<h3>Abstract</h3> <b>Objective:</b> To see whether a behaviourally based group parenting programme, delivered in regular clinical practice, is an effective treatment for antisocial behaviour in children. <b>Design:</b> Controlled trial with permuted block design with allocation by date of referral. <b>Setting:</b> Four local child and adolescent mental health services. <b>Participants:</b> 141 children aged 3-8 years referred with antisocial behaviour and allocated to parenting groups (90) or waiting list control (51). <b>Intervention:</b> Webster-Stratton basic videotape programme administered to parents of six to eight children over 13-16 weeks. This programme emphasises engagement with parental emotions, rehearsal of behavioural strategies, and parental understanding of its scientific rationale. <b>Main outcome measures:</b> Semistructured parent interview and questionnaires about antisocial behaviour in children administered 5-7 months after entering trial; direct observation of parent-child interaction. <b>Results:</b> Referred children were highly antisocial (above the 97th centile on interview measure). Children in the intervention group showed a large reduction in antisocial behaviour; those in the waiting list group did not change (effect size between groups 1.06 SD (95% confidence interval 0.71 to 1.41), P&lt;0.001). Parents in the intervention group increased the proportion of praise to ineffective commands they gave their children threefold, while control parents reduced it by a third (effect size between groups 0.76 (0.16 to 1.36), P=0.018). If the 31 children lost to follow up were included in an intention to treat analysis the effect size on antisocial behaviour was reduced by 16%. <b>Conclusions:</b> Parenting groups effectively reduce serious antisocial behaviour in children in real life conditions. Follow up is needed to see if the children9s poor prognosis is improved and criminality prevented. <h3>What is already known on this topic</h3> Children who persistently display a high level of antisocial behaviour are at high risk of social rejection, juvenile delinquency, and long term unemployment; the cost to society is high While some behaviourally based parenting programmes have been shown to be effective in university centre trials with volunteers or specially selected cases, most trials of psychological treatments for children in real life settings have shown no effect <h3>What this study adds</h3> An evidence based intervention is available for use in regular clinical practice that effectively reduces antisocial behaviour in referred children The intervention works well with children at risk of criminality from a combination of highly antisocial behaviour, multiple psychopathology, and social deprivation

Multicentre controlled trial of parenting groups for childhood antisocial behaviour in clinical practice Commentary: nipping conduct problems in the