Structural differences in the brain could be responsible for anti-social behaviour, claims a new study. A look at the experiment and its findings.
What Is anti-social behaviour?
‘Anti-social personality disorder’ or ‘conduct disorder’ in those over 18, manifests itself through violence, aggression, lying, stealing and further violations of other people’s rights. In a child these symptoms are often attributed to lack of maturity and incomplete brain development. However, when they persist into adolescence and adulthood, disordered behaviour can have serious implications. While treatment remains experimental and vague, a new research reveals that the root cause of the disorder may be neurological.
A team of scientists led by Dr Luca Passamonti, a neurologist at Cambridge University (UK) and Dr Graeme Fairchild, a psychology professor at the University of Southampton (UK), scanned the brains of 58 men between the ages of 16 to 21, who had been diagnosed with conduct disorder. The researchers then compared these scans with those of 25 healthy men around the same age.
The scientists then conducted another scan, this time using men from Southampton aged 13-18, 37 of whom had behavioural problems and 32 of whom were healthy. In both cases, the team found differences in ‘structural covariance and cortical thickness’ between the healthy brains and the brains of those diagnosed with conduct disorder in adolescence.
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A different brain?
According to the scans, the brains of those diagnosed with conduct disorder had higher ‘structural covariance’ — a measure of how much two random variables change together. This essentially means the thickness of various regions of the brain — cortex or cortices — were more similar and directly proportional in adolescents with the conduct disorder. Relative cortical thickness varied more inversely in the brains of individuals not affected by anti-social behavioural issues.
* The study, published in the Journal of Psychology and Psychiatry earlier this month, found that two cortices in particular exhibited this difference, the orbitofrontal cortex and medial temporal cortex. In those with conduct disorder, these two regions were more similar in terms of thickness than they were in “healthy,” unaffected brains.
* While the medial temporal cortex deals with memory, the orbitofrontal cortex is involved in the cognitive process of decision making. Therefore, an abnormality within that region, like the relative difference in its thickness could contribute to atypical brain functioning. This might manifest physically such as aggression and a general inabaility to take decisions.
Is there a cure?
The neurological differences between the two groups do not account for biological factors that can contribute to one’s personality and demeanor. Only half of the potential causes of behavioural problems are linked to genetics or inherited traits. As a result, scans alone cannot be used to identify or predict which individuals might develop behavioural issues. However, monitoring the relative thickness of the orbitofrontal and medial temporal cortices in individuals diagnosed with conduct disorder can help determine the effectiveness of treatment.
* For children and adolescents, this treatment typically consists of intensive one-on-one coaching and behavioural therapy to improve the child’s social, emotional and educational decision-making skills.