Naturally absorbed polyunsaturated fatty acids, lithium, and suicide-related behaviors: A case-controlled study

Objective Previous studies have investigated the effects of omega-3, omega-6 and lithium on suicide-related behaviors separately. This study was performed to comprehensively investigate the effects of naturally absorbed EPA, DHA, arachidonic acid and lithium in relation to suicide attempt and deliberate self-harm, with adjustment for each other. Methods We analyzed plasma EPA, DHA, arachidonic acid levels and serum lithium levels of 197 patients including 33 patients with suicide attempts, 18 patients with deliberate self-harm, and 146 control patients. Results Multivariate logistic regression analysis with adjustment for age, gender, EPA, DHA, arachidonic acid and log-transformed lithium levels revealed that the negative associations with EPA levels (adjusted OR 0.972, 95% CI 0.947–0.997, p = 0.031) and log-transformed lithium levels (adjusted OR 0.156, 95% CI 0.038–0.644, p = 0.01) and the positive association with DHA levels (adjusted OR 1.026, 95% CI 1.010–1.043, p = 0.002) were significant in patients with suicide attempts than in control patients. The analysis also demonstrated that the positive association with arachidonic acid levels (adjusted OR 1.015, 95% CI 1.005–1.025, p = 0.004) was significant in patients with deliberate self-harm than in control patients. Limitations The limitations are relatively small number of patients and the effects of demographics of individual patients could not be adjusted for the analyses. Conclusions The present findings suggest that, as naturally absorbed nutrients, higher EPA and lithium levels may be associated with less suicide attempt, and that higher arachidonic acid levels may be associated with more deliberate self-harm.