A Manitoba judge says there is strong evidence that the smoking cessation drug Champix played a role in a psychotic episode that led to a Manitoba soldier being charged with assault.

Malcolm Gallant, 30, pleaded guilty earlier this year to assault and careless use of a firearm. The charges stem from an episode in 2011, in which the Canadian Forces member choked his girlfriend and took guns to their neighbours' house.

At his sentencing hearing this week, Justice Shawn Greenberg handed Gallant a conditional discharge, meaning that if he follows certain conditions for one year, no conviction will be added to his criminal record.

Greenberg noted that testimony during the trial found that Gallant's behaviour was highly out of character. She concluded that Gallant's "bizarre behaviour ... was likely induced by a drug called Champix which he had been taking to assist him in quitting smoking."

Court heard that Gallant had no prior history of psychological problems. Witnesses testified that three days before the incident, Gallant stopped taking Champix, which contains the drug varenicline tartrate. He then suffered from a bout of insomnia, and had been drinking during the evening of the incident.

His girlfriend testified that after Gallant watched several episodes of a TV show about military counter-terrorism, he began displaying bizarre behaviour. He ripped his shirt into pieces, chased her, and choked her. After his girlfriend escaped, Gallant then terrified neighbours, armed with a shotgun.

Gallant apologized in court to the victims.

"I'm a normal, law-abiding young man who had been taking prescription medication and had consumed alcohol," he said. "For that, I'm sorry to every person I hurt and scared that horrible night."

The makers of Champix, Pfizer Canada, advise in the product's insert that there have been several reports of serious psychiatric symptoms in patients being treated with Champix, including psychosis, mood swings, depressed mood, aggression, hostility, changes in behavior, suicidal behaviour and suicide.

It adds that drinking alcohol can increase the risk of psychiatric side effects during treatment with Champix.

Health Canada has said it has completed several reviews of Champix, and is assured that the its benefits outweigh the risks.

Winnipeg pharmacist Steve Burczynski says his pharmacy fills new Champix prescriptions every two weeks. He says the drug is usually taken for 12 weeks and can very effective in helping people stop smoking.

Health Canada issued a statement in May, 2013, saying that the product insert for both Champix and another smoking cessation drug, Zyban, had recently been changed to advise that patients should consider nicotine replacement therapies, such as nicotine patches, gum, and lozenges before taking non-nicotine medicines such as Champix or Zyban.

With a report from CTV Winnipeg's Beth Mcdonell