HQ Team
July 18, 2024: Conduct disorder is a result of extensive changes in the structure of the brain and is most noticeable in the cerebral cortex, or the outer layer, a study funded by the US National Institute of Mental Health finds.
Conduct disorder refers to a group of behavioural and emotional problems characterized by a disregard for others. Children with conduct disorder have a difficult time following rules and behaving in a socially acceptable way. Their behaviour can be hostile and sometimes physically violent.
Researchers studied magnetic resonance imaging data from youth aged between seven and 21 years of age, and who had participated in 15 studies from around the world.
Analyses compared the surface area and thickness of the cerebral cortex and the volume of deeper subcortical brain regions between 1,185 youth diagnosed with conduct disorder and 1,253 youth without the disorder.
The cortical and subcortical brain measures between boys and girls, age of symptom onset — childhood compared to adolescence — level of empathy and other prosocial traits, ranked high and low, were also analysed in the neuroimaging study.
Subcortical brain regions
Youth with conduct disorder had lower total surface area across the cortex and in 26 of 34 individual regions, two of which 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 behaviours that are challenging for people with the disorder.
“The most pronounced difference was a smaller area of the brain’s outer layer, known as the cerebral cortex, which is critical for many aspects of behaviour, cognition and emotion,” according to a statement from NIMH.
The associations with brain structure did not differ between boys and girls and were seen across conduct disorder subgroups based on age of onset and level of prosocial traits.
Youth who exhibited signs of a more severe form of the disorder, indicated by a low level of empathy, guilt, and remorse, showed the greatest number of brain changes.
Spans all 4 lobes
These findings from the largest, most diverse, and most robust study of conduct disorder to date are consistent with a growing body of evidence that the disorder is related to the structure of the brain.
It also provides new evidence that brain changes are more widespread than previously shown, spanning all four lobes and both cortical and subcortical regions.
“They offer new avenues for investigating potential causal links between differences in brain structure and symptoms of conduct disorder and for targeting brain regions as part of clinical efforts to improve diagnosis and treatment,” according to the statement.
“Conduct disorder has among the highest burden of any mental disorder in youth. However, it remains understudied and undertreated,” said co-author Daniel Pine, MD, chief of the Section on Development and Affective Neuroscience at NIH’s National Institute of Mental Health.
Diagnosis, treatment
“Understanding brain differences associated with the disorder takes us one step closer to developing more effective approaches to diagnosis and treatment, with the ultimate aim of improving long-term outcomes for children and their families.
“Critical next steps are to follow children over time to determine if differences in brain structure seen in this study are a cause of conduct disorder or a long-term consequence of living with the disorder,” he said.
Conduct disorder is classified in the spectrum of disruptive behaviour disorders, which also includes the diagnosis of oppositional defiant disorder. It often occurs simultaneously with other psychiatric conditions, including depression, attention deficit hyperactivity disorder, and learning disorders.
