Anaesthetics may take away the pain of trauma memories (April 2019)

According to an account in the Times newspaper on March 21st, anaesthetics may not only dull physical pain, but may also help reduce mental anguish associated with traumatic memories.  People who were sedated after recalling a previously heard emotional stories had fuzzier memories of the emotional portions of the story 24 hours later, according to the study, published today (March 20) in the journal Science Advances.   

A week before the sedation, Galarza Vallejo and her colleagues at the University of Madrid, showed the participants two picture slideshows accompanied by audio stories. Both stories started with neutral content, then took a dark turn in the middle (a car accident involving a child in one and a kidnapping of a young woman in the other), before resolving with a neutral ending.    On the day of the procedure, right before the anesthesia was administered, the researchers showed the participants the first slide of just one of the stories, with some parts blocked out, and asked them what fill in the blanks. The goal was to trigger reactivation of the memory, making it vulnerable to alteration.

As the participants woke in the recovery room, half took a multiple-choice test about both stories. The other half took the same test, but 24 hours after the anaesthetic procedure. 

Findings

The researchers found that participants performed significantly worse  in recalling the stories once 24 hours had elapsed. They had a particularly hard time recalling the emotional parts of the story.  The fact that the memories changed only after 24 hours had passed indicated that the change was happening during the process of memory re-consolidation. 

From this finding, the researchers think that an anaesthetic process could be used to treat disorders in which abnormal emotional memory plays a role including trauma/PTSD.  However, as they write, ‘disorders such as PTSD are multifaceted and involve recurrent, intrusive recollections of the traumatic memory.’  They are often associated with life-or-death situations and the recurrent nature of traumatic recall might make it harder to erase them from the mind in the simple way used in the experiment.