Scientists in the United Kingdom have observed an abnormal pattern of connectivity in a subgroup of youth with Conduct Disorder, a psychological condition associated with aggressive and antisocial behavior. Their new research was published in the journal Social Cognitive and Affective Neuroscience.
“There have been several studies investigating brain activity in youths and adults with severe antisocial personality disorder (called Conduct Disorder in youths, and Antisocial Personality Disorder in adults), but far fewer studies looking at functional connectivity between different brain areas in these individuals,” explained study author Graeme Fairchild of the University of bath.
“We were interested to see whether there were differences between youths with Conduct Disorder and typically-developing youths in functional connectivity between the amygdala (which is involved in emotion processing, and particularly understanding emotions in others) and other parts of the brain.”
“We also tested whether elevated psychopathic traits (deficits in guilt, remorse and empathy) were related to changes in functional connectivity. All of this was done using functional MRI methods in the context of a task involving viewing facial expressions of anger or sadness (and neutral faces).”
A previous study conducted by Fairchild and his colleagues found teenagers with Conduct Disorder had difficulty recognizing facial expressions and were less likely to look at the eye region of a face.
The new study compared 46 male youths with Conduct Disorder to 25 typically-developing youths (aged 16-21 years). The researchers observed reduced amygdala activity in participants with Conduct Disorder when viewing angry or sad faces. But they uncovered something unexpected when they examined brain connectivity.
“To our surprise, we found that the youths with Conduct Disorder but elevated psychopathic traits showed normal patterns of functional connectivity (similar to the typically-developing youths),” Fairchild told PsyPost. “The specific connection that we found to be altered in the low psychopathic traits group was the pathway between the amygdala and the prefrontal cortex (and within that region, an area called the anterior cingulate cortex, which is also strongly anatomically connected to the amygdala).”
Those with elevated psychopathic traits resembled typically-developing controls. Youths with Conduct Disorder and lower psychopathic traits, on the other hand, displayed an abnormal pattern of connectivity.
“The brains of youths with Conduct Disorder, but low levels of psychopathic traits, seem to be less well connected — the changes in connectivity that normally happen in the brains of typically-developing individuals while they are viewing emotional faces seem to be disrupted in this group,” Fairchild explained.
The study has some limitations and there is need for further research.
“In this study, we only looked at angry and sad faces (plus neutral faces as a comparison condition),” Fairchild said. “The abnormalities in connectivity seemed to be most evident for angry faces, but ideally we would have included a broader range of facial expressions, including happy expressions, to see whether there is a specific problem for anger or negative facial expressions in general.”
“We also cannot say that the changes in functional connectivity in the brain cause the young people to develop antisocial behavior – it’s possible that engaging in antisocial behavior (e.g. serious physical fights) exposes them to highly stressful or traumatic experiences which alter the way different parts of the brain talk to each other.”
“Lastly, the study only focused on male youths, so we do not know whether the findings apply to females with Conduct Disorder,” Fairchild continued. “We also need to know much more about the consequences of changes in functional connectivity in the brain – we speculated in the paper that this might explain why youths with Conduct Disorder but low levels of psychopathic traits are more prone to developing anxiety and depression, but it would be interesting to test this hypothesis in a longitudinal study.”
“It’s worth emphasising that changes in the brain are just one part of the story that explains why these youths show severe antisocial behavior – they are also much more likely to grow up in poverty and to experience maltreatment in childhood, and to have delinquent friends in their peer groups,” he added. “We need to know whether the changes we (and many other research groups) have observed in the brains of youths with Conduct Disorder are modifiable and normalise with successful psychological or pharmacological treatment.”
The study, “Psychopathic traits influence amygdala-anterior cingulate cortex connectivity during facial emotion processing“, was authored by Michael P. Ewbank, Luca Passamonti, Cindy C. Hagan, Ian M. Goodyer, Andrew J. Calder, and Graeme Fairchild.
