The relationship between neuropeptide Y levels with insight and functionality in patients with schizophrenia

Objectives: The issue of functioning in psychiatry has become a prominent topic in recent years. The fact that psychiatric diseases, especially schizophrenia, are among the top five diseases that cause disability loss increases the importance of this issue. Increasing functionality in schizophrenia patients will enable them to be more active in social life, reduce their stigmatisation and contribute to the remission of the disease. In order to achieve this, it is first necessary to understand the mechanisms that cause loss of functionality. Neuropeptides have been the subject of investigation in the context of the aetiology of schizophrenia, with some studies demonstrating their effects. Given that neuropeptide Y is highly prevalent in the central nervous system and has been linked to behavioural and emotional effects, as well as stress resistance, it has been postulated that it may also influence social functioning and insight in schizophrenia patients. The objective of this study is to compare patients diagnosed with schizophrenia and healthy controls on measures of social functioning and insight, as well as to assess the relationship between neuropeptide Y levels and social functioning and insight. Material and Method: The participants selected for the patient group in the study will be outpatients who applied to the Karadeniz Technical University (KTU) Faculty of Medicine Psychiatry Outpatient Clinic between July 2023 and October 2023. They will have been evaluated by at least one clinician with a clinical interview and diagnosed with schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). The patients whose diagnosis of schizophrenia was confirmed according to DSM-5 by a second interview conducted by the research assistant conducting the study, who met the inclusion criteria and did not include the exclusion criteria, were in remission for at least three months and agreed to participate in the study. The study included 40 patients who applied to the KTU Faculty of Medicine Psychiatry Outpatient Clinic between July 2023 and October 2023. These patients were diagnosed with schizophrenia and were in remission. The study was completed with 40 patients. The control group comprised 40 healthy volunteers who were matched with the patient group in terms of age, gender and education level, who met the inclusion criteria and did not meet the exclusion criteria and who agreed to participate in the study. Once all participants had been informed about the study, they were asked to complete a sociodemographic and clinical data form. The Positive and Negative Symptom Scale (PANSS) was employed to assess the patient groups. The Wisconsin Card Matching Test (WCST), the Auditory Verbal Learning Test (AVLT), the Stroop Test and the Trail Making Test (TMT) were employed to assess the cognitive functions of all participants. Blood samples were collected from all participants simultaneously from the matched patient and control groups between 08:00 and 12:00 on the same day of the cognitive tests. Serum NPY levels were then measured using an ELISA kit. Results: In the evaluation of cognitive functions, the AVLT, instant memory, learning, recall after surprise, long-term memory, verbal learning curve, recall by recognising test sections, Stroop test section 1, section 2, section 3, section 4, section 5, total time in the patient group compared to the control group, Stroop section 5 number of corrections and Stroop Interference duration, WCST number of completed categories and failure to maintain set-up score total error sections, Trail Making Test section A duration, section B duration and section B duration minus section A duration demonstrated inferior performance. A significant relationship was observed between clinical insight and social functioning, but not with cognitive insight. Each increase in the G12 score was associated with a loss of 11.36 points in functioning, indicating that insight was as effective as 14.5% in impairment in functioning. A correlation was observed betbetween NPI levels and social functioning or insight. Conclusion: The results of our study demonstrated that serum NPY levels were significantly lower in schizophrenia patients compared to the control group. Furthermore, there was a clear correlation between NPY levels and cognitive functions in the control group. The potential of NPY as a predictor of schizophrenia is an area that warrants further investigation. Nevertheless, the relationship between NPY levels and functionality and insight could not be determined. NPY may prove to be a valuable candidate for future therapeutic discovery in the treatment of diseases such as schizophrenia and in increasing functionality. The objective of this study was to contribute to the existing body of literature in this field, which has been limited in its findings. Key Words: Schizophrenia, Social Functioning, Insight, NPY, Cognitive Functions, Wisconsin Card Sorting Test, Auditory Verbal Learning Test, Stroop Test, Trail Making Test, PSP, BCIS