The killings of Nick and Chloe Waterlow at the hands of a mentally ill family member who had refused treatment have sparked a parliamentary inquiry into the adequacy of the state's psychiatric laws.
Anthony Waterlow was found not guilty of the murder of his father, a prominent Sydney curator and arts educator, and sister on the grounds of mental illness, after stabbing them both during a psychotic episode in 2009.
Mr Waterlow had refused treatment and was not taking antipsychotic medication at the time, despite years of sickness.
Labor MLC Linda Voltz told State Parliament yesterday that Mr Waterlow was now medicated and only now aware of the "awful realities" of what he had done.
" 'I am terribly shattered by what I have done. I miss my family incredibly. I'm so, so sorry and I will be for the rest of my life,' " she quoted Mr Waterlow as saying.
In light of this and similar cases, Ms Voltz said, an inquiry should examine whether the current guidelines around when a doctor can intervene and require a patient to undergo treament should be changed, particularly in cases in which patients' capacity to make decisions for themselves may be compromised.
"It is not accepted for patients who suffer from dementia or Alzheimer's [to refuse treatment], yet for the mentally ill a whole different standard of capacity is applied," she said.
A transparent public inquiry was important before a change to the law, she said, given the "history of coercive treatment in this state has not been among our finest hour".
The inquiry, which was given unanimous support by the NSW upper house, will examine whether the state should "move to capacity-based, best-interest mental health legislation to ensure that treatment of people with mental illnesses is not restricted due to their decision-making incapacity".
Now in NSW, doctors can only intervene if they believe a patient is at risk of harm or of harming someone else.
The call for the inquiry was foreshadowed by a recent academic paper by three Australian psychiatrists who said the current laws played a role in the Waterlow killings.
"The current system ... involves doctors making a prediction that it is impossible to make," University of Sydney psychiatrist Dr Christopher Ryan told the Herald in July.
"Mr Waterlow, he was seen by a number of psychiatrists, some of them very senior ... apparently they made the judgment he wasn't likely to harm himself or anybody else, and, frankly, he was sick for 10 years and he didn't - until right at the very end."
The Minister for Mental Health, Kevin Humphries, said a more general review of the Mental Health Act 2007 is also under way, with a discussion paper due in the coming weeks.
"Along with the establishment of the NSW Mental Health Commission, this review is yet another vital step forward in the NSW government's plan to improve mental health services and delivery for every person in the state," Mr Humphries said.