Serum BDNF Is Positively Associated With Negative Symptoms in Older Adults With Schizophrenia

Older adults with chronic schizophrenia are at greater risk for functional disability and poorer health outcomes than those without serious mental illness. These individuals comprise 1-2% of the elderly population in the United States and are projected to number approximately 15 million by 2030. The symptoms of schizophrenia can be disabling for individuals, significantly reducing quality of life. Often, the negative symptoms (NS) are the most resistant to treatment and are considered a marker of illness severity, though they are challenging to measure objectively. Biomarkers can serve as objective indicators of health status. Brain-derived neurotrophic factor (BDNF) is a potential biomarker for schizophrenia and may serve as an important indicator of illness severity.

A cross-sectional study with 30 older adults with chronic schizophrenia. Participants were assessed on serum levels of BDNF and psychiatric symptoms (Positive and Negative Syndrome Scale). Pearson's bivariate correlations (two-tailed) and linear regression models were used.

A significant positive association ( p < .05) was found between higher serum levels of BDNF and greater severity for the NS items of passive, apathetic, social withdrawal, and emotional withdrawal. In multivariate analyses, the association remained significant.

Although the association between BDNF and NS was not in the expected direction, the data corroborate findings from previous work in patients with schizophrenia. It is possible that higher serum levels of BDNF reflect compensatory neuronal mechanisms resulting from neurodevelopmental dysfunction.