"To co-operate or not?" Risky co-operative behavior in Schizophrenia and the effect of vasopressin.

Risky co-operation is when an individual chooses to co-operate in a social situation despite the possibility of the partner refusing to co-operate. Although this is a deviation from rational behavior, it may have helped humans in societal adaptation. Risky co-operation holds significance in social functioning. However, the status of risky cooperative behavior in schizophrenia, a disorder with impaired social cognition, is yet to be investigated. Moreover, the underlying neurobiology is unexplored. 27 individuals with schizophrenia and 30 healthy volunteers performed an iterative stag hunt game, an ecologically valid, neuroeconomics game to measure risky cooperative behavior. The patients and healthy volunteers were matched on age and sex. An independent group of patients (n = 30) later performed the stag hunt game with intranasal vasopressin or saline in a counterbalanced crossover study design. Patients with schizophrenia, compared to healthy controls, switched from high-risk situations to a low-risk situation at lower payoff, suggesting impaired co-operation in a risky situation. Group differences were significant even after controlling for general risk- taking tendency and subjective mood state. In part-II of the study, there was no statistically significant difference in risky co-operative behavior with vasopressin. The results suggest impaired risky co-operative behavior in schizophrenia, which could influence the functional outcome. The study also provides a testable, ecologically valid paradigm for risky co-operative behavior in schizophrenia. Though single dose vasopressin did not influence the risky co-operative behavior, long term study with repeated administration is needed for a definitive conclusion.