L-5HTP in depression resistant to re-uptake inhibitors. An open comparative study with tranylcypromine.

L-5HTP and tranylcypromine were compared in an open, but controlled and cross-over study, in patients suffering from major depression; all were non-responders to several reuptake inhibitors, including oxaprotiline and fluvoxamine. After four unsuccessful sleep-deprivations, L-5HTP or tranylcypromine were given during four weeks in a crossover design. Of 17 patients given L-5HTP during both treatment periods, none responded, whereas of 26 patients treated with tranylcypromine, 15 responded. Thus, L-5HTP is not a therapeutically effective alternative in depressed patients who have not responded to reuptake inhibitors.