Decision making measured by the Iowa Gambling Task in alcohol use disorder and gambling disorder: a systematic review and meta-analysis

Background and aims: Gambling disorder (GD) and alcohol use disorder (AD) have similar features, such as elevated impulsivity and decision-making deficits, which are directly linked to relapse and poor therapeutic outcomes. Our aim was to assess decision-making characteristics in GD and AD patients compared to healthy controls (HC) based on one of the most frequently used measures of decision-making: the Iowa Gambling Task (IGT). Methods: In our systematic literature search of three databases, we identified 1198 empirical articles that mentioned decision-making deficits with the use of the IGT in patients diagnosed with either AD or GD. Possible effects were calculated using meta-analysis. In the end, 17 studies (including 1360 participants) were suitable for inclusion in the meta-analysis reporting data for 23 group contrasts. Results: The random effects estimate indicated impaired IGT performance in both AD patients (N = 500; d = -0.581, CI:-89.5 < delta < -26.6%) and an even greater deficit in GD patients (N = 292; d = -1.034, CI:-156.1 < delta < 50.7%) compared to HCs. Sampling variances were calculated for both AD (v(1) = 0.0056) and GD groups (v(2) = 0.0061), from which the z-score was calculated (z = -21.0785; p < 0.05), which indicates a statistically significant difference between AD and GD groups. No significant moderating effects of age, gender or education were found. Conclusions: There is enough evidence to support that decision-making deficit associated with addictive disorders, and that the deficit is more expressed in gambling disorder than in alcohol use disorder. Impaired decision -making plays an important part in poor therapeutic outcomes, thus provides a promising opportunity for cognitive intervention.