Omega-3/6 supplementation for mild to moderate inattentive ADHD: a randomised, double-blind, placebo-controlled efficacy study in Italian children

Recently there has been a growing interest in non-pharmacological treatments for ADHD. We evaluated the efficacy of a specific Omega-3/6 dietary supplement (two capsules containing 279 mg eicosapentaenoic acid [EPA], 87 mg Docosahexaenoic Acid [DHA], 30 mg gamma linolenic acid [GLA] each) in ameliorating inattentive symptoms in inattentive-ADHD children (6–12 years) with a baseline ADHD-RS-Inattention score ≥ 12. Secondary objectives included changes in global functioning, severity of illness, depression, and anxiety symptoms, learning disorders and in the fatty acids blood levels. The study was a randomised, double-blind, placebo-controlled efficacy and safety trial with a 6-month double-blind evaluation of Omega-3/6 vs placebo (Phase-I) and a further 6-month-open-label treatment with Omega-3/6 on all patients (Phase-II). In total 160 subjects were enrolled. No superiority of Omega-3/6 supplement to placebo was observed on the primary outcome (ADHD-RS-inattention score) after the first 6-months, with 46.3% of responders in the Omega-3/6 group and 45.6% in the placebo group; a slight (not statistically significant) reduction in Omega-6/3 ratio blood levels was measured in the active treatment group. Twelve months after enrolment, percentages of responders were similar between groups. A mild statistical, although not clinically significant, improvement was observed on the ADHD-RS-total score in the Omega-3/6 group but not on the ADHD-RS-Inattention score; a slight (not-statistically significant) reduction in Omega-6/3 ratio was observed in the group taking active treatment only during Phase II. In conclusion, no clinical beneficial effects of Omega-3/6 were detected on inattentive symptoms, suggesting a limited role of Omega-3/6 dietary products in children with mild ADHD-I. Trial registration : At the time of the Ethical submission, according to the clinical trial Italian law, registration was not mandatory for food additive as Omega 3/6 were then classified. The trial was approved by the Ethical Committee of the Cagliari University Hospital (resolution n. 662; September 22nd, 2011).