TORONTO — All it took was one brief argument with her husband over lottery tickets for Deb Mulligan’s life to change forever.

She recalls the day four years ago when she told him she was worried his purchases were turning into an addiction.

That’s when Brian Mulligan suddenly lost his temper.

“He said he couldn’t wait until he was dead and said: ‘Maybe I should kill you first,“’ the 58-year-old woman said in an interview from her home in Tillsonburg, Ont.

“If I hadn’t looked at him, I probably would’ve continued home,” said Mulligan. “But I looked at him and his eyes were as black as the ace of spades.”

She dialled 911.

The 59-year-old big rig truck driver was arrested, held in jail for 18 days before being moved to a psychiatric facility. He now lives in a nursing home in nearby London, Ont.

Shortly before the incident, Brian Mulligan had been diagnosed with Pick’s disease, which is a rare form of dementia. His wife had been the first to recognize the symptoms — he was increasingly depressed, agitated and often times, unpredictable.

According to the Alzheimer Society of Canada, the number of cases of domestic violence involving people suffering from dementia is rapidly growing, with the need for police to establish a strategy to deal with these types of calls reaching a “critical” point.

“I think it is very frightening to imagine what things will look like in a very short number of years if we don’t have such a (national dementia) plan,” said the group’s CEO, Naguib Gouda.

Recent statistics from the society show that in 2010, there were over 110,000 new cases of dementia a year, or one new case every five minutes.

Within a generation, the society says, the numbers of Canadians living with dementia will more than double to 1.1 million.

Mary Schulz, the group’s director of education, said putting a person with dementia in jail can be a terrifying ordeal, especially since many times, the person may not know why they are there.

“Just imagine a strange environment, perhaps people with guns and sticks, uniforms and hats,” she said. “That’s a really volatile situation for someone who is already anxious, afraid and already feeling like they have to defend themselves.”

Earlier this month, the group officially asked police in Sault Ste. Marie to reassess their policy after the northwestern Ontario community saw an increase in these incidents.

“It’s mostly an elderly couple living together most of their lives. One now has dementia and we know that with dementia, there are responsive behaviours,” said Carolyn Cybulski, the executive director of the local chapter.

“There is a possibility that people with dementia can become aggressive or angry with their caregivers and sometimes the family members really don’t know what to do,” she said.

Cybulski said in some cases, the aggressive behaviour may be an indicator of an undiagnosed medical issue.