“ Into the bowl in which their wine was mixed, she slipped a drug that had the power of robbing grief and anger of their sting and banishing all painful memories”
-Homer, the Odyssey
Morphine and other opiates have been used by humans since the earliest times. The poppy has been a powerful cultural symbol for hundreds or, even, thousands of years. When a chemical agent has ‘traveled’ with humans for such a long span of time it usually means it has strong evolutionary value. A fascinating study just published in the New England Journal of Medicine suggests morphine has the power to blunt the emotional aftereffects of trauma in people who’ve been severely injured.
Military researchers examined the records of almost 700 soldiers with combat injury and found that those who received morphine in the field had nearly a 50 percent reduction in rates of PTSD, two years later. If such a finding is accurate, it opens the possibility that the risk of PTSD can be substantially reduced if opiates are administered close to the time of trauma. This observation may have considerable impact on clinical care.
I’m particularly excited by this finding because my research team, in coordination with a research team at Shriners Burns Hospitals in Boston, published a similar finding almost 10 years ago in a sample of children hospitalized with burn injury. In our study, we found that the more morphine that burned children were prescribed during their hospitalization, the greater the reduction in PTSD symptoms over six months following discharge.
So what’s going on here? How may a relatively short duration of treatment delivered in the wake of a trauma prevent a serious and debilitating psychiatric problem such as PTSD? First, it’s important to understand that PTSD is a disorder of important natural systems that prepare animals and humans to survive when faced with threat. These systems promote the accurate appraisal of threat, the engagement of bodily systems required to manage threat (e.g. fight, flight, freeze) and the prompt termination of the threat response when the threat signal abates.
Many of the symptoms of PTSD can be seen as expressions of the dysfunction of one or more of these systems (e.g. flashbacks, intrusive memories, dissociation, hypervigilance, avoidance).
So how may opiate treatment prevent PTSD? There are a number of possible mechanisms. First, we know that opiates diminish pain signals. Might they diminish the risk of PTSD by diminishing the perceived appraisal of threat at the time of trauma? Pain is a very important driver of threat perception while the trauma is occurring. Second, opiates are potent blockers of the norepinepherine system, which is responsible for consolidating memory. Might opiates prevent the consolidation of traumatic memory by blocking the system responsible for consolidating this memory? Many investigators have postulated that blocking the norepinepherine system may offer a way to secondarily prevent PTSD. A third possible mechanism relates to the role of opiates in systems responsible for affiliative behavior. Morphine has a similar chemical structure as oxytocin, a well described chemical related to this system.
Although these findings are exciting and promising, we must use great caution before morphine is indiscriminantly prescribed to traumatized individuals in our emergency rooms and hospital units. Approximately 20 to 40 percent of traumatized individuals will develop PTSD. We don’t want to prescribe a powerful and potentially addictive substance to the 60 to 80 percent of traumatized individuals who won’t develop PTSD. Further, evolution has given us powerful natural systems to manage threat and trauma. We must be very cautions about using chemicals to interfere with these systems in those not at risk.
Research that points to an effective preventative intervention can–and should–have a major impact on clinical care. However, we must carefully consider how this information is used to guide the standard of care in our field.