A placebo controlled evaluation of L-tryptophan in depression in the elderly

Two groups of unmatched patients attached to a Geriatric Hospital suffering from mild to moderate depression considered suitable for drug therapy were randomly allocated either 6 grams L-tryptophan daily or a similar dose of identical placebo for six weeks on a double-blind basis. Ratings (HRS and a 7 point global evaluation) were made pretrial and fortnightly up to and including six weeks. Both groups steadily improved, but there was no statistical difference between the L-tryptophan patients and those receiving placebo. Therefore, it would appear that L-tryptophan is not an effective anti-depressant.