Also, low cortisol levels disinhibit retrieval of traumatic memories, so the affected individual thinks more about the trauma. All of this elicits an uncontrolled sympathetic response, so the patient remains in a constant state of hyperarousal characteristic of PTSD.
“In theory we should have some really simple ways to prevent PTSD from occurring if we get in there soon enough: reducing noradrenergic overactivity via alpha2-adrenergic receptor agonism with an agent such as clonidine; postsynaptic beta-adrenergic blocking with a drug such as propranolol; or alpha1-adrenergic receptor blocking, as with prazosin. All of these approaches reduce noradrenergic tone and therefore should be effective, in theory, to prevent PTSD.
“We should also be able to use indirect strategies to reduce noradrenergic overactivity: GABA agents like benzodiazepines, alcohol, and gabapentin oppose noradrenaline action in the amygdala. I’m not suggesting drinking all the time to prevent PTSD, but there’s a strong association in several studies, with about a 50% reduction in rates of PTSD in those who are intoxicated at the time of the trauma,” according to Dr. Bisson.
Unfortunately, to date, none of those pharmacologic approaches have been effective when studied in randomized trials.
One pharmacologic intervention
Only one drug, hydrocortisone, was rated an “intervention with emerging evidence of efficacy” for prevention of PTSD symptoms in adults when given within the first 3 months after a traumatic event. Three placebo-controlled, randomized trials have shown a positive effect.
“It should be said that most of the studies of hydrocortisone have been done in individuals following extreme physical illness, such as septic shock sufferers, so the generalizability is a bit of a question. Nevertheless, it’s the one agent that has meta-analytic evidence of being effective at preventing PTSD, although more research is needed,” Dr. Bisson said.
Results of randomized trials featuring those agents have been “really disappointing” in light of what seems a sound theoretic rationale, he continued.
“We’re really struggling from a pharmacologic perspective to know what to do. I would say we are still at the experimental stage, and there’s no real good evidence that we should give any medication to prevent PTSD,” Dr. Bisson said.
Early psychosocial interventions
The ISTSS guidelines rate only two single-session interventions for prevention as rising to the promising level of “emerging evidence” of clinically important benefit: single-session eye movement desensitization and reprocessing (EMDR), which in its multisession format is a well-established treatment with strong evidence of efficacy in established PTSD, and a program known as Group 512 PM, which combines group debriefing with group cohesion–building exercises.
“Group 512 PM was done in groups of Chinese army personnel helping in recovery efforts following a 2008 earthquake in China that killed 80,000 people. It resulted in nearly a 50% reduction in PTSD versus no debriefing. This cohesion training might be a clue to us as something to work on in the future,” Dr. Bisson said.
The ISTSS guidelines deem there is insufficient evidence to recommend single-session group debriefing, group stress management, heart stress management, group education, trauma-focused counselling, computerized visuospatial task, individual psychoeducation, or individual debriefing.
“In six randomized controlled trials over nearly the last 20 years, we see a strong signal that individual psychological debriefing isn’t effective. So, certainly, going into a room with an individual or a couple and talking about what they’ve been through in great detail and getting them to express their emotions and advising them that’s a normal reaction doesn’t seem to be enough. And rather worryingly, the people who tend to do worse with that sort of intervention are the people who’ve got the most symptoms when they started, so they’re the ones at highest risk of developing PTSD,” Dr. Bisson said.
Multisession prevention interventions such as brief dyadic therapy and self-guided Internet interventions are supported by emerging evidence. Less promising, and with insufficient evidence to recommend, according to the ISTSS, are brief interpersonal therapy, brief individual trauma processing therapy, telephone-based cognitive-behavioral therapy (CBT), and nurse-led intensive care recovery programs.
For multisession early treatment interventions for patients with emerging traumatic stress symptoms within the first 3 months, the new ISTSS guidelines recommend as standard therapy CBT with a trauma focus, EMDR, or cognitive therapy. Stepped or collaborative care is rated as having “low effect.” There is emerging evidence for structured writing interventions and Internet-based guided self-help. And there is insufficient evidence to recommend behavioral activation, Internet virtual reality therapy, telephone-based CBT with a trauma focus, computerized neurobehavioral training, or supportive counseling.