Dr. John Mann on Depression and Alcohol: NBC News

August 12, 2014
Blurb
 Dr. J. John Mann, a professor of psychiatry at Columbia University and director of the molecular imaging and neuropathology division at the New York State Psychiatric Institute, said Williams' recent return to rehab "is probably highly relevant."
"What happens in someone like Robin Williams is that alcohol can change the whole equation. When they drink they are different. They are altered. Their decision making process is changed. Their probability of acting on emotions increases," he said. "The lesson for anybody suffering from a mood disorder is that alcohol is a tremendous risk factor for suicide."
Read more:  http://www.nbcnews.com/storyline/robin-williams-death/robin-williams-funny-face-depression-n178756