As a player and a man, Carlton (Cookie) Gilchrist was outspoken, often erratic. He once refused to be part of the Canadian Football Hall of Fame when tabbed for membership, in part because he believed he hadn't been paid enough during his career.

So as he aged and his depression and anger hardened, it became obvious to his family that something else was wrong. That something turned out to be chronic traumatic encephalopathy (CTE), a degenerative brain disease linked to repetitive head trauma.

Gilchrist was one of eight former CFL players who were part of a landmark study released Tuesday that examined 202 former football players, from high school to university to the professional ranks, and discovered CTE in 177 of them. Seven of the former CFLers had CTE. Five of those players were allowed to be identified by their families. They were: Charles Collins, a running back with the Montreal Alouettes and Saskatchewan Roughriders; Edward Roth, a Winnipeg Blue Bomber lineman; Doug MacIver, a Winnipeg defensive lineman; Eddie LeBaron, a quarterback for the Calgary Stampeders; and Gilchrist, a star running back with the Hamilton Tiger-Cats, Saskatchewan and Toronto Argonauts, who also spent five seasons in the American Football League.

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The study, lead by neuroscientist Dr. Ann McKee of Boston University and the Concussion Legacy Foundation, was aimed at gaining a greater understanding of CTE and its effects while also bringing clarity and relief to family members who saw their fathers and husbands slip away mentally, some worse than others.

"I did a book on my dad and I have 10,000 hours of recorded conversations with him and you can hear him change," said son Scott Gilchrist, who lives in Toronto. "He did know there was something going on. He said he'd kill the person who signed his kids to a [football] contract. Watching him pass away was the worst three days of my life."

Gilchrist died of cancer in 2011 at the age of 75.

Scott Gilchrist had a special affinity for his father's condition. In November, 2013, Scott was having the outside of his home renovated and noticed a tool had been left atop the scaffolding. Afraid it could fall off and hit one of his children, Gilchrist climbed to the top of the scaffolding only to fall 10 metres and break an orbital bone, his jaw and numerous ribs. Worst of all, he suffered a brain injury that to this day can leave him grasping for words.

"I [understand] more now about my dad. I can relate to the frustration he felt," he said.

Other families in the study said there were blessings to donating their loved one's brain. Mary Roth saw a 2011 PBS News Hour report on CTE and considered donation for her dad, Edward, who had also played five years at Indiana University. Prior to their father's death in 2013 at 84, Mary and her brother thought he was stricken with Alzheimer's. The study results showed CTE instead.

"It's nice knowing we don't have to worry about Alzheimer's [running in the family]," Roth said.

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Pamela Collins recalled how surprised researchers were to hear of her husband's behaviour before his death. They weren't expecting Charles to have been able to go to the bathroom by himself or brush his teeth after seeing how badly his brain was riddled with CTE. And unlike most of the other CTE sufferers, Collins was neither edgy nor menacing; merely forgetful.

"He was always kind – and he still loved football. His grandsons play at West Point and Wake Forest," Pamela noted. "The game is different than when Charles played … this study will help make it better because Charles wanted that."

Collins was 66 when he was killed in a 2012 car accident.

Making certain types of contact sports safer has become the sporting issue of our time. CTE can only be detected by an autopsy. Scientists say there are dozens of variables that could be contributing to its appearance in a brain – how many years an athlete played, at what position, potential genetic factors.

The data strongly suggests that the most plausible culprit is multiple hits to the head.

"When you're talking about brain issues, there are two different things," said Tim Fleiszer, a former CFL player and now executive director of the Concussion Legacy Foundation Canada. "There's acute concussion, which is very different than CTE, which we're theorizing can be caused by the accumulative subconcussive hits an athlete receives in the course of their career … Hopefully, at this point, we can start moving past whether or not there's a link between football and CTE and start working towards solutions."

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Fleiszer insisted there are ways to lessen the risk of football players leaving the game with brain damage.

"We just want to reduce the number of times athletes get hit in the head in Canada. The type of things you can do in football is reducing the amount of contact that happens in practice. Seventy-five per cent of the hits football players are taking are happening in practice," Fleiszer said.

Randy Ambrosie, a 10-year CFL veteran, was hired as the league's 14th commissioner earlier this month. The next day, results from the Canadian Sports Concussion Project in Toronto confirmed CTE was present in the brain of former B.C. Lion Rick Klassen, who had died of lymphoma last December at 57. Klassen had requested that his brain be studied after his death. The CFL Players' Association (PA) quickly responded to the CTE news, saying it was "time for the CFL to follow the National Football League and NCAA in eliminating unnecessary contact in practices to reduce the risk to players."

"I think that the relationship with the PA is going to be, on my part, a big priority and player safety is an absolute priority," Ambrosie stated. "So while I won't be disrespectful to the PA and negotiate [through] the media, I've said it before; I'll say it again – I love these guys. I want them to be successful."