Serum Occludin Levels Are Elevated in Schizophrenia: A Case-Control Study

In this study, it was aimed to compare the serum occludin levels of patients with schizophrenia and healthy controls. There are few studies examining the relationship between and blood-brain barrier (BBB) permeability and the pathogenesis of schizophrenia. We hypothesized that schizophrenia patients' serum occludin levels could vary from those of healthy controls. The study included 39 patients with schizophrenia and 38 healthy controls. Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS) were used to determine the severity of symptoms. Serum occludin levels were measured from venous blood samples. The levels of occludin in the schizophrenia group were found to be significantly higher than those in the control group. When age, gender, Body Mass Index (BMI) and smoking were controlled, it was observed that the significant increase continued. Serum occludin concentration and the SANS-measured negative symptoms of schizophrenia showed a significant negative correlation. The cut-off value for occludin level was calculated by ROC analysis.These results regarding occludin levels suggest that dysregulation of the BBB may contribute to the etiology of schizophrenia.