I first took anti depressants, or "ADs" as I like to call them, in 1995, when I was in nursing school. Back then I didn't know it was an idiopathic disease with a genetic component, that could be activated and exacerbated by adverse life circumstances. After years of off and on an alphabet of pharmaceuticals, ECT and various homeopathic remedies I have reached the following conclusion; depression is shit awful and 15% of the people who have it kill themselves.
Robin Williams, IMO, succumbed to the disease of depression. I'm sure he was doing everything right, probably on medication and in therapy, being transparent, etc. But he died of his disease, and it really sucks.