Inside Robin Williams' Parkinson's Struggle

ETONLINE

Allison Janney opened up to ET about her brother's suicide in 2011 and reflected on the death of Robin Williams.

The questions continue to pile up as we learn more about Robin Williams’ death, including his secret battle with Parkinson's Disease. We're taking an in-depth look at the challenges faced by Parkinson's patients, and hearing more from those who loved Robin.

PICS: Remembering Robin Williams

"It is actually common for patients who have Parkinson's Disease to experience depression or anxiety," said Dr. Irene Richard, who is on the board of Michael J. Fox's Parkinson's foundation.

Dr. Richard told us about some of the symptoms that Williams could have been facing, such as tremors, and decreased dexterity.

Robin's friend Michael J. Fox was diagnosed with Parkinson's in 1991 and yesterday he tweeted that he was "stunned" to learn about Robin's diagnosis. Robin was a contributor to Michael's foundation and they both struggled with similar problems such as alcoholism, depression and career uncertainty.

Double Emmy nominee and Mom star Allison Janney went through a similar loss when she lost her brother to suicide in 2011 after a long battle with addiction. She explained her grieving process to us, saying, "It's one of the hardest things...I did lose a family member in a similar way and it's incredibly tragic...You go second-guessing every choice you made [but] it's not your fault. You can't blame yourself. You have to forgive."

She goes on, "Try to remember the good things and celebrate the birthday and those dates."

We caught up with Williams' Happy Feet Two co-star Sofia Vergara, who said, "I felt so honored to be a part of a movie where [Robin] was a part of the cast. He was such an energetic person. It's sad."

Robin was fond of Sofia and gushed about her in 2011, saying, "To be in the same room with her -- it's Christmas early."