Correlation between myelin basic protein levels in cerebrospinal fluid and motor speed in patients with schizophrenia.

Alterations in the white matter have been implicated in schizophrenia. Myelin basic protein (MBP), a component of the myelin sheath, in the cerebrospinal fluid (CSF) has been suggested as a biomarker for white matter damage in demyelinating diseases. This prompted us to examine the CSF-MBP levels in patients with schizophrenia. We analyzed the CSF-MBP levels in 152 patients with schizophrenia and 117 age- and sex-matched controls. A significant positive correlation between age and CSF-MBP levels was observed both in the patients (p < 0.001) and controls (p = 0.014). No significant difference was observed in the CSF-MBP levels between the two groups. However, among a subsample of the patients (N = 32), a significantly negative correlation was observed between CSF-MBP and age-adjusted motor speed score of the brief assessment of cognition in schizophrenia (ρ = -0.59, p < 0.001). Further, among patients who underwent diffusional magnetic resonance imaging of the brain (N = 27), the CSF-MBP levels showed a significantly negative correlation with the mean kurtosis value in the right temporo-parietal region (p < 0.001). Our results suggest that the CSF-MBP level has limited utility as a diagnostic marker; however, higher CSF-MBP levels are associated with poorer motor speed, which may be associated with regional white matter damage in the brain in patients with schizophrenia.