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 sym ptom response during tryptophan depletion and future depressive episodes, Methods: Twelve subjects with prior major depressive episodes in remission and medication-free for greater than or equal to 3 months (patients), and 1 2 matched healthy (control) subjects received two tryptophan depletion test s I week apart. During follow-up the Hamilton Depression Rating Scale was a dministered weekly for I month, monthly for 3 months, and once at 6 and 12 months, Results: With results from both tests, tryptophan depletion has a sensitivi ty of 78%, specificity of 80%, positive predictive value of 70%, and negati ve predictive value of 86% to identify future depressive episodes. Survival analysis shows that mood response to tryptophan depletion reliably predict s major depressive episodes during the follow-up year (r =.2725, p =.014), Conclusions: Tryptophan depletion may be clinically useful in identifying i ndividuals at risk for future major depressive episodes, (C) 2000 Society o f Biological Psychiatry.