Abstract
I read with interest the article on clinical effects of acute tryptophan depletion that was recently published in your Journal [1]. The authors described the effects of tryptophan depletion on healthy volunteers and patients with depression, panic disorder, social anxiety disorder, obsessive-compulsive disorder, and other psychiatric conditions. I would like to expand on this topic. Tryptophan depletion has also been used in alcoholism studies. A study of the effects of tryptophan depletion on mood and urge to drink in patients with co-morbid major depression and alcohol dependence has demonstrated that tryptophan depletion leads to an increase in the urge to drink [2]. Another study investigated the effect of tryptophan depletion on measures of impulsive behaviour in men with or without a family history of alcoholism [3]. Tryptophan depletion impaired performance on the behavioural inhibition task in the males with positive family history compared with the males without relatives with alcohol dependence. A similar earlier study demonstrated that tryptophan-depleted individuals with a family history of alcoholism made more commission errors (responses to stimuli associated with punishment or loss of reward) than did tryptophan-depleted individuals without a family history of alcoholism suggesting a propensity for impulsive responses in the setting of lowered serotonin function [4]. Another study examined the effects of tryptophan depletion on alcohol cue-induced craving in abstinent patients with alcohol dependence [5]. The tryptophan depletion test may be a useful tool in studies of alcohol misuse and research on a family predisposition to alcohol use disorders.