St Kilda great Danny Frawley was suffering from the neurological disorder, chronic traumatic encephalopathy (CTE), at the time of his sudden death.
Frawley's wife Anita said an analysis of the former Richmond coach's brain showed signs of Stage II CTE.
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The former Saints captain died in a car crash in September last year, the day after his 56th birthday.
Anita said the Victorian coroner was yet to release the official report, but wanted to speak out about it immediately to help others.
"This is an issue for the community, it is not about a particular sport or sports, we need more research to diagnose and assist people living with the disease," she told the Herald Sun.
"As his wife for over 30 years, I strongly suspected there was more going on with Danny than straightforward depression.
"I am very grateful for the work of the Australian Sports Brain Bank in shining a light on this disease."
Anita stated at the time of Frawley's death that the AFL great had "deteriorated" in the weeks leading up to the tragedy.
She said her husband saw incredible improvement after years of counselling, prescribed medication and psychiatric treatment for depression but decided to cut all that out of his life after feeling "bullet-proof" and confident that he'd beaten the disease.
Frawley felt ‘bullet-proof’ in lead-up to death
Anita said her husband began to spiral again after making the decision to remove himself from a support network of mental health professionals.
“The reason I am making this public is that I want this to be a reminder to all those grappling with mental health conditions and to those whom have made progress with their wellbeing that you should always seek help from professionals when considering making decisions surrounding your mental health, even when you feel as though you have fully recovered," Frawley's wife said at the time.
Frawley is the second prominent Australian football figure to be diagnosed with CTE, a degenerative condition linked to concussions and brain trauma.
In February it was revealed legendary Geelong ruckman Graham "Polly" Farmer was suffering from Stage III CTE when he died last year following tests on tissue from his brain at Sydney's Royal Prince Alfred Hospital.
CTE can only be diagnosed after a person's death.
Frawley, also a leading media figure after his coaching career finished, spoke publicly about his mental health battles in years leading up to his death.
with Yahoo Sport staff