There are several questions and answers about the illness called depression.
Depression is a mood disorder that affects most of the activities of daily living.
The most common effects are on sleep, eating, energy, and sex drive. We have been able to identify many of the chemical changes in depression. Depression does the same thing to our mood and lifestyle whether the cause is internal or external in nature. Scientists can now identify a over 400 neurotransmitters in the brain. When we are under prolonged stress, depression often results in a shortage of one of these chemicals.