Especially as the wars in Iraq and Afghanistan continue, more and more people are becoming aware of the debilitating effects of Post-Traumatic Stress Disorder (PTSD). Not only war, but natural disaster or a personal trauma such as a sexual assault or a severe accident can also cause PTSD.

Memories tied to strong emotion are naturally more vivid. This is a survival mechanism — strong emotions are associated with important situations, so it is naturally more important to remember those situations in order to avoid them in future (or seek them out, in the case of strong positive emotions).

But what appears to happen in PTSD is that a memory is associated with an emotion so strong that, unlike normal memories, it doesn’t slowly fade. Instead, it’s repeatedly triggered by anything that reminds you of the original situation — and both the memory and the emotion come back full force, over and over again.

A recent study in Nature discusses a potential way to overcome PTSD using the “window of opportunity” that’s created by recalling the memory. It appears that memories are like shirts: when you take them out, you unfold them, and when you put them back in the drawer, you refold them slightly differently. This process is referred to as “reconsolidation.”

Taking a memory-erasing drug just after recalling a memory can prevent it from being recalled again — as if you took the shirt out and tossed it away, and it never made it back into the drawer. But these drugs have unpredictable and sometimes unfortunate results in the complex human mind. Could there be an alternative that works without the drug?

It turns out that there could be. The Nature paper describes a preliminary attempt using a conditioned response to an electric shock. The experimenters found, as expected, that if they associated a visual stimulus (a colored square) with a mild electric shock, the experimental participants would react with measurable tension to the reappearance of the square, even if the shock did not accompany it.

However, if they repeated the reappearance of the square without the shock a number of times during the “window of opportunity” that the reconsolidation process opens up — between three minutes and a few hours after the initial restimulus — the reaction was extinguished, and did not reappear at testing one day and one year afterwards. Doing the extinction training six hours afterwards instead of a few minutes, or not doing it at all, left the conditioning in place both in the short-term and after a year.

While this is a long way from being a cure for PTSD, it does suggest some directions. It also provides a mechanism and rationale for a hypnotherapy technique developed by Andrew Newton, which I was fortunate enough to learn from him.

This technique begins by establishing the spatial directions that the client associates with the past and the future, which differ from person to person. The client then imagines a vividly coloured photograph of the traumatic event, approaching from the “past” direction.

Over several minutes, the client imagines the color fading out of the photograph and leaving it as a black-and-white or sepia image, faded by the sun. The client then imagines screwing up the photograph and throwing it away in the “past” direction.

If possible, a vivid positive image, contrasting with the traumatic event, should then be introduced, for the client to imagine as coming from the “future” direction. This image is allowed to remain colorful and clear.

By taking advantage of the “window of opportunity” for detaching a memory from its associated emotion, this technique and others like it are able to allow the memory to continue to exist — important for avoiding similar situations in the future — without the previous distressing emotional effects.

References

Schiller, D., Monfils, M., Raio, C., Johnson, D., LeDoux, J., & Phelps, E. (2009). Preventing the return of fear in humans using reconsolidation update mechanisms Nature, 463 (7277), 49-53 DOI: 10.1038/nature08637