There are many biological causes of clinical depression. The brain has been studied extensively to understand the chronology of brain function, the influence of neurotransmitters and hormones and other biological processes and also how central they are - to the development of depression.
The brain is a commander-in-chief of the human body. It controls the basic functions of our bodies, our movements, and our thoughts and emotions.
Researchers studying clinical depression tend to look at several aspects of brain function including the structures of the limbic system and the function of neurotransmitters within neurons.
’Limbic System’ is the area of the brain that governs activities such as emotions, physical and sexual drives, and the stress response.It's activities are significantly complex and any irregularity in any part of it, including how neurotransmitters function, could take a toll on an individual's mood and behavior.
'Hypothalamus' is a small structure located at the base of the brain, responsible for body temperature, sleep, appetite, sexual drive, stress reaction, and the regulation of other activities. It also controls the function of the pituitary gland which in turn regulates key hormones.
Neurotransmitters and Neurons: They are special chemicals called neurotransmitters carrying out many very important functions, like: helping transfer messages throughout structures of the brain's nerve cells. These nerve cells, called neurons.
Neurotransmitters have been found to be associated with clinical depression. They function within structures of the brain that regulate emotions, reactions to stress and the physical drives of sleep, appetite, and sexuality.
Theories about how neurotransmitters may be related to a person's mood have been based upon the effects that antidepressant medications can have relieving depression in some people. It is believed that these medications are effective because they regulate the amount of specific neurotransmitters in the brain.
However, whether that neurotransmitters play central role in the development or treatment of clinical depression is ambiguous.