Abused and neglected children are more likely to be delinquent and to exhibit criminal and violent criminal behaviour as adults. This was one of the findings of a recent comparison of abused and neglected children and children with no history of abuse and neglect.

The cycle-of-violence hypothesis, or the notion of an intergenerational transmission of violence, holds that abused children become abusers, and victims of violence become violent offenders. However, a recent review of research found surprisingly little empirical evidence to support this hypothesis.

Despite widespread belief in the cycle of violence, problems of methodology in previous studies have made it difficult to draw conclusions about the long-term consequences of early childhood victimization. These problems include the lack of a control group against which the abused and neglected group could be compared. Another problem is the retrospective design of the studies, requiring the researcher to rely on delinquents' ability to remember details about their early childhood.

Improving on past work, this study included a relatively clear definition of abuse and neglect; a prospective design in which the development of children was followed rather than traced backward in time; a large sample group; a control group matched as closely as possible in age, sex, race and approximate social class background; and an assessment of the long-term consequences of abuse and neglect beyond adolescence and juvenile court and into adulthood.

From official records of a metropolitan area in the United States, the study identified a large sample of cases of child abuse and neglect from about 20 years ago, and established a matched control group of non-abused children. The objective was to determine the extent to which both groups subsequently engaged in delinquent, adult criminal and violent criminal behaviour.

All cases of physical and sexual abuse and neglect validated and substantiated by the county juvenile court and adult criminal courts from 1967 to 1971 were initially included. Of 2,623 cases, 908 were retained for the study.

The term "physical abuse" refers to cases in which an individual had "knowingly and willfully inflicted unnecessarily severe corporal punishment" or "unnecessary physical suffering" upon a child.

"Sexual abuse" refers to charges ranging from the relatively nonspecific ones of "assault and battery with intent to gratify sexual desires" to more specific and detailed charges.

"Neglect" refers to cases in which the court found a child to have no proper parental care or guardianship, or to be destitute, homeless or living in a physically dangerous environment.

Children for the control group were selected from county birth-record information and records of more than 100 elementary schools. They were matched as closely as possible with those in the abused and neglected group on age, sex, race and approximate family socio-economic status during the period under study. Altogether, the researchers were able to find matches for 73.7% (or 667) of the abused and neglected children.

In both the control group and the abused and neglected group, there were about equal numbers of males and females and about twice as many whites as blacks. The mean age of subjects in both groups was approximately 26, with 85% between the ages of 20 and 30.

Official records were used to gather information about the children's delinquent behaviour, adult criminal behaviour and violent criminal behaviour.

Generally, abused and neglected children were significantly more likely than their counterparts in the control group to be arrested for delinquency, adult criminality and violent criminal behaviour (see figure). Overall, abused and neglected children had more arrests as juveniles (26% versus 17%), as adults (29% versus 21%) and for any violent offence (11% versus 8%).

In support of the cycle-of-violence hypothesis, these results indicate that abused and neglected children were more likely to become delinquents, adult criminals and violent criminals than children who had not been abused or neglected.

However, these results do not imply that every abused or neglected child will become a delinquent or a criminal. Although 26% of victims of child abuse and neglect had juvenile offences, 74% did not. Similarly, 11% had been arrested for a violent offence while 89% had not.