Harmful gambling often involves problems controlling impulsivity, cognitive biases (such as believing that successive losses mean being closer to win), issues with decision making and a penchant for risk-taking. These behaviours are in large part controlled by an area at the front of the brain called the prefrontal cortex. Research has shown that gambling disorder has been linked to differences in brain activity patterns, including an altered response to stress. 

There is an urgent need to improve treatments for gambling disorder, with the most common treatment intervention cognitive behavioural therapy (CBT), having limits to its usefulness, with high rates of relapse and drop out being commonplace. tDCS has been shown to help to enhance CBT and treatment outcomes in other mental health disorders, but very little work has previously looked at gambling.

The research at UEL aimed to investigate the potential of tDCS to improve treatment approaches for gambling disorder. A particular goal was to investigate the high variability of tDCS results across studies, which is in part due to participants individual differences, and to a lack of complete understanding of how tDCS acts on specific brain areas and cognitive functions.

Dr Gomis-Vicent studied the effects of tDCS on different areas of the prefrontal cortex to explore the effects of different protocols in gambling behaviour. In addition, clinical case studies with gambling disorder patients were conducted at the National Problem Gambling Clinic (NPGC), to investigate the effects of tDCS combined with CBT across eight weekly sessions. Lastly, the capability of tDCS to modulate people stress reactions was assessed by measuring physiological responses (e.g brain activation, heart rate, sweating), to explore potential differences between participants with different gambling severity and impulsivity levels.

Overall, results from Dr Gomis-Vicent's research showed that tDCS was able to influence the way participants made gambling-related decisions when targeting dorsal and ventral areas of the prefrontal cortex. In addition, the intervention combining tDCS and CBT resulted in a reduction of gambling severity and cravings. There were tDCS effects on brain activation that indicated short and long term effects of the clinical intervention. Moreover, tDCS effects were able to modify stress levels. Results also showed that gamblers with higher impulsive levels had higher stress activation compared with lower impulsive gamblers, and that arousal was higher during gambling-related wins compared with losses.

These findings contribute to show the potential of tDCS to modulate cognitive and physiological mechanisms associated with gambling disorder, and the role of impulsivity in gambling behaviour.

Nevertheless, although impulsivity seems to be a shared element across most gamblers, there are multiple interrelated factors, such as genetics, childhood trauma, personality traits and psychiatric comorbidities that interact reciprocally. These factors, together with the heterogeneity of tDCS effects in each individual, contribute to the complexity of creating effective treatment interventions for gambling disorder. Future research addressing such intricacy could help to identify adequate protocols to treat each individual situation more effectively.