Research on links between dietary omega-3 polyunsaturated fatty acids and depression continues to show promise. Numerous epidemiological, cross-sectional, and treatment studies support the association between depression and low omega-3 levels, either absolute concentrations or a higher ratio of omega-6 to omega-3 fatty acids. It is now time, conclude Parker et al. (p.
969), for more specific investigations. Two examples appear in this issue. Treatment of depressed children ages 8—12 was tested in a double-blind study by Nemets et al. (p.
1098). A 50% reduction in depressive symptoms occurred in seven of 10 children receiving omega-3 fatty acids but none of 10 receiving placebo. The difference in response became apparent at week 8. The omega-3 fatty acids were a combination of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) that is commonly available without a prescription. No side effects were reported. Sublette et al. (p.
1100) measured baseline fatty acids in depressed adults and tracked suicide attempts over 2 years. Suicide attempts were more likely among those with a
low baseline DHA level and a high ratio of omega-6 to omega-3 fatty acids. EPA and arachidonic acid were not related to outcome. Changes in serotonin and corticotropin levels are among the possible mechanisms for DHA's effect.