Canadians are most accustomed to hearing about post-traumatic stress disorder among returning soldiers, but a newly published study suggests that almost one in 10 civilians meets the criteria for PTSD at some point in his or her lifetime.

Researchers at McMaster University in Hamilton have released the findings of a national survey that appear in the latest issue of the quarterly journal CNS Neuroscience and Therapeutics.

They conducted a telephone survey of 2,991 people, age 18 and over, from across Canada in July and August 2002, and found the prevalence rate of lifetime PTSD was estimated at 9.2 per cent.

Based on the responses, they estimate that at any given time, 2.4 per cent of the population is experiencing the disorder.

Altogether, 76.1 per cent of respondents reported exposure to at least one event sufficient to cause PTSD, such as the unexpected death of a loved one, sexual assault or seeing someone badly injured or killed.

"Most people who experience a trauma may experience symptoms, but they usually resolve on their own," said researcher Michael Van Ameringen, co-director of McMaster's Anxiety Disorders Clinic and associate professor in the department of psychiatry and behavioural neurosciences.

"But for nine per cent of people, the symptoms that you get after experiencing a trauma might continue on."

He decided to conduct the study because there was a dearth of statistics on the prevalence of PTSD in the civilian population in Canada.

Health-care providers need to take notice, he said.

Concern arises weeks after trauma

"I think mental-health professionals and primary-care people need to be aware that traumatic events are common and that people do develop PTSD, and I think clinicians don't usually look for this kind of disorder when they're seeing people," he said Wednesday in an interview from Hamilton.

"Particularly with sexual assault it's often not very easy for people who have been assaulted to go and ask for help."

After a traumatic event, a person typically feels numb and can be keyed up, anxious, not sleep and depressed.

"People re-experience the trauma, so they can be replaying it in their head, they can have a re-experiencing event such as flashbacks, they can have nightmares of the event and they avoid things that remind them of the trauma," Van Ameringen said.

If a person still isn't sleeping, eating or going to work or school a couple of weeks after a trauma, then there should be concern that the individual might be developing post-traumatic stress disorder, he said.

Katy Kamkar, a clinical psychologist at the Centre for Addiction and Mental Health, said it was a "great study" in that it tried to look at the prevalence of PTSD in Canada, and that if the findings can be repeated in another study, "we can reach stronger conclusions."

"It's a significant disorder, it's a serious disorder, and when a person has PTSD, the person does need help, absolutely, because it does have a big impact on various areas of your functioning," said Kamkar, who works in the centre's work stress and health program.

It often goes hand in hand with other disorders such as depression and substance abuse, she noted.

Risk of developing PTSD can involve a number of factors, including:

• Severity of the trauma.
• Proximity to the trauma.
• Previous traumatic events the person might have suffered.
• Social supports.
• Whether the individual had a traumatic childhood.

"We do recommend early treatment to prevent exacerbation of the symptoms. And often it's a combination of medication and psychological treatment," Kamkar said.

The psychological treatment would involve education about anxiety and components of PTSD, as well as exposure exercises that involve talking about the trauma.