ABSTRACT
RATIONALE: Recently, a number of studies have challenged the finding that acute tryptophan depletion (TD) increases depressive symptoms in medicated, formerly depressed patients. The present study examined the effects of acute nutritional TD on remitted depressed patients currently treated with selective serotonin reuptake inhibitors. In an attempt to clarify conflicting earlier findings, the effects of a number of clinical variables on outcome were also investigated. METHODS: Ten patients underwent TD in a double-blind, controlled, balanced crossover fashion. The control session followed the procedure of Krahn et al. (1996 Neuropsychopharmacology 15:325-328). Sessions were 5-8 days apart. RESULTS: TD was significantly related to increased scores on clinician-rated depression and anxiety scales, and on self-rated depression, anxiety, and somatic symptoms. The control challenge had no effect, despite the fact that the reductions in plasma tryptophan during the control session were unexpectedly high. Some evidence was found for a threshold in the relationship between reduction of plasma tryptophan and mood response. CONCLUSIONS: The mood effect of TD in medicated, formerly depressed patients was confirmed. A threshold may exist for mood effects following TD, implying that recent negative findings may have been caused by insufficient depletion. No other predicting or mediating factors were identified, although the variable "history of response pattern to medication" deserves further study.
Subject(s)
Depressive Disorder/psychology , Selective Serotonin Reuptake Inhibitors/therapeutic use , Tryptophan/deficiency , Adolescent , Adult , Affect/drug effects , Aged , Amino Acids/metabolism , Behavior/drug effects , Depressive Disorder/drug therapy , Depressive Disorder/metabolism , Diet , Double-Blind Method , Female , Humans , Male , Middle Aged , Psychiatric Status Rating Scales , Selective Serotonin Reuptake Inhibitors/adverse effects , Tryptophan/bloodABSTRACT
We have previously hypothesized that patients with major depression and anger attacks may have a greater central serotonergic dysregulation than depressed patients without such attacks. We wanted to compare the prolactin response to fenfluramine challenge, as an indirect measure of central serotonergic function, in depressed patients with and without anger attacks. We recruited 37 outpatients (22 men and 15 women; mean age: 39.5+/-10.5) with DSM-III-R major depressive disorder, diagnosed with the SCID-P. Their initial 17-item Hamilton Rating Scale for Depression score was >/=16. Patients were classified as either having or not having anger attacks with the Anger Attacks Questionnaire. All patients received a single-blind placebo challenge followed by a fenfluramine challenge (60 mg orally) the next day. Plasma prolactin measurements were obtained with double antibody radioimmunoassay before and after both placebo and fenfluramine challenges, and fenfluramine and norfenfluramine blood levels after each challenge were determined by gas chromatography. Of the 37 study participants, 17 (46%) were classified as having anger attacks. There were no significant differences in age, gender, fenfluramine, or norfenfluramine blood levels between depressed patients with and without anger attacks. Depressed patients with anger attacks showed a significantly blunted prolactin response to fenfluramine challenge compared to patients without anger attacks. As previous studies have shown blunted prolactin responses to fenfluramine in impulsive aggression among patients with personality disorders, our results support our hypothesis that depressed patients with anger attacks may have a relatively greater serotonergic dysregulation than depressed patients without these attacks.
