In a prepared statement, Susan Schneider said her husband continued his decades-long battle with depression and anxiety, and he was in the early stages of Parkinson's when he was found dead at his suburban San Francisco home on Monday.
Schneider said her husband, the celebrated Oscar-winning actor and comedian, wasn't prepared to publicly share his Parkinson's diagnosis.
"Robin's sobriety was intact and he was brave as he struggled with his own battles of depression [and] anxiety as well as early stages of Parkinson's disease, which he was not yet ready to share publicly," Schneider said, according to published reports.
"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," she said.
Besides depression and anxiety, Williams had struggled on and off with substance abuse over the years.
According to the U.S. National Institutes of Health (NIH), Parkinson's disease is a movement disorder that occurs when nerve cells in the brain don't produce enough of the brain chemical dopamine. Symptoms begin gradually and then progress. They include trembling of the hands, arms, legs, jaw and face; stiffness of the arms, legs and trunk; slowed movement; and poor balance and coordination.
As symptoms worsen, people may have trouble walking and talking, and can experience problems such as depression and sleep difficulties.
There's no cure for Parkinson's disease, but there are medicines and therapies that can help improve symptoms, according to the NIH.
Williams' suicide Monday refocused public attention on depression, its sometimes link to substance abuse and, in tragic cases, suicide.
He was last seen alive at his suburban San Francisco home about 10 p.m. Sunday, according to the Marin County coroner's office. Shortly before noon on Monday, the Sheriff's Department received an emergency call from the home, where he was soon pronounced dead. Sheriff's officials said Tuesday that Williams committed suicide by hanging himself, according to the Associated Press.
Williams, who was 63, had struggled for decades with substance abuse and depression, and routinely made references to those personal battles in his comedy routines.
"Cocaine is God's way of telling you you are making too much money," he would quip.
Williams had been dealing with severe depression recently, said his publicist. Early last month, he had checked himself into a rehab facility for substance abuse, according to published reports. His publicist told People magazine at the time that "after working back-to-back projects, Robin is simply taking the opportunity to fine-tune and focus on his continued commitment [to sobriety], of which he remains extremely proud."
In 2006, he had sought treatment for alcohol addiction at the Hazelden center in Springbrook, Ore., according to published reports.
Despite Williams' well-documented personal battles, mental health experts point to major strides in recent decades in the treatment of people who struggle with depression and substance abuse, which are often twin afflictions.
The most effective treatments are medication and talk therapy, said Dr. Jeff Borenstein, president and CEO of the Brain and Behavior Research Foundation in New York City. This dual approach works for most people who are dealing with depression, he said.
"It's extremely difficult to live with depression. The pain is described by people as the worst pain possible. But the majority of people treated for depression get better," he said.
Surprisingly, Borenstein added, there's still a stigma that's often attached by some to depression. But, it's just as much a disease -- not a sign of a personal shortcoming -- as a physical ailment like cancer or heart disease, he said.
"Unfortunately, in our society that [stigma] is still tolerated by some people," Borenstein said. "We no longer accept prejudice against race or religion or sexual orientation, but there are still people who have this prejudice when it's a psychiatric condition," he said.
What's also troubling, Borenstein added, is that too many people with depression don't seek treatment. "That is a major problem in our country," he said. "It's important that people be aware of depression so that they can encourage a loved one to seek treatment."
Dr. Scott Krakower, assistant unit chief of psychiatry at Zucker Hillside Hospital in Glen Oaks, N.Y., explained that there's often a direct link between depression and self-medicating with drugs or alcohol. "Substance abuse is one of the risk factors for suicide, especially if you have a history of depression," he said.
Krakower reiterated that depression is very treatable, though it can sometimes take time.
"It can be frustrating for the patient," he said. "They can go through a lot of different medications before they find one that works. People usually look for immediate gratification, but treating depression can be a lengthy process."
People who are depressed should seek treatment, which is helpful for the vast majority of patients, Krakower emphasized. And, those around them need to be supportive, he said.
For many of Williams' fans, his signature talent was his manic, brilliant brand of comedy. But he also tackled many dramatic film roles, including ones in "Awakenings," "Dead Poets Society" and "What Dreams May Come." He won an Academy Award for his performance as a therapist in the film "Good Will Hunting," and captured three Golden Globes, for "Good Morning, Vietnam," "Mrs. Doubtfire" and "The Fisher King."
To learn more about depression and its treatment, visit the U.S. National Library of Medicine.