Robin Williams' widow Susan speaks out for first time about his death

Comedian Robin Williams' widow Susan Williams is opening up for the first time since about her husband's August 11, 2014 death, says depression didn't kill him.

''It was not depression that killed Robin, ''Susan told "Good Morning America" about his diagnoses, with was Diffuse Lewy Body Dementia or Dementia with Lewy bodies. ''Depression was one of let's call it 50 symptoms and it was a small one.''

''I’ve spent this last year trying to find out what killed Robin. To understand what we were fighting, what we were in the trenches fighting and one of the doctors said, 'Robin was very aware that he was losing his mind and there was nothing he could do about it,'' Susan added, saying that the symptoms include anxiety, delusions and impaired movement.

''If Robin was lucky, he would've had maybe three years left. And they would’ve been hard years. And it’s a good chance he would’ve been locked up,'''Susan added to ABC News.

She also detailed the last conversation she had with him, when he asked if she wanted a foot rub.

''And I said, 'It's OK, honey. Not — you know, it's OK. You don't have to tonight.’ And I'll never forget the look in his eyes of just, sad because he wanted to. And I wished — you know? Then he came back in the room a couple of times. Once to his closet. And he said — and then he laughed. And he said, ‘Goodnight, my love.' And I said, 'Goodnight, my love,''' Susan described.