Frequently bullied kids 'twice as likely' to be depressed at 18

A study of just under 4,000 teenagers in the UK has found that bullying - "victimization by peers" - during adolescence is associated with a higher risk of depression in young adulthood.

Not telling someone at school about victimization was more common than keeping quiet about it at home.

The study published in The BMJ was led by experimental psychologist Prof. Lucy Bowes of the University of Oxford in the UK.

It had a longitudinal observational design to examine the relationship between bullying at 13 years of age and depression at 18 years of age.

A survey about bullying was completed at the younger age, and a computer-based clinical assessment of depression was completed as the 3,898 participants entered adulthood in the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK community-based birth cohort.

A dose-response relationship was observed between increasing amounts of adolescent bullying and depression in later years:

• In the group of teenagers who had reported no victimization at all, just over 5% went on to have depression
• A greater burden of the mental ill health was seen among the teenagers who had reported being bullied at 13 years of age between one and three times in a 6-month period - 7.1% had depression at 18
• The proportion of depressed people at this age rose to 14.8% in the teenagers who had reported being bullied by their peers more than once a week.

In terms of a comparison against rates of persistent depression - experiencing depressive symptoms for more than 2 years - 10.1% of those who reported frequent victimization said that they suffered this compared with 4.1% of those in the nonvictimized group.

Teenagers were more likely to tell someone at home about bullying than someone at school - most teenagers (up to three quarters) reported never telling their teachers about their victimization, whereas as little as a quarter of teenagers reported that they kept quiet at home.

If there was physical bullying such as being hit or beaten up, an adult was told about this by 75% of those affected. The kinds of bullying experienced by the children as they entered the teenage years included:

• Having personal belongings taken - which affected 16.5% of study participants occasionally (one to three times in total) in a 6-month period
• Having lies told about them by their peers - 11.4% affected occasionally
• Being called nasty names - 8.9% were affected by this frequently (over four times in the period) and 8.7% very frequently (more than once a week)
• Someone hitting or beating up on them - 8.6% occasionally
• Experiencing their peers not hang around with them as a deliberate means to upset them - 7.3% affected occasionally
• Being threatened or blackmailed - 7.1% occasionally
• Being tricked - 6.6% occasionally
• Being pushed to do something they did not want to do - 6.3% occasionally
• Having games deliberately spoilt - 3.4% occasionally.

Could bullying be to blame for a third of depression?

The observational study could not establish a definitive relationship between cause and effect, but if bullying does directly lead to depression, the authors say that up to 30% of the condition in early adulthood could be attributable to victimization in earlier teenage years, potentially explaining a "substantial contribution to the overall burden of depression."

They add that interventions to reduce bullying in schools could have mental health benefits among young adults.

An editorial in the same issue of the journal says that the study "offers clear anti-bullying messages that should be endorsed by parents, school authorities, and practitioners internationally."

The article, by Maria Ttofi, a lecturer in psychological criminology at the University of Cambridge in the UK, is introduced with the statement that "probably the one thing beyond schoolwork that young people have in common is the need to fit in with their peer group." She continues:

"When young people do not fit in, things may turn ugly. We have all heard stories of young people being the target of racist, homophobic, or other forms of bullying. Bullying can hamper the psychosocial development of young people."

References:

1.  Peer victimisation during adolescence and its impact on depression in early adulthood: prospective cohort study in the United Kingdom, Lucy Bowes, The BMJ, doi: 10.1136/bmj.h2469, published online 2 June 2015.
2.  Adolescent bullying linked to depression in early adulthood, Maria Ttofi, The BMJ, doi: 10.1136/bmj.h2694, published online 2 June 2015.