Joel Cauchi, 40, had armed himself with a pigging knife when he launched his unprovoked attack at Sydney's Bondi Junction Westfield in April 2024.
He killed six shoppers and injured 10 others, before he was shot dead by Inspector Amy Scott.
Diagnosed with schizophrenia as a teen, he had been successfully treated first in the public and then the private system.
As an inquest into the tragedy spans into its third week, evidence will be given by those who treated him for more than a decade.
Two nurses and a psychiatrist who saw Cauchi at a private clinic in Toowoomba in Queensland are expected to take the stand on Monday.
That doctor, who cannot be legally identified, gradually weaned Cauchi off his anti-psychotic medication after he complained of the side-effects.
By July 2019, he was not taking anything.
And early the following year, he had moved to Brisbane and had stopped seeing a psychiatrist.
The inquest hopes to uncover how Cauchi became completely detached from the state's mental health system by early 2020, counsel assisting Peggy Dwyer SC said during inquest openings.
"The court seeks to understand whether there were opportunities to reintegrate Mr Cauchi that were missed or could've been pursued more assertively," she said at the time.
The inquest has heard from Queensland police officers who interacted with Cauchi and who witnessed signs of a deterioration in his mental condition from 2021 to 2023.
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