Cushing's syndrome, tryptophan and depression.

Fifteen patients with active Cushing's syndrome have been compared with 15 other patients who had been treated successfully for Cushing's syndrome and with 13 patients with other pituitary tumours. Depression was the main psychiatric diagnosis made by the CATEGO programme after Present State Examinations. Patients with active Cushing's syndrome were significantly more depressed (Hamilton Rating Scores), than were the other patients. Compared with the control patients, those with active Cushing's syndrome had slightly lower plasma concentrations of total tryptophan, though the concentrations of freely diffusible tryptophan were not significantly changed.