(Series: critical commentaries on depression trials. Prior posts: 1, 2, 3, 4)
Antidepressants only marginally outperform placebos (Khan & Brown, 2015) – which has led to a number of novel strategies to try to improve treatment for patients suffering from depressive disorders. Adjunctive Nutraceuticals present one such strategy: providing patients with specific forms of dietary supplements in addition to antidepressants (Wikipedia: Nutraceuticals). This is in line with general dietary supplements: the industry has grown considerably in the last decades, and more than half of the US adult population consume dietary supplements regularly (Wikipedia: Dietary Supplements). Interestingly, meta-analyses have repeatedly failed to find any evidence for positive effects of dietary supplements such as Vitamin C on numerous health outcomes – ranging from the common cold to cancer – in general population samples (Hemilä & Chalker, 2013; Lee, Oh & Myung, 2015).
In a new paper entitled “Adjunctive Nutraceuticals for Depression: A Systematic Review and Meta-Analyses”, Sarris et al. investigated whether adjunctive nutraceuticals provide significant benefits to patients with Major Depression. They reviewed 40 studies in total: 9 studies on folic acid, folinic acid, methylfolate, or a combination of folic acid and vitamins B6 and B12; 8 on tryptophan (or 5-HTP) and omega-3; 4 on S-adenosylmethionine; 2 on zinc, inositol, vitamin C, and vitamin D; and 1 for creatine, B12, and an amino acid combination. The mean sample size per study was small (n=63), and only 31 of the 40 studies were randomized placebo-controlled trials.