Disruptive children may have smaller brains rather than being naughty
Disruptive children may have smaller brains than well-behaved youngsters rather than simply being naughty, a new study suggests.
British researchers found significant brain changes in children who exhibit prolonged bad behaviour, such as lying, stealing, fighting, rule-breaking, animal cruelty, arson and bullying.
Brain scans showed “significant reductions” in areas such as the outer layer of the brain – the cortex – which regulates behaviour and emotion.
Areas deep within the brain, associated with functions such as emotion regulation, language and reasoning, such as the amygdala, were also lower in volume, scans revealed.
Severely disruptive behaviour in youngsters is known as “conduct disorder” and it affects about 7 per cent of boys and 3 per cent of girls aged between five and 10, with prevalence rising slightly in teenage years.
‘More than ordinary childish mischief’
According to the Royal College of Psychiatrists, it is much more than ordinary childish mischief or adolescent rebelliousness, with long-lasting and extreme aggressive behaviours.
Dr Marlene Staginnus, the joint lead author, from the Department of Psychology at the University of Bath, said: “It is clear that children who have this disorder cannot simply be labelled naughty.
“Although we don’t yet know how the differences that we have identified could be used to improve treatment for children with conduct disorder.
“Given that conduct disorder is such a significant contributor to our global mental health burden, we really need to see investment in research at similar levels to that of ADHD and autism.”
The findings, published in journal The Lancet Psychiatry, were based on brain scans of 1,185 children diagnosed with conduct disorder which were compared to scans from 1,253 youngsters without the condition.
Children with conduct disorder had lower total surface area across the outer layer of the brain in 26 of 34 individual regions, two of which also showed significant changes in cortical thickness.
They also had lower volume in several subcortical brain regions, including the amygdala, hippocampus and thalamus, which play a central role in regulating behaviour.
Youngsters who exhibited signs of a more severe form of the disorder, showing low levels of empathy, guilt, and remorse, had the greatest number of brain changes.
Different brain development
It is still unclear what causes these differences, but the researchers said it appeared brain development is different in children with conduct disorder and which could be caused by childhood adversity and maltreatment.
Dr Stephane De Brito, one of the study authors, from the Centre for Human Brain Health at the University of Birmingham, said: “There is a lot of work examining potential risk factors, but it is still unclear what are the causes of those brain structural differences in young people with conduct disorder.
“We suspect that early adversities, for example, experiences of childhood maltreatment might play an important role.
“And by understanding how conduct disorder links to later issues, including criminality in adulthood, but also anxiety and depression, we start to see how important it is to understand and help young people and their families.”
Conduct disorder is usually diagnosed in childhood or adolescence and often leads to poor social and mental health outcomes.
Dr Yidian Gao, the lead author, from the School of Psychology and Centre for Human Brain Health at the University of Birmingham, added: “We know very little about this disorder even though it can carry a high burden for families and societies.
“It provides the most compelling evidence to date that conduct disorder is associated with widespread structural brain differences.”