Is depression linked only to sadness?

Biology has an explanation that rightly describes depression as much more than just sadness, just like psychology does. According to psychology, depression relates to the secretion of a hormone, known as Cortisol, which is secreted by the body in response to stress.

According to biology, depression is related to the lower levels of a single molecule in our body, which is acetyl-L-carnitine (ALC). On testing the blood of various healthy and depressed people, it was found out that ALC level in the people suffering from depression was considerably low.

Reports tell that sadness is a major symptom of depression, but there are many other symptoms and sadness is not the only link that can be there with depression. Other symptoms are loss of energy, difficulty in thinking, and loss of interest in previously pleasurable activities.

Studies also tell that those having extremely low levels of ALC have treatment-resistant depression, and that’s really a point of concern.