The psychological impact on the women who survived Tuesday's shooting at a Pittsburgh health club will likely be exacerbated because the incident occurred in a location considered to be a safe haven and an unlikely backdrop of a brutal killing spree.
"Traumatic events, especially when they're so utterly sudden and unpredictable and in a safe place like a health club, are that much harder to cope with," said Dr. Paul Ragan, an associate professor of psychiatry at Vanderbilt University in Nashville, Tenn.
"LA Fitness is certainly a place that we all associate with some level of safety and comfort and security."
The suspected shooter, George Sodini, 48, entered the Bridgeville, Pa., LA Fitness club just after 8 p.m. Tuesday where he proceeded to turn off the lights before he began shooting into a dance class.
Sodini is believed to have killed three women and injured several others, some critically, before turning the gun on himself.
"The situation is made worse because it's not like these people were out on a street in a high–risk neighborhood or somewhere at war," said Nadine Kaslow, a professor of psychiatry at Emory University School of Medicine in Atlanta.
"You go to a gym for self care, to get some relief and to get a break from the stress of life," Kaslow said. "People think of it as a safe place."
The women who witnessed the shooting first-hand, as well as the gym patrons who were bystanders to the incident, will likely suffer from acute stress disorder, a common response to a traumatic event that often morphs into post-traumatic stress disorder in later months, experts say.
"Acute stress disorder is something that's similar to post traumatic stress disorder but it emerges much more quickly," Vanderbilt's Ragan said.
"When you first see a person with acute stress disorder they look numb," said Ragan, who has worked as a military psychiatrist, adding that experts have coined a term, "the thousand yard stare," for the look on traumatized victims' faces.
"They seem dazed and confused, the world seems very unreal to them and later they often have amnesia and don't remember all the elements of the traumatic event," Ragan said.
He said a full-blown acute stress disorder can sometimes take as long as a week to develop.
It's common for people who witness traumatic events to begin to replay the incident in their minds over and over again, especially if there are everyday triggers that remind them of the event, experts say.
"The whole ordeal becomes an intrusive memory," Ragan said. "Similar situations will trigger the memory of what happened and will bring back the whole experience."
Knowing that the alleged shooter turned off the lights before he began shooting into the gym class, Ragan said that a sudden loss of light or darkness may be hard for those witnesses and survivors to cope with in the coming weeks.
"Turning off the lights, that's psychological warfare," Ragan said. "That's an attempt to invoke more terror."
Ragan said that he has treated Vietnam veterans who are unable to attend barbecues because the smell of burning reminds them too much of their time in service. Similarly, Ragan says a sudden loss of light may stimulate difficult memories for those LA Fitness survivors.
"Turning off the lights may trigger the re-experience of the trauma and cause the images and the intrusive thoughts to appear to people," Ragan said. "They will likely be physically restless, jumpy."
Survivor's guilt is another psychological problem many of the women who escaped the shooting alive may have to cope with, Emory's Kaslow said.
"Even though they will obviously feel relieved and grateful that they survived this random act by someone, there will be some sense of 'why wasn't it me?'" she said.
As for recovery, experts say, the shooting bystanders and witnesses must return to a normal life as quickly as possible.
"It turns out if you avoid the place where the incident occurred and your only memory of that place is traumatic, that seems to promote a sort of fixation on it," Ragan said.
"You want to make new memories when you're ready, you don't want to live your life with the gym being associated with the traumatic event."