Joel Cauchi, 40, was experiencing acute psychotic symptoms when he killed six people and injured 10 others, including a nine-month-old baby, inside Westfield Bondi Junction shopping centre.
Dawn Singleton, 25, Ashlee Good, 38, Jade Young, 47, Pikria Darchia, 55, Yixuan Cheng, 27 and security guard Faraz Tahir, 30, all died in the April 13, 2024, attack.
Cauchi had been successfully treated for schizophrenia since he was a teenager but he was weaned off antipsychotic medication and fell through the cracks before the deadly incident.
Andrea Boros-Lavack, who treated Cauchi for eight years, initially gave evidence he did not have chronic schizophrenia and he was not unwell at the time of the attack.
"I honestly believe, that is my opinion, that it was nothing to do with psychosis," she told the inquest in the deaths.
That answer "was shocking, it was genuinely shocking," counsel assisting Peggy Dwyer SC said on Tuesday.
As she outlined findings and recommendations the coroner could make about events leading to the April 2024 attack, Dr Dwyer said Dr Boros-Lavack's answer - recanted the next day - had caused distress to the families of the victims.
Her characterisation of his mental health illness as prolonged first episode psychosis was "at best misconceived," Dr Dwyer said.
But it was "more likely (a) deliberately disingenuous" attempt to justify her own decision to wean him off medication and her statement that he was not unwell at the time of the attack, the coroner was told.
Dr Boros-Lavack, through her lawyer, disputes she suggested Cauchi was not unwell at the time.
The inquest is probing issues including whether Cauchi's mental health was appropriately managed and whether there were missed opportunities to detect his deterioration.
There were multiple red flags in the months after Cauchi was taken off his medication, Dr Dwyer said.
But they were not noted by the treating psychiatrist when she discharged him into the care of his GP, she said.
The psychiatrist has since accepted there were deficiencies in the way she handed over Cauchi's care, including not flagging his relapse symptoms or the high risk that he would relapse.
Dr Dwyer said the concession was welcome but would not be accepted by the coroner as genuine because Dr Boros-Lavack had been "lacking in insight" as a witness.
"It was exceptional the level of belligerence and confrontation Dr Boros-Lavack demonstrated in the witness box," the counsel assisting said.
"It's highly concerning that someone charged with the care of some of the most vulnerable in our society would be so unwilling to reflect and learn".
The families of Cauchi's victims have called for the psychiatrist to be referred to a regulatory body following her evidence, the inquest was told.
Dr Dwyer said it was an option open to State Coroner Teresa O'Sullivan, noting the inquest was not charged with reviewing the psychiatrist's treatment history.
Dr Dwyer recommended the implementation of a preventative mental health care model, rather than a crisis-driven approach.
"It's an opportunity to look at this tragedy and see whether there are broader reforms that could save lives," Dr Dwyer said.
The inquest continues.
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