In her first interview since his death, Susan Williams, wife of the Oscar-winning actor, claims the symptoms of Lewy Body Dementia was one of many factors that led to his suicide.

The news of his death shocked the world of entertainment, and led to an international outpouring of grief for a much-loved actor, but many assumed that Robin Williams’ suicide was a result of the depression demons that had plagued him in the past.

However, in a TV interview with US news network ABC, his widow, Susan, claims that it was the symptoms of Lewy Body Dementia that was a key cause in his decision to end his life.

‘Lewy body dementia is what killed Robin,’ Williams said. ‘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.’

Asked whether her husband's suicide was his way of taking back control, she replied; ‘in my opinion, oh, yeah. I mean, there are many reasons. Believe me. I’ve thought about this. Of what was going on in his mind, what made him ultimately commit... you know, to do that act. And I think he was just saying, “No.” And I don't blame him one bit. I don't blame him one bit.’

Susan Williams says that while Robin had fought drink and drug addiction in the past, he was ‘completely clean and sober’ when he died, but was struggling with depression and anxiety.

He also had distinct physical symptoms which included stiffness, slumping, a shuffling gait and ‘losing his ability in his voice,’ she said.

‘It's one minute, totally lucid… And then five minutes later, he would say something that wasn't... it didn't match.’

In a previous print interview with US magazine, People, Susan revealed that it was not depression that killed Robin.

‘Depression was one of let’s call it 50 symptoms, and it was a small one,’ said Susan.

She claims that the symptoms of his LBD started taking their toll in the last year before his death at the age of 63 in August 2014, but worsened in the months leading up to his death.

Dementia with Lewy bodies accounts for around 4 per cent of all dementia cases, although it is often under-diagnosed, and the Alzheimer’s Society believes that as much as 10 per cent of cases could be caused by the presence of proteins in nerve cells (Lewy Bodies).

Hallucinations can be one of the first symptoms of dementia with Lewy bodies, and you may see colours, shapes, animals or people that aren't there. Some people develop a shuffling walk, tremors, stiff limbs, dizziness, fainting and falls.

Confusion and memory loss may follow but aren't usually one of the first signs of the condition, but sleep difficulties and depression are quite common.

Robin Williams’ wife Susan admits that his ‘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.’