You cannot completely prevent post-traumatic stress syndrome from developing. Some factors increase the risk of a person developing this syndrome, and other factors can decrease the risk. Mr. Beaulieu mentioned a healthy lifestyle and good mental health. A person who, from the outset, is well grounded, has a good social network and a healthy lifestyle, may be much better equipped to deal with trauma, be it PTSS or drug addiction. Certainly, a lot of research could be undertaken to determine which factors contribute to this situation within the armed forces today.
On April 3rd, 2008. See this statement in context.