Stimulating the addicted brain The effects of transcranial direct current stimulation and cognitive bias modification in alcohol users

In this PhD project we investigated a new intervention in which we combined brain stimulation with cognitive training. We used a form of training called cognitive bias modification (CBM) aimed at retraining dysfunctional automatic reactions towards alcohol. We investigated whether transcranial direct current stimulation (tDCS) applied over the dorsolateral prefrontal cortex (DLPFC) could improve this training. We carried out four studies: two with heavy drinkers, to investigate the processes that were involved; and two with clinical samples, to investigate the treatment potential. We found some evidence for a reduction in craving due to tDCS in the heavy drinkers. However, patients reported very low craving, therefore this could not be studied properly. We found a small cognitive facilitation due to tDCS during the training. But on post-intervention bias scores we found no evidence for an enhancement effect of tDCS on CBM. In one study we have found a promising trend on relapse one year after patients left the clinic in the group that received tDCS and CBM. The effect could not be discerned from a general tDCS effect or a CBM enhancement effect. Nevertheless, it offers promise for the future of tDCS research. The main limitations in our studies were the absence of craving in the patients, and the reliability of some of the computer tasks. Although the specific combinations investigated in this thesis were not very successful. It is important to further investigate CBM and tDCS because they are feasible techniques that show some potential in treatment for different disorders.