Evidence for a differential visual M300 brain response in gamblers

Objective: Gambling disorder is the first behavioral addiction recognized in the DSM-5. This marks the growing realization that both behavioral and substance-related addictions are manifestations of an ‘addicted brain’ displaying similar altered neurophysiological mechanisms. A decreased electrophysiological visual P300 is considered a hallmark effect of substance-related addictions, but has not yet been shown in behavioral addictions. Methods: Magnetoencephalographic recordings of 15 gamblers and 17 controls were taken as they performed a cue-reactivity paradigm in which they passively viewed addiction- and non-addiction-related cues. Results: The main finding of the study is a reduction in the magnetic counterpart of P300 (M300) for gamblers beyond cue condition over frontal regions. Additionally, we found a significant group by cue-type interaction. Gamblers exhibited heightened sensitivity to addiction-related cues in regions corresponding to the frontoparietal attentional network, whereas controls exhibited an opposite effect localized to the right insula. Conclusions: The results suggest that a reduced P300 characterizes addictions in general, not just substance-related addictions, thus providing important neurophysiological support for the inclusion of behavioral addictions in the DSM-5 and in the incentive-sensitization theory. Significance: The study offers important insights into neural mechanisms underlying behavioral addictions, and may assist in developing better prevention and intervention strategies.