The Die Is Cast: Decision-Making Under Risk and Under Ambiguity in Schizophrenia and Alcohol Use Disorder

Patients with schizophrenia (SZ) tend towards riskier decision-making (DM). Yet the specificity of these findings, as well as the impact of impairments in executive functions (EF), has not been sufficiently clarified. In a preregistered study (https://osf.io/n7z6y) 40 SZ, 50 patients with alcohol use disorder (AUD) and 36 healthy controls (HC) completed an n-back task (as EF challenge), the Game of Dice Task (GDT; DM under risk) and the Iowa Gambling Task (IGT; DM under ambiguity). AUD and SZ performed worse than HC in the n-back task and riskier in the GDT. In the IGT, only AUD performed riskier than HC and preferred disadvantageous Deck B compared to SZ. However, controlling for demographics and IQ abolished significance. Correlations of performance in the GDT and IGT with working memory differed between groups. Taken together, both patient groups show a deficit in the reflective system, whereas only AUD show impairments in the impulsive system. Thus, the direct comparison of DM in SZ and AUD reveals a differential DM profile of SZ and AUD. Our results suggest that both groups may benefit from EF training, especially in planning, categorization and cognitive flexibility, whereas AUD could additionally profit from impulse control and inhibition training. However, the findings need replication with well-matched samples, and the link between EF and DM in SZ should be examined more carefully with experimental approaches.