not good stuff

Depression.

The doctors said that a recently discovered substance, serotonin, was one of the compounds responsible for human beings felt. A lack of serotonin impaired one's capacity to concentrate at work, to sleep, to eat, and to enjoy life's pleasures. When this substance was completely absent, the person experienced despair, pessimism, a sense of futility, terrible tiredness, anxiety, difficulties in making decisions, and would end up sinking into a permanent gloom, which would lead to either complete apathy or suicide. Other doctors ... said that any drastic change in life could trigger depression.