I had just arrived home Monday when my son, Brent, called.

“Dad, did you hear? Robin Williams died,” he said.

“Are you sure?” I replied. “I saw him on a late-night talk show recently and he looked pretty good.”

Then on Thursday, Williams’ wife disclosed that the actor-comedian was in the early stages of Parkinson’s Disease, suffered from depression, and committed suicide.

“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.

As most of you know, I have Parkinson’s Disease. I learned that I had it in 1995. I have experienced various stages of depression from time to time over the last 19 years. Parkinson’s Disease, a degenerative neurological disorder that affects about one million Americans, can lead to a range of physical and mental symptoms.

The condition may cause tremors, impaired posture and balance, muscle stiffness, speech issues, and cognitive impairment. For the beloved actor and comic Robin Williams, the potential changes in his ability to use his voice - something 90 percent of Parkinson’s patients struggle with - may have been particularly difficult to face.

On top of that, mood disorders like anxiety and depression are symptoms of Parkinson’s; the disease may actually cause chemical changes in the brain that can make people more likely to suffer from those mental health issues. It can be difficult to diagnose depression in those patients because it displays itself in similar ways as Parkinson’s itself does.

“For people with Parkinson’s, depression is quite common and disabling - and it is the symptom most overlooked,” the Parkinson’s Disease Foundation notes on its website. “researchers have found that people with Parkinson’s who were depressed had more trouble with daily activities and were more likely to begin medication for motor symptoms sooner than those without depressive symptoms.”

Williams’ death has led to an outpouring of grief from his friends, colleagues and fans around the country, but it has helped heighten the national consciousness around depression.

At least half of all Parkinson’s patients may suffer from clinical depression at some point during the curse of the disease, according to some estimates.

The good news: over the past decade, researchers have placed increasing focus on investigating these aspects of the disease, and today we have a better understanding of how to treat mood disorders in Parkinson’s and increase quality of life.

In a 2012 study, conducted by the National Parkinson Foundation, 61 percent of 5,557 Parkinson’s patients surveyed reported that they also suffered from depression with symptoms that ranged from mild to severe.

Both conditions are associated with a shortage of dopamine, a neurotransmitter that helps regulate movement and control the brain’s pleasure center.

Dopamine is a feel-good chemical. If you are low in dopamine, you are not going to feel so good said Joyce Oberdorf, president and CEO of the National Parkinson Foundation.

If you suffer from depression and need help, the National Suicide Prevention Hotline is available 24 hours a day at 800-273-8255.