Published in Biological Psychiatry, the study provides important insight into how eating disorders develop and the biological and behavioural trajectories that are involved over time.
By identifying which brain areas may play a role in the onset of unhealthy eating behaviours such as dieting, binge-eating and vomiting, and which mental health problems both predate and accompany their development, the research could ultimately help support early intervention and inform approaches to help those with eating disorders.
It is estimated that 1.25 million people in the UK have an eating disorder (BEAT, 2020) and this usually starts in adolescence or emerging adulthood (between the ages of 15 and 25). They are characterised by several unhealthy or disordered eating behaviours (DEBs) including dieting, binge-eating and purging which involves vomiting, laxative use and excessive exercise. Previous research has shown that children and young people who show milder forms of these behaviours often go on to be diagnosed with eating disorders later in life.
The study is part of IMAGEN project and analysed data from 1386 healthy adolescents from eight countries. Using brain scans and measures of depression, anxiety, attention deficit hyperactivity disorder (ADHD), conduct disorder and emotional problems, the study compared those adolescents who did and those who didn’t develop three types of disordered eating behaviours – dieting, binge-eating and purging - over a period of five years.
Our research has shown differences in brain areas years before adolescents develop disordered eating behaviours, indicating that it could be possible to recognise which children and young people are at risk of being diagnosed with eating disorders later in life. – Dr Sylvane Desrivières, lead author, from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), King’s College London
He continued, ‘We have shown that signs of depression in this population develop alongside unhealthy eating behaviours, suggesting that they may have a similar causal pathway which could be linked to the differences in brain structure. By finding factors both in terms of brain structure and mental health that could target individuals who are likely to develop eating disorders our study could help inform earlier and more effective interventions.’
Data on eating behaviours, ADHD, conduct disorder, emotional and mental health problems was assessed over time at 14, 16 and 19 years whilst brain scan data was analysed at age 14 to gauge what differences in structure may predict the onset of disordered eating behaviours.
Analysis showed that all three types of disordered eating behaviours developed alongside signs of depression, whereas signs of ADHD and conduct disorder predated the development of unhealthy eating behaviours
Researchers found that adolescents who developed both disordered eating behaviours and depressive symptoms showed differences in volume in certain brain areas at the age of 14.
More specifically the study showed that the development of binge-eating behaviours was predicted at the age of 14 by larger volumes of grey matter in parts of the striatum, which are usually involved in reward processing. In contrast, the development of both purging behaviours and signs of depression was predicted by lower volumes of grey matter in the areas of the prefrontal cortex which is associated with control and decision making.
Eating disorders are common and have a significant impact on public health but they are highly stigmatised and often considered as trivial or self-inflicted. In our study we have examined the possible precursors of these disorders in young people in the community and firmly positioned them as brain-based disorders that potentially share causal pathways with common mental disorders such as depression.– Ulrike Schmidt, contributing author, Professor of Eating Disorders at the IoPPN
She added, ‘These findings are very exciting as they pave the way towards innovative approaches to the prevention of eating disorders that could potentially focus on the identified brain areas, be delivered even before a young person develops clinical symptoms and have greater effectiveness by preventing several disorders at the same time.’
The research was funded by the Medical Research Foundation and the Medical Research Council. When presented at the Academy for Eating Disorders’ International Conference on Eating Disorders (ICED) in June 2020, the study won the award for best presentation.
Reference: Zhang, Z. et al. (2020) Development of disordered eating behaviors and comorbid depressive symptoms in adolescence: neural and psychopathological predictors. Biological Psychiatry. DOI: 10.1016/j.biopsych.2020.06.003
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