Brain-derived neurotrophic factor (BDNF) gene not associated with antidepressant-induced mania

Background: Brain-derived neurotrophic factor (BDNF) plays an important role in the regulation of synaptic plasticity and neurotransmitter release across multiple neurotransmitter systems. Recent studies have suggested that BDNF plays a role in the pathogenesis of bipolar disorder (BPD). Moreover, increasing BDNF production might be one of the mechanisms involved in the alleviation of depression and aggravation of mania in antidepressant treatment. Objectives: Thus, we hypothesized that a genetic variant within the BDNF gene might influence susceptibility to antidepressant-induced mania, as has been suggested previously. Methods: We performed a case-control study to test for allelic frequency and genotype distribution differences across six BDNF polymorphisms between 27 patients with antidepressant-induced mania (IM+) and 29 patients without antidepressant-induced mania (IM-). Results: We did not observe any significant difference in either allelic or genotype frequencies between the two groups. Conclusions: Our results did not support the BDNF link to mania hypothesis proposed previously. However, a larger sample would allow for greater power to determine smaller effects of the BDNF gene in antidepressant-induced mania.