Reduced metabolism in brain "control networks" following cocaine-cues exposure in female cocaine abusers

Objective

Gender differences in vulnerability for cocaine addiction have been reported.Though the mechanisms are not understood, here we hypothesize that genderdifferences in reactivity to conditioned-cues, which contributes to relapse,are involved.

Method

To test this we compared brain metabolism (using PET and ¹⁸FDG)between female (n = 10) and male(n = 16) active cocaine abusers when they watched aneutral video (nature scenes) versus a cocaine-cues video.

Results

Self-reports of craving increased with the cocaine-cue video but responsesdid not differ between genders. In contrast, changes in whole brainmetabolism with cocaine-cues differed by gender (p<0.05); femalessignificantly decreased metabolism (−8.6%±10) whereasmales tended to increase it (+5.5%±18). SPM analysis(Cocaine-cues vs Neutral) in females revealed decreases in frontal,cingulate and parietal cortices, thalamus and midbrain (p<0.001) whereasmales showed increases in right inferior frontal gyrus (BA 44/45) (only atp<0.005). The gender-cue interaction showed greater decrements withCocaine-cues in females than males (p<0.001) in frontal (BA 8, 9, 10),anterior cingulate (BA 24, 32), posterior cingulate (BA 23, 31), inferiorparietal (BA 40) and thalamus (dorsomedial nucleus).

Conclusions

Females showed greater brain reactivity to cocaine-cues than males but nodifferences in craving, suggesting that there may be gender differences inresponse to cues that are not linked with craving but could affectsubsequent drug use. Specifically deactivation of brain regions from“control networks” (prefrontal, cingulate, inferior parietal,thalamus) in females could increase their vulnerability to relapse since itwould interfere with executive function (cognitive inhibition). Thishighlights the importance of gender tailored interventions for cocaineaddiction.