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

The beloved comedian's personal assistant found Williams hanging from his belt in a bedroom of his California home on Monday, sparking speculation about his long public battle with addiction.

But Susan Schneider, issuing a statement through an agency, said the 63-year-old's most recent problems had been with his mental health and with Parkinson's, a degenerative nerve disorder.

"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," she said.

"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."

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," 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.

Williams, an Oscar-winner and veteran of movies, stand-up shows and hit television series, was one of Hollywood's most popular entertainers and his death triggered an outpouring of emotion.