Improving decision-making and cognitive impulse control in bulimia nervosa by rTMS: An ancillary randomized controlled study.

OBJECTIVE: Impaired decision-making and inhibitory control may be involved in the pathophysiology of psychiatric disorders like bulimia nervosa (BN). Their improvement after neuromodulation may underpin clinical improvement. We assessed the effects of rTMS on these cognitive functions in a sample of women with BN.

METHODS: Thirty-nine participants (22 in a sham group and 17 in an rTMS group) were assessed before and after 10 high frequency rTMS sessions over the left dorsolateral prefrontal cortex (DLPFC).

RESULTS: The between-group analyses revealed no differences in the final neuropsychological performances. The within-group analyses showed that inhibitory control improved in both the go/no-go task (p = .03) and the BIS cognitive impulsivity subscale (p = .01) in the rTMS group only. Switches toward good choices on the Iowa gambling task significantly improved in the rTMS group only (p = .002), and understanding of the task contingencies increased between the two assessments, also in the rTMS group only (p = .03).

DISCUSSION: This preliminary evidence suggests that modulation of left DLPFC might improve two putative cognitive biomarkers of BN.