Serum hyperhomocysteine and cognitive impairment in first-episode patients with schizophrenia: Moderated by brain cortical thickness

Abstract

The mechanism by which high homocysteine (HCY) may aggravate cognitive impairment in patients with schizophrenia is not well understood. We aimed to test the hypothesis that hyperhomocysteinaemia may exacerbate cognitive deficits by mediating the decrease in cortical thickness in patients with schizophrenia. One hundred and sixty-seven first-episode patients with schizophrenia (FEPS) and 120 healthy controls (HCs) were included. Psychopathology and cognitive function were assessed using the Positive and Negative Symptom Scale and Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB), respectively. Brain cortical thickness was measured by 3.0 T high-resolution magnetic resonance imaging. Serum HCY levels were tested using a sandwich enzyme-linked immunosorbent assay. Our findings showed that HCY levels in the FEPS were significantly higher than those in the HCs (P < 0.001). The MCCB total and subtest scores in the patients were significantly lower than those in the HCs (P < 0.001). The HCs had significantly higher cortical thickness than the patients (P < 0.001). Serum HCY levels were negatively correlated with Working Memory, Attention/Vigilance, and MCCB total scores in the FEPS (P < 0.05). Brain cortical thickness had positive moderating effects on cognitive impairment in FEPS with high HCY after controlling for sex, age, and education (P < 0.05). In HCs with high HCY, brain cortical thickness had no mediating or moderating effects on cognitive impairment. Compared with HCs, FEPS had thinner grey matter thickness, furthermore, the grey matter thickness might play a crucial role in relationship between high HCY and cognitive deficits.