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

Abstract

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 9 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 followups, 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.

Alcohol-Specific Computerized Interventions to Alter Cognitive Biases: A Systematic Review of Effects on Experimental Tasks, Drinking Behavior, and Neuronal Activation

“…ApBM was shown to modify alcohol avoidance and approach bias (AvB/ApB) in the expected direction in social drinkers (54), hazardous drinkers (HZD) (55), risky drinkers (51), and AUD (26)(27)(28). However, replication of these effects failed in six studies in social (53), heavy (48,50,52,53), hazardous drinkers (49), and AUD (42,46). Loijen et al (43) reported an ApB reduction in AUD but did not test this effect against a control group, thereby limiting the statistical explanatory power.…”

“…Additionally, one study did find HD to drink significantly less than controls during a taste test (50). Four studies with hazardous and heavy drinkers observed no effects of ApBM on alcohol consumption at 1-week, 1-month, or 3-month post-intervention (41, 48,49,51).…”

“…In the seven pre-clinical experimental laboratory studies investigating both bias change and drinking outcomes, four reported consistent (non-)effects (i.e. bias change and drinking behavior change, or no bias change and no drinking behavior change), with one study reporting a bias as well as a drinking change (54), and three showing neither a bias change nor a drinking change (48,49,52). One study (55) reported a bias but no drinking change in the whole group analysis, but reported a significant drinking reduction for those whose bias had been changed successfully by the intervention.…”

A Meta-Analysis of Transcranial Direct Current Stimulation on Substance and Food Craving: What Effect Do Modulators Have?

“…Although we tried to explore various regulatory variables, there are still some possible influencing variables, which are not discussed in this paper, such as tDCS combined with other treatments (cognitive bias modification, emotional regulation). tDCS combined with cognitive bias modification has shown limited effect on treatment outcomes (95)(96)(97). Moreover, emotional regulation can help the curative effects of tDCS (98)(99)(100)(101); after emotion regulation training, using tDCS has better results (100).…”

Better Together? Coupling Pharmacotherapies and Cognitive Interventions With Non-invasive Brain Stimulation for the Treatment of Addictive Disorders

“…Interestingly, a further study found that tDCS over the left DLPFC significantly decreased the engagement bias toward drug cues in abstinent methamphetamine users (Shahbabaie et al, 2018). Finally, a recent study evaluated the effects of 4 sessions of combined tDCS targeting the right inferior frontal gyrus and cognitive bias modification training in high-risk drinkers (AUDIT score >8) and found no effect on drinking measures or alcohol approach biases (Claus et al, 2019).…”