Data from epidemiological studies have suggested that low folate levels may increase the risk of depressive symptomatology in the general population leading to the hypothesis that folic acid supplements may influence mood.
However, in a randomized, double blind, parallel group, placebo-controlled trial with 112 young people with an increased familial risk of mood disorder, folic acid supplements at a dose of 2.5 milligrams per day did not significantly affect the incidence of mood disorder.
Data published in the Journal of Affective Disorders indicated that, “there was post-hoc evidence that folic acid delayed the time to onset of mood disorder in those participants who became unwell.
“In addition, the mood disorders in the folate treated participants, when they occurred, tended to be clinically milder.”
Scientists from Oxford University in England noted that their study was limited by not recruiting the targeted number of subjects, and because the rate of onset of mood disorders was lower than they expected.
“Thus we cannot exclude that a larger participant sample or different experimental design would have shown a significant beneficial effect of folate prophylaxis.”
Source: Journal of Affective Disorders
Volume 167, Pages 306-11, doi: 10.1016/j.jad.2014.06.011
“Folic acid supplementation for prevention of mood disorders in young people at familial risk: A randomised, double blind, placebo controlled trial”
Authors: Sharpley AL, Hockney R, McPeake L, Geddes JR, Cowen PJ.