Robin Williams Had Parkinson's Disease
Robin Williams was in the early stages of Parkinson's disease before his death, his widow has said.
Susan Schneider said the actor "was not yet ready to share publicly" his struggles with the degenerative disease as he also fought depression.
She also said the 63-year-old Oscar-winner, who openly dealt with alcoholism and drug addiction during his career, was sober when he died.
"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," Ms Schneider said.
She added that Williams' family hoped others would use his tragic death to seek help "to treat whatever battles they are facing so they may feel less afraid".
Williams was found hanged in the bedroom of his northern California home on Monday.
He was last seen alive by his wife at about 10.30pm the previous evening before she went to bed.
Ms Schneider did not provide details on when Williams was diagnosed with Parkinson's, an incurable nervous system disorder that affects movement.
The disease progresses gradually, often beginning with a slight tremor in one hand.
Williams had long been a supporter of the Michael J Fox Foundation for Parkinson's Research, founded by the fellow film and television star who has famously confronted the disorder.
The foundation has raised more than $450m (£270m) since it was established in 2000.
Fox was among the countless stars who paid tribute to Williams after his death, writing on Twitter: "Famously kind, ferociously funny, a genius and a gentle soul. What a loss."
It is not immediately clear if anyone outside Williams' immediate family knew he had the disease.
The star of hit movies including Good Will Hunting, Good Morning, Vietnam and Mrs Doubtfire had recently grappled with severe depression, according to friends and family.
He checked himself back into rehab last month to "fine-tune" his sobriety, his publicist said.
Williams' death sent shockwaves through the entertainment industry, and fans, including Hollywood's elite and politicians, paid tribute to the popular comedian.
His widow said: "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."