications on PTSD related to natural disaster reported the highest mean of remission rate (60.0%), whereas those on PTSD related to physical disease reported the lowest mean of remission rate from PTSD (31.4%). When publications on natural disaster were used as a reference group, the only type of traumatic events to differ from natural disaster was physical disease. No other measured predictors were associated with remission from PTSD. Long-term remission from PTSD without specific treatment varies widely and is higher in studies with the baseline within five months following trauma.