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Fast and complete desensitisation

- using the natural memory reconsolidation process

Over the last couple of years, some important research has taken place that reveals how processes of desensitisation and extinction can be much more effective than used to be assumed.

The principles revealed by this research are simple but subtle. It can be difficult initially to grasp the processes involved since they are somewhat counter-intuitive and initially perplexing.

The classic paradigm of conditioned/learned emotional responses and extinction is that of Pavlov's dogs, established well over a century ago. The dogs would learn a conditioned physiological response when, for example, a bell is repeatedly paired with an electric shock. If the bell is subsequently repeatedly presented without the electric shock, the conditioned response would subside - it would be extinguished. This became the basis of all the forms of exposure therapy and desensitisation that currently prevail in modern CBT approaches to anxiety. Some cognitive therapists prefer to emphasise the idea of 'behavioural experiments' rather than exposure, but the underlying principles must be the same. 

The problem with the classical extinction paradigm is that it was not a very reliable process. Extinction would certainly take place - but the conditioned response would often return, particularly if the unconditioned stimulus - the electric shock or other trauma - were presented again. Thus, it is a common clinical observation that after a traumatised person has undergone a desensitisation process, all may seem well until he or she encounters the next trauma. This may then reinstate all the old traumatic stress reactions. It is as if the original trauma reactions have just been inhibited by the extinction process, but are still present. Each time the conditioned stimulus is presented without the aversive event (e.g. the electric shock), a new memory is installed in which the shock did not happen. These new memories then compete with and inhibit the old trauma memories - but the latter are not actually modified. 

Research over the last couple of years, by Monfils and colleagues, provides a subtle but radical new perspective. The investigators found that if the conditioned stimulus is presented once briefly - and this presentation is followed by a gap in time, before a sustained process of extinction (repeated presentation of the CR) takes place, the original traumatic stress response is fully and permanently modified. If this gap in time, after the initial presentation of the CS, is not allowed - e.g. if there is immediately a sustained process of exposure (as in most clinical approaches to desensitisation) - the complete and permanent modification of the stress response does not occur. 

What seems to happen is that when the traumatic memory is accessed briefly (and then nothing bad happens), a neurobiological process takes place that results in the memory becoming 'labile' and open to modification. This process takes a certain time. Attempting to desensitise when the memory of the trauma is not labile will just result in additional non-trauma memories being laid down, but the original trauma memory will not itself be modified. The researchers found that the memory is labile after 10 minutes from the original brief exposure, and at one hour, but by 6 hours it was no longer labile - and it would not initially be labile until a few minutes had passed. When extinction/desensitisation took place during the labile period, a complete modification of the anxiety response took place - the CR would not be reinstated. When the extinction/desensitisation took place outside the labile period, the CR remained likely to be reinstated. 

These processes were found to take place in both rats and humans. The phenomenon is known as 'memory reconsolidation'. Whilst the research was based on mild experimental trauma (mild electric shocks) the principles and processes discovered have enormous implications for therapeutic work with real life traumas. 

I have found the principles make any desensitisation process quicker, easier, and more effective. My procedure is simple. I ask the person to bring the traumatic memory briefly to mind - let them be with it for a few seconds - and then I ask them to put it aside. I then engage the person in more neutral tasks or conversation, perhaps discussing their hopes or more positive experiences and interests. After a few minutes, I ask the person to go back to the traumatic memory and now we engage in the desensitisation using a combination of eye movements and energy methods. I do not ask the person to engage in a prolonged reliving of the trauma. The result is often remarkable in its speed and completeness. 


žMonfils, M., Cowansage, K. K., Klann, E., & LeDoux, J. E. (2009). Extinction-Reconsolidation boundaries: Key to persistent attenuation of fear memories. Science, 324, 951-955.

žSchiller, D., Monfils, M., Raio, C. M., Johnson, D. C., LeDoux, J. E., & Phelps, E. A. (2010). Preventing the return of fear in humans using reconsolidation update mechanisms. Nature, 463, 49-53.

An excellent powerpoint explanation of this research and its implications, from the Cognitive Behavioral Institute of Albuquerque 2012 Annual Convention, can be found here: click

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