Birth before 26 weeks of gestation is associated with a high prevalence of neurologic and developmental disabilities in the infant during the first two years of life.

Research on bullying can be traced to the 1960s; however, back then, it was called mobbing and was described as collective aggression against others of the same species.¹ Systematic intervention research started when 3 young boys killed themselves in short succession in Norway, all leaving notes that they had been bullied by their peers.² Since then, it has been repeatedly reported that being a victim of bullying increases the risk of adverse outcomes, including physical health problems,³ behavior and emotional problems and depression,⁴ psychotic symptoms,⁵ and poor school achievement.⁶ Furthermore, being bullied is associated with an increased risk of suicide ideation and suicide attempts,⁷ with some evidence that those who are both victims and bullies (hereafter referred to as bullies/victims)⁸ are at higher risk for suicidality.⁹ In contrast, the major adverse outcome of being a bully in childhood has been reported to be offending.^10,11 However, bullying is still commonly viewed as just a harmless rite of passage or an inevitable part of growing up.¹²

Bullying is the systematic abuse of power and is defined as aggressive behaviour or intentional harm-doing by peers that is carried out repeatedly and involves an imbalance of power. Being bullied is still often wrongly considered as a ‘normal rite of passage’. This review considers the importance of bullying as a major risk factor for poor physical and mental health and reduced adaptation to adult roles including forming lasting relationships, integrating into work and being economically independent. Bullying by peers has been mostly ignored by health professionals but should be considered as a significant risk factor and safeguarding issue.

Background: Participant drop-out occurs in all longitudinal studies, and if systematic, may lead to selection biases and erroneous conclusions being drawn from a study.Aims: We investigated whether drop out in the Avon Longitudinal Study of Parents And Children (ALSPAC) was systematic or random, and if systematic, whether it had an impact on the prediction of disruptive behaviour disorders.Method: Teacher reports of disruptive behaviour among currently participating, previously participating and never participating children aged 8 years in the ALSPAC longitudinal study were collected. Data on family factors were obtained in pregnancy. Simulations were conducted to explain the impact of selective drop-out on the strength of prediction.Results: Drop out from the ALSPAC cohort was systematic and children who dropped out were more likely to suffer from disruptive behaviour disorder. Systematic participant drop-out according to the family variables, however, did not alter the association between family factors obtained in pregnancy and disruptive behaviour disorder at 8 years of age.Conclusions: Cohort studies are prone to selective drop-out and are likely to underestimate the prevalence of psychiatric disorder. This empirical study and the simulations confirm that the validity of regression models is only marginally affected despite range restrictions after selective drop-out.

Bullying is a serious problem for schools, parents, and public-policymakers alike. Bullying creates risks of health and social problems in childhood, but it is unclear if such risks extend into adulthood. A large cohort of children was assessed for bullying involvement in childhood and then followed up in young adulthood in an assessment of health, risky or illegal behavior, wealth, and social relationships. Victims of childhood bullying, including those that bullied others (bully-victims), were at increased risk of poor health, wealth, and social-relationship outcomes in adulthood even after we controlled for family hardship and childhood psychiatric disorders. In contrast, pure bullies were not at increased risk of poor outcomes in adulthood once other family and childhood risk factors were taken into account. Being bullied is not a harmless rite of passage but throws a long shadow over affected people’s lives. Interventions in childhood are likely to reduce long-term health and social costs.