Neuropsychiatric correlates of cerebrospinal fluid biomarkers in Alzheimer's disease

Background: The aim of this study was to explore the relationship between cerebrospinal fluid biomarkers and neuropsychiatric symptoms in people with Alzheimer’s disease. Psychosis, agitation, apathy and depression were assessed using standardised measures in 32 patients with mild Alzheimer’s disease. Methods: The levels of the 42-amino-acid form of β-amyloid (Aβ1–42), tau and p-tau (phosphorylated at threonine 181) were quantified using the conventional enzyme-linked immunosorbent assay method. Results: Our result shows that apathy is significantly correlated with tau and p-tau but not with Aβ1–42. There were no significant correlations between indices of psychosis/agitation,or depression and cerebrospinal fluid Aβ1–42, tau or p-tau concentrations. Conclusion: Our finding suggests that apathy is associated with the level of neurofibrillary tangles in people with mild Alzheimer’s disease. In contrast, the overall levels of neurofibrillary tangles or amyloid plaques do not seem to be associated with depression or psychosis, indicating that other brain changes contribute to these symptoms.