Early on a summer morning in his Vernon, B.C., apartment, Kenneth Barter gave in to his delusions.
Foreign agents were warning him that the man smoking a cigarette on his couch, a good friend with whom he had been drinking the night before, was plotting to kill Kenneth's father. So he rose from his bed, and struck Nathan Mayrhofer with a hammer.
Then he chopped his friend's body up with a meat cleaver (as he learned on the TV show Dexter, he later said) and shoved the parts in his fridge. His mother and his father, a former police officer, discovered the remains two days later - after their son, in a bizarre confession, told them he had been hypnotized.
The killing happened in August, 2010. At the time, Kenneth, 37, had been on a six-month wait list to see a psychiatrist. His appointment was scheduled for October.
Two weeks ago, he was found not criminally responsible for murder and sentenced indefinitely to a secure mental hospital. It was justice, bluntly administered, leading to the old, frustrating question: Why didn't the system step in earlier and save two lives?
Mental-health advocates have fought the stereotype that mental illness leads to violent crime, aware of the stigma this creates for already-isolated patients, most of them much more likely to be hurt than to hurt another. When the most bizarre crimes occur, mental illness comes as an automatic explanation, deduced in hindsight from ranting Facebook posts and odd behaviour - as with Jared Lee Loughner, charged with killing six in a shooting spree in Arizona, and Richard Kachkar, accused of killing a Toronto policeman in a snowplow rampage.
Those men have yet to be diagnosed as mentally ill by trained professionals. But for most crimes, expert says, that would be looking in the wrong place. Research has found that less than 15 per cent of mental-health patients ever commit a criminal offence of any kind.
'It's not The Shining we're talking about," says Christian Joyal, a neuropsychologist at the University of Quebec, Trois-Rivières. Yet while crimes such as the ones Jared Loughner and Kenneth Barter are accused of are rare, new research is showing that with the right mix of symptoms and circumstances, the link between mental illness and violent crime is stronger than advocates might like to admit.
"The vast majority will not be violent. But who will be?" Dr. Joyal says. "If you don't want to stigmatize everyone, you should know who is at higher risk."
Under pressure to identify high-risk patients, psychiatrists are working to develop better screening tools and build on the early findings of brain scans. But as they do, medical staff will need resources, hospital beds and time to make diagnoses - three things in short supply in Canada's mental-health system.
They mainly hurt the ones they love
"You probably have more chances of winning the lottery than of being killed by a psychotic person you don't know," says Dominique Bourget, a clinician in the forensic psychiatry and schizophrenia program at Royal Ottawa Hospital.
People with schizophrenia - a disorder estimated to affect .5 to 1 per cent of the population that often brings on powerful delusions and hallucinations - may indeed have a higher risk of homicide or arson.
By analyzing 20 international studies, Seena Fazel, a senior psychiatrist at Oxford University, calculated that the homicide rate among male patients with schizophrenia was about five times higher than in the general population. (For women, the risk was about eight times higher, though the sample size was smaller.) He found a similar correlation with bipolar disorder, in which patients typically cycle between depression and mania.
But people with a mental illness rarely harm strangers. More often, the victims are people they love - family, friends, caregivers. A Quebec study of 64 cases in which offspring killed parents found that about 67 per cent had a psychotic disorder.
But substance abuse is the big risk factor. In Dr. Fazel's research, when drug or alcohol addiction was involved, the homicide risk among people with schizophrenia rose to 12 times greater than the general population's. People with mental illness, especially schizophrenia, are more likely than others to suffer from alcohol and drug addictions.
But the homicide rates were no lower among addicts without an underlying mental illness. "If you were thinking about it from a public-safety strategy, you would actually target substance abuse everywhere you could find it," Dr. Fazel says.