Folic acid, folinic acid and depression

Today I saw a research paper on folic acid accidently while searching for some literature on antidepressant experiment protocol in animals. The research paper [1] states that the folic acid exhibits antidepressant property through opioidergic mew and delta receptors. Delta opiod receptor agonists are reported to be potential antidepressant agents [2].

The dosage of folic acid mentioned in the clinical trials is between 500 microgram - 800 microgram per day [3].

On the basis of current data, we suggest that oral doses of both folic acid (800 µg daily) and vitamin B12 (1 mg daily) should be tried to improve treatment outcome in depression [3].

References:

[1]. Evidence for the involvement of the opioid system in the antidepressant-like effect of folic acid in the mouse forced swimming test. Behavioral Brain Research. 2009 Jun 8;200(1):122-7.
[2]. The Antidepressant - like Effects of Delta-Opioid Receptor Agonists. Molecular Interventions. June 2006, 6:162-169;doi:10.1124/mi.6.3
[3]. Treatment of depression: time to consider folic acid and vitamin B12. Journal of Psychopharmacology. January 2005 vol. 19 no. 1 59-65.