Researchers from the University of Southern California (US) have found that children suffering from binge eating disorders (BED) have an increased proportion of grey matter densities indicative of abnormal brain development.
“In children with binge eating disorder, we see abnormality in brain development in brain regions specifically linked to reward and impulsivity, or the ability to inhibit reward,” said lead author Stuart Murray from the Keck School of Medicine of USC.
“These kids have a very, very heightened reward sensitivity, especially toward calorically dense, high-sugar foods. The findings underscore the fact that this is not a lack of discipline for these kids.”
Murray and his team analysed MRI brain scans of 71 children aged 9 to 10 suffering from binge eating and 74 children at the same age without the condition.
The team focussed on the areas of the brain related to reward and impulsivity, analysing children’s orbitofrontal cortex (OFC), which contains nodes to reward taste, as well as the dorsolateral prefrontal cortex (DLPFC), which has areas for inhibiting impulses and control.
To assess the link between the children’s binge-eating behaviour and possible brain differences, all children were asked to self-respond to the 24-itemed Behavioural inhibition System/Behavioural Activation System Scale (BIS/BAS scale).
The scale measures participants’ tendencies towards goal-oriented hedonistic pursuit as well as self-inhibition with the BIS measuring participants’ goals away from things unpleasant such as “I worry about making mistakes” while the BAS scale is oriented towards something desirable such as “when I see an opportunity for something I like, I get excited right away.”
In children with BED, the team found elevated levels of grey matter density at areas that should be “pruned” as part of the developmental process.
Pruning is a natural phase of brain development; as children grow up, grey matter is systematically reduced across specific regions to remove connection points between neurons that are no longer used for efficiency.
However, for children with BED, there were elevated densities of grey brain matter in areas linked to impulse control, inhibition of behaviour and decision making, such as the DLPFC, superior frontal gyrus and the anterior cingulate cortex.
Additionally, a small cluster of increased grey matter density was also seen in the OFC, which contains areas that respond to food rewards.
When linking brain development to behaviour, the team found that the impaired development for children with BED had a negative relationship with their BAS score, which measures hedonistic pursuit meaning that children with BED respond less to reward than an average child.
The authors theorised that the behaviour of children with BED were not motivated by the rewards of eating but rather a lack of self-control, a behaviour echoed in adult studies with BED.
Though the authors could not find the precise relationship between disordered behaviour and brain structure, Murray said that the study “suggests to me that binge eating disorder is wired in the brain, even from a very, very early age.”
“The question that we don’t know, which is something that we will address in time, is whether successful treatment of binge eating disorder in kids helps correct brain development. The prognosis of almost all psychiatric diseases is better if you can treat them in childhood.”
Nonetheless, the authors concluded that their findings “warrant further interrogation,” to determine the relationship between structural characteristics and brain activity in disorders “to more clearly elucidate how these associations relate to BED psychopathology.”