LONDON, Ontario, Dec. 14 (UPI) -- A survey of Canadian peacekeeping veterans with service-related disabilities found 30 percent suffered clinical depression.

The study, published in the Canadian Journal of Psychiatry, found the rates of probable post-traumatic stress syndrome were 11 per cent for those deployed once and 15 per cent for those deployed more than once.

The random, national survey of more than 1,000 disabled veterans who had served with the Canadian Forces from 1990 to 1999 found peacekeepers were more likely to have PTSD and more severe symptoms if they were young, single or had multiple deployments.

"This study has important clinical implications because understanding such risk factors can help predict potential psychiatric problems in veterans who have been deployed," study leader J. Donald Richardson of the St. Joseph (OTCBB:STJO)'s Health Care, in London, Ontario, said in a statement.

"The high rates of depression observed in deployed veterans can have a significant impact when they seek treatment for PTSD because depression must be aggressively treated to help patients respond more effectively to psychotherapy."