Psychology Today's website has an article about "acute stress disorder" which may be of interest. It mentions the benefits of cognitive therapy. Other resources also recommend techniques like eye movement desensitization and reprocessing ("EMDR"), a technique that enjoyed some success in treating Vietnam veterans in recent years.
Caveat: obviously, don't believe everything you read in the Wikipedia -- it's a massive free for all in the information department -- but respect it as an attempt to get the information out there, so that interested parties can go on to research it further on their own.