Tryptophan depletion in patients with obsessive-compulsive disorder who respond to serotonin reuptake inhibitors.
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 cross-over 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.


CONCLUSIONS
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.
Barr
L C
LC
Clinical Neuroscience Research Unit, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven.
Goodman
W K
WK
McDougle
C J
CJ
Delgado
P L
PL
Heninger
G R
GR
Charney
D S
DS
Price
L H
LH
D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D001923:Brain Chemistry / Q000187:drug effects; D003864:Depression, Chemical; D004032:Diet; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000097:blood / Q000188:drug therapy* / Q000523:psychology; D010555:Personality Inventory; D010919:Placebos; D011569:Psychiatric Status Rating Scales; D012701:Serotonin / Q000096:biosynthesis / Q000502:physiology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D014364:Tryptophan / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism
D000596:Amino Acids; D010919:Placebos; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors; D014364:Tryptophan