It does wear off after a few years; at least it did for me. Now I can hear a car backfire without dropping to the ground (yes I did this once and felt pretty foolish). But I still freeze for a moment when I hear a distant firework or other load bang, and my mind immediately tries to identify the "weapon" sound signature. But I still feel uncomfortable in large crowds, and always scan for an easy exit.
I'm no expert, but both roquetman's and mattdeboard's stories sound like they might be Post-Traumatic Stress Disorder (symptoms include "Having an exaggerated response to things that startle you", and "Feeling more aware (hypervigilance)") [0], for which treatment exists that's apparently effective at least for some people. Continuing the recent suicide-prevention theme on HN, "Going through a trauma may increase a person's suicide risk. Studies also show that suicide risk is higher in persons with PTSD." [1] So please, if people find themselves having symptoms like this, consider getting help.
Indeed, but not every one of the reactions described idan, mattdeboard, or roqetman is attributable to a disorder. For example, freezing and trying to analyze the sound whenever an explosive noise occurs (or even ducking for cover) is not necessarily a pathological reaction - it could simply be a learned and throughly ingrained response. The patterns you learn in situations where your life depends on a trained behavior tend to be imprinted very deeply.
There are a couple of other things that need to go wrong until the diagnosis of PTSD is applicable. Sadly, this is not exactly made easier by the fact that people tend to have vastly different reactions and symptoms.
Yes; I do not believe I have combat-related PTSD. However I do believe that an early adulthood -- 18 to 31 -- spent in the Marine Corps does deeply ingrain certain modes of thought. When those modes are cemented by lengthy combat tours they can be hard to shake.
I think for me personally it is a highly anticipatory, self-protective mode. I am constantly assessing and "war gaming" where scenarios/situations might veer. This includes my daily commute, shopping trips and unfortunately romantic relationships.
