Cyberbullying is more strongly related to suicidal thoughts in children and adolescents than traditional bullying, according to a new analysis published in JAMA Pediatrics.

Some estimates suggest that - depending on the country of origin - between 5% and 20% of children are victims of physical, verbal or exclusion-based bullying. Previous studies have also confirmed that bullying is a strong risk factor for adolescent suicide.

Suicide is one of the biggest causes of death in adolescents worldwide. In the US, about 20% of adolescents seriously consider suicide and between 5% and 8% of adolescents attempt suicide each year.

The relationship between cyberbullying and suicide has only been explored in a few studies, but evidence has suggested that cyberbullying is as equal a risk factor for suicidal ideation - thoughts about suicide - as traditional bullying.

The new analysis, from researchers in the Netherlands, tests this evidence by reviewing all available medical literature on the subject. This "meta-analysis" looked at 34 studies focusing on the relationship between bullying and suicidal ideation, and nine studies looking at the relationship between bullying and suicide attempts.

The researchers limited their evidence to studies on "peer victimization." Other kinds of victimization, such as assault, sexual abuse or robbery, were not included.

They also excluded some studies looking at self-harm, because the reasons why someone may self-harm can be different to the reasons why someone may think about committing suicide.

Research looking at youth in hospitals or juvenile detention centers was also omitted, because the researchers wanted to make sure they could generalize their findings to the usual population.

Overall, the meta-analysis included 284,375 participants.

Large meta-analysis contradicts findings of some previous individual studies

The researchers found an association between cyberbullying and suicidal ideation in 70,102 of the participants. The meta-analysis did not find a difference between older and younger children or boys and girls in how likely they were to have suicidal thoughts.

This contradicts some individual studies that had suggested girl victims have immediate increased risk for suicidal ideation, while boys are likely to have suicidal thoughts only if they suffer prolonged episodes of bullying.

Another area where the findings of the meta-analysis differed from some individual studies was the extent of the association between cyberbullying and suicidal ideation.

Though previous evidence had indicated that cyberbullying has an equal association with suicidal thoughts as traditional bullying, the meta-analysis found that the association was stronger for cyberbullying.

The authors suggest a reason for this:

"Potentially, the effects of cyberbullying are more severe because wider audiences can be reached through the internet and material can be stored online, resulting in victims reliving denigrating experiences more often."

As the studies in the meta-analysis mainly looked at suicidal ideation, with some studies looking at non-successful suicide attempts, the analysis cannot explain precisely how cyberbullying might be associated with children who have committed suicide.

However, the researchers acknowledge that "suicidal ideation is thought to invariably precede suicide attempts, and suicide attempts are the strongest known risk factor for future actual suicide."

The authors conclude:

"This meta-analysis establishes that peer victimization is a risk factor of suicidal ideation and suicide attempts. Efforts should continue to identify and help victims of bullying, as well as to create bullying prevention and intervention programs that work."