A Cross-Sectional Comparative Study: Could Asprosin and Peptide Tyrosine-Tyrosine Be Used in Schizophrenia to Define the Disease and Determine Its Phases?

<b>Background/Objectives</b>: We aimed to evaluate asprosin and peptide tyrosine-tyrosine (PYY) levels in schizophrenia patients and the relationships between these levels and clinical severity, as well as whether these two hormones have a role in determining the disease and/or the phases of the disease. <b>Methods</b>: This study included 50 patients with schizophrenia in the remission phase, 50 in the acute phase, and 50 controls. The Positive and Negative Syndrome Scale (PANSS) was filled out for patients. The patients' biochemical parameters and asprosin and PYY levels were measured. <b>Results</b>: Levels of asprosin and PYY were significantly different in all three groups (<i>p</i> < 0.001, <i>p</i> < 0.001). In the remission phase group, asprosin levels had a negative effect on PANSS general symptomatology scores (<i>p</i>: 0.002, <i>p</i> < 0.001). In the acute phase group, while PYY levels showed a negative effect on PANSS general symptomatology scores (<i>p</i>: 0.031), asprosin levels had a negative effect on all subscales of PANSS (<i>p</i> < 0.001). In the acute phase, a one-unit decrease in asprosin levels was associated with a 93% increase in PANSS total scores. The results of the receiver operating characteristic (ROC) analysis to distinguish the acute phase showed that PYY could not be used for diagnosis (<i>p</i>: 0.066), but asprosin was associated with the acute phase of schizophrenia (<i>p</i> < 0.001) and both asprosin and PYY were associated with the disease (<i>p</i> < 0.001, <i>p</i> < 0.001). <b>Conclusions</b>: We think that both asprosin and PYY can be used as potential biomarkers to identify schizophrenia, and only asprosin to identify the phases of the disease. PYY and asprosin levels may be markers that can be used to determine clinical severity.