Lack of relapse with tryptophan depletion following successful treatment with ECT

OBJECTIVE: Although the antidepressant mechanism of ECT is unknown, there are considerable data to support serotonergic involvement. The effects of tryptophan depletion were studied in patients with major depression treated successfully with ECT. METHOD: Five patients who had been successfully treated with ECT for major depression were studied in a randomized, double-blind, crossover design comparing tryptophan depletion to a placebo procedure. RESULTS: No effect of tryptophan depletion on mood symptoms was observed despite more than an 85% decrease in total serum tryptophan. CONCLUSIONS: These data suggest that presynaptic serotonin availability may not be necessary for the acute maintenance of an antidepressant response to ECT.