Robin Williams was a comedy genius - quick witted and full of vivacious spark and energy.
But in 2013, everything changed when the sharpness and humour that had made the Hook actor a global star suddenly abandoned him. What followed was 12 agonising months of depression, motor disturbances and extreme anxiety as Robin's brain was hijacked by an undiagnosed disease. Then on August 11, 2014 - eight years ago today - Robin took his own life.
Until 2013, everything had been fine. But at a celebration for his two-year wedding anniversary to third wife Susan Schneider, the star complained that 'gut discomfort' was making him anxious.
He developed a resting tremor in his left hand - thought to have been caused by an old shoulder injury - along with a slew of seemingly unconnected ailments that came and went.
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The Mrs Doubtfire star suffered stomach cramps, heartburn, and digestive issues.
He started having trouble with his sight and smell, he was more anxious than ever and began having disturbed sleep.
His limbs would sometimes freeze mid-movement for no obvious reason, while his voice became weaker, his posture less rigid. Sometimes he just froze on the spot.
"It was like this endless parade of symptoms, and not all of them would raise their head at once," his wife Susan told New York Times culture reporter, Dave Itzkoff, for his biography, Robin.
“It was like playing whack-a-mole. Which symptom is it this month? I thought, is my husband a hypochondriac? We're chasing it and there's no answers, and by now we'd tried everything."
Fellow actor Billy Crystal recalled the alarming rate at which his friend's health deteriorated, revealing how in just a matter of months, his appearance had changed entirely.
Meeting him in Los Angeles to watch a play that autumn, Billy said: "I hadn't seen him in about four or five months at the time, and I was a little taken aback by how he looked. He was thinner and he seemed a little frail."
Over dinner, the once-cheery Robin 'seemed quiet', Billy said, and sometimes stared at him, looking like he had something to say. And when the time came to say goodbye, Robin burst into uncharacteristic tears.
"He wasn’t feeling well, but he didn't let on to me all that was going on," Billy said. "As he would say to me, 'I’m a little crispy'. I didn't know what was happening, except he wasn’t happy."
Still in the dark as to the root of his ill-health, Robin arrived in Vancouver to shoot Night at the Museum: Secret of the Tomb, where his makeup artist Cheri Minns said it was obvious that something was massively wrong.
"He wasn't in good shape at all," she said. "He was sobbing in my arms at the end of every day. It was horrible. Horrible. But I just didn’t know."
While on location he suffered a huge panic attack and stopped going out at night. Cheri tried to convince him to do some stand-up to get his confidence back, but Robin broke down, sobbing: "I don't know how anymore. I don’t know how to be funny."
Once back in California, he was prescribed various anti-psychotic medications, but they only made matters worse.
By that point, he was hooked in a cycle of paranoia thoughts, waking in the night worrying that friends were in danger and anxiously obsessing about one thing after another, conjuring up delusions.
"Robin was losing his mind and he was aware of it," Susan told medical journal, Neurology, revealing he repeatedly said he wanted a "reboot for his brain."
She continued: "Can you imagine the pain he felt as he experienced himself disintegrating? And not from something he would ever know the name of, or understand? Neither he, nor anyone could stop it - no amount of intelligence or love could hold it back."
Finally, an answer came on May 28, 2014, when doctors delivered the news that he was suffering from Parkinson's disease. But while Susan was hopeful that it could be treated, Robin didn't believe the diagnosis.
What followed was a barrage of tests, medication, alternative treatments and even a stint in rehab - but still he grew worse.
On August 11, 2014 Robin kissed his wife goodnight, retired to his own bedroom with his iPad and took his own life aged 63.
Initially, it was thought that depression was to blame - he had been more than down in the weeks prior to his death.
But an autopsy would later reveal he had actually been suffering from Lewy body dementia - an aggressive, incurable brain disorder that is associated with a higher risk of suicide.
The second most common neurodegenerative dementia after Alzheimer's, it is often misdiagnosed as Parkinson's due to an overlap in symptoms such as impairment of motor function.
Robin had been planning to undergo neurological testing the week before his death. But even if he had been diagnosed correctly, Susan believes the outlook would have been crushingly bleak.
And she suspects his tragic death was borne out of that fear.
"I think he didn't want to go. I think he thought: "I'm going to get locked up and never come out,'" she told the Guardian.
*If you're struggling and need to talk, the Samaritans operate a free helpline open 24/7 on 116 123. Alternatively, you can email jo@samaritans.org or visit their site to find your local branch.
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