Cerebrospinal fluid tau protein levels in schizophrenia.

Increased cerebrospinal fluid (CSF) tau protein levels are generally considered to provide a sensitive marker of neurodegenerative processes such as Alzheimer's disease (AD). Since a more pronounced cognitive decline has been described in older schizophrenic patients, it has been hypothesized that these patients might be at a higher risk of developing AD. CSF levels of total tau protein and tau protein phosphorylated at threonine 181 (phospho-tau) were determined among 19 older and younger patients with schizophrenia compared to 20 age-matched healthy controls. No significant differences in CSF total tau and phospho-tau levels arose between patients with schizophrenia and controls. Although our results do not exclude a progressive neurodegenerative pathology, they provide evidence against major neuronal degeneration such as an AD-related pathology associated with increased tau levels in schizophrenia.