Emulsified omega-3 fatty-acids modulate the symptoms of depressive disorder in children and adolescents: a pilot study

BACKGROUND: The prevalence of mood disorders in children is a growing global concern. Omega-3 fatty acids (FA) are emerging as a promising adjuvant therapy for depressive disorder (DD) in paediatric patients. The primary objective of this pilot, single-centre, randomized, double-blind controlled study was to compare the efficacy of an Omega-3 FA fish oil emulsion with a control oil emulsion alongside standard treatment for depressive symptoms in children and adolescents suffering from depressive disorder (DD) and mixed anxiety depressive disorder (MADD). METHODS: 38 children (12 patients were treated and diagnosed for at least 1 month before enrolment, 26 patients were first-time diagnosed as DD) aged 11–17 years were randomised 1:1 to the intervention (Omega-3 FA, 19 patients) or active comparator (Omega-6 FA, 19 patients) groups. Children’s depression inventory (CDI) ratings were performed at baseline, every 2 weeks for a 12-week intervention period and at 4-week post-intervention. 35 patients (17 in Omega-3 and 18 in Omega-6 groups) who completed the whole intervention period were evaluated. Patients from Omega-3 group were stratified according to diagnosis into two subgroups (DD—10/17 and mixed anxiety depressive disorder (MADD)—7/17 patients) and in the Omega-6 group into DD—10/18 and MADD—8/18 patients. Groups were evaluated separately. Differences between-groups were tested with the Student´s t test or non-parametric Mann–Whitney U test. Two-way ANOVA with repeated measures and Friedman test were used to analyse the Treatment effect for response in CDI score. p < 0.05 was considered significant in all statistical analyses. RESULTS: Significant reductions in CDI scores in 35 analysed patients who completed 12 weeks intervention were observed after 12 weeks of intervention only in the Omega-3 group (p = 0.034). After stratification to depressive disorder and mixed anxiety depressive disorder subgroups, the DD subgroup receiving the Omega-3 FA fish oil showed statistically greater improvement (score reduction after 8 week treatment of −9.1 CDI, p = 0.0001) when compared to the MADD subgroup (score reduction after 8 week treatment −4.24 CDI, p = 0.271). CONCLUSIONS: CDI scores were reduced in the Omega-3 group and the depression subgroup had greater improvement than the mixed depressive/anxiety group. An Omega-3 fatty acid rich fish oil emulsion may be an effective adjuvant supplement during the treatment of depressive disorders in children. Trial registration ISRCTN81655012 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13034-017-0167-2) contains supplementary material, which is available to authorized users.