Effects of acute tryptophan depletion on mood in bulimia nervosa

Background: The present study investigated the role of serotonin in the pat hophysiology of bulimia nervosa (BN) by studying the affective and appetiti ve responses of women ill with BN to an acute tryptophan depletion (ATD) pa radigm. Methods: Twenty-two women with BN and 16 healthy control women (CW) were st udied on 2 separate days during the follicular stage of the menstrual cycle . Participants drank a control nth of essential amino acids (100 g + 4.6 g tryptophan) on one day and a tryptophan deficient (100 g - 4.6 g tryptophan ) mixture (ATD) on the other in a double-blind fashion. Mood/appetite ratin gs and blood samples were taken at baseline and at intervals rip to 420 min utes. Participants were then presented with an array of foods and were allo wed to binge and vomit if they desired. Results: CW and BN women had a similar and significant reduction in plasma tryptophan levels and the tryptophan: LNAA ratio after ATD, After ATD, the BN women had a significantly greater increase in peak (minus baseline) depr ession, mood lability, sadness and desire to binge compared to the CW. BN s ubjects and CW had similar-peak changes in mood after rite control amino ac id mixture, BN subjects and CW consumed similar amounts of food after the t wo amino acid treatments. Conclusions: Women with BN seem more vulnerable to the mood lowering effect s of ATD, suggesting they have altered modulation of central 5-HT neuronal systems. (C) 2000 Society of Biological Psychiatry.