T222. IMPAIRED COST-BENEFIT COMPUTATION IN SOCIAL CONTEXT IN PATIENTS WITH SCHIZOPHRENIA

BACKGROUND: Social withdrawal is one of core negative symptoms in schizophrenia, which dampens their social outcomes and prognosis. However, the underlying behavioral mechanisms of this symptom are poorly understood. In the present study, we aimed to explore the capacity of cost-benefit computation under social context in schizophrenia patients. METHODS: We recruited twenty-six patients, who met the criteria for diagnosis of schizophrenia, and thirty-one healthy controls matched for their age and gender ratio. All the participants were administrated to Effortful Job Interview Task, which is a novel behavioral paradigm where participants were asked to make an effort to get job offers. Before their taking effort, they were required to decide whether they would like to get involved in a less challenging job interview with no bonus point or a more challenging one with varied bonus points (i.e., 5, 15, 25 points, higher points indicate higher chance of getting a job offer). RESULTS: In healthy controls, there was a main effect of prize on the choice percentage of challenging job interview (F (2, 90) = 68.577, p <0.001), with higher percentage of picking challenging interview under large (25) and medium (15) bonus points than low bonus point (5). Schizophrenia patients, however, exhibited lower percentage of challenging interview choices under medium (p =.015) and large (p <.01) bonus points than healthy controls, as reflected by a significant Group x Prize interaction effect (F (2, 110) = 6.478, p <0.01). In addition, we observe significant negative correlations between percentage of challenging interview choices under large bonus and amotivation sub-score on the Scale for the Assessment of Negative Symptoms (r = -0.49, p = 0.01). Interestingly, patients with schizophrenia displayed spared experience of pleasantness when they received a job offer as compared with healthy controls (p = .09). But, they showed blunted aversive experience towards the outcomes of failure as compared to healthy controls (p < .01). DISCUSSION: These findings suggest that impaired social cost-benefit computation may play a central role in the symptoms of social withdrawal in schizophrenia, which may facilitate the clinical intervention of negative symptoms.