Tryptophan depletion and risk of depression relapse: a prospective study of tryptophan depletion as a potential predictor of depressive episodes.
BACKGROUND
This study investigated the relationship between depressive symptom response during tryptophan depletion and future depressive episodes.


METHODS
Twelve subjects with prior major depressive episodes in remission and medication-free for > or =3 months (patients), and 12 matched healthy (control) subjects received two tryptophan depletion tests 1 week apart. During follow-up the Hamilton Depression Rating Scale was administered weekly for 1 month, monthly for 3 months, and once at 6 and 12 months.


RESULTS
With results from both tests, tryptophan depletion has a sensitivity of 78%, specificity of 80%, positive predictive value of 70%, and negative predictive value of 86% to identify future depressive episodes. Survival analysis shows that mood response to tryptophan depletion reliably predicts major depressive episodes during the follow-up year (r =.2725, p =.014).


CONCLUSIONS
Tryptophan depletion may be clinically useful in identifying individuals at risk for future major depressive episodes.
Moreno
F A
FA
Department of Psychiatry, College of Medicine, The University of Arizona Health Sciences Center, Tucson 85724, USA.
Heninger
G R
GR
McGahuey
C A
CA
Delgado
P L
PL
D000328:Adult; D018592:Cross-Over Studies; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000378:metabolism* / Q000628:therapy; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012720:Severity of Illness Index; D014364:Tryptophan / Q000172:deficiency*
D014364:Tryptophan