Impaired social cognition is a characteristic feature of schizophrenia, which is associated with the level of community functioning. Socioeconomic games are well-established in behavioral economy and widely used to examine decision-making strategies. They can also provide a useful method in the investigation of social decision-making in psychiatric diseases such as schizophrenia. The strength of these games compared to classic paradigms is that they allow observing subjects directly engaged in interpersonal situations, thus real-time interactions with implicit processes become available to investigation.

Investigating decision-making strategies in schizophrenia patients and healthy controls.

29 healthy controls and 58 patients with schizophrenia were compared by a series of Ultimatum Game interactions in a computerized setting. In this game two players have to split a sum of money. The proposer offers a portion to the responder, who decides to either accept or reject the offer. Rejection results in no income to either of the parties. Cognitive testing included emotion recognition, memory and executive function. Symptoms were assessed by MINI 5.0 and Positive and Negative Symptom Scale.

Association between offer and probability of acceptance was different in schizophrenia patients and controls (Chi2 = 18.8, n = 87, df = 4, p = 0.0009): schizophrenia was associated with an increased likelihood of acceptance at lower offers and a decreased likelihood of acceptance at higher offers. Ratio of inconsistent decisions was significantly higher in the schizophrenia group (Chi2 = 4.7, df = 1, p = 0.03).

Our results suggest that schizophrenia patients are impaired in socioeconomic interactions requiring decision-making, which may result in unstable behavioral strategies.