Sex Differences in Cerebral Metabolism Among Abstinent Cocaine Users

In a recent article, Linda Chang, M.D., and colleagues (1) reported that there were sex differences in cerebral metabolism in the frontal lobes of abstinent cocaine users. These data support the findings of a single photon emission computed tomography study (2) and a self-report study (3). The possibility that clinical presentation and symptoms may also be different between male and female cocaine users was not discussed by Dr. Chang et al. (1); therefore, attention is called to reports that give clues as to how sex differences in the effects of cocaine use could translate clinically.

Brady et al. (4) reported higher rates of affective and anxiety disorders in men than in women with cocaine dependence. This finding was at odds with the female-male ratio of people with alcohol dependence and the general population. Others have reported that recent cocaine use in psychiatric inpatients was associated with violent behavior in women but not in men (5). Finally, a study comparing psychiatric emergency room patients with and without urine samples positive for cocaine suggested that recent cocaine use was associated with suicidal behavior in men and with violent behavior in women (6, 7). These three pieces of information suggest that the clinical effects of cocaine use on mood and impulse regulation need to be studied separately in men and women.

The study by Dr. Chang et al. provides exciting new evidence that the neurobiological effects of cocaine differ by sex. Clinical studies suggest an increased risk for mood disturbance in men and violence in women. A caveat is that women with antisocial personality disorder may be overrepresented in groups of cocaine users (4); this may account for an increase in violence. Alternatively, antisocial traits may develop more frequently in women using cocaine than in men. These hypotheses need testing in future studies.