Individuals who exhibit antisocial behavior over a lifetime have a thinner cortex and smaller surface area in key brain regions relative to their counterparts who do not engage in antisocial behavior, new research shows.
However, investigators found no widespread structural brain abnormalities in the group of individuals who exhibited antisocial behavior only during adolescence.
These brain differences seem to be “quite specific and unique” to individuals who exhibit persistent antisocial behavior over their life, lead researcher Christina O. Carlisi, PhD, of University College London, said during a press briefing.
“Critically, the findings don’t directly link brain structure abnormalities to antisocial behavior,” she said. Nor do they mean that anyone with a smaller brain or brain area is destined to be antisocial or to commit a crime.
“Our findings support the idea that, for the small proportion of individuals with life-course–persistent antisocial behavior, there may be differences in their brain structure that make it difficult for them to develop social skills that prevent them from engaging in antisocial behavior,” Dr. Carlisi said in a news release. “These people could benefit from more support throughout their lives.”
It was published online Feb. 17 in the Lancet Psychiatry (doi: 10.1016/S2215-0366[20]30002-X).
Support for second chances
Speaking at the press briefing, coauthor Terrie E. Moffitt, PhD, of Duke University, Durham, N.C., said it’s well known that most young criminals are between the ages of 16 and 25.
Breaking the law is not at all rare in this age group, but not all of these young offenders are alike, she noted. Only a few become persistent repeat offenders.
“They start as a young child with aggressive conduct problems and eventually sink into a long-term lifestyle of repetitive serious crime that lasts well into adulthood, but this is a small group,” Dr. Moffitt explained. “In contrast, the larger majority of offenders will have only a short-term brush with lawbreaking and then grow up to become law-abiding members of society.”
The current study suggests that what makes short-term offenders behave differently from long-term offenders might involve some vulnerability at the level of the structure of the brain, Dr. Moffitt said.
The findings stem from 672 individuals in the Dunedin Multidisciplinary Health and Development Study, a population-representative, longitudinal birth cohort that assesses health and behavior.
On the basis of reports from parents, care givers, and teachers, as well as self-reports of conduct problems in persons aged 7-26 years, 80 participants (12%) had “life-course–persistent” antisocial behavior, 151 (23%) had adolescent-only antisocial behavior, and 441 (66%) had “low” antisocial behavior (control group, whose members never had a pervasive or persistent pattern of antisocial behavior).
Brain MRI obtained at age 45 years showed that, among individuals with persistent antisocial behavior, mean surface area was smaller (95% confidence interval, –0.24 to –0.11; P less than .0001) and mean cortical thickness was lower (95% CI, –0.19 to –0.02; P = .020) than was those of their peers in the control group.
For those in the life-course–persistent group, surface area was reduced in 282 of 360 anatomically defined brain parcels, and cortex was thinner in 11 of 360 parcels encompassing frontal and temporal regions (which were associated with executive function, emotion regulation, and motivation), compared with the control group.
Widespread differences in brain surface morphometry were not found in those who exhibited antisocial behavior during adolescence only. Such behavior was likely the result of their having to navigate through socially tough years.
“These findings underscore prior research that really highlights that there are different types of young offenders. They are not all the same; they should not all be treated the same,” coauthor Essi Viding, PhD, who also is affiliated with University College London, told reporters.
The findings support current strategies aimed at giving young offenders “a second chance” as opposed to enforcing harsher policies that prioritize incarceration for all young offenders, Dr. Viding added.