Anatomy and physiology

It is estimated that more than 20% of the population of the United States suffers from some form of depression, which has its root cause in the nervous system (specifically neurotransmitters and their associated enzymes/activators/inhibitors). In this paper, answer the following questions:

What are the main types of antidepressant medications?
What is are the main mechanisms of action of antidepressant medications?
Are these medications over-prescribed in modern-day society?
Are there alternative strategies to help treat depression?