A university student who armed herself with three knives before repeatedly stabbing her sister to death has been jailed for at least four years and three months.
Kathleen Worrall, now 22, told prison officers she thought her sister's gasping was feigned so she stabbed her again, saying, "You're faking it, stop faking it".
She told a psychiatrist that during the attack her sister said, "No Kathleen, I love you, I love you, please stop".
Worrall pleaded guilty to the manslaughter of Susan Worrall, 18, who suffered more than 50 stab wounds, at the family home in Strathfield, in Sydney's west, on October 10, 2008.
The crown accepted the plea on the basis she was suffering from "an abnormality of the mind" - a mood disorder associated with her non-compliance with her medication regime.
The side-effects of the medication for her congenital disorder included a substantial increase in her weight.
She told a psychiatrist that as a 20-year-old she "looked like a Gladiator".
In the NSW Supreme Court on Friday, Justice Elizabeth Fullerton jailed Worrall for a minimum of four years three months and a maximum of six years.
Worrall wrote to the judge saying her sister had been her "best friend", they were like "two halves of a whole" and she felt unqualified love for her.
Justice Fullerton accepted Worrall, described by her mother as gentle and loving, was remorseful.
About a week before the stabbing, the sisters fought over a hair straightener.
On the day of the stabbing, Worrall armed herself with three knives before changing her mind twice about stabbing her.
But after she discovered her sister had changed the password on their computer, she grabbed her as she came out of the bathroom, repeatedly stabbing her.
