[Skip to Navigation]
April 1994

Tryptophan Depletion in Patients With Obsessive-Compulsive Disorder Who Respond to Serotonin Reuptake Inhibitors

Author Affiliations

From the Clinical Neuroscience Research Unit, the Abraham Ribicoff Research Facilities, the Connecticut Mental Health Center (Drs Barr, Goodman, McDougle, Heninger, and Price) and the West Haven (Conn) Veterans Affairs Medical Center, (Drs Delgado and Charney), Department of Psychiatry, Yale University School of medicine, New Haven, Dr Goodman is currently with the University School of Medicine, New Haven. Dr Goodman is Currently with the University of Florida School of Medicine, Gainesville. Dr Delgado is currently with the Veterans Affairs Medical Center, University of Arizona School of Medicine, Tucson.

Arch Gen Psychiatry. 1994;51(4):309-317. doi:10.1001/archpsyc.1994.03950040053007

Methods:  The effects of short-term tryptophan depletion were examined in 15 patients with DSM-III-R obsessive-compulsive disorder who had demonstrated symptom reduction following treatment with serotonin reuptake inhibitors. Patients received a 24-hour, low-tryptophan (160-mg/d) diet followed the next morning by a drink of 15 amino acids. A double-blind, placebo-controlled crossover design was used.

Results:  The diet and the amino acid drink reduced free plasma tryptophan levels by a mean of 84% 5 hours later. Short-term tryptophan depletion did not significantly change mean ratings of obsessions and compulsions. In contrast, mean depression ratings were significantly increased with tryptophan depletion compared with the control (tryptophan-supplemented) testing.

Conclusion:  Maintenance of serotonin reuptake inhibitor—induced improvement of obsessive and compulsive symptoms, unlike remission of depressive symptoms, may not depend on ongoing short-term availability of serotonin.

Add or change institution