Serotonin is mainly present in the brain, bowels, and blood platelets of the human body and is at times referred to as the ‘happy chemical’ as its high levels contribute to happiness and well-being.
Serotonin acts like a neurotransmitter that the body uses to pass messages between the nerve cells to influence a range of functions, such as emotions, sleep-wake cells, appetite, and the body clock as a whole.
Role of serotonin in body health
Since serotonin cells are widely distributed in our body, they play an important role in regulating a variety of physical and psychological body functions. In fact, almost all of the 40 million brain cells are influenced by serotonin, either directly or indirectly.
Relation between serotonin and depression
Like other medical complications, depression is a complex condition that can be caused by a number of factors. While serotonin is one of the causes, experts have yet to figure out the exact details.
Researchers who are studying the link between serotonin and depression have found that while low levels of serotonin don’t regulate depression, the intake of SSRIs, or selective serotonin reuptake inhibitors for increasing serotonin is an effective treatment for depression. However, it is advised to ask an endocrinologist before taking antidepressants.
Another theory is that depression impacts the regeneration of brain cells, a continuous process believed to be brought about by serotonin. Neuroscientists are of the opinion that depression is a result of the suppression of new brain cells of which stress is the main culprit.
Having said that, while it is widely believed that deficiency of serotonin plays a role in boosting depression, they have yet to determine its levels in the brain. It is, therefore, inconclusive whether a shortage of serotonin neurotransmitters in the brain can cause depression or allow any other mental illness to foster.
While blood levels of serotonin are measurable from other parts of the body, researchers have no idea if these levels reflect the levels of serotonin in the brain.
There is also an indication that the role of diminished serotonin can trigger depression in people, particularly those with a past history of illness. Interestingly, it has been found that in patients suffering from more severe forms of depression, low plasma levels of serotonin are hardly the cause.
Antidepressant medicines that are used to treat serotonin, like SSRIs, are known to relieve the symptoms of depression, but how they work is not fully comprehended as yet. Again, while inflammation can cause depression in vulnerable cases by lowering the serotonin levels, the diminished efficacy of SSRIs in such patients is laid threadbare because of its high inflammatory side effects.
Increasing the serotonin activity in people who are depressed does not affect mood directly, but rather causes secondary positive shifts in the automatic emotional response system of the body.
So the moot point is, whether it is the low level of serotonin that causes depression or the depression itself that is responsible for the serotonin levels to dip.