Core symptoms of anorexia nervosa, including the urge to restrict food intake and feeling fat, are reduced after just one session of a non-invasive brain stimulation technique, according to King’s College London research published today in PLOS ONE.
This new study is the first randomised control trial to assess whether repetitive transcranial stimulation (rTMS), already an approved treatment for depression, is also effective in reducing symptoms of anorexia.
Up to 20 per cent of people with anorexia die prematurely from the disorder and treatments in adults are moderately effective, with only 20-30 per cent of people recovering from the best available talking therapies.
Given the urgent need to improve treatments, researchers are increasingly looking towards emerging neuroscience-based technologies that could target the underlying neural basis of anorexia.
Dr Jessica McClelland, Post-doctoral Researcher at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King’s College London, and first author of the study, said: ‘With rTMS we targeted the dorsolateral prefrontal cortex, an area of the brain thought to be involved in some of the self-regulation difficulties associated with anorexia. This technique alters neural activity by delivering magnetic pulses to specific regions of the brain, which feels like a gentle tapping sensation on the side of the head.
‘We found that one session of rTMS reduced the urge to restrict food intake, levels of feeling full and levels of feeling fat, as well as encouraging more prudent decision-making. Taken together, these findings suggest that brain stimulation may reduce symptoms of anorexia by improving cognitive control over compulsive features of the disorder.’
In the study, 49 people completed food exposure and decision-making tasks, both before and after a session of either real or placebo rTMS. Symptoms of anorexia were measured immediately prior to and following rTMS, as well as 20 minutes and 24 hours after the session.
The food exposure task sought to provoke anorexia symptoms by asking participants to watch a two-minute film of people eating appetising food, such as chocolate and crisps, while the same items were in front of them. They then had to rate the perceived smell, taste, appearance and urge to eat these foods.
For the decision-making task participants had to choose between a smaller, variable amount of money (£0-£100) available immediately and a larger, fixed amount (£100) available after four different time points (a week, month, year or two years).
Compared to the placebo group, they found that participants who had real rTMS showed a tendency for more prudent decision-making – that is, they waited for larger, later rewards (i.e. delayed gratification), rather than choosing the more impulsive smaller, sooner option.
The study authors point out that although these findings were only a statistical trend, there is a clear improvement in symptoms and decision-making abilities following just one session of rTMS. It is likely that with a larger sample and multiple sessions of rTMS these effects would be even stronger.
Core symptoms of anorexia nervosa, including the urge to restrict food intake and feeling fat, are reduced after just one session of a non-invasive brain stimulation technique, according to King’s College London research.
Professor Ulrike Schmidt, senior author of the study, from the IoPPN at King’s College London, added: ‘Anorexia nervosa is thought to affect up to 4 per cent of women in their life-time. With increasing illness duration, anorexia becomes entrenched in the brain and increasingly difficult to treat. Our preliminary findings support the potential of novel brain-directed treatments for anorexia, which are desperately needed.
‘Given the promising findings from this study, we are now assessing whether rTMS has longer-lasting therapeutic benefits in a world-first clinical trial of rTMS treatment, involving 20 rTMS sessions, in people with anorexia nervosa.’
Funding: This study represents independent research part-funded by the National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust and King’s College London.
The IoPPN’s Eating Disorders Research Group at King’s College London is currently recruiting for a longer-term study of rTMS to examine the neural mechanisms underlying the effects of rTMS. Find out more about the TIARA study: Transcranial magnetic stimulation and Imaging in AnoRexia nervosa.
Source: Kings College London
Image Credit: The image is adapted from the King’s College London video.
Video Source: The video is credited to Kings College London.
Original Research: Full open access research for “A Randomised Controlled Trial of Neuronavigated Repetitive Transcranial Magnetic Stimulation (rTMS) in Anorexia Nervosa” by Jessica McClelland, Maria Kekic, Natali Bozhilova, Steffen Nestler, Tracy Dew, Frederique Van den Eynde, Anthony S. David, Katya Rubia, Iain C. Campbell, and Ulrike Schmidt in PLOS ONE. Published online March 23 2016 doi:10.1371/journal.pone.0148606
A Randomised Controlled Trial of Neuronavigated Repetitive Transcranial Magnetic Stimulation (rTMS) in Anorexia Nervosa
Anorexia nervosa (AN) is associated with morbid fear of fatness, extreme food restriction and altered self-regulation. Neuroimaging data implicate fronto-striatal circuitry, including the dorsolateral prefrontal cortex (DLPFC).
In this double-blind parallel group study, we investigated the effects of one session of sham-controlled high-frequency repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC (l-DLPFC) in 60 individuals with AN. A food exposure task was administered before and after the procedure to elicit AN-related symptoms.
The primary outcome measure was ‘core AN symptoms’, a variable which combined several subjective AN-related experiences. The effects of rTMS on other measures of psychopathology (e.g. mood), temporal discounting (TD; intertemporal choice behaviour) and on salivary cortisol concentrations were also investigated. Safety, tolerability and acceptability were assessed.
Fourty-nine participants completed the study. Whilst there were no interaction effects of rTMS on core AN symptoms, there was a trend for group differences (p = 0.056): after controlling for pre-rTMS scores, individuals who received real rTMS had reduced symptoms post-rTMS and at 24-hour follow-up, relative to those who received sham stimulation. Other psychopathology was not altered differentially following real/sham rTMS. In relation to TD, there was an interaction trend (p = 0.060): real versus sham rTMS resulted in reduced rates of TD (more reflective choice behaviour). Salivary cortisol concentrations were unchanged by stimulation. rTMS was safe, well–tolerated and was considered an acceptable intervention.
This study provides modest evidence that rTMS to the l-DLPFC transiently reduces core symptoms of AN and encourages prudent decision making. Importantly, individuals with AN considered rTMS to be a viable treatment option. These findings require replication in multiple-session studies to evaluate therapeutic efficacy.
“A Randomised Controlled Trial of Neuronavigated Repetitive Transcranial Magnetic Stimulation (rTMS) in Anorexia Nervosa” by Jessica McClelland, Maria Kekic, Natali Bozhilova, Steffen Nestler, Tracy Dew, Frederique Van den Eynde, Anthony S. David, Katya Rubia, Iain C. Campbell, and Ulrike Schmidt in PLOS ONE. Published online March 23 2016 doi:10.1371/journal.pone.0148606