Biological Rhythm Disturbances and Metabolic Syndrome Comorbidity in Patients with Schizophrenia
Abstract
Objective: Biological rhythm disturbances and sleep abnormalities are common in schizophrenia and have been associated with metabolic dysfunction in the general population. However, the association between circadian disturbances and metabolic syndrome (MS) comorbidity in schizophrenia remains insufficiently understood. This study investigates the associations of sleep quality, chronotype, and biological rhythm disturbances with MS in patients with schizophrenia. Methods: A total of 82 patients were included in this study. Sleep quality, chronotype, and biological rhythm disturbances were evaluated using the Pittsburgh Sleep Quality Index (PSQI), Morningness–Eveningness Questionnaire (MEQ), and Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN). Physical activity level and dietary habits were also evaluated. Separate binary logistic regression analyses were conducted to examine the associations of PSQI, MEQ, and BRIAN total scores with MS after adjustment for age and sex. Results: Patients with and without MS did not significantly differ regarding PSQI, MEQ, or BRIAN total scores. In age- and sex-adjusted logistic regression analyses, no significant associations were detected between MS and PSQI total (P = .406), MEQ total (P = .195), or BRIAN total scores (P = .623). Conclusion: In this exploratory sample of patients with schizophrenia, no significant associations of subjective sleep quality, chronotype, or biological rhythm disturbances with MS were detected. Given the modest sample size, these findings should be interpreted cautiously and warrant confirmation in larger longitudinal studies incorporating objective sleep and circadian measures. Cite this article as: Kurtulmuş A, Hopur İlhan A, Şahinbaş EE, Baran Boz B, Özer BU, Görmez A. Biological rhythm disturbances and metabolic syndrome comorbidity in patients with schizophrenia. Neuropsychiatr Invest. 2026, 64, 0027, doi: 10.5152/NeuropsychiatricInvest.2026.26027.