Hawkey E, Nigg JT. (2014) Clin Psychol Rev 34(6): 496-505. Epub 2014 Jun 2.
Interest in the value of omega-3 (n-3) fatty acid supplementation for treatment of ADHD remains high. No prior meta-analysis has examined whether ADHD is associated with alterations in blood lipid levels and meta-analyses of supplementation have reached conflicting conclusions.
We report two new meta-analyses. Study 1 examined blood levels of omega-3 fatty acids in relation to ADHD. Study 2 examined a larger sample of randomized intervention trials than previously reported.
Study 1 included 9 studies (n=586) and found lower overall blood levels of n-3 in individuals with ADHD versus controls (g=0.42, 95% CI=0.26-0.59; p<.001). Study 2 included 16 studies (n=1408) and found that n-3 supplementation improved ADHD composite symptoms; using the best available rating and reporter (g=0.26, 95% CI=0.15-0.37; p<.001). Supplementation showed reliable effects on hyperactivity by parent and teacher report, but reliable effects for inattention only by parent report.
Omega-3 levels are reduced in children with ADHD. Dietary supplementation appears to create modest improvements in symptoms. There is sufficient evidence to consider omega-3 fatty acids as a possible supplement to established therapies. However it remains unclear whether such intervention should be confined to children with below normal blood levels.