Hardened criminals have an abnormal brain structure and display aggressive behavior from early childhood, suggests a major study.

The brain scans of almost 7,000 45-year-olds were analyzed – one third had a history of antisocial behavior ranging from physical combat to absenteeism.

Lifelong people had structurally smaller and thinner brains, some of which were in areas responsible for controlling behavior and emotions.

The researchers also examined their criminal records and interviewed their teachers and daycare staff, identifying a group of 80 adults with a “persistent” history of antisocial behavior and physical abuse, ranging from the bite of other children in daycare domestic violence as an adult.

Those who only caused problems in adolescence, however, did not have significant brain differences from the general population.

Experts said the results are a “valuable” snapshot of what drives crime and how to prevent it.

Criminals Have “Smaller Brains”: “Disability” May Explain Why Offenders Steal and Are Violent

Life criminals have smaller brains and this may explain why they lie, steal or are violent, scientists say. They analyzed the brain scans of almost 700 people. Pictured: the average brain of a lifetime criminal. The blue areas indicate the smallest parts compared to someone who has never committed a crime. The darker the shade of blue, the stronger the change

Criminals Have “Smaller Brains”: “Disability” May Explain Why Offenders Steal and Are Violent

Criminals Have “Smaller Brains”: “Disability” May Explain Why Offenders Steal and Are Violent

Pictured: The brain of an average lifetime criminal from four angles. The blue areas are where the cortex is statistically thinner compared to someone who has not committed a crime

The study led by University College London and published in The Lancet used data from a cohort of 672 people from New Zealand.

Participants’ level of antisocial behavior was measured every two years, from the ages of seven to 26, using self-report and reports from parents, caregivers, and teachers.

Participants were followed until adulthood and 80 had what researchers call “lifelong” antisocial behavior. They had been sentenced five times between 26 and 28 years of age.

A total of 151 had adolescent antisocial behavior and 441 had no history of persistent antisocial behavior.

The researchers took brain MRIs of participants at the age of 45 and compared the cortical surface and cortical thickness of 360 different regions of the cortex.

On average, across the brain, those who were antisocial in adulthood had a smaller area in 282 of 360 brain regions than people who had no history of antisocial behavior.

They also had a thinner cortex in 11 of the 360 ​​regions. The areas concerned were previously linked to antisocial behavior by their involvement in the regulation of emotions, motivation and behavior of driving goals.

Co-author Dr. Terrie Moffitt said, “I think what we have seen with this data is that it actually works with a certain brain handicap, so I think for me it changes my conception of “persistent life course” antisocial individuals now, to think of someone living their life with a certain level of disability, and to deal with that as part of their lifestyle. “

The authors say that the study provides the first solid evidence suggesting that the underlying brain differences are linked to antisocial behavior.

The study’s lead author, Dr. Christina Carlisi, said that those who commit crimes throughout their lives could benefit from “more lifelong support.”

She said: “Our results support the idea that, for the small proportion of people with persistent antisocial behavior throughout life, there may be differences in their brain structure that make them difficult to develop social skills. which prevent them from engaging in anti-social behavior. ‘

No general differences in brain structure were found for the adolescent group compared to the general population or the lifelong antisocial group.

The researchers said these results have implications for how the criminal justice system treats juvenile offenders.

Criminals Have “Smaller Brains”: “Disability” May Explain Why Offenders Steal and Are Violent

Criminals Have “Smaller Brains”: “Disability” May Explain Why Offenders Steal and Are Violent

In the photo: the average brain of a life criminal from four angles. Shades of blue indicate smaller areas compared to a teenage criminal. The darker the shade, the stronger the changes


Scientists have repeatedly shown that head injuries are linked to crime.

Traumatic brain injury (TBI) can cause lacerations and bruises in the brain. Internal bleeding can also occur.

According to British researchers who published results in 2018, up to 60% of those in detention have suffered a severe blow to the head, whether from falls, assaults or road accidents.

The results of the study also show that prisoners with TBI are more likely to behave badly in detention, to reoffend and to follow poor treatment.

These injuries, which affected serial killer Fred West and the famous twin gangsters Kray, are thought to alter the structure of the brain, making people less able to regulate their behavior and more at risk for psychiatric disorders.

Professor Huw Williams, associate professor of clinical neuropsychology, University of Exeter, led the study published in the journal The Lancet Psychiatry.

He commented on today’s study, which found that life criminals have smaller brains.

The team analyzed brain scans controlling head trauma, as well as IQ and socioeconomic status, for example. But Professor Williams said he would have liked the researchers to explain the TBI more.

The data showed that “a history of head injuries” was reported by 11% of life criminals, 19% of adolescents and 10% of the normal population.

Professor Williams said, “We now know that relatively mild TBIs can have an effect on the brains of young people in the longer term. Especially if repeated.

“At 45, people may not remember such events – or consider them serious enough to be reported.

“That said, this is a fascinating and well-conducted study that helps us to reconstruct the neuroscience of crime.”

They said that the majority of delinquent teens have a low mastery of crime but do not continue to exhibit anti-social behavior as adults. This makes them “very good candidates to reform and rehabilitate”.

Dr. Carlisi said: “Most people who exhibit antisocial behavior do so mainly in adolescence, probably due to navigation in socially difficult years, and these people do not exhibit structural brain differences.

“It is also these individuals who are generally capable of reforming themselves and becoming precious members of society.”

Dr. Moffitt said: “Political approaches to juvenile delinquency often range from punitive measures to approaches that give young offenders the opportunity to reform.

“Our results confirm the need for different approaches for different offenders.”

Dr. Moffitt warned against brain imaging as a screening tool to identify people who could become life criminals.

Indeed, understanding the differences in brain structure is not robust enough to be applied on an individual level.

In addition to this, the team recognized that MRI scans were done at the age of 45, so it is not clear whether structural brain differences were a cause of antisocial behavior or the result of a lifetime. troubled associated with crime.

Those who commit crimes for life may have a smaller brain because they use drugs, smoke, have poor mental health or have lower IQs – more research is needed to find out.

Co-author Professor Essi Viding said: “It is unclear whether these brain differences are inherited and precede antisocial behavior, or if they are the result of a lifetime of confounding risk factors (eg , drug addiction, low IQ and mental health issues) and are therefore the result of a persistent antisocial lifestyle. “

Speaking at a Science Media Center conference, academics not involved in the study praised the results – the most important for comparing the brains of people with different criminal tendencies.

Professor Huw Williams, associate professor of clinical neuropsychology, University of Exeter, said the study was “fascinating”.

He said: “This is a valuable and insightful contribution to the debate on the causes of crime.

“There is clearly a strong theme that the brain systems for controlling mood and behavior are somewhat different in those who continue to offend beyond adolescence.

“This reinforces the need to help children and young people who are struggling with self-regulation get help as soon as possible in order to reduce the risk of behavioral escalation.

“Maybe in schools, to help manage behaviors that could lead to school exclusion.”

Kevin McConway, Professor Emeritus of Applied Statistics, The Open University, said: “These research findings are consistent with the hypothesis that lifelong antisocial behavior results from abnormal brain development

“The study cannot tell us from what age these brain differences were present, since the participants’ brains were only scanned at 45 years of age.

“One possibility is that the differences appeared at some point well after the start of life. In this case, they cannot be the cause of lifelong antisocial behavior, as they occurred after the onset of antisocial behavior.

“Another possibility is that the differences were there from an early age for a reason, perhaps genetic.”

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