Oxytocin, social cognition, and neurocognitive function in male patients with schizophrenia: A prospective study

This study examined serum oxytocin levels during an acute psychotic episode and following antipsychotic treatment response in male patients with schizophrenia, and explored associations with social cognition and functional cognitive domains.

The sample consisted of 51 male patients meeting DSM-5 criteria for schizophrenia who were assessed during an acute psychotic episode, and 41 healthy male controls. Sociodemographic characteristics, clinical symptoms, and functional status were evaluated using the Sociodemographic and clinical data form(SDVF), Positive and Negative Syndrome Scale (PANSS), Global Assessment of Functioning (GAF), Cognitive Assessment Interview-Turkish Version (CAI-TR), and Reading the Mind in the Eyes Test (RMET). Serum oxytocin levels were measured using enzyme-linked immunosorbent assay (ELISA). Patients who met the predefined treatment response criterion (≥25% reduction in PANSS total score, N = 33) underwent a second evaluation after a mean follow-up period of 12 weeks.

Mean serum oxytocin levels were significantly lower in the patient group (143.94 ± 104.88 pg/mL) than in the control group (254.12 ± 152.58 pg/mL) (t₆₈.₂₈ = 3.93, p < 0.001, d = 0.86). Among the 33 treatment responders, oxytocin levels increased significantly from the acute episode to follow-up (152.55 ± 108.75 to 214.15 ± 115.79 pg/mL; t = 3.27, p = 0.003, d = 0.57). Baseline oxytocin levels were negatively correlated with PANSS Positive and General Psychopathology scores, and positively correlated with RMET and GAF scores. Increases in oxytocin levels following treatment occurred in parallel with improvements, particularly in social cognitive functioning.

These findings indicate that oxytocin levels in patients with schizophrenia are associated with social cognitive functioning and increase in parallel with improvements following treatment. Peripheral oxytocin levels may represent a promising candidate biomarker in schizophrenia.