The world received an unexpected shock when news broke of Robin William’s death in August last year, having committed suicide at his home in Calfornia after battling severe depression.

Tonight Channel 5′s controversial documentary Autopsy: The Last Hours of Robin Williams aired, with forensic pathologist Dr Richard Shepherd delving into the actor’s final hours using the autopsy report to uncover what exactly drove Robin to end his own life.

Flowers and photographs laid in honour of the late Robin Williams
(Eric Risberg/AP/PA)

Months before his tragic death, Robin had checked into Hazelden Addiction Treatment Centre to tighten his grip on his sobriety and after a stint in rehab he returned home on August 5, 2014.

Despite his bubbly façade, once the cameras stopped rolling his smile dropped, humour faded and he struggled with both depression and various different illnesses.

Richard said Robin’s autopsy revealed the actor had been taking a variety of prescription drugs to ease the symptoms of an enlarged prostate, depression, Parkison’s disease and, unbeknown to the actor, dementia – all of which he chose to deal with out of the public eye.

Robin appeared at an art gallery just two days before he died and according to close friends of his, showed no signs outward signs of suffering while in public.

It was behind closed doors cracks began to appear, with his wife describing Robin’s peculiar behaviour the night before the tragedy.

The actor had a collection of expensive watches which he had stuffed into socks and taken to his friend for safekeeping.

Later that evening he returned home, wished his wife goodnight and settled in his bedroom he slept in alone as he had trouble sleeping.

We will never be 100% certain on what exactly happened in the hours leading up to Robin’s suicide though, autopsy in hand, Richard painted a picture of his final moments.

There was evidence on his body of self-harm yet no presence of alcohol or cocaine (a drug he had openly struggled with for years) was found in his body.

While Autopsy: The Last Hours of Robin Williams indeed managed to delve into the final moments of the actor as well as drawing attention to mental health issues, many viewers felt the documentary was a crass invasion into the late actor’s privacy and certain scenes were more graphic than needed be.

Not all agreed, though.

We may never know what what caused Robin Williams to take his own life and we really don’t need to. The beloved actor will always be remembered for the wonderful performer he was and for putting a smile on the world’s face even if he didn’t wear one himself.