Striking new research proposes taking a common anti-inflammatory drug soon after experiencing a traumatic event could help people forget upsetting memories and reduce their risk of developing post-traumatic stress disorder (PTSD).
"Persistent distressing, involuntary or 'intrusive' memories are a core feature of PTSD," explained lead author on the new study Vanessa Hennessy. "Unlike other psychological disorders, the onset of PTSD caused by a single trauma can reliably be traced back to the occurrence of a specific, often life-threatening event that generates long-lasting intrusive memories."
So researchers have long looked for ways to block that immediate traumatic memory formation that can often lead to PTSD. Several drugs have been proposed as potential useful candidates, from an old antibiotic called doxycycline to a frequently used anesthetic called propofol.
This new research focused on a common anti-inflammatory drug called hydrocortisone. The drug is essentially a synthetic form of the stress hormone cortisol and is often used as an immunosuppressive agent in autoimmune disease.
Prior studies have found many PTSD patients seem to display low baseline cortisol levels. So it has been hypothesized that low cortisol levels could hinder a person's ability to return to their average physiological state following a traumatic event and administering a drug such as hydrocortisone to someone soon after a trauma may help them forget that event faster.
To test this hypothesis a research team from University College London recruited 120 healthy adults. The cohort was shown two clips of extreme violence from a French film called Irreversible. Prior studies have established scenes from this movie can reliably induce distressing intrusive memories following viewing.
Immediately after viewing the film half the cohort was given either 30 mg of hydrocortisone or a placebo. And following some blood tests the participants then filled out daily surveys for the next week, recording the vividness of any subsequent intrusive memory.
Overall, those in the hydrocortisone group reported fewer intrusive traumatic memories over the course of the following week. However, the researchers found significant sex-based differences in responses, particularly in regards to each subject's sex hormone levels.
Men with high levels of estrogen seem to respond most positively to the memory-erasing effects of hydrocortisone. However, women with high levels of estrogen showed the opposite effect, with hydrocortisone actually increasing their reports of intrusive memories.
"Our work shows how important it is to do careful experiments with healthy people to work out whether and how a drug like hydrocortisone could work," said Hennessy. "After all, our results seem to show that there might be conditions that make the drug harmful in some people."
The researchers are not blind to the many caveats that accompany a study such as this. It is, of course, impossible to ethically investigate whether an intervention blocks real-life trauma memories. You couldn't literally traumatize a group of trial participants and then give half a placebo. So using videos is one technique to try and safely model traumatic events, but it is entirely possible these studies are not analogous to real-life trauma.
The researchers also can only speculate as to how hydrocortisone could affect the development of traumatic memories. Plus it is even more of a mystery how sex hormones could influence intrusive memories and future work will certainly have to investigate whether certain hormonal profiles could be more suitable for these kinds of cortisol-based treatments.
The new study was published in the journal Translational Psychiatry.
Source: University College London