Omega-3 polyunsaturated fatty acids, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are an attractive therapeutic option for health problems. Genetic and environmental factors influence serum levels of EPA and DHA. Also, omega-3 fatty acids are known to be essential for the growth and the development of the human brain. It is also well known that diet and nutrition influence depression. Several randomized controlled trials have reported the beneficial effects of omega-3 fatty acids in depressive disorders. Meta-analyses have indicated some advantages of omega-3 fatty acids in depressive disorders, suggesting that omega-3 fatty acids might have an influence on the pathophysiology of depression. It is possible that the intake of higher levels these acids might result in a lower prevalence of depression.