Kate Johnson

April 17, 2012

April 17, 2012 (Arlington, Virginia) — A history of childhood trauma in police recruits who are without psychiatric symptoms is a "profound" predictor of posttraumatic stress disorder (PTSD), new research shows.

Here at the Anxiety Disorders Association of America (ADAA) 32nd Annual Conference, the longitudinal prospective cohort study of police officers suggests that a positive history of childhood trauma may be used to place law enforcement and military personnel.

"I think the view is that this kind of information could be used not to exclude people from service but to provide resilience-building training and/or to triage people into different roles," said Charles Marmar, MD, who is professor and chair of the Department of Psychiatry at the New York University Langone Medical Center in New York City.

The ongoing study measured biologic risk and resilience factors in 400 police academy recruits from New York City and the San Francisco Bay area during a period of 8 years.

The study showed that 25% of the recruits experienced trauma before the age of 13 years — a rate similar to that in the general population. "It could have been exposure to violence, a motor vehicle accident, abuse, and other causes," he said.

Psychological, Biological Reactivity

Although "not a single one of our 400 recruits had a significant chronic axis 1 psychiatric disorder at the time of screening," when shown a video of real-life, dangerous police situations, those recruits who reported a history of childhood trauma showed initial alterations in psychological and biological reactivity that were predictive of PTSD 4 years later, .

In response to the video, those who had experienced early childhood trauma reported significantly higher levels of subjective distress and also had elevations of salivary catecholamine and sustained 3-methoxy-4-hydroxyphenylglycol (MHPG) reactions.

"So in young, healthy recruits with no current psychiatric illness, the endocrine response is already upregulated if they have a history of childhood trauma," said Dr. Marmar.

Additionally, acoustic startle reactivity in the form of eye blink, skin conductivity, and heart rate was increased in response to the video in recruits who had experienced childhood trauma.

Once on active duty, the police officers experienced a personal life threat approximately once every 4 months. Those with a history of childhood trauma showed greater adrenergic and glucocorticoid reactivity to these "critical incidents," said Dr. Marmar.

Genetic Vulnerability

Those with a family history of anxiety, mood disorders, or substance abuse also were more vulnerable to PTSD at 4 years — likely evidence of genetic vulnerability.

Four years after recruitment, the single strongest predictor of PTSD symptoms is the intensity and duration of panic-like symptoms at the time of critical incident exposure, Dr. Marmar concluded.

"If you have the genetic vulnerability and you're exposed to early childhood trauma, you're predisposed to emotion dysregulation in terms of terror, horror, helplessness at the time of traumatic exposure, and that in turn predicts PTSD."

In addition, he said that 4 distinct patterns are emerging from the sample.

According to Dr. Marmar, in the largest group, 75% showed little or no PTSD symptoms at any time during the first 4 years of service.

The remaining 25% fell into 3 groups. The first group showed high anxious reaction at the time of coming into police service and quickly accommodated. The second group became symptomatic as a result of their first traumatic event and then accommodated. Finally, the largest group showed a linear growth of PTSD symptoms every year during police service.

"So 16% to 17% of our sample is becoming more symptomatic progressively with cumulative exposure of every year of police service," said Dr. Marmar.

Career Limiting?

Commenting on the study findings for Medscape Medical News, Melissa Hunt, PhD, associate director of clinical training at the University of Pennsylvania's Department of Psychology, in Philadelphia, said "that ultimately, this kind of research will be used for screening people out of certain professions: 'That kid shouldn't be a Green Beret, maybe this one shouldn't be a police officer.' "

She added that it remains unclear whether some of the factors predictive of PTSD that were identified by the study might actually be beneficial to job performance.

"If you've got something like an exaggerated acoustic startle, or eye blink — something as simple and basically reflexive as that — could it actually predict better performance? Because you're more aware, you're more reactive, more alert, which, if you think about it, is the only evolutionary reason for all of these changes in response to early trauma," she said.

"I'd be fascinated to know if they've got access to any job performance measures, because it could go either way — it could make them more effective or less effective — it could make them more likely to be overreactive, to fire their weapon inappropriately. We just don't know."

Dr. Marmar and Dr. Hunt have disclosed no relevant financial relationships.

Anxiety Disorders Association of America (ADAA) 32nd Annual Conference. Session 316R, presented April 13, 2012.


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