Comparison of serum orexin and ghrelin levels between deficit and non deficit schizophrenia patients

Schizophrenia is known to have a heterogeneous nature. Although current treatment options appear to be successful in treating positive symptoms, we can't say the same thing about the negative symptoms. Researches about the etiology of deficit syndrome (DS), which can be defined as a subtype characterized by severe negative symptoms and cognitive impairment, would lead researches about new treatment options. There are several studies investigating the role of hormones on the etiology of schizophrenia. But there are limited studies exploring the role of orexin and ghrelin in schizophrenia. In our study, we aimed to investigate the relationship between these molecules and schizophrenia and DS by examining serum levels of orexin and ghrelin in patients with deficit syndrome and non-deficit schizophrenia (ND). The study included 23 patients in the DS group, 27 patients in the ND group, and 20 healthy controls (HC). The groups were matched for age, gender, and body mass index to exclude confounding factors. Serum levels of orexin A, B and ghrelin were measured using the ELISA method in venous blood samples obtained from the participants. It was observed that orexin A levels were significantly lower in both DS and ND patients compared to the HC group. Only DS patients had significantly lower serum Orexin-B levels compared to the HC group. Orexin levels were found to be similar among the patient groups. There was no significant difference in ghrelin levels between the groups. Correlation analysis between serum levels of orexin A, orexin B, ghrelin, and clinical parameters revealed a statistically significant negative correlation between orexin B and BPRS (Brief Psychiatric Rating Scale) and SANS (Scale for the Assessment of Negative Symptoms) scores, while a significant positive correlation was found between orexin B and CGI (Clinical Global Impression) score. The data obtained from our study support the potential role of orexin in the etiology of schizophrenia, while no significant relationship was found between ghrelin and schizophrenia. Our study specifically identified a relationship between orexin B levels and deficit syndrome, making it the first study to examine this association. Keywords: Schizophrenia, Orexin, Ghrelin, Deficit Syndrome