Robin Williams found it "very difficult" to watch his "senses being stripped away" by Parkinson’s disease, a close friend told The Telegraph.
The Hollywood star was in the early stages of the condition at the time of his death, his wife revealed in a statement on Thursday, saying she had tried to support him as he struggled with the diagnosis on top of his depression and anxiety.
Williams, who had fought a life-long battle with depression, had hidden his recent news from many who knew him but confided in a neighbor and friend of over a decade.
The Oscar-winning actor and comedian was said to have been worried that the progressive neurological disorder would have an impact on his film and TV work, the income from which was helping support his family.
His friend said Williams had “envisioned how Parkinson's would limit his ability to work and that was terrifying."
It is thought the entertainer agreed to star in a number of films, including "Mrs. Doubtfire 2" and a sequel to "Night at the Museum," in his final months, to complete as many projects as he could before his symptoms became too noticeable.
His friend said the actor was terrified of his own mortality and that after the shock of his open heart surgery in 2009, it was "very difficult" to watch his “senses and abilities being stripped away from him.”
Early Parkinson's symptoms often include feeling tired and weak, as well as poor hand co-ordination, problems with handwriting, and a sensation of tremors in the arm.
The two friends would often go on bike rides together around their hometown of Tiburon, north of San Francisco, but the trips had become less and less frequent in recent months.
“Robin loved to cycle and staying fit and active,” the friend, who last saw him three weeks ago, said. “However, the fear of losing control of one's body, and not being able to exercise — which is a major mood elevator for lots of athletes — was frightening to him.
“Parkinson's definitely compounded his worries and the depths of depression,” the friend said. “Imagine holding a stack of pennies. At some point you simply can't hold the weight of one additional penny placed in your hand.”
Parkinson's disease is an incurable nervous system disorder that involves a loss of brain cells controlling movement.
It can cause tremors, rigid, halting walking, slowed speech, and sometimes dementia. Symptoms worsen over time, though they can often be treated with drugs.
Depression is often present even in early stages and can sometimes precede tremors that help doctors make the diagnosis, according to experts.
Actor Michael J Fox, who has long had the disease and is known for his efforts to fund research into it, tweeted that he was stunned to learn Williams had early symptoms.
"Stunned to learn Robin had PD. Pretty sure his support for our Fdn predated his diagnosis. A true friend; I wish him peace," Fox tweeted.
Williams' wife, Susan, said in her statement: “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.
“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.”
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