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<δ<-26.6%) and an even greater deficit in GD patients (N=292; d=-1.034, CI:-156.1<δ<50.7%) compared to HCs. Sampling variances were calculated for both AD (v1=0.0056) and GD groups (v2=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.