Yutaka Matsuoka and Daisuke Nishi
National Center of Neurology and Psychiatry, Japan
Combat experience, physical and sexual abuse, natural disaster, or serious accidents can cause posttraumatic stress disorder (PTSD) in some people. PTSD is associated with suicidal thoughts and behavior, problems at work, and adverse life consequences. Psychological intervention that includes a program of modified prolonged exposure has been shown to be effective for reducing PTSD symptoms. However, there is an urgent public health need to develop an intervention strategy, which is easy to use and disseminate, to prevent PTSD.
Recent studies on the role of polyunsaturated fatty acids in the development of PTSD suggest that nutritional intervention may be one way of controlling the severity of PTSD that may develop. A number of animal studies have suggested a link between PTSD and the clearance of fear memory from the hippocampus through the process of neurogenesis that is mediated by the intake of omega-3 polyunsaturated fatty acids1, and we reported the potential benefit of omega-3 polyunsaturated fatty acids in our previous small, open-label pilot trial published in 20102. In that study, we asked 15 consecutive patients who were admitted to the intensive care unit (ICU) of a Japanese general hospital immediately after accidental injury to take fish oil capsules for a period of 12 weeks. The capsules taken daily contained 1,470 mg of docosahexaenoic acid (DHA) and 147 mg of eicosapentaenoic acid (EPA) – equivalent to 140 g of grilled Pacific saury (Cololabis saira). The participants gave blood samples at the beginning and end of the study to confirm their use of the fish oil capsules. The average score of their PTSD symptoms was significantly lower than that seen in similar accident-injured patients who previously participated in a cohort study and did not take fish oil supplements. Among the 11 patients who completed our study, 2 who had low DHA erythrocyte levels before the study (at baseline) had developed PTSD or major depression by the end of the trial. This finding suggests that the baseline DHA erythrocyte level in daily life might be important, irrespective of whether omega-3 fatty acid supplementation is started after an accident or other traumatic event.
On March 11, 2011, the Great East Japan Earthquake left around 18,000 dead or missing. Previous studies have shown that rescue workers are at high risk for PTSD, but no appropriate preventive strategy for the disorder has been developed to date. We therefore conducted a 12-week, randomized, single-blind, parallel-group trial to determine whether fish oil supplementation could attenuate PTSD symptoms among medical rescue workers deployed during the acute disaster phase after the earthquake3. The rescue workers either took fish oil capsules (containing 1,568 mg DHA and 156.8 mg EPA) daily as well as attended psychoeducation or they just attended psychoeducation. When adjusted for age, sex, and PTSD symptoms at baseline, no significant differences in PTSD symptom score were seen between the two groups. However, the change in PTSD symptom score that occurred from baseline to 12 weeks after taking the capsules among women in the two groups was -3.9 (P=.04) after adjusting for the PTSD symptoms they had at baseline; men showed no negative score. This indicates that fish oil supplementation might be a safe strategy for preventing PTSD in women.
Our latest work produced a controversial finding4. To examine whether arachidonic acid (AA), EPA, and DHA are associated with risk for PTSD, we conducted a prospective nested case-control analysis among consecutive patients severely injured in motor vehicle accidents (MVAs) who were admitted to the ICU. After adjusting for confounding factors (i.e., age, sex, frequency of drinking alcohol, smoking status, and level of education), those patients with the highest levels of AA just after injury (at baseline) were less likely to develop PTSD compared with those with the lowest levels of AA; a similar result was found for EPA. Therefore, low levels of AA and EPA might be risk factors for PTSD.
The findings of these three studies suggest it would be beneficial to include nutritional intervention among the preventive measures for PTSD, with polyunsaturated fatty acids in particular showing potential for the prevention or early prediction of PTSD. Further study is needed to clarify fully the relationship between polyunsaturated fatty acids and risk for PTSD.
1. Matsuoka Y. Clearance of fear memory from the hippocampus through neurogenesis by omega-3 fatty acids: a novel preventive strategy for posttraumatic stress disorder? Biopsychosoc Med. 2011;5:3.
2. Matsuoka Y, Nishi D, Yonemoto N, Hamazaki K, Hashimoto K, Hamazaki T. Omega-3 fatty acids for secondary prevention of posttraumatic stress disorder after accidental injury: An open-label pilot study. J Clin Psychopharmacol. 2010 30(2):217-219.
3. Nishi D, Koido Y, Nakaya N, et al. Fish Oil for Attenuating Posttraumatic Stress Symptoms among Rescue Workers after the Great East Japan Earthquake: A Randomized Controlled Trial. Psychotherapy and Psychosomatics. 2012;81(5):315-317.
4. Matsuoka Y, Nishi D, Hamazaki K. Serum Levels of Polyunsaturated Fatty Acids and the Risk of Posttraumatic Stress Disorder. Psychotherapy and Psychosomatics. 2013;82(6):408-410.