Shock therapy could free victims of bad memories
UNPLEASANT memories can be wiped out by electric shock therapy used to treat psychiatric patients, a study has shown.
The discovery raises the possibility of helping victims of post-traumatic stress disorder by freeing them of their demons.
ECT triggers a brief epileptic fit by delivering a jolt of electricity to the brain via electrodes placed on the head. In the new study, researchers tested its effect on memory on 39 patients already receiving ECT for depression.
Participants were told two emotionally unpleasant stories presented in the form of a slideshow with a voiceover. A week later, story memories were "cued" by showing the first slide partially covered.
Immediately afterwards, one group of patients was given ECT. A day later, patients were tested on what they could recall about events relating to the first slide.
Those who had undergone ECT struggled, while the memories of patients who had not received the therapy were unaltered.
Only those memories that were reactivated by the cue were disrupted by ECT, according to the findings reported in the journal Nature Neuroscience. The scientists, led by Dr Marijin Kroes, from the Donders Institute for Brain, Cognition and Behaviour at Radboud University in the Netherlands, wrote: "We found that a single ECT application in unipolar-depressed patients following memory reactivation disrupted reactivated, but not non-reactivated, memory for an emotional episode.
"Our data provide evidence for disruption of reactivated emotional episodic memories by invasive interference with normal neural activity."