Although the gifted comedian had spoken before about his depression, Parkinson’s experts have noted how the incurable and debilitating nervous system disorder that causes tremors and slowness of movement also affects people emotionally.
“The neurochemicals that are impacted by Parkinson’s disease and the pathways that control motor functions are also integrally involved in the control of mood,” said Dr Irene Richard, a neurology professor at the University of Rochester in New York.
More than half of those who suffer from Parkinson’s also experience clinical depression, according to the National Parkinson Foundation, which advises all Parkinson’s patients to be screened for depression.
The 63-year-old Oscar-winning comedic virtuoso, whose madcap style and dramatic versatility made him one of film and television’s top stars, was found dead at his home in northern California on Monday.
Williams’ widow, Susan Schneider, said the comedian “was not yet ready to share publicly” his struggles with Parkinson’s, which affects about one million people in the United States.
“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,” Schneider said in the statement.
“We actually believe that (depression) is part of the disease itself. It’s related to the brain dysfunction in Parkinson’s disease,” Richard said.
Actor Michael J Fox, boxer Muhammad Ali, and singer Linda Ronstadt have all be diagnosed with Parkinson’s. Ronstadt said last year the disease had robbed her of her singing voice.
“Stunned to learn Robin had PD,” Fox said on Twitter. “Pretty sure his support for our Fdn (foundation) predated his diagnosis. A true friend; I wish him peace.”
Williams, whose starring roles included Mrs Doubtfire and Good Will Hunting, had been open about his struggles with alcohol and had gone to a Minnesota rehabilitation centre this summer to “fine-tune” his sobriety, his publicist said in July.
Schneider said Williams was sober when he died and was also suffering from anxiety.
Friends of the comedian, who first shot to prominence as a friendly alien in late 1970s TV series Mork & Mindy, described him as a man who masked his depression and thrived from performing for a crowd.
“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,” Schneider said.
Funeral arrangements are pending.
A full toxicology report will take two to six weeks to complete, local officials said.
Meanwhile, Fifi Geldof, speaking of her shock at Williams’s death, has revealed she had been hit with a “full-whack depression” following the death of her sister Peaches.
The 31-year-old said she was still able to “mask” her depression, but the mood had grown since her sister’s death.
“I wear a permanent mask so I won’t feel judged for feeling how I actually feel,” she said on Instagram.
“You can’t escape it, it just simmers under the surface when it’s not hitting you full whack.
“People wouldn’t have the first clue of it to look at me, or talk to me, though.”
Writing of Robin Williams, she revealed: “Devastated by the news. Depression needs to be taken a lot more seriously. No one should feel pushed to those actions by their all-encompassing misery.
“Makes me so sad that he had the world crying with laughter whilst drowning in his own tears.”
Fifi added: “I think this has prompted me to want to speak out publicly about my own depression which I’ve suffered from for years.
“Just in a feeble attempt to bring some more awareness and understanding to something that oughtn’t to be surrounded by such a stigma.”
Meanwhile, Williams will receive a “meaningful” remembrance at this month’s Emmy Awards.
Awards show producer Don Mischer said plans for the Los Angeles ceremony’s traditional “in memoriam” sequence were being discussed.
He said organisers of the Emmy Awards were still coming to terms with the Good Morning, Vietnam and Mrs Doubtfire star’s death, but intended to give him the tribute he deserved.