The Effects of Treatment in Psychotic Disorders-Changes in BDNF Levels and Clinical Outcomes: Systematic Review

Psychotic disorders are associated with significant impairment in functioning, and their treatment remains a great therapeutic challenge. Patients are at a higher risk of suicide and premature mortality. Biomarkers, such as brain-derived neurotrophic factor (BDNF), play a vital role in neurotransmission and neurodevelopment. Decreased levels of BDNF alter neuronal signaling and cause the appearance of symptoms such as the impairment of working memory. A literature search was performed using the PubMed data base. Following the inclusion and exclusion criteria, 24 original articles were selected. We collected available data showcasing the influence of antipsychotic and non-pharmacological treatments, in patients suffering from psychotic disorders, on clinical conditions and BDNF levels in serum or plasma. In this review, we outline emerging data regarding the influence of different antipsychotic drugs and non-pharmacological treatment methods on BDNF and discuss their role as predictors of treatment outcome. Most studies conducted with antipsychotics saw an increase in BDNF levels; however, no positive correlation between change in BDNF and PANSS scores was observed. Studies based on non-pharmacological methods varied based on the treatment applied. Therefore, it is difficult to draw definite conclusions.

Serum brain-derived neurotrophic factor and glial cell-derived neurotrophic factor in patients with first-episode depression at different ages

OBJECTIVES

We investigated the differences in serum brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) levels and clinical symptoms with first-episode depression at different ages.

METHODS

Ninety patients (15-60 years old) diagnosed with first-episode depression were enrolled as the study group, and they were divided into early-onset, adult and late-onset groups. The age-matched control groups were healthy volunteers. Serum BDNF and GDNF concentrations were determined by enzyme-linked immunosorbent assay (ELISA). GraphPad Prism 9 was used for t tests, one-way ANOVAs, chi-square tests, and correlation analyses. p < 0.05 indicated significant differences.

RESULTS

Serum BDNF and GDNF levels were lower in the whole study group and the three subgroups than in the healthy groups. Illness severity, anxiety and education were higher in the early-onset than late-onset patients. Serum BDNF levels were lower in the adult than late-onset patients. Serum BDNF levels were negatively correlated with patient CGI-SI scores. After the LSD test for multiple comparisons, the results were also significant.

CONCLUSIONS

Low serum BDNF and GDNF levels may be involved in the pathophysiology of first-episode depression, and there were differences in serum BDNF levels at different ages, verifying that serum BDNF and GDNF could serve as potential biomarkers of depression. KEY POINTSDepression is often conceptualised as a systemic illness with different biological mechanisms, but satisfactory explanations have not been provided thus far.The aim of our study was to investigate differences in serum BDNF and GDNF levels and their relationships with clinical symptoms in patients with first-episode depression at different ages.The potential of the neurotrophic factor hypothesis to advance the diagnosis and treatment of depression will be a very exciting new strategy for future research.