If we try to control all of life's circumstances, we will be rife with dissatisfaction. This is because we can't make pleasant experiences last, and we can't prevent experiences that are unpleasant to us from arising. So, the cause of our dissatisfaction is this tendency to live in a constant state of craving, a state I like to call "want/don't want." We want pleasant experiences to last and we don't want unpleasant ones to arise.
How he managed and treated a recurring depression he had for a good part of his life in the article I'm excerpting below. His methods are in keeping with how I suggest people deal with all mental health issues. Holistically. What works for people is generally a combination of several things that varies from person to person. No two of us is alike.