Clinical Review

Fortnightly review: Aggressive behaviour in childhood

BMJ 1998; 316 doi: (Published 17 January 1998) Cite this as: BMJ 1998;316:202
  1. Stephen Scott, child and adolescent psychiatrist (Stephen.Scott{at}
  1. a Department of Child and Adolescent Psychiatry, Institute of Psychiatry, London SE5 8AF


    Increasing numbers of children who behave in a defiant and aggressive way are being excluded from school. Outside school the victims of these children's aggression have included young children and elderly people. At the extreme, two children recently convicted of murder in England were only 10 years old. Often these children are portrayed as inexplicably “evil” or “possessed.” In fact a great deal is known about the factors leading to such behaviour, and how to prevent it.1


    Many thousands of articles have been written about human aggression, in disciplines as varied as molecular genetics, endocrinology, ethology, social anthropology, education, criminology, and town planning. It would be impossible to review them all. This article is based on personal reading, mainly in psychology, psychiatry, and medicine.


    Conduct disorder is the commonest psychiatric disorder of childhood, occurring in 4% of a rural population and 9% of an urban one.2 Three times as many boys as girls are affected. In younger children conduct disorder is characterised by temper tantrums, hitting and kicking people, destruction of property, disobeying rules, lying, stealing, and spitefulness. In adolescence it may include bullying and intimidation of others, frequent fighting, carrying and sometimes using a knife, cruelty to people or animals, more serious stealing, mugging, extensive drug misuse, truanting from school, running away from home, and arson.

    The children are not usually content and well adjusted. Typically they have low self esteem and believe they are bad, often showing marked misery and unhappiness. Their ability to get on with their lives is impaired. A third have specific reading retardation (dyslexia), defined as being two standard deviations below the mean on a reading test after allowing for IQ.3 They lack the social skills to maintain friendships and are rather isolated.4

    Continuity of behaviour

    The difficulties would matter less if most of the children grew out of it. However, 40% of 7 and 8 year olds with conduct disorder become recidivist delinquents as teenagers; and over 90% of recidivist juvenile delinquents had conduct disorder as children. Well over half of future recidivist delinquents can be predicted at age 7 from the child's aggressive behaviour together with the family's ineffective child rearing practices.5 On the other hand, where protective factors exist, the outcome can be good: figure 1) shows the school report of the 9 year old Winston Churchill, whose conduct was “exceedingly bad.”

    Fig 1
    Fig 1

    School report of Winston Churchill, aged 9 years. Published with permission of Sir Winston Churchill Archives Trust

    Summary points

    The origins of persistent youth aggression and violence are to be found in early childhood

    Aggressive behaviour in children (conduct disorder) occurs in nearly 10% of children in an urban population

    90% of recidivist juvenile delinquents have had conduct disorder at age 7

    Harsh, inconsistent parenting is the main cause of conduct disorder, but child hyperactivity and lower IQ also contribute

    Children with conduct disorder are usually rather sad and fail at school and with friends

    Programmes to improve parenting are effective in reducing antisocial behaviour in children under 10; adolescents are far harder to treat

    Effective preventive programmes require input from both the parent(s) and the school

    For vulnerable adolescents, the risk of developing an aggressive lifestyle will remain high while they have easy access to a subculture of violence and while few constructive alternatives are available to them

    The adult manifestations are widespread. The psychiatric disorders that follow conduct disorder are alcoholism, drug dependence, and antisocial personality disorder6; non-psychiatric antisocial behaviours include theft, violence to people and property, drunk driving, use of illegal drugs, carrying and using weapons, and group violence with vandalism5; failure in school has a high continuity with unemployment7; and relationship difficulties also persist, with a high rate of marital violence, family break up and divorce, and abuse of the next generation of children.7

    Economic cost

    Health service resources spent on children with conduct disorder are considerable: 30% of child consultations with general practitioners are for behaviour problems,8 and 45% of community child health referrals are for behaviour disturbances-with an even higher level at schools for children with special needs and in clinics for children with developmental delay, where challenging behaviour is a common problem.9 Psychiatric disorders are present in 28% of paediatric outpatient referrals.10 Social services departments expend a lot of effort trying to protect disruptive children whose parents can no longer cope without hitting or abusing them. Education costs include funding special schools for emotionally and behaviourally disturbed children. Law enforcement agencies and the probation service have to detect and prevent delinquency and bring to justice the delinquents; in addition there is the cost of personal and property damage. Moreover, the rate of unemployment and receipt of state benefits is high.7

    Causes of aggressive behaviour

    Environment and genes

    Twin and adoption studies suggest a large shared (family) environmental effect, a moderate non-shared (unique) environmental effect, and a modest genetic effect. Typical twin concordance rates for adolescent delinquency are 87% for monozygotic twins and 72% for dizygotic twins.11 Adoption studies suggest that genetically vulnerable children-that is, children whose birth parents were antisocial-may be especially susceptible to unfavourable family conditions, so that an interaction is seen (fig 12 The genetic element seems to be stronger for adult criminality than childhood conduct disorder and delinquency.13 To understand what these environmental and genetic factors might be, we need to turn to other studies.

    Fig 2
    Fig 2

    Criminality in young adults who had been adopted, according to congenital and postnatal risk. Adapted from Bohman12

    Parental rearing style

    Five aspects of how parents bring up their children have been shown repeatedly to be strongly associated with long term antisocial behaviour problems: (a) poor supervision, (b) erratic, harsh discipline, (c) parental disharmony, (d) rejection of the child, and (e) low involvement in the child's activities.14 One study showed that among antisocial boys aged 10, differences in parenting styles predicted over 30% of the variance in aggression two years later.15

    Parent-child interaction pattern

    Direct observation in the home shows that much aggressive behaviour in children is influenced by the way parents behave towards them. In many families with antisocial children the parents do little to encourage polite or considerate behaviour by the child-such behaviour is often ignored and rendered ineffective.16 Yet frequently when the child yells or has a tantrum he or she gets attention; often the parent gives in, so the child wins and soon learns to adapt accordingly. The coexistent unresponsiveness to the child's communications and emotional needs contributes further to the child's disturbance.

    Parental influence on children's emotions and attitudes

    Difficulties can often be traced back to infancy. A high proportion of toddlers who go on to develop conduct problems show disorganised attachment patterns, experiencing fear, anger, and distress on reunion with their parent after a brief separation. This behaviour is likely to be a response to frightening, unavailable, and inconsistent parenting.17 The security of infant attachment can be predicted with substantial certainty before the child is even born, from the emotionally distorted, confused style in which the mother talks about relationships with her own parents.18

    By middle childhood, aggressive children are quick to construe neutral overtures by others as hostile and have difficulty judging other people's feelings. They are poor at generating constructive solutions to conflicts, believing instead that aggression will be effective.19 This quickness to take offence at the slightest opportunity is reflected on the street in sensitivity to “dis” (disrespect), which can lead to swift retribution. This indicates the fragile self esteem and confrontational view of the world that these young people have come to develop after experiencing years of frustration and failure. Some find that being violent makes them feel good about themselves and gives them control.

    Difficulties with friends and at school

    In the school playground these children lack the skills to participate and take turns without upsetting others and becoming aggressive. Peer rejection typically ensues quickly,20 and the children then associate with the other antisocial children, who share their set of values.

    Those with difficulty reading typically fail to get any qualifications by the time they leave school, and they become unemployed. This may contribute to persisting antisocial behaviour.21

    Predisposing child characteristics

    Hyperactivity (also known as attention deficit hyperactivity disorder) is predominantly genetically determined.22 Children who show this restless, impulsive pattern of behaviour do not necessarily start off aggressive, but over time a proportion become so.23 They have difficulty waiting their turns in social encounters and games and so easily provoke retaliation and get into fights. Where hyperactivity and conduct disorder coexist from an early age the long term outlook is especially poor.23

    Delinquents have repeatedly been shown to have an IQ that is 8-10 points lower than law abiding peers-and this is before the onset of antisocial behaviour.24 Other traits predisposing to conduct problems include irritability and explosiveness, lack of social awareness and social anxiety, and reward seeking behaviour.

    The interplay between a child's characteristics and the environment is complex. As children grow older, their environment is increasingly determined by their own behaviour and choices. There may be turning points when certain decisions set the scene for years to come.25 Thus it is not simply a young person's level of antisocial behaviour per se that determines later outcome but also how the behaviour shapes the social world inhabited later on. This has important implications for intervention.


    Treatment needs to be targeted at major modifiable risk factors and its outcome measured objectively.26 It should preferably be at an early age as conduct disorder can be reliably detected early,5 has high continuity,27 is amenable to treatment at a young age,4 and is very hard to eradicate in older children.28 In this section I discuss interventions for general aggressiveness only in children under 12; interventions targeting youth crime have been excellently reviewed by Farrington.29

    Parent training programmes for reducing antisocial behaviour in children

    Little published evidence exists that individual psychotherapy (whether psychodynamic or cognitive behavioural), pharmacotherapy, general eclectic family work, or formal family therapy are effective in treating conduct disorder.4 Behaviourally based programmes to help parents, however, have consistently been shown to be effective. For example, the pioneering work of Patterson and colleagues15 showed that directly instructing parents while they interact with their children leads to significant and lasting reduction in behavioural problems. Many other studies have replicated this.30 The content of a typical parenting programme is shown in the box.

    Elements in parenting programmes

    • Play and good times together-To cut into the cycle of defiant behaviour and recriminations, it is essential to replace it with some positive experiences for both sides and begin to mend the relationship. Some parents are unable to play with their children and need to learn how to recognise and respond to their needs

    • Praise and recognition for good behaviour-The child needs to receive praise for mundane behaviour such as eating nicely and getting dressed quickly; then he or she will do it more often. Yet some parents find it hard to praise and fail to recognise positive behaviour, with the result that it becomes less frequent

    • Clearly expressed expectations-Rules need to be explicit and constant; commands need to be firm and brief. Thus shouting at a child to stop being naughty does not tell him what he ought to do, whereas, for example, telling him to play quietly gives a clear instruction, which makes compliance easier

    • Consistent and calm consequences for misbehaviour-Aggression needs a firm and calm response (for example, by putting the child in a room for a few minutes rather than using counter aggression). Some parents utter a string of dire threats that are usually not carried out; they may give in to the child's whining for a quiet life, thus unwittingly teaching him or her that it pays to whine

    • Planning ahead to avoid trouble-Fairly simple measures may improve a difficult situation (for example, no longer taking the child to the supermarket, or taking a favourite book to entertain the child while at the doctor's surgery)

    Developing a programme

    Firstly, the tone of the approach is vital. “Professional” overtures showing parents how to do things while treating them as unskilled and incompetent leave them feeling even more of a failure and lead to a high dropout rate. A more collaborative approach is much more effective.31 Secondly, unfocused social support may be appreciated by parents but often does not improve parenting.32 33 To get results the professionals need to be trained in the specific methods-a manual and a training centre are necessary. Thirdly, most consistently effective programmes have at least 10 sessions; to increase the effects, a booster is desirable several months later. Fourthly, intervention needs to be early, since teenage treatments have only small effects.29

    Training using videotapes

    Although conventional one-to-one treatment is effective, a more cost effective approach is needed to treat larger numbers. Webster-Stratton and colleagues developed a series of videotapes for training groups of parents without their children present.30 The videos show short vignettes of parents and children in common situations. They show the powerful effect of parents’ behaviour on their child's activity, with examples of “right” and “wrong” ways to handle children. Ten to 14 parents attend a weekly two hour session for 12 weeks. Two therapists lead the group and promote discussion, so that all members grasp the principles; role play is used to practise the new techniques. Practical homework is set each week and carefully reviewed with a trouble shooting approach.


    The origins of persistent youth aggression and violence are found in early childhood


    Outcome studies in the United States of this package have shown it to be just as effective as the accepted ideal of giving individual instruction to the parent with the child present. Objective measures of the child's antisocial behaviour show improvement; appropriate parental behaviour increases, with a large reduction in smacking. The gains are maintained at one year follow up.30 The cost is a quarter that of individual treatment. In Britain two randomised controlled trials are in progress to replicate the findings with referred cases.

    Other training programmes

    Among more intensive programmes, the one developed by Puckering et al entails one day a week for 16 weeks.34 This programme has been shown to be effective in improving parenting in quite damaged families and enabling children to come off “at risk” child protection registers.

    Failure of parent training

    However, even in the best hands about a third of children do not improve with parent training. In many cases, this is due to lack of change in parental behaviour, often because of parental psychiatric difficulties such as depression, drug and alcohol problems, and personality difficulties. In other cases, the children have comorbid problems maintaining their behaviour, such as mental retardation, severe language disorders, or severe hyperactivity.

    Management of hyperactivity

    Hyperactivity is distinct from conduct disorder, although they often coexist. Psychological treatment has to be rather different. Rewards have to be given more contingently and more frequently and have to be changed more often. Tasks have to be broken down into shorter components. Specific, clear rules have to be set for each different situation, as these children have difficulty generalising. School is often particularly difficult as the demands for concentration are great, the distractions from other children higher than at home, and the level of adult supervision lower. However, use of the principles outlined above can lead to useful improvements.35

    Management with drugs (usually methylphenidate or dexamphetamine) is reserved for children with severe symptoms in both home and school (hyperkinetic syndrome). This syndrome occurs in just over 1% of boys. The short term effects of drug treatment are large; less is known about long term benefits.

    Interventions at school

    Effective techniques exist for helping parents to get their children to read.36 One parent-child reading programme with 5 year olds reduced the proportion of children in the “very poor” category of reading from 26% to 14%.36 Teachers can be taught techniques to reduce disruptive behaviour in the classroom. Teaching younger children directly to cope with their peers in a non-aggressive way has had mixed results so far,37 although children can be taught to use non-aggressive means of resolving conflict at school.38

    Early preventive educational programmes can reduce later antisocial behaviour. In the United States the Perry/High Scope project gave educational input to deprived children aged 3-4 before they went to school. By age 27 they had better peer relationships, they received fewer state benefits, and the level of repeat arrests was reduced from 35% to 7%, compared with randomly allocated controls who recived no intervention39 Several ambitious programmes have now started in North America for primary school age children that combine parental and school interventions, but the results are not yet known.40


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