Evidence for a genetic etiology of early-onset delinquency

Age at onset of antisocial behavior discriminates persistent and transitory offenders. The authors proposed that early-onset delinquency has an underl ying genetic influence that manifests in problems related to inhibition, wh ereas late-onset delinquency is more environmentally mediated. To test thes e notions, they selected 36 early starters, 86 late starters, and 25 nondel inquent controls from a large sample of Ii-year-old twins and compared them on several measures related to inhibition and a peer group measure. As exp ected, early starters had more psychological, behavioral, and emotional pro blems related to inhibition than late starters and controls. A longitudinal analysis indicated an increase in antisocial behavior among peers of late starters shortly before their delinquency onset. Family history data and a twin analysis provided evidence of greater genetic influence on early-onset than late-onset delinquency.