Late NRL coach Paul Green had been living with a "severe" and undiagnosed case of Chronic Traumatic Encephalopathy prior to his death by suicide, says his widow Amanda.
North Queensland's sole premiership-winning coach and a former Rothmans Medal-winning playmaker, Green took his life aged 49 on August 11.
His passing was met with an outpouring of grief and shock from the rugby league community as family and friends admitted they had not realised the extent of his mental health struggles.
But speaking to The Australian newspaper, Amanda Green said post-mortem analysis of her late husband's brain had revealed signs of CTE, a brain condition thought to be caused by repeated head trauma.
Professor Michael Buckland from the Australian Sports Brain Bank said Green had suffered one of the more "severe" cases of the condition he had seen, which may have affected his impulse control and decision-making prior to his death.
"It was not him, it was the brain disease," Buckland told the Australian.
"The only known cause for the organic brain disease is exposure to repetitive head impacts.
"I suspect he would have been coping with stuff he didn't understand for quite a while.
"He didn't have mental health problems; he just couldn't control stuff that was going on in his head."
Green had suspected her husband was not living with depression as had been speculated originally and said the diagnosis afforded some "peace" and "relief" to the family.
"I was able to sit (son) Jed down and explain 'Daddy's brain was sick, that's why he did what he did'. The diagnosis has helped them understand what happened," she said.
"For my daughter Emerson it has also given her a sense of relief because of what's being said (that Green had depression).
"She now understands that he wasn't in that space and there's nothing we could have done because he was sick. We just didn't know it."
Former AFL players Danny Frawley and Shane Tuck were both diagnosed with CTE following their own deaths, while South Sydney great Mario Fenech is currently living with the condition.
Green said she would continue to raise awareness of CTE.
"My goal is to shine a light on Paul's diagnosis, so we can advance our approach to detection, education, treatment and support for people suffering from CTE," she said.
