The 'Mrs. Doubtfire' was diagnosed with Lewy body dementia that made him forget his lines and suffer from a shuffling gait prior to his death.

• May 7, 2018

AceShowbiz - Robin Williams was struggling with a brain disorder that caused him to lose many qualities from his prime and eventually led to his death. A new biography titled "Robin" (Henry Holt & Co.) by Dave Itzkoff that will be out this month details the final stages of Williams' life before he took his own life at the age of 63.

According to the biography, Williams was initially diagnosed with Parkinson's disease, but he started to show other symptoms. He would cry uncontrollably, struggled to remember his lines and suffered from a shuffling gait. As experts failed to recognize the symptoms at first, some blamed drugs and alcohol for his problem.

The "Mork & Mindy" star reached a crisis point during the filming of "Night at the Museum: Secret of the Tomb" in early 2014. He reportedly suffered a severe panic attack and was placed on antipsychotic medication.

"He was sobbing in my arms at the end of every day. It was horrible. Horrible," makeup artist Cheri Minns recalled. "I said to his people, 'I'm a makeup artist. I don't have the capacity to deal with what's happening to him.' "

Minns suggested to Williams that he return to stand-up comedy as a way out of his depression, but he refused. "He just cried and said, 'I can't, Cheri. I don't know how anymore. I don't know how to be funny,' " she went on sharing.

Williams' health quickly deteriorated following the failure of his short-lived 2013 television show "The Crazy Ones". He lost weight, his voice became tremulous, and he stooped. His "Mork & Mindy" co-star Pam Dawber witnessed this when she joined Williams on his last TV show in a bid to raise ratings.

She said she noticed big changes in the comedian. "I would come home and say to my husband, 'Something is wrong. He's flat. He's lost the spark. I don't know what it is,' " she said in the book.

Billy Crystal additionally described his old friend as "uncharacteristically quiet" when they met after a four-month absence. Crystal said Williams looked frail and skinny, and after they said their goodbyes after dinner, Williams burst into tears. "What's the matter?" Crystal asked. "Oh, I'm just so happy to see you. It's been too long. You know I love you," Williams said.

In May 2014, he was diagnosed with Parkinson's. He checked into rehab "where he could meditate, do yoga and focus on further 12-step work that, it was hoped, would help him manage his illness." But the real illness could not be cured with meditation.

Three months after Williams committed suicide by hanging himself with his belt, the autopsy results came in and a neuropathologist diagnosed him with a neurodegenerative disease called diffuse Lewy body dementia. It is the second-most-common type of progressive dementia after Alzheimer's disease, as protein deposits in the brain affect thinking, memory, emotions and body movements.

Unfortunately, due to his unawareness of the disease, he didn't get the right treatment for his condition.