The Calgary man found not criminally responsible for stabbing to death five students at a house party in April 2014 addressed the family of his victims for the first time Wednesday.
Speaking at a review board hearing to determine what privileges, if any, he would be granted while in custody at the Southern Alberta Forensic Psychiatry Centre, de Grood said he was "deeply sorry."
"No one deserves the pain they are going through, no one deserves the pain that I have caused."
De Grood, who doctors believe was in a state of psychosis at the time of the killings, stabbed to death Lawrence Hong, 27; Joshua Hunter, 23; Jordan Segura, 22; Kaitlin Perras, 23; and Zackariah Rathwell, 21.
Psychiatric expert testimony presented at his trial revealed de Grood thought the apocalypse was coming when he killed the five students, who were at a house party in the Brentwood neighbourhood celebrating the end of the school year.
Afterward, he revealed that he'd heard what he believed to be the devil's voice telling him to "Kill them before they get you." He was convinced he was a sun god and that a war between the Illuminati, werewolves, and vampires was going to take place.
At trial, both the crown and defence agreed he was not criminally responsible.
De Grood's medical team said they don't believe he should have any privileges right now and recommended the next review board hearing take place a year from now, according to the CBC. The board accepted those recommendations. Dr. Sergio Santana of the Southern Alberta Forensic Psychiatry Centre also said de Grood is exhibiting signs of Post Traumatic Stress Disorder (PTSD).
"He is fragile, but he's developed some resilience."
Michael Spratt, an Ottawa-based criminal lawyer told VICE privileges in this case would typically be things like allowed access to the grounds, escorts to the community, frequent family visits, and other activities that will assist in treatment and reintegration.
As it stands, de Grood will be under 24-hour supervision.
Spratt said the main consideration when granting privileges should be public safety.
"Privileges should never be denied as punishment. It is not uncommon for privileges to be granted gradually to ensure that the patient is ready and the public won't be jeopardized."
Spratt said de Grood's apology is not unusual for this type of hearing.
"The person is at the hospital and being treated because they did not know that they did wrong. It is a sign treatment is working when a patient gains insight and appreciation of their mental health issues and the impacts of their actions."
Follow Manisha Krishnan on Twitter.