Idelson Guerrier, 31, was set to appear in court Monday. His trial has been pushed back to early September.
In June, staff at Notre-Dame Hospital's psychiatric ward discovered that Guerrier allegedly attacked an elderly patient.
Prosecution lawyer Marylen Laviolette said psychiatrists at the Philippe-Pinel Institute, a psychiatric facility in Montreal, are evaluating Guerrier to see if he understood what he was doing at the time of the incident. She said a saffing shortage at the institute is to blame for the trial's delay.
Defence lawyer Francois Berichon said the ordeal has been difficult for Guerrier's wife.
"Of course she cares about that. This is her husband. He has three children. This is really sad," said Berichon.
Police are investigating any possible connection between Guerrier and two other deaths that occurred within six days of the attack, at the same hospital.