Therapy of depression by phenylalanine. Preliminary note.

To 23 subjects with endogenous depression after a previous unsuccessful treatment with common antidepressive drugs (imipramine-like or MAO inhibitors) dl- or d-phenylalanine was given in dialy oral doses of 50 or 100 mg during 15 days. A complete euthymia was obtained in 17 subjects between one and 13 days of treatment. No important adverse reaction was observed.