Robin Williams' widow, Susan Williams, for the first time since her late husband's suicide, has publicly spoken about the circumstances that preceded the actor and comedian's death, revealing that it was not depression that led Robin Williams to take his own life.

In interviews with People magazine and with ABC News, Susan Williams revealed that Lewy body dementia was responsible for the 63-year-old "Jumanji" star's suicide, which took place on Aug. 11, 2014, in the home he shared with her in Tiburon, Calif, as HNGN previously reported.

"It was not depression that killed Robin," Susan Williams said in the People magazine interview. "Depression was one of, let's call it 50 symptoms, and it was a small one."

"This was a very unique case and I pray to God that it will shed some light on Lewy bodies for the millions of people and their loved ones who are suffering with it. Because we didn't know. He didn't know," she added.

On Tuesday, glimpses of an interview with Susan Williams were aired on ABC's "Good Morning America," with additional segments scheduled to be broadcast later that evening on the network's other shows, according to New York Times.

"Lewy body dementia is what killed Robin," Susan Williams said in the interviews. It wasn't until after his death that an autopsy confirmed he had the disease. "It's what took his life and that's what I spent the last year trying to get to the bottom of, what took my husband's life."

Robin Williams, who had been diagnosed with Parkinson's disease three months before his death, had "this endless parade of symptoms" since fall 2013, "and not all of them would raise their head at once," his wife said.

Lewy body dementia is frequently confused with Parkinson's because of their overlapping symptoms and takes place after certain protein bodies disrupt normal brain functions such as concentration, judgment, thinking, mood, movement and behavior according to the National Institute of Health, ABC News reported.

"If Robin was lucky, he would've had maybe three years left," Susan Williams said, according to Good Morning America. "And they would've been hard years. And it's a good chance he would've been locked up."