"I can't comment whatsoever on any issues of mental illness. To my knowledge, there's been no indication in the past," his lawyer, Allan Fay, told reporters.
Fay also described his client as "overwhelmed" but "able to carry on a conversation."
De Grood, the son of a senior Calgary police office, will likely face five counts of first-degree murder.
In what police described as the "worst mass murder in Calgary’s history," De Grood stabbed a 22-year-old man, two 23-year-old men, a 23-year-old woman and a 27-year-old man at a University of Calgary house party in the early hours of Tuesday morning.
Police said they believe he had been invited to the party.
Police Chief Rick Hanson said he felt for Matthew's father, Inspector Douglas de Grood.
"I can’t describe, I think, adequately the absolute devastation they feel," Hanson said.
He also assured residents that federal prosecutors would handle the case to ensure impartiality.