The course of PTSD in naturalistic long-term studies: High variability of outcomes. A systematic review

BACKGROUND: With a lifetime prevalence of 8% posttraumatic stress disorder (PTSD) is one of the most common mental disorders; nevertheless, its longitudinal course is largely unknown. AIMS: Our aim was to conduct a systematic review summarizing available findings on the prospective, naturalistic long-term course of PTSD and its predictors. METHODS: Databases MEDLINE and PsycINFO were searched. Main selection criteria were: 1) naturalistic cohort study with a follow-up period of at least 3 years, 2) adult participants with observer-rated or probable PTSD at baseline. RESULTS: Twenty-four cohorts (25 studies) were retrieved (14 with observer-assessed, 10 with probable PTSD). In total, they comprised about 10,500 participants with PTSD at baseline that were included in the long-term follow-ups. Studies investigating patient populations with observer-assessed PTSD found that between 18% and 50% of patients experienced a stable recovery within 3-7 years; the remaining subjects either facing a recurrent or a more chronic course. Outcomes of community studies and studies investigating probable PTSD varied considerably (remission rates 6-92%). Social factors (e.g. support) as well as comorbid physical or mental health problems seem to be salient predictors of PTSD long-term course and special focus should be laid on these factors in clinical settings. CONCLUSIONS: Included studies differed notably with regard to applied methodologies. The resulting large variability of findings is discussed. More standardized systematic follow-up research and more uniformed criteria for remission and chronicity are needed to gain a better insight into the long-term course of PTSD.