The widow of comedian Robin Williams has suggested that it was not depression that drove her husband to take his life in August 2014.

In an interview with People Magazine, Susan Williams says “It was not depression that killed Robin. Depression was one of let’s call it 50 symptoms, and it was a small one.”

Williams revelaed that her husband was suffering from a debilitating brain disease called Diffuse Lewy Body dementia or dementia with Lewy bodies (DLB). She says that this may have led him to suicide.

The disease causes causes changes in mental status, hallucinations and impairment of motor function and his widow said that the symptoms were getting more severe in the months leading up to his death. Williams said the anxiety, delusions and impaired movement "present themselves like a pinball machine. You don't know exactly what you're looking at."

'Robin was very aware that he was losing his mind and there was nothing he could do about it,' " she added.