One in five young people has been a victim of cyber-bullying, which experts warn can cause more psychological damage than traditional forms of bullying.
Hate emails, threatening texts and humiliating images posted on social networking sites are twice as likely to be targeted at girls as boys, according to new research by Anglia Ruskin University (ARU).
Cyber-victims can suffer more because they feel unable to escape from online and mobile phone threats. The hidden identities of cyber-bullies as well as the ability for messages and images to "go viral" within minutes, amplifies the threat, said Steve Walker, the study's co-author and principle lecturer in child and adolescent mental health at ARU.
The potentially devastating consequences of cyber-bullying were highlighted by the suicide of Holly Grogan, 15, in 2009. The schoolgirl jumped to her death after enduring a torrent of abusive messages on her Facebook page.
The ARU survey of nearly 500 10- to 19-year-olds found that half of those bullied said their mental health had suffered as a result. More than a quarter had missed classes and more than a third stopped socialising outside school because they felt scared or embarrassed by the bullying. The online survey was followed by two focus groups which analysed in more depth the experiences and fears of 17 youngsters in London and Leeds.
Mr Walker said: "They cannot come home from school, shut their bedroom door and feel safe, because as soon as they switch on the computer or receive a text, the potential is there. It is much harder to avoid than traditional bullying because avoiding the internet and mobile phones just isn't an option; these are as much part of a young person's life as brushing their teeth."
He added: "Anti-bullying campaigns and professionals working with young people need to be smarter and more in tune with technology so they pick it up, because cyber-bullying poses a serious public health problem."
Research by Beatbullying found that cyber-victims were often targeted in person as well. However, Richard Piggin, Beatbullying's deputy chief executive, said perpetrators tended to underestimate the impact of cyber-bullying because they could not see the distress they caused.
The charity's cyber-mentor scheme has provided real-time peer support for 1.2 million young people since 2009. It wants the social networking industry to show greater responsibility and quickly take down abusive content. The ARU study found that intimidating messages and images circulated on social networking sites such as Bebo were the most common forms of cyber-bullying, followed by texts.
Sue Steel at the National Children's Bureau, who is co-ordinator of the Anti-Bullying Alliance, said: "Cyber-bullying is particularly unpleasant as it can affect children every time they switch on their phone or computer ... It infiltrates the home, taking away children's safe spaces. It's just as serious as physical bullying, but it may be harder for parents and carers to spot."
Victims of bullying
Megan, from Cheshire, was 15-years-old in 2009 when she took a fatal dose of tablets after classmates posted spiteful messages on the internet about her appearance and clothing. An inquiry found that she had suffered from bullying, and had not wanted to go to school the next day.
The 15-year-old public schoolgirl from Cheltenham jumped to her death from a road bridge in 2009 after enduring a torrent of abuse on her Facebook page. Friends said that she had been a victim of cyber-bullying.
The 14-year-old cut her life short last month after suffering relentless bullying on the internet. A memorial Facebook page for her was also targeted with hate messages. Danni's parents blamed the authorities for failing to help her.
'I was called fat and ugly – and I believed them'
Georgia's school friends turned against her during her first year of secondary school and started calling her a "snob".
The name calling moved on to hateful messages, sent by a large number of school mates on Bebo, the social networking site popular with children. "They would call me fat and ugly and tell me I was useless, so I started to believe it," the 15-year-old from Kent said. She soon stopped eating and became increasingly withdrawn.
The turning point came when her parents found a note she had written, detailing an attempt to hang herself. They told the school, which arranged for counselling sessions with the charity Beatbullying and also spoke to the cyber-bullies. Many had no idea how much pain they were causing.
Georgia is now a cyber-mentor, helping young people deal with online bullying.
How to help
Parents and teachers should ask specific questions about abusive and humiliating texts, emails and images if they are worried about a child.
There is no standard way of dealing with cyber-bullying but every threat should be reported to the moderator. Keep every text, email and website link as evidence. Ask to see the school's bullying policy and insist they take it seriously. Contact the police if you are worried about specific threats.
Contact charities like Beatbullying or Childnet for advice and support.Reuse content