Researchers able to reduce anxieties without asking people to think about them consciously, making it more appealing than current therapies

Scientists have raised hopes for a radical new therapy for phobias and post-traumatic stress disorder (PTSD) with a procedure that can dampen down fears linked to painful memories.

The advance holds particular promise for patients because in early tests, researchers found they could reduce anxieties triggered by specific memories without asking people to think about them consciously.



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That could make it more appealing than exposure therapy, which aims to help patients overcome their phobias by making them confront their fears in a safe environment, for example by encouraging them to handle spiders or snakes in the clinic.



The new technique, called fMRI decoded neurofeedback (DecNef), was developed by scientists at the ATR Computational Neuroscience Lab in Japan. Mitsuo Kawato, who worked with researchers in the UK and the US on the latest study, said he wanted to find an alternative to exposure therapy, which has a 40% drop-out rate among PTSD patients.



“We always thought this was ambitious, but it worked the way we hoped it would,” said Ben Seymour, a clinical neuroscientist and member of the team at Cambridge University. “We don’t completely erase the fear memory, but it is substantially reduced.”



The procedure uses a computer algorithm to analyse a patient’s brain activity in real time and pinpoint moments when their fears can be overwritten by giving them a reward. In the latest study, the reward was a small amount of money.



Volunteers who took part in the study had their brain activity recorded while images of red, green, blue or yellow circles flashed on a screen in front of them. After viewing 50 or so images, a computer algorithm analysed the brain scans and identified the brain activity linked to each colour image.



A brain image showing a pattern activity across the brain associated with one of the fear-triggering stimuli. Photograph: Mitsuo Kawato/Ben Seymour

The next part of the study was more painful. The volunteers watched another sequence of images flash up, but this time, two colours of circles, for example, red and green, were followed by unpleasant, but tolerable electric shocks. Brain activity and sensors on the skin showed the participants came to fear those images being shown.



Having induced fearful memories in the volunteers, the scientists then tried to erase them. This time, the patients rested in the brain scanner and thought about whatever they wished. They were not asked to think about the painful memories, and none reported doing so.



But even in rest, the brain is active. And from time to time, the electrical activity of the brain resembled the patterns linked to green circles or red circles, even when the volunteers were not thinking about them. When the algorithm spotted this, it flashed up a message telling the participant they had earned a monetary reward, to be picked up after the experiment.



“We don’t want them to think about fear when they are in the scanner,” said Seymour. “They are not aware what we are detecting in the brain activity.”



Each volunteer had painful memories for both green and red circles, but the scientists tried to erase only one of them. This allowed them to judge how well the procedure worked. And work it did. After three one-hour sessions, the brain scans showed no signs of anxiety when people were shown the images that previously made them flinch, and sensors on their skin found their anxiety response had halved. Details of the research are published in Nature Human Behaviour.



The scientists are now investigating how long the fear is dampened down for. “It might be that it’s not long lasting, that the fear memory comes back. We don’t think it will, but we want to test that,” Seymour said.



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The Japanese team has already started scanning patients with phobias and PTSD. “Hopefully in a few years, we can start systematic DecNef therapy,” Kawato told the Guardian.



One avenue the team is exploring amounts to a library of brain activity signatures that correspond to the wild and varied fears that humans suffer. Armed with that, a patient could arrive at a clinic, declare their phobia, and have therapy to retrain their brain so they no longer feel terrified.



Jonathan Lee, a psychologist at the University of Birmingham, said the work served as an early proof of concept. “The idea of counter-conditioning to reduce fear expression is by no means new, but the potential to achieve it outside the realm of consciousness is intriguing and would certainly have translational benefits,” he said.



But Lee warned that it may be much harder to treat patients unconsciously if they have truly traumatic memories. “I just doubt that this will be possible in a clinical situation. First, any attempt to induce the pattern of activity without triggering fear and anxiety might be doomed to failure. Or by activating the pattern, this might inevitably lead to the production of fear and anxiety,” he said.

