OTTAWA - The number of former soldiers suffering from post-traumatic stress has more than tripled since Canada first deployed troops to Afghanistan, say new figures released by Veterans Affairs Canada.

With the country's involvement in the war set to continue until 2011, the numbers are only expected to get worse.

The rising tide of psychiatric disorders among relatively young men and women is the biggest challenge facing the system of veterans' care, which until recently had been geared toward geriatric issues, said Veterans Affairs Minister Greg Thompson.

"It is the challenge of the future," he said in an interview with The Canadian Press.

Of the 10,252 (Veterans Affairs) clients with a psychiatric condition, 63 per cent have a (post traumatic stress disorder, or PTSD) condition, said a briefing note prepared for Thompson last summer.

"Over the past five years, the number of clients with a psychiatric condition has tripled, increasing from 3,501 to 10,252; the number of clients with a PTSD condition has more than tripled, increasing from 1,802 to 6,504 as of March 31, 2007."

The statistics represent those who are no longer serving in uniform. The Defence Department keeps its own, separate tally of members suffering from stress injuries.

Figures obtained last summer by The Canadian Press show that of 1,300 Canadian Forces members who served in Afghanistan since 2005, 28 per cent had symptoms suggestive of one or more mental-health problems. The numbers are based on post-deployment screening.

Of those, just over six per cent were possibly suffering from PTSD and another five per cent showed symptoms of major depression.

On Thursday, the Commons defence committee voted to hold hearings on the impact of post traumatic stress within the military, but at the insistence of Conservative MPs witnesses will be heard behind closed doors.

Both National Defence and Veterans Affairs have faced repeated warnings during the last year about the looming mental-health crisis.

"Without an aggressive response, many veterans have the potential to harm themselves or others," Veterans Affairs staff wrote in a note to Thompson.

"The earlier the intervention, greater the chances of recovery."

The Conservatives responded in the 2007 federal budget with $9 million, allowing the veterans department to open five operational stress-injury clinics across the country. The new centres are in addition to the Defence Department's existing five stress clinics, which first began appearing in the late 1990s.

New Democrat defence critic Dawn Black says the measures taken to date have not been adequate.

"When they talk about support for our troops, the mental and social help they need, clearly it is not there," she said.

But Thompson said health-care professionals in both departments are working together, trying different early-intervention strategies, but getting around emotional barricades erected by most soldiers has proven to be daunting.

"Many of them still suffer in silence," he said.

Senior commanders have acknowledged the reluctance of soldiers to come forward after they've experienced symptoms of stress injury.

Compounding the problem is a shortage of psychiatrists and other mental-health staff within the military.

The auditor general took issue with the shortage last fall, issuing a sharp rebuke saying the system cannot meet the growing demand.

"As a result, members are being sent to civilian private practitioners, where it is difficult for the department to monitor their care," Sheila Fraser said last October.

The military hopes to double the number mental-health staff by 2009, going to 447 from 229 at an estimated price tag of $98 million.

Prior to going overseas soldiers are given briefings that involve a psychiatrist, a social worker, and a mental-health nurse. Their services are also available at Kandahar Airfeld for troops in theatre.

Within four months of coming home there is post-deployment screening.

PTSD is a complicated condition that can involve nightmares, flashbacks, vivid memories, sleeping disorders, anger and substance abuse.