A person showing lifelong antisocial behavior has significant physical differences in their brain when compared with healthier individuals, reports a new research in The Lancet.
This is important information as children and teens who show signs of antisocial behavior are often stigmatized and are at an increased risk for poor physical and mental health along with higher incarceration rates. Antisocial behavior can be defined as a range of unacceptable activities that can cause harm to an individual, to their community and to their environment. This can include both physical and mental harm.
One of the most commonly accepted development theories of crime was given by Terrie Moffitt. It has affected juvenile justice policy across the globe as well as clinical diagnosis and treatment. This developmental taxonomy theory proposes that antisocial acts are committed by two very distinguished groups. According to this theory, antisocial behavior can be either early onset and life long, or it can arise in adolescence and be limited to pre-adult period.
It has been seen that lifelong antisocial behavior has a prevalence of less than 10 percent in population. However, adolescence-limited antisocial behavior is greater than 25 percent.
The study’s objective was to see if there were any significant physical differences in the brains of these two groups compared to people showing no symptoms of antisocial disorder. The study was funded by the US National Institute on Aging, Health Research Council of New Zealand, New Zealand Ministry of Business, Innovation and Employment, UK Medical Research Council, Avielle Foundation, and Wellcome Trust.
The data was taken from Dunedin Study, a longitudinal investigation of health and behaviour in a population-representative birth cohort. The participants included 672 patients who had been diagnosed with either life-long persistent anti-social behavior (12%) or adolescence-limited antisocial behavior (23%). Another group was included that showed low antisocial behavior (66%).
All of the subjects were from New Zealand and 93% of them were white. Eligible participants were either diagnosed or had self-reported conduct problems from the ages of 7 to 26 years. The study used MRI scanning of the brain to observe any differences in brain surface morphometry.
The study showed that people diagnosed with life-long persistent antisocial behavior had smaller brain surface areas and lower cortical thickness compared to the low antisocial behavior group. The thinner cortical thickness was observed in frontal and temporal regions of the brain. These brain areas have been shown to control executive function, affect regulation and motivation.
However, no significant differences were observed in adolescence-limited group as compared to either non-antisocial behavior or life-course-persistent groups.
It is important to highlight that though both antisocial behaviour trajectory groups had features of reduced cortical thickness compared with the low group without antisocial behaviour (in different areas of the brain), the differences were not statistically significant.
Several explanations can account for these physical differences in brain but the most plausible one can be linked to genetics. Surface area and cortical thickness are under distinct genetic control. Surface area of brain is more strongly heritable and has been shown as prone to disruption by early age trauma. This is a known risk factor for life-course persistent antisocial behaviour. Other risk factors for antisocial behaviour includes substance abuse, low IQ, and psychiatric comorbidity (other psychiatric disorders).