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Robin Williams’ Widow Reveals the True Cause of His Suicide in an Emotional New Interview

So heartbreaking.

In an emotional new interview with Good Morning America that aired Tuesday, Susan Schneider opens up about her late husband Robin Williams' August 2014 suicide.

Susan discusses many things in the interview, but perhaps the most shocking is what she says caused Robin's suicide. It's not depression, like many believe, but a debilitating brain disorder called Lewy Body Dementia, which dramatically affects one's thinking, emotions and behavior.

"Lewy Body Dementia killed Robin," Susan says definitively in the interview. "It's what took his life. And that's what I've spent the last year trying to get to the bottom of. What took my husband's life?"

Susan reveals the disorder was causing Robin to lose his mind. "He was keeping it together as best as he could, but the last month he could not. It was like the dam broke."

She opens up more about Robin's final days, specifically the morning of his suicide. "[His assistant] sent me a text and said, 'He's not up yet. What should I do?'" Susan reveals, trying to hold back tears. "That 20-minute car ride, I just screamed the whole way, 'Robin!'"

The interview is very heartbreaking to watch, but Susan offers moments of levity in it. "My favorite movie of Robin Williams was Robin Williams being a human being, not an actor," she says with a warm disposition. "Best movie in the world."

Watch the emotional sit-down above, and give us your thoughts in the comments.