As U.S.-led forces prepare to withdraw from the long Afghanistan war, some 13.5 percent of Canadian veterans who served there are suffering mental disorders related to their deployments.

Since the invasion of Afghanistan in late 2011, more than 40,000 Canadian Forces personnel have been deployed to support the coalition mission, with thousands experiencing symptoms related to posttraumatic stress disorder (PTSD) and other war-related mental illnesses. Although much has been said about the American experience in the war, researchers publishing Tuesday in CMAJ point to key differences among coalition countries in culture and the care of returning veterans — in addition to widely varying experiencing in the war itself.

A sample of more than 2,000 veterans among the 30,513 men and women deployed to South Asia — outside of duty stations in North American and Europe — was taken to analyze health records for war-related diagnoses. Consisting primarily of young men under age 40 in the Regular Forces, 13.5 percent had been diagnosed with a mental disorder with PTSD most common, prevalent in eight percent of the sampling, followed by depression at 6.3 percent. Nearly one in four of those suffering from depressive disorders were also suffering from PTSD, as defined by the Diagnostic and Statistical Manual of Mental Health Disorders, fourth edition.

Interestingly, an additional 5.5 percent experienced a mental health disorder deemed unrelated to their wartime service.

When looking at wartime experience, Canadian veterans who had served in the more dangerous places in Afghanistan, such as the capital city of Kandahar, were more likely to experience mental disorders.

"Deployment to Kandahar was associated with a particularly increased risk: it was almost 6 times the risk associated with deployment to the United Arab Emirates or Arabian Gulf and 2 times the risk associated with deployment to multiple locations or Kabul," the researchers wrote.

In addition, lower-ranking Army personnel were more likely than others, including airmen and seamen, to develop mental disorders.

"This study provided a precise and methodologically rigorous estimate of the impact of the mission on the risk of mental disorders during continued military service," the researchers wrote. "These findings will have implications in terms of service delivery and veterans' benefits.

The researchers said follow-up study of the sampling would also assess the delivery of mental health care to veterans in Canada with regard to outcomes. A small contingent of Canadian personnel remain in Afghanistan for training purposes, after Canada withdrew the last of its combat forces in 2011.

Source: Zamorski M, Boulos D. Mental Disorders In 13.5 Percent Of Canadian Forces Personnel Deployed To Afghanistan. CMAJ. 2013.