The quantity and strength of evidence for effects of omega-3 fatty acids on the neurological conditions assessed vary greatly. Due to the small number of studies that met our inclusion criteria, further research is necessary before substantive conclusions can be drawn. The paucity of evidence in this area suggests that a great deal of epidemiological and clinical research remains to be done before any conclusions can be drawn or policy recommendations can be made regarding the health effects of omega-3 fatty acids on normal cognitive function with aging, dementia, and neurological diseases.