People who persistently lie, steal and bully have smaller brains, a major study suggests. Scientists said young children who kept being naughty should be targeted with far more help, and parenting classes, to save them from a life of crime. Researchers said that going “off the rails” as a teenager was fairly normal. But they said far more attention should be paid to toddlers and young children who were persistently badly behaved, and could be at risk of a life of antisocial behaviour, because of the way their brains were formed. The study by University College London involved 672 adults who underwent MRI scans at the age of 45, and whose life histories were analysed. Those who had exhibited behavioural problems throughout life – such as lying or bullying in school, or aggression, violence and crime in later life – were found to have markedly different brains to those who had not. Such cases had thinner cortexes, and a smaller surface of grey matter. No such changes were found among those who behaved badly only in their adolescence. The research, the first major study to show such differences, could not show whether the bad behaviour is caused by the unusual structure of the brain – or whether such actions shape the brain. But they said it showed the need to intervene far earlier, and offer support to children and teenagers to prevent patterns becoming entrenched. Previous studies have linked childhood abuse and deprivation to changes in the brain. The study, published in The Lancet, used MRI brain scans from 672 45-year-olds, and reports from parents, carers and teachers, and self-reported problems between seven and 26-years-old. Among the group, 80 people had what was classed as “"life-course-persistent” antisocial behaviour, 151 had adolescent-only antisocial behaviour, and 441 had no history of persistent antisocial behaviour. On average, across the entire brain, those who behaved badly into adulthood had a smaller surface area and lower cortical thickness than people who changed their ways as they grew up. They also had a smaller surface area in 282 of 360 brain regions, and had thinner cortex in 11 of 360 regions. The affected areas of the brain regulate emotions, motivation and self-control. Study lead author Dr Christina Carlisi, of University College London (UCL), said: "Our findings support the idea that, for the small proportion of individuals with life-course-persistent antisocial behaviour, 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 behaviour. "These people could benefit from more support throughout their lives.” Terrie Moffitt, Professor of Social Development at King"s College London, said: "I think what we"ve seen with these data is they are actually operating under some handicap at the level of the brain ... living life with some level of disability.” Researchers called for more help for young children with behavioural problems, including parenting classes to help families cope. Essi Viding, Professor of Developmental Psychopathology at University College London, said more compassion should be shown to children and young people who got into trouble.