A woman with a mental illness who killed her husband with an axe will live in the community under a lifetime supervision order after a judge spared her a jail term.

Lucia Colella, 75, stabbed and bludgeoned to death her husband, 76-year-old Antonio Colella, in the bedroom of their Adelaide home in July 2014, the Supreme Court heard.

A paramedic went to the couple's home in Rawson Street, Alberton, about 7:45am one Sunday in response to a medical duress alarm.

Mr Colella was found with stab wounds to his neck and chest and Ms Colella had self-inflicted stab wounds.

She later told police at hospital "Mm, I've done it, I killed my husband".

Ms Colella had a history of mental illness, which included hearing voices and hallucinations.

She had previously been prescribed antipsychotic medication but was not taking any at the time of the killing due to its side effects.

A psychiatrist told the court that Ms Colella was sleep deprived as a result of the constant demands of housework and looking after her husband.

She had no memory of the killing.

Last December, Justice Kevin Nicholson found Mrs Colella not guilty of murder due to mental incompetence despite the fact that "the objective element of the offence of murder was established".

He declared that Mrs Colella was liable to supervision with "a limiting term of life".

Colela faces custody if conditions are not met

Today, Justice Nicholson published the reasons for his findings and decision, and approved the conditions of Ms Colella's release into the community on a licence.

"This has brought to an end a component only of a very serious and distressing incident, not just from Ms Colella and her family's point of view but from the community's point of view," Justice Nicholson said.

He warned Ms Colella she would face being placed in custody if she failed to follow the conditions.

"If she does not observe the requirements of the Parole Board and her medical treating team, including taking any medication, or the medication that is prescribed without fail, that she will be brought back before the court and it is open to the court to cancel the licence conditions and to order that she be detained in custody."