Alexithymia and stress-induced brain activation in cocaine-dependent men and women

Alexithymia means a reduced capacity to identify and describe one's own feelings. Both stress and an alexithymic response to stress can contribute to relapse into drug abuse, but to our knowledge the neural processing of an alexithymic response to stress in cocaine-dependent individuals has not been examined.

In a functional magnetic resonance imaging session,17 male and 10 female abstinent cocaine-dependent subjects participated in script-guided imagery of neutral or stressful situations. Spatial preprocessing and statistical analysis of brain images were performed using Statistical Parametric Mapping Software (SPM2). Blood oxygen level-dependent contrasts between stress and neutral imagery were correlated voxelwise with scores on the 26-item Toronto Alexithymia Scale (TAS).

Male cocaine users demonstrated a positive correlation between TAS scores and activation in the right putamen and middle frontal cortex during stressful, compared with neutral, imagery. In contrast, no brain regions showed a negative correlation with TAS scores. Female subjects demonstrated a negative correlation between TAS scores and activation in the right amygdala, thalamus, putamen, and left frontal and bilateral temporal cortices, and no positive correlations with TAS scores during stressful, compared with neutral, imagery.

Women with greater alexithymic features showed reduced left-hemispheric cortical and right-hemispheric subcortical activation during processing of stress. However, men showed an opposite correlation in the right frontal cortex and putamen, suggesting that responses to stress in the putamen (activation v. deactivation) and frontal cortex (activation v. deactivation, as well as right v. left correlations) are critically different in association with alexithymia between male and female cocaine-dependent patients.