We tested the theory that Gamblers and ADHD participants would exhibit common disfunction in frontal cortical reward processing. We predicted that this commonality would be revealed both in behavioural performance in gambling and in brain electrical activity measured by EEG.
Our first discovery was that ADHD participants behave quite unlike Gamblers on a version of the Iowa Gambling Task. In fact ADHD participants in some cases substantially outperform healthy controls. This finding was reported in 2015 (Abouzari, Oberg, Gruber & Tata; Behavioural Brain Research). We suggested in that paper that previous reports of poor performance on the Iowa Gambling Task among adults with ADHD might be due to a failure to screen for co-morbid gambling. In fact we found that the sub-group with both problem gambling and ADHD performed worse than gambling alone, suggesting that co-morbidity might cause an exaggeration of gambling tendencies.
We went on to investigate the difference between ADHD with and without comorbid gambling by comparing brain electrical responses to feedback in the Iowa Gambling Task. We discovered that ADHD gamblers exhibited substantially greater feedback-related frontal theta power, whereas ADHD non-gamblers were indistinguishable from controls. We reported this result in 2016 (Abouzari, Oberg & Tata: Behavioural Brain Research). This finding suggests that problem gambling entails a distinct frontal cortex disregulation that is independent of ADHD.
Abouzari, M., Oberg, S., & Tata, M. (2016). Theta-band oscillatory activity differs between gamblers and nongamblers comorbid with attention-deficit hyperactivity disorder in a probabilistic reward-learning task. Behavioural Brain Research, 312, 195-200. http://dx.doi.org/10.1016/j.bbr.2016.06.031
Abouzari, M., Oberg, S., Gruber, A., & Tata, M. (2015). Interactions among attention-deficit hyperactivity disorder (ADHD) and problem gambling in a probabilistic reward-learning task. Behavioural Brain Research, 291, 237-243. http://dx.doi.org/10.1016/j.bbr.2015.05.041
Abouzari, M., & Tata, M. S. (2015) The Neurobiology of Bad Decisions: disordered reward processing in ADHD and Problem Gambling. Psychiatry Grand Rounds and Lethbridge Regional Hospital. June 2015