Article open access publication

Occurrence of delayed-onset post-traumatic stress disorder: a systematic review and meta-analysis of prospective studies.

Scandinavian Journal of Work, Environment & Health, Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140

Volume 40, 3, 2014

DOI:10.5271/sjweh.3420, Dimensions: pub.1072738446, PMID: 24599261,



  1. (1) Bispebjerg Hospital, grid.411702.1, Capital Region






OBJECTIVE: Post-traumatic stress disorder (PTSD) develops according to consensus criteria within the first 1-6 months after a horrifying traumatic event, but it is alleged that PTSD may develop later. The objective was to review the evidence addressing occurrence of PTSD with onset >6 months after a traumatic event (delayed-onset PTSD). METHODS: Through a systematic search in PubMed, EMBASE, and PsycINFO, we identified 39 studies with prospective ascertainment of PTSD. A meta-analysis was performed in order to obtain a weighted estimate of the average proportion of delayed-onset PTSD cases, and meta-regression was used to examine effects of several characteristics RESULTS: Delayed-onset PTSD was reported in all studies except one, and the average prevalence across all follow-up time was 5.6% [95% confidence interval (95% CI) 4.3-7.3%]. The proportion with delayed-onset PTSD relative to all cases of PTSD was on average 24.5% (95% CI 19.5-30.3%) with large variation across studies. In six studies with sub-threshold symptom data, delayed-onset PTSD seemed most likely an aggravation of early symptoms. The proportion with delayed-onset PTSD was almost twice as high among veterans and other professional groups compared to non-professional victims. CONCLUSION: Descriptive follow-up data suggest that PTSD may manifest itself >6 months after a traumatic event, delayed-onset PTSD most often, if not always, is preceded by sub-threshold PTSD symptoms, and a higher proportion of PTSD cases are delayed among professional groups. Contextual factors and biased recall may inflate reporting of PTSD and a cautious interpretation of prevalence rates seems prudent.

Research Categories

Main Subject Area

Fields of Research

Links & Metrics

NORA University Profiles

University of Copenhagen

Dimensions Citation Indicators

Times Cited: 54

Field Citation Ratio (FCR): 14.19

Relative Citation ratio (RCR): 1.61

Open Access Info