a. Amin hữu cơ, não bộ con người giao tiếp với chính nó sinh hóa. Các hóa chất sinh học có liên quan đến quá trình này được gọi là chất dẫn truyền thần kinh. Có khả năng được nhiều chất dẫn truyền thần kinh tham gia vào các quá trình phức tạp của bộ não con người, | Mood Disorders 157 mood disorders as well as an observed reduction in suicide in the elderly D. Etiology of Depression As with most psychological disorders the causes of depression are multiple and overlapping. It is customary to divide etiological theories of depression into biological psychological and social factors. 1. Biological Factors a. Biogenic Amines The human brain communicates with itself biochemically. The biological chemicals that are involved in this process are referred to as neurotransmitters. There are likely to be numerous neurotransmitters involved in the complex processes of the human brain however two chemicals from the amine family have been implicated in the disordered functioning of the brain in depression according to Nemeroff in 1998. The first serotonin or 5-hydroxy-tryptophan 5-HT is the most active biological amine in the human brain. A second biogenic amine noradrenaline NA has also been implicated. The biogenic amine theory of depression postulates that levels of 5-HT and NA are present in subnormal levels in the parts of the human brain that regulate mood. The mechanism of action of virtually all antidepressant compounds is to effectively increase the level of activity of these compounds. b. Neuroendocrine Factors Research by Nemeroff in 1998 indicated that the state of depression is associated with alterations in the level and activity of various endocrine glands particularly the adrenal gland and the thyroid gland. This research demonstrated that higher levels of corticosteroids such as cortisol are associated with depression as are alterations in responsiveness of the adrenal gland to the suppressive effects of artificial corticosteroids such as dexamethasone. Other hormonal disturbances include alterations in thyroid gland function. c. Genetic Factors There have been numerous family and molecular studies of depression however progress has been limited by the fundamental problem of phenotypic identification. The controversy .
