Jessica Camilleri cut off her mother Rita's head and removed her eyes after dragging her by the hair in a frenzied attack in July 2019.
The 29-year-old was initially jailed for at least 16 years and two months over the "gruesome and brutal" killing.
She was found guilty of manslaughter rather than murder after forensic psychiatrists told a jury she suffered substantial mental impairments and lost control of her actions.
Camilleri later appealed that sentence and in May she had five years sliced off the term, making her eligible for parole in July 2031.
But that date was pushed back a year by the NSW District Court on Monday.
Camilleri pleaded guilty after attacking two prison guards, ripping hair from their scalps on separate occasions in 2021 while in custody at Silverwater jail in Sydney's west.
The pair cannot be named for legal reasons, but both previously told the court of the impact the attacks had left on them.
"When I went back to the office, I had people point out a bald patch of hair on the left side of my scalp," a guard attacked during a routine room inspection in August 2021 said.
Another guard handcuffing Camilleri for transfer two months later was similarly set upon and still has nightmares about it.
"It has shattered my sense of safety," she said.
Camilleri was sentenced to 22 months with a non-parole period of 15 months for assaulting the guards.
She will now be eligible for release in mid-2032.
24°C