A 21-year-old man died after being found hanged in his cell at Leicester Prison, an inquest has heard.
Lloyd Joseph Skelton had suffered "catastrophic" brain damage, the hearing at Leicester Town Hall was told.
He died in Leicester Royal Infirmary on September 1, 2014.
Giving evidence to the inquest, Detective Constable Lorna Granville said Mr Skelton, who had a passion for music, had been on remand awaiting sentencing after being convicted of assault and threatening behaviour.
She said he had a history of mental instability and was placed on segregation due to his violent, unpredictable behaviour.
He was discovered by prison officers hanging in his cell on August 29, and was taken to hospital, where he died.
Dr Ian Mclaren (COR), of Leicester Royal Infirmary's critical care unit, said Mr Skelton died from a "catastrophic" brain injury and cardiac arrest.
He added: "His heart only continued to beat because we continued to keep his lungs functioning.
"The cause of death was an anoxic brain injury and cardiac arrest which resulted from hanging."
Dr Mclaren said it was not possible to be certain how long it would have taken for the brain injury and cardiac arrest to have occurred.
Psychiatric nurse Clemence Hwandi, who treated Mr Skelton while in Leicester Prison, said he was "a very likeable young man with some ambition and a passion for music".
Mr Hwandi told the inquest Mr Skelton had been in the Bradgate Unit at Leicester General Hospital, where he was diagnosed with depression in 2013.
He said that when he next saw Mr Skelton, in Leicester Prison in June 2014, he was a changed person.
Mr Hwandi said: "He had been a very smart young man who kept a low profile, but when I saw him he had overgrown Afro-style hair."
The inquest, which is expected take up to nine days, continues.
