Investigation of motivational dysfunction and its relation to weight gain and smoking in schizophrenia with electrophysiological and neuropsychological methods

Objective: Striatal dysfunction is thought to be important in the pathophysiology of schizophrenia. It was reported that the patients did not have any problems during the liking phase but that tthey had problems in wanting phase. The amount of eating and smoking among schizophrenic patients is also increasing and the importance of reward is gaining attention. In this perspective, both neuropsychological and electrophysiological methods were examined for motivation and reward in schizophrenia patients. The aim of the study was to investigate the relationship between social cognition and neurocognitive functions to understand the motivational functions of the schizophrenia patients by experimental tasks and EEG activating the orbitofrontal cortex. Method: Sixty patients with schizophrenia and 30 healthy controls were included in the study according to the Mental Health and Diseases Outpatient Clinic of Dokuz Eylül University Hospital. Social motivation tests, neurocognitive tests, clinical interviews evaluating anticipatory and consummatory anhedonia self-questionnaires were applied. In the EEG, an experimental motivation assessment were applied to the participants. Results: There was a statistically significant difference between the schizophrenia patients and healthy controls in terms of motivational and electrophysiological assessments. In addition, it was found that the average amplitudes of P300 were increased in schizophrenia patients under reward condition in the Monetary Incentive Delay Task and they responded to the incentive cues with lower CNV values than healthy controls. There was no significant relationship between weight gain and smoking in terms of motivational and electrophysiological evaluation. Conclusion: As a result of our study, it was seen that schizophrenia patients showed motivational disorder when compared with healthy controls. As a result of electrophysiological examinations, it was found that the patients responded differently than the healthy ones. Again, when evaluated in terms of neuropsychological and anhedonia-specific features, patients were found to perform worse. When electrophysiological findings of weight gain and cigarette smoking and the results of experiments evaluating motivation were examined, no statistically significant relationship was found. Motivational disorder in schizophrenia needs to be examined in detail with neuroscientific studies.