The men's 50 metres backstroke national record holder, who had been expected to compete in that race as well as the 100m backstroke, 50m butterfly and 50m freestyle at the Games, was sent home from a training camp in Chartres earlier this week,

Swimming Australia said that the decision was taken due to "some well-being challenges, including the use of medication".

Cooper, an Olympic bronze medallist in the mixed 4x100m medley relay at Tokyo 2020, has spoken on Instagram about the decision.

He acknowledged that Swimming Australia's decision was in the best interests of the team, but claimed that the use of medication which led to him being sent home did not relate to a prohibited substance.

"The last few day (sic) have been tough," Cooper wrote.

"I’ve had to undergo a lot of self reflection and examination.

"The decision made to send me home was based on my behaviour and mental health and was made in my best interest and that of the team competing at the Commonwealth Games.

"My misuse of medication was not banned substances.

"It was ultimately my well being and mental health that resulted in me going home.

"It was difficult to accept in myself that I needed to address my mental health but I believe that it is an ever present issue in all communities, including that of a professional athlete.

"I am grateful to Swimming Australia for helping to identify an issue and offering their support and resources to help me."

The 18-year-old said that while he had been looking forward to competing at the Commonwealth Games, he believed the decision to be in the best interests of his career.

"More than anything I wish I could be there, racing with my team and cheering them on," Cooper said.

"The team means so much to me and I have made friends for life but the decision was not made in the interest of the next few weeks, rather the interest for the future of my swimming career."

Cooper thanked those who had offered him assistance since the news was announced, and also revealed he has decided to leave Rackley Swim Club, expressing his gratitude to coaches, support staff and team-mates.

He said he plans to use the coming weeks as a time of reflection, and pledged to continue working with Swimming Australia.

"For the next few weeks I will be reflecting and resetting for the future," Cooper said.

"I will use this time of reflection to also examine the current issues.

"There are always two sides to a story and I shall continue to work positively and confidentially with Swimming Australia."

Swimming Australia declined to comment further on Cooper's Instagram post.

The Australian swimming team was embroiled in a scandal at the London 2012 Olympics, with a review the following year finding that a "culturally toxic" environment had contributed to its poor performance.

Six members of the team were later fined for using the drug Stilnox during a "bonding session" prior to the Games.

The sedative Stilnox had been banned by the Australian Olympic Committee, and the six athletes concerned admitted that they engaged in "childish" and "stupid" pranks at a training camp in Manchester.

According to The Sydney Morning Herald, Swimming Australia has denied that Stilnox was the medication in question which led to Cooper being sent home.

As well as his Olympic bronze, Cooper won silver in the mixed 4x100m medley relay at the International Swimming Federation World Championships in Budapest last month.

He won gold in the men's 50m and 100m backstroke and bronze in the men's 50m butterfly at the Australian National Championships in May, with his 50m backstroke time of 24.44 seconds a national record.