A Randomized Trial of Combined tDCS Over Right Inferior Frontal Cortex and Cognitive Bias Modification: Null Effects on Drinking and Alcohol Approach Bias

Background: Deriving novel treatments for alcohol use disorders (AUDs) is of critical importance, as existing treatments are only modestly effective for reducing drinking. Two promising strategies for treating AUDs include cognitive bias modification (CBM) and transcranial direct current stimulation (tDCS). While each strategy has shown positive results in reducing drinking or alcohol-related constructs (e.g., craving), initial tests of the combination of CBM and tDCS have shown mixed results. The present study investigated the degree to which combining CBM and tDCS (2.0 mA anodal current over F10) could reduce alcohol approach biases and alcohol consumption. Methods: Seventy-nine at-risk drinkers were randomized to 1 of 4 conditions in a 2 × 2 factorial design: verum CBM/verum tDCS, verum CBM/sham tDCS, sham CBM/verum tDCS, or sham CBM/sham tDCS. Participants completed a baseline assessment of alcohol approach bias and drinking quantity/frequency (i.e., drinks per drinking day [DDD] and percent heavy drinking days [PHDD]), 4 sessions of combined CBM and tDCS, and follow-up assessments of approach bias and alcohol consumption. Results: Results indicated that while participants did demonstrate significant alcohol approach biases at baseline, neither CBM, tDCS, nor the interaction reduced the bias at the follow-up. In addition, there was evidence of a trend toward reducing DDD from baseline to the 1-week/1-month follow-ups, but there was no significant effect of the intervention on either DDD or PHDD. Conclusions: These results partially replicated null results presented in similar CBM/tDCS trials and suggest that this combination, at least with anodal stimulation over dorsolateral or inferior frontal sites, may have limited utility to reduce drinking.