Preventing Traumatic Memory Consolidation

Is it possible to inoculate, or de-traumatize, someone who has just experienced a probably-traumatic event?

This would entail somehow interfering with the traumatization process, if slightly after the initial fact of the event. When distress and shock overwhelm the mind’s normal ability to process and integrate an experience, it is consolidated, or stored, as a traumatic memory. Traumatization arises from the individual’s subjective experience of an event, as well as subsequent coping process, especially during the six hour post-event memory consolidation period.

What if, after a potentially traumatic experience, we could disrupt or modify the memory consolidation to prevent the event from having traumatic impact? Two studies have attempted this, with some success.

These were both analog studies, which means that actual trauma cases were not involved. Rather, they experimentally induced a minor traumatic experience with healthy volunteers, via the trauma film paradigm of exposure to a series of video clips of people and animals being hurt, killed, or otherwise in distress. Most participants (across studies and experimental conditions) did have at least some intrusive imagery in the week following exposure, which provided plenty of opportunity to discern the possible impact of interventions designed to reduce post-traumatic symptoms. While analog studies cannot be regarded as definitive, they do provide preliminary information about the potential value of interventions that can then be tried in clinical settings.

In the instant-classic Tetris study (Holmes et al, 2009), 40 participants were exposed to the trauma video, then half an hour later were randomized into either a no-task group, or 10 minutes of playing the Tetris video game. Tetris was used because as a visual activity it would divert some of the cognitive capacity that might otherwise be used to consolidate traumatic imagery. Tetris is uniquely suited to create cognitive overload, in that (a) it taps both visual and logical thinking, and (b) it progressively increases in difficulty until the player can no longer keep up. And it worked: in the week following the initial trauma exposure, those in the Tetris condition suffered fewer than half the number of intrusive imagery events than the no-task participants.

In a more recent study (Pile, Barnhofer, & Wild, 2015), a different strategy was tried: to alter the meaning-making associated with the event, to mitigate the traumatizing aspect. They exposed 115 participants to the trauma video, then (as per random assignment) to either (a) further neutral videos [control condition], (b) the same distressing videos [exposure only], or (c) the same distressing videos, but this time including additional information about what eventually happened to the people in the videos [exposure plus updating the meaning].

The primary finding was that introducing additional information reduced the traumatic impact of the initial traumatic exposure. That is, those in the update group experienced fewer symptoms of post-traumatic stress (e.g., intrusive imagery) than other participants. This was presumably because the additional information allowed participants to bring a broader perspective to bear on what they had seen in the videos, mitigating traumatic impact.

Both of these strategies are promising and, pending further research support, could realistically be applied in clinical practice settings. The biggest challenge, for either strategy, is to arrange for trauma victims to receive the intervention soon after the event, within the consolidation window. This might be accomplished in part by educating the public as to the value of such interventions (when the value has become well established) so that it would become routine to obtain the intervention in a timely manner.

The meaning-making strategy would require someone qualified to debrief the trauma victim, soon after the event, and try to help the individual to arrive at a more constructive perspective on what happened. This could occur at hospitals, police stations, rape crisis centers, or any place that routinely deals with people very soon after a potentially traumatic event. Those agencies who do not have a qualified debriefer on staff could make a referral to a telephone debriefer. Note that it is something of a leap from providing additional information on outcomes of filmed events, in an analog study, to developing a structured debriefing strategy that would achieve equivalent benefit with actually-traumatized individuals. So a clinical intervention based on the Pile et al study would have to be developed before it could be tested and applied in the field.

The cognitive overload/disruption strategy would only require an inexpensive electronic gadget for the video game. This could easily be utilized while people are waiting for other services in hospital emergency rooms and elsewhere. The Tetris intervention is also particularly well suited to a public education approach, in that people could readily self-treat with Tetris, post-event.

These promising non-drug interventions have the potential to do a lot of good at a very low cost. The Tetris intervention is particularly appealing because it is inexpensive, relatively easy to disseminate, and likely to be acceptable to a wide range of clients, including children as well as those who prefer not to talk about it. It is also already developed and practice-ready, except for determining the ideal dose and timing. These advantages also apply to research, and I hope some enterprising researcher will take this idea and run with it, soon.

References

Holmes, E. A., James, E. L., Coode-Bate, T., & Deeprose, C. (2009). Can playing the computer game “‘Tetris’” reduce the build-up of flashbacks for trauma? A proposal from cognitive science. PLoS ONE 4(1): e4153. doi:10.1371/journal.pone.0004153

Pile V, Barnhofer, T., & Wild, J. (2015). Updating versus exposure to prevent consolidation of conditioned fear. PLoS ONE 10(4): e0122971. doi:10.1371/journal.pone.0122971