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Mark Phillips arrives at court in St. Thomas, Ont., on April 10, 2018.

GEOFF ROBINS/The Globe and Mail

As the federal government prepares to legalize the recreational use of marijuana, an Ontario judge has ruled that cannabis-induced psychosis led a man to a seemingly hate-filled attack on a family, in what appears to be the first case of its kind in Canadian criminal courts.

The man who committed the attack, Mark Phillips, is a Toronto lawyer with an otherwise clean record, and the great-grandson of Nathan Phillips, a former mayor after whom the civic square in front of Toronto City Hall is named. The 37-year-old pleaded guilty Tuesday to assault causing harm in the Dec. 7 incident in St. Thomas, in southwestern Ontario, in which he cracked a man’s rib with a baseball bat.

Sergio Estepa was with his wife, Mari, teenage son and a family friend, speaking Spanish in the parking lot of a St. Thomas mall when a stranger, Mr. Phillips, approached and told them to stop speaking French, according to evidence in court.

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He then came at them with a baseball bat, repeatedly screaming “ISIS,” saying he was arresting the family, and calling for help. The family also called for help.

Ontario Court Justice John Skowronski said that, in ordinary circumstances, such an attack would call for a penitentiary sentence ­– that is, at least two years in federal prison. But he accepted the recommendation of defence lawyer Steven Skurka that Mr. Phillips be given a conditional discharge, on the condition that he complete three years of probation. A conditional discharge means that, once his probation is successfully finished, Mr. Phillips will not have a criminal record.

Addressing the family, whose members had told the court in emotional victim-impact statements about the nightmares and anxiety they had experienced, Justice Skowronski said he wanted them to know that what happened to them was an aberration for the country. “Canada is a country of immigrants, different nations, skin colours, accents, names,” he said, adding that his name had not come from this country.

“This is something that took place because of a mental illness.”

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Although Crown prosecutor Lisa Defoe had urged a suspended sentence and probation, which would have left Mr. Phillips with a criminal record, she, too, had accepted the defence argument that the attack was caused by cannabis-induced psychosis.

“At first blush this may appear to be a hate crime,” she told Justice Skowronski, “but it’s important for the Crown not to react emotionally.”

Mr. Skurka had told the court that Peter Collins, a forensic psychiatrist at the Centre for Addiction and Mental Health in Toronto, had uncovered after several sessions with Mr. Phillips that he had been smoking marijuana heavily, including three or four joints earlier on the day of the attack.

With marijuana legalization on the horizon, the case raises questions about mental-health risks and new challenges for the legal system. According to Mr. Skurka, Dr. Collins warned that higher levels than in the past of tetrahydrocannabinol (THC), the active ingredient in cannabis, is creating a higher incidence of drug-induced psychosis.

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Mr. Phillips’s parents said he had been having irrational fears about Nazis, Muslims and terrorists. In one incident the same day as the attack, he shouted about North Korea and was kicked out of Air Canada Centre in Toronto.

Dr. Collins ­found that Mr. Phillips’s actions were not those of a hate crime, but of cannabis-induced psychosis.

“In my professional opinion, Mark Aaron Phillips suffered from a drug-induced psychosis in and around the time of the event that led to his arrest,” he wrote in his report.

Mr. Skurka had also read to the court from a medical journal that said that paranoid and grandiose delusions similar to those caused by schizophrenia can also be caused by cannabis use.

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“This is someone without any history of discrimination, racism or violence,” Mr. Skurka said in an interview outside the courtroom, after sentencing.

Mr. Estepa said in an interview that he could not understand how a man of Mr. Phillips’s education and training as a lawyer could have been unaware of the effects of marijuana before using it.

“I can’t believe that in 2018, people don’t know that marijuana can affect your mind-state,” he said.

When asked by Justice Skowronski whether he had anything to say, Mr. Phillips replied, “I’m very, very sorry for what happened.”

Mr. Phillips withdrew from his practice of personal injury law after the incident, but hopes to resume working as a lawyer. He will need the Law Society of Ontario’s approval to do so.

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Mr. Estepa met his wife after they moved to Canada separately from Colombia in the early 2000s. In his victim-impact statement, he described the pain of hearing his son treated as an outsider.

“Here in his home country, someone told him, ‘You don’t belong here.’ ”

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