Conduct disorder (CD) in young people is linked to significant differences in brain structure compared to typically developing children, new research published in The Lancet Psychiatry reveals. CD is generally diagnosed based on a pattern of behavior that violates societal norms and the rights of others. According to the Diagnostic and Statistical Manual of Mental Health Disorders, fifth edition (DSM-5), the criteria for diagnoses include aggressive behavior that causes or threatens physical harm to people or animals, conduct that causes property loss or damage, deceitfulness or theft, and serious violations of rules. These behaviors must cause significant impairment in social, academic, or occupational functioning and be present for at least 12 months, with one symptom occurring in the past 6 months, to meet the full criteria for the disorder. CD is further categorized by the onset age: childhood-onset type (before age 10), adolescent-onset type (no symptoms before age 10), and unspecified onset.
The prevalence of CD varies based on a number of factors but is estimated to affect approximately 2-10% of children, with higher rates observed in males than females. Assessments can be administered by mental health professionals which can be helpful, alongside family reports and clinical observation, in diagnosing the disorder.
Researchers from the Universities of Bath and Birmingham, in collaboration with other international teams, conducted the largest study of its kind, analyzing brain structure in 1,185 children diagnosed with CD and 1,253 typically developing children. Dr. Yidian Gao, the study’s lead co-author, emphasized the importance of the study’s large sample size, which is 10-20 times larger than previous studies, and the inclusion of data from children across North America, Europe, and Asia.
The team referenced standardized methods from the ENIGMA Consortium to ensure consistency and reliability. MRI data revealed extensive structural differences in the cortical surface area, particularly in the prefrontal cortex, which is crucial for behavior and emotion regulation. The study also identified changes in the amygdala, the area of the brain associated with antisocial behavior and emotion recognition. Some of the brain differences in children with CD overlapped with those seen in children with ADHD. Overall, the team noted that children with CD had significantly reduced surface area in the brain’s outer layer, the cortex, and reduced volume in several subcortical regions. These findings suggest that brain development in children with CD differs from their peers. Children with CD and “callous-unemotional traits,” characterized by limited empathy and lack of guilt, showed particularly distinct brain differences compared to neurotypical children.
The Centers for Disease Control and Prevention (CDC) recommends that children with CD engage in regular physical activity, including aerobic and vigorous exercise, eat a healthy diet centered on fruits, vegetables, whole grains, legumes (for example, beans, peas, and lentils), lean protein sources, and nuts and seeds and get the recommended amount of sleep each night based on their age. It’s almost important for these children to lean on strong support systems whenever possible.
The study’s authors stressed the need for more research centered on CD in general, given its large impact on global mental health. Dr. Stephane De Brito from the University of Birmingham specifically highlighted the importance of understanding how early childhood adversities, such as abuse and neglect, might contribute to these brain differences.
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