BACKGROUND: Eicosapentaenoic acid (EPA) is suggested to be protective against posttraumatic stress disorder (PTSD) from two observational studies. We previously conducted a randomized controlled trial and found no effect of docosahexaenoic acid (DHA) for prevention of PTSD. This secondary analysis aimed to determine whether change in blood levels of EPA is associated with PTSD symptoms.

METHODS: The percentages of EPA, DHA, and arachidonic acid (AA) were measured in erythrocyte membranes at baseline and posttreatment in 110 participants with severe physical injury who were randomly assigned to receive either a daily dose of 1,470mg DHA and 147mg EPA or of placebo for 12 weeks. Associations between change in erythrocyte fatty acid levels during the trial controlling for each baseline level and PTSD severity at 12 weeks were analyzed by treatment arm.

RESULTS: In the omega3 supplements arm, changes in EPA+DHA (p=.023) and EPA (p=.001) as well as the EPA:AA ratio (p=.000) and EPA: DHA ratio (p=.013) were inversely correlated with PTSD severity. Change in AA was positively correlated with PTSD severity (p=.001).

LIMITATION: This trial was conducted at a single-center in Japan and PTSD symptoms in most participants were not serious.

CONCLUSIONS: Increased erythrocyte level of EPA during the trial was associated with low severity of PTSD symptoms in patients receiving omega3 supplements.