Some -- many? -- emergency services, such as police, fire, ems, recommend or even require that after certain events that everyone involved participate in Critical Incident Stress Management/Debriefing (CISM or CISD, depending on the program) in order to deal with after effects such as PTSD.
Three authors -- two psychologists and a criminal justice teacher (and FBI retiree) wrote an article on CISD/CISM, focused on law enforcement (FBI in particular), that argues basically that CISD and CISM are bunk. "Pseudoscience" in their eyes, something that looks scientific on the surface, but has no valid scientific underpinnings. When I read it I was surprised that they note that not only are there
not any scientifically valid studies supporting CISD/CISM, but there are at least two (if I recall correctly -- they may cite more) studies that show CISD/CISM cause longterm
harm. Their criteria is not whether people "feel good" immediately after going through a debriefing, but whether they show any ill effects in the long term.
You may read the article for yourself at this link:
http://cjb.sagepub.com/cgi/content/abstract/35/10/1337" onclick="window.open(this.href);return false;
I agree with those above that people who prepare themselves, who think through the likely consequences of various scenarios, who train themselves and have some idea of what to do, are much less likely to be traumatized by real life events. I doubt any amount of counseling can make up for not being prepared for a high stress encounter, whether it is self-defense, responding to a fire or medical emergency, or even risky sports. If you've never even thought of jumping from an airplane, and I suddenly without warning strap a chute to you and throw you out several hundred feet above the ground I doubt you will enjoy the experience or even get your ripcord pulled. If I send you to Airborne school for three weeks, you'll not only be prepared, you probably can't WAIT to get out of that airplane.
I encourage you to read the article. It was very educational for me.