Abstract
BACKGROUND: A growing body of evidence implicates oxidative stress in the pathophysiology of schizophrenia. This study aimed to analyze the pairwise correlations among the four variables in patients with schizophrenia: oxidative stress (lipid peroxidation), the niacin skin response, cognitive function, and clinical symptoms. METHODS: This cross-sectional observational case-control study included 40 patients with chronic schizophrenia and 40 matched healthy controls. Plasma lipid peroxidation (LPO) levels, the niacin skin flush response, and cognitive function were assessed in all participants. Symptom severity in patients was evaluated using the Positive and Negative Syndrome Scale (PANSS). Regression analyses were conducted to examine the relationships among LPO levels, the niacin skin response, clinical symptoms, and cognitive function. RESULTS: Plasma LPO levels were significantly higher in the patient group than in the healthy controls, whereas cognitive function and the niacin skin flush response were significantly reduced. Within the patient group, correlation analysis revealed that LPO levels were negatively associated with the total flush area at concentrations 1 and 2 measured at 5 min. Furthermore, significant negative correlations were observed between cognitive function and clinical symptoms across multiple dimensions (all P < 0.05). CONCLUSION: Patients with chronic schizophrenia exhibited elevated oxidative stress (LPO), impaired cognitive function, and attenuated niacin skin flush response. Importantly, oxidative stress showed a negative correlation with the niacin response, while cognitive performance was also negatively correlated with clinical symptom severity. These findings suggest that oxidative stress may be involved in the pathophysiological process of schizophrenia, and that the attenuated niacin skin response could serve as a measurable marker of dysfunction in the peripheral inflammation-oxidative stress axis. CLINICAL TRIAL: Not applicable.