Review

Scand J Work Environ Health 2014;40(3):215-229    pdf full text

doi:10.5271/sjweh.3420

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

by Utzon-Frank N, Breinegaard N, Bertelsen M, Borritz M, Eller NH, Nordentoft M, Olesen K, Rod NH, Rugulies R, Bonde JP

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.

This article refers to the following texts of the Journal: 2013;39(4):325-334  2012;38(3):282-290