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

Abstract

Substance addiction and food addiction are significant social problems worldwide. In previous studies of substance addiction, transcranial direct current stimulation (tDCS) has been used to influence craving of substance or food. However, the reported effects are not always consistent due to inconsistent experimental settings. The way modulators influence the effect of tDCS on substance addiction is worth exploring. This meta-analysis was conducted to estimate the effect size of tDCS on substance and food craving and to investigate the influence of potential modulators. We systemically identified and reviewed studies on substance/food craving using tDCS that were published between January 2008 to January 2020. A total of 32 eligible studies were identified. Hedges' g was computed as an indicator of the effect of tDCS and some potential moderators (substance type, stimulation sites, current intensities, number of sessions, duration of stimulation, and study design) were examined using subgroup analysis. Random effects analysis revealed a total medium effect size [Hedges' g = 0.536, 95% confidence interval (CI): 0.389–0.683, after adjusting Hedges' g = 0.416, 95% CI: 0.262–0.570] preferring active over sham stimulation to reduce craving. A significant difference was observed between the number of sessions (repeated stimulation was better than single stimulation). The duration of stimulation may have a positive influence on the effects of tDCS. No other significant differences were found in other subgroups analysis. In conclusion, our results provided evidence that tDCS can be an effective way to reduce craving of substance or food, and longer multiple stimulus durations in all can more effectively reduce craving; however, the influences of modulators still need be to be examined in depth in future.

Transcranial direct current stimulation (tDCS) reduces motivation to drink ethanol and reacquisition of ethanol self-administration in female mice

“…This suggests that tDCS might decrease the rate of relapse in abstinent alcohol-dependent patients. This is similar to what is observed in humans 19 , 77 , 78 . The amount of ethanol intake per session was noticeably higher in sham animals during the first week of reacquisition than in the last week of the training sessions.…”

“…Recent meta-analyses have provided additional evidence that tDCS over the DLPFC reduces craving and ethanol consumption. Interestingly, larger effects were found with repeated stimulations than with single stimulation 77 , 78 , and a level B (possible efficacy) recommendation has been proposed for tDCS in addiction/craving 79 .…”

Neurobiological regulation of eating behavior: Evidence based on non-invasive brain stimulation

“…For instance, studies showing a diminished craving for sweet foods included mostly participants with either frequent food craving [102][103][104], BED or subBED [99], thus demonstrating a study population that exhibits dysregulated eating behaviors. A recently published meta-analysis evaluated the effects of modulators in tDCS studies on food and substance craving and concluded that the stimulation site (anodal left or right DLPFC) and current intensity (1 or 2 mA) do not influence tDCS outcomes [123]. However, stimulation duration made a significant difference, meaning that a longer total stimulation time was associated with a stronger craving reduction [123].…”

How structural and functional MRI can inform dual-site tACS parameters: A case study in a clinical population and its pragmatic implications

“…Multiple studies showed that both single and multiple sessions of DLPFC stimulation reduced craving in crack [35], marijuana [36], heroin [37], alcohol [38], methamphetamine [39], and nicotine [40] use disorders. However, there have been other tES studies that reported no significant differences between active and sham groups in terms of self-reported drug craving (see this systematic review [41] and this meta-analysis [42]). The neural substrate of the mechanism of action leading to various effects and how to optimize stimulation montage by targeting networks known to be dysregulated in SUDs are not clear yet [43,44].…”