Disordered gambling: the evolving concept of behavioral addiction

Abstract

The reclassification of gambling disorder within the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) addictions category marks an important step for addiction science. The similarities between gambling disorder and the substance use disorders have been well documented. As gambling is unlikely to exert actively damaging effects on the brain, the cognitive sequelae of gambling disorder may provide insights into addictive vulnerabilities; this idea is critically evaluated in light of recent structural imaging data. The second part of the review analyzes a fundamental question of how a behavior can become addictive in the absence of exogenous drug stimulation. The relative potency of drug and nondrug rewards is considered, alongside evidence that cognitive distortions in the processing of chance (for example, the illusion of control and the gambler's fallacy) may constitute an important added ingredient in gambling. Further understanding of these mechanisms at neural and behavioral levels will be critical for the classification of future behavioral addictions, and I consider the current research data for obesity and binge eating, compulsive shopping, and internet gaming disorder.

Keywords: dopamine; internet gambling disorder; pathological gambling.

Figure 1

Using PET with the [¹¹C]raclopride ligand, we compared baseline binding as a marker of dopamine D₂/D₃ receptor availability in nine males with gambling disorder against nine male healthy participants. We detected no group difference in binding potential in regions of interest encompassing the overall striatum or the limbic subdivision that includes the nucleus accumbens. A representative image from one participant (a healthy control) is shown centrally, illustrating the striatal localization of raclopride binding. Despite the absence of a group difference, raclopride binding within the gamblers was negatively related with trait-impulsivity levels, on a measure of mood-related impulsivity (urgency) that shows robust group differences between gambling disorder and controls. Data redrawn from Ref. .

Figure 2

Effects of insula damage on gambling-related cognitive distortions. The slot machine task (top left) displayed two reels; one icon was selected on the left reel, and the right reel then spun and stopped to a standstill. Matching icons delivered wins; if the right reel landed one position from a match (as shown), this was considered a near miss. After each outcome, participants rated their motivation to continue to play the game. The bar chart (top right) displays this motivational ratings following near misses, compared to full misses (which do not land adjacent to the pay line). The typical motivational response to near misses (see also Refs. , , and 111) was inverted in the group with insula damage. In the roulette task (bottom left), participants made consecutive red/blue predictions on a random wheel. In healthy participants, the likelihood of choosing either color decreased linearly as a function of the preceding run length of that color; this negative recency is the gambler's fallacy effect. As for the slot machine task, the gambler's fallacy was abolished in the group with damage to the insula region. Data redrawn from Ref. .