Michael J. Fox Reacts to Robin Williams's Parkinson's Diagnosis

Robin Williams and Michael J. Fox in 2004 (WireImage)
Robin Williams and Michael J. Fox in 2004 (WireImage)

Not even Michael J. Fox knew Robin Williams had been diagnosed with Parkinson's disease.

Fox, who's become the public face of the disease, took to Twitter on Thursday after it had been revealed that Williams was struggling with the early stages of Parkinson's. Williams, who had been open about his issues with depression and addiction, was found dead on Monday after hanging himself in his northern California home.

Williams was a philanthropist who gave his time to numerous organizations such as the USO and St. Jude Children's Research Hospital. He also supported The Michael J. Fox Foundation. The two friends — who both got their start on TV sitcoms (Mork and Mindy for Williams and Family Ties for Fox) — were photographed together (see photo above) at a 2004 benefit for Parkinson's research.

The foundation released the following statement: "Depression is a symptom of Parkinson's disease, separate from the emotional response that comes with a diagnosis. As many as 50 percent of people with Parkinson's show clinically significant symptoms of depression at some point in their disease course. Depression in Parkinson's may be due to the underlying changes in brain chemistry and circuitry from the disease itself. Evidence for this includes the fact that depression can predate a Parkinson's diagnosis by a decade or more. More information is available on our Depression and Anxiety page. The Michael J. Fox Foundation continues to pursue a single, urgent goal: the eradication of Parkinson's disease. Explore our website for more information, connections to the Parkinson's community, and resources for living with Parkinson's disease."

Williams's widow, Susan Schneider, broke the surprising news about her late husband in a statement on Thursday. She also addressed claims that Williams, who dealt with drug and alcohol addiction for decades, was using again in his final days.

[Related: The Family Robin Williams Leaves Behind]

"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," Schneider said. "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."

Fox, 53, stayed silent about his 1991 Parkinson's diagnosis for seven years before speaking about it publicly. Last September, he described the tough period that followed.

"My first reaction to [the diagnosis] was to start drinking heavily," he told Howard Stern on Stern's Sirius XM Radio show. "I used to drink to party, but now I was drinking alone and ... every day. Once I did that it was then about a year of like a knife fight in a closet, where I just didn't have my tools to deal with it."

Fox credited his wife, Tracy Pollan, as well as therapy and Alcoholic's Anonymous with helping him through. He went on to found his nonprofit, which the New York Times has described as "the most credible voice on Parkinson’s research in the world," in 2000.

[Related: Twitter Takes Action Over Zelda Williams Harassment]