The Roles of Neurotransmitters, Hormones and Brain-derived Neurotrophic Factors in the Pathogenesis of Depression

Depression is one of the fi ve leading causes of disability and disease burden worldwide. Neurotransmitters and hormones have been the focus of pathogenic studies in depression. Since knowledge of depression’s neurophysiology has become more advanced, evidence currently shows that in depression underactivation of serotonergic and noradrenergic systems play major roles in the pathogenesis of neurotransmitters, while elevated hypothalamic-pituitary-adrenal (HPA) axis activity is a hallmark of stress responses and hormonal dysfunction. Other hormones such as thyroid hormones, growth hormone, prolactin and gonadal hormones have also been found signifi cant. Recently, there has been greater concern that Brain-derived neurotrophic factor (BDNF) might also be involved in the pathogenesis of depression. Future research may shift from dealing with neurotransmitters to focus on the interventions that modulate the HPA axis and BDNF for the treatment of depression. Chiang Mai Medical Journal 2009;48(1):35-41.