Hollywood actor Robin Williams, found dead this week after an apparent suicide, was suffering from depression, anxiety and the early stages of Parkinson's Disease, his wife has said. 

In a statement, Susan Schneider said the 63-year-old had been suffering with his mental health and with Parkinson's, a degenerative nerve disorder.

She said: "It is our hope in the wake of Robin's tragic passing, that others will find the strength to seek the care and support they need to treat whatever battles they are facing so they may feel less afraid."

"Robin's sobriety was intact and he was brave as he struggled with his own battles of depression, anxiety as well as early stages of Parkinson's Disease, which he was not yet ready to share publicly," she said.

The coroner of Marin County, outside San Francisco, where the couple lived has opened an inquiry into the death, but has confirmed it as a suspected suicide, pending toxicology reports.

"Robin spent so much of his life helping others," Ms Schneider said.

"Whether he was entertaining millions on stage, film or television, our troops on the frontlines, or comforting a sick child - Robin wanted us to laugh and to feel less afraid.

"Since his passing, all of us who loved Robin have found some solace in the tremendous outpouring of affection and admiration for him from the millions of people whose lives he touched. 

"His greatest legacy, besides his three children, is the joy and happiness he offered to others, particularly to those fighting personal battles," she added.

Mr Williams's appeal stretched across generations and genres, from family fare as the voice of Disney's blue Genie in 'Aladdin' to his portrayal of a fatherly therapist in the 1997 drama 'Good Will Hunting,' for which he earned his sole Oscar.

But many remembered the master of impressions for his tender portrayal in 'Mrs Doubtfire', when he played the part of a British nanny whose identity he assumed as a divorced father to be with his children.