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.

Reports in Australia say that it could knock as much as Â£200m (A$425m) off its value.
The parent company of the bank plans to float the Glasgow-based lender in Australia later this year.
Chancellor George Osborne announced he was phasing out the bank levy.
He also announced plans to introduce an 8% surcharge on bank profits, in addition to corporation tax.
That knocked share prices of smaller UK banks which are already traded.
A bank analyst at the Commonwealth Bank of Australia calculated that would knock A$425m off its valuation, and suggested that could push National Australia Bank (NAB) to sell off a larger stake in order to meet its target for raising capital.
A spokesman for the NAB was reported by the Melbourne Herald Sun saying the move would have no impact on the parent bank's earnings.
A spokesman in Glasgow for Clydesdale Bank, which includes the Yorkshire Bank brand, declined to comment.
Clydesdale Bank is seen at the Melbourne headquarters and in the Australian media as a drag on NAB, having amassed a large portfolio of bad property loans, and the high costs of redress for mis-selling financial products.
The new NAB chief executive, Andrew Thorburn, has made it a priority to split Clydesdale, handing up to 80% of it to NAB investors and selling the remainder on London and Australian exchanges.
Earlier this week, senior staff at NAB in Melbourne set out the case for investing in the spun-off UK bank, to institutional investors in Australia.
They portrayed it as one of the so-called challenger banks which is best placed to take on the British market's 'big five'.
A killer who spent a decade protesting his innocence before confessing his guilt, was a "highly disturbed individual", his widow told an inquest.
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The surcharge tax on bank profits announced in the Budget is being seen as another blow for the sale of Clydesdale Bank.