Simon Hall, 36, was found hanged at Wayland Prison, Norfolk, in 2014.
Hall, jailed for killing Joan Albert, 79, claimed his innocence until 2013 when he said he was "seriously violent" and there had been "sexual aspects" to the murder, the inquest heard.
His widow Stephanie said she had believed in Hall's innocence.
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Dr William Long, a senior forensic psychologist with the prison service, told Norfolk Coroner's Court that after he made his confession, Hall "had changed from resisting his conviction to a man that admitted he was seriously violent".
Meetings at Hollesley Bay Open Prison, where Hall was held before being transferred to Wayland after he took an overdose of his anti-smoking medication on 8 September 2013, he spoke openly about his issues and was under constant supervision. He was considered to be at high risk of suicide and self-harm.
Jurors have heard that Hall was also a user of Spice, a substance smoked by some inmates that was recently made illegal under new legislation.
Mrs Hall, who had campaigned for Hall to be cleared before his confession, said he was not "receiving the adequate help and support he needed".
She told the inquest: "The year after we married I publicly campaigned to clear his name, believing him to be a gross miscarriage of justice victim."
Mrs Hall told the jury when she first met Hall, he did nothing to suggest he had murdered Mrs Albert.
She said she kept in touch with her husband after he confessed to the murder.
She said when he was in Hollesley Bay Prison, near Woodbridge, they spoke "all the time".
By the time he moved to Wayland Prison, near Watton however, contact was "minimal".
However, she said she had her final phone conversation with her husband, the night before he died.
"The telephone conversation ended with him telling me he loved me and I told him the same back. He certainly didn't seem suicidal," she said.
Mrs Albert, 79, was murdered at her home in Capel St Mary, near Ipswich, Suffolk, in December 2001.
The inquest continues.
A killer who spent a decade protesting his innocence before confessing his guilt, was a "highly disturbed individual", his widow told an inquest.