Teenage eating disorders linked to brain development issues, study finds

The development of a teenager's brain can play a key role in the link between mental health and disordered eating in young people, according to a new study. The research from King's College London investigated the links between the disorders, brain structure, and genetics.

It was found that the process of brain maturation can play a factor in whether teenagers start developing disordered eating patterns. The process of brain maturation is where the volume and thickness of the cortex - outer layer of the brain - decreases during adolescence.

These changes to the brain have been shown to have an effect on whether teens develop two kinds of disordered eating - restrictive or emotional/uncontrolled - as a young adulthood.

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Restrictive eating is where you deliberately limit the food you intake to control your body weight and how you look - dieting or purging. On the other hand, emotional or uncontrolled eating, such as binge-eating, is where someone consumes food in response to negative emotions or compulsive urges.

The study, led by the Institute of Psychiatry, Psychology and Neuroscience at King's College, involved 996 teens from England, Ireland, France and Germany, first when they were 14 years old and then again when they had turned 23.

At both ages, the participants had an MRI scan, provided genetic data and completed questionnaires about their wellbeing and eating behaviours, in order to see a comparison over nine years. Once this was done, the now 23-year-olds were categorised into three types of eating behaviour.

These groups were: healthy eaters (42%), restrictive eaters (33%) and emotional or uncontrolled eaters (25%). These results show that over half of the participants had developed a disordered eating habit by the time they become a young adult.

The study also found that each group had different patterns of mental health and behaviour over time. The young people who developed either of the unhealthy eating habits at 23 had higher levels of internalised (anxiety and depression) and externalised (inattention, conduct issues or hyperactivity) problems at the age of 14, compared to healthy eaters. This is not to say that healthy eaters did not experience these problems too, but it was significantly higher in unhealthy eaters.

It was shown that the internalised problems significantly increased over the nine years in unhealthy eaters, while external problems reduced across all three groups. However, the emotional or uncontrolled eating group presented the highest external problems.

In comparison to healthy eaters, restrictive eaters dieted more throughout their teenage years, while emotional eaters increased their dieting between the ages of 14 and 16 and their binge-eating between age 16 and 19. Despite trying to restrict their diets, the study has shown that unhealthy eating behaviours can be linked to obesity and high BMI - body mass index.

Through comparing the MRIs of the participants at age 14 and 23, the study found that, in unhealthy eaters, their brain maturation was delayed and less pronounced. Researchers have said that this shows that delayed maturation plays a role in the link between mental health problems at an early age developing into unhealthy eating problems as a young adult.

If maturation of the brain occurs, this will affect the maturation of the cerebellum - the region of the brain that controls appetite - hence the development of eating disorders later on.

PhD student and first author of the study, Xinyang Yu, said: "Our findings reveal how delayed brain maturation during adolescence links genetics, mental health challenges and disordered eating behaviours in young adulthood, emphasising the critical role of brain development in shaping eating habits."

Professor Sylvane Desrivières, Professor of Biological Psychiatry at King's, added: "Our findings highlight the potential benefits of improved education aimed at addressing unhealthy dietary habits and maladaptive coping strategies. This could play a crucial role in preventing eating disorders and supporting overall brain health."

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