Dear Editor,

It was very interesting to read the paper by Coppen & Bailey. Enhancement of antidepressant action of fluoxetine by folic acid,a randomised placebo controlled trial, J.Affective Disorder 2000 Nov 60:121-30. I think there is a lot of research work which implicates Serotonin ,Norepinephrine deficiency. Others implicate Hpothalamico-Pitutary-Adrenal Dysfunction. Also the number of patients which participated in the study was small, especially with the drop out which could give a misleading result; I think we ought to have in a large number study, patients with depressive illness with normal serum folic acid, low serum folic acid, and compare whether adding folic acid to fluoxetine to those two groups will have any increase in the antidepressant action of fluoxetine. Further work is needed before a firm conclusion is reached.