Robin Williams was sober and battling early stages of Parkinson's disease when he committed suicide early this week, his widow said.
In a statement issued Thursday, William's wife Susan Schneider called her late husband a wonderful man and father, and acknowledged that he had been "fighting personal battles" including depression.
But she assured the public that he had been sober when he took his own life Monday in their Tiburon home. Williams, 63, had publicly shared his cocaine use when he did standup comedy in the 1980s, but had since gone to rehab, and said he had been clean for the last 20 years.
The Marin County Coroner determined that Williams committed suicide by "asphyxia." Williams' personal assistant found him in a bedroom.
Read Schneider's statement in full:
"Robin spent so much of his life helping others. 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.
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."
Williams' death shocked fans and friends alike, despite his candor about decades of struggle with substance abuse and mental health.
Parkinson’s is caused by the loss of brain cells that produce a message carrying-chemical, or neurotransmitter, important for movement. There is no cure and drugs used to combat the condition usually become less effective over time.
Tremors, sometimes starting out in just one hand, are among the early symptoms.
Schneider did not offer details on when the actor comedian had been diagnosed or his symptoms.
Actor Michael J. Fox, who has long had the disease, is known for his efforts to fund research into it. He said on Twitter Thursday that he was "stunned" by the news.
Stunned to learn Robin had PD. Pretty sure his support for our Fdn predated his diagnosis. A true friend; I wish him peace.
— Michael J. Fox (@realmikefox) August 14, 2014
Pop star Linda Ronstadt revealed in 2013 that she had Parkinson's and said the disease had robbed her of her ability to sing. Boxer Muhammad Ali, the late radio personality Casey Kasem and the late Pope John Paul II are among other well-known figures diagnosed with the disease.
Parkinson's affects about 1 million people nationwide, 6 million globally. The cause isn't known but genes are thought to play a role.
There is no standard test for Parkinson's; doctors rely on symptoms, medical history and neurological exams to make the diagnosis.
Dr. Tanya Simuni, director of the Parkinson's Disease and Movement Disorders Center at Northwestern University's medical school in Chicago, said patients often react to the diagnosis with surprise and despair.
Depression is often present even in early stages and can sometimes precede tremors that help doctors make the diagnosis, Simuni said.
Referring to Williams, she said it's important to emphasize that not everyone who is depressed is at risk for Parkinson's, "especially in this tragic case."
She noted that many can live for years without severely debilitating symptoms, but also that 20 years after diagnosis, as many as 80 percent develop dementia. Antidepressants are among drugs commonly prescribed for the disease, along with medication to help control jerky movements.
Dr. Christopher Gomez, neurology chairman at the University of Chicago, said while it makes sense to think that a diagnosis could make someone feel depressed, depression and Parkinson's have a deeper, more organic connection. They are thought to affect the same regions of the brain, although their neurological relationship isn't well understood, he said.
"It's downright curious that there's so much depression in Parkinson's," Gomez said.
SUICIDE PREVENTION: If you know someone who needs help, you can contact the National Suicide Prevention Lifeline by calling 1-800-273-TALK (8255).
The Associated Press contributed to this report.