Former AFL player Shane Tuck heard voices, had suicidal thoughts and was forced to stay in a psychiatric ward under a mental health order in the years leading up to his death.
An inquest into Mr Tuck's death was told he experienced many head knocks as both a Richmond player and professional boxer before being diagnosed with degenerative brain condition CTE after dying at the age of 38.
The long-awaited inquest started in Melbourne on Wednesday, one day shy of the third anniversary of his death.
It's investigating what lessons sporting codes can learn from Mr Tuck's experience and the link between his head knocks and CTE.
Coroner John Cain said the inquest was not about blaming individuals or finding culpability over his death.
"We must learn from this and be better equipped in the future," Judge Cain said.
Counsel Assisting the Coroner Gideon Boas said Mr Tuck took his own life in 2020 after a long period of mental health decline, which his wife Katherine first noticed in 2006.
He was treated for anxiety, depression and heart palpitations in 2010, three years before retiring from Richmond.
He then became a professional boxer and, one month after losing consciousness during a fight, revealed he had suicidal thoughts.
Mr Boas said in 2018 Mr Tuck started hearing voices telling him that he was "no good", was twice admitted to psychiatric wards and was once placed under a mental health order stopping him from leaving hospital.
He said high-profile cases of CTE in footballers including Mr Tuck, Graham 'Polly' Farmer and AFLW player Heather Anderson showed there was significant public interest in examining the condition's link to sport.
"Studies have suggest at least 17 per cent of people who experience repetitive concussions or mild traumatic brain injuries experience CTE," Mr Boas told the inquest.
AFL lawyer Ben Ihle said the league had a "state of the art" approach to concussion and was focused on protecting player wellbeing in the short, medium and long term.
He said accidental and incidental knocks during games had been significantly reduced due to an effort by the AFL.
Mr Tuck's family did not attend the opening of the inquest in person but Judge Cain said they were watching remotely.
The hearing is set to hear evidence from international concussion expert Robert Cantu before returning to court next week.
Tuck's family are separately involved in a concussion class against the AFL and several football clubs, filed in Victoria's Supreme Court by South Australian-based Griffins Lawyers.
Former Melbourne player Shaun Smith and Adelaide Crows premiership player Darren Jarman are also named in the class action.
A second class action has been filed by Melbourne-based Margalit Injury Lawyers on behalf of ex-Geelong player Max Rooke and more than 100 other former players.
Additionally, former players Ty Zantuck, Liam Picken and Gary Ablett Sr have all filed individual lawsuits over their concussion injuries.
Last month, Supreme Court Justice John Dixon asked lawyers to explore merging their claims as they overlapped and explored similar issues.
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