Children who are bullied at school over several years are up to four times more likely to develop psychotic-like symptoms by the time they reach early adolescence.
Researchers at the University of Warwick found children who suffered physical or emotional bullying were twice as likely to develop psychotic symptoms by early adolescence, compared to children who are not bullied. However, if they experienced sustained bullying over a number of years that risk increases up to four times.
In a study published in the Archives of General Psychiatry, the research team, led by Professor Dieter Wolke, Professor of Developmental Psychology, followed 6,437 children from birth to 13 years.
The children took part in annual face-to-face interviews, psychological and physical tests. Parents were also asked to complete questionnaires about their child's development. When they reached 13 years of age they were interviewed about experiences of psychotic symptoms in the previous six months.
Psychotic symptoms include hallucinations, delusions such as being spied on or bizarre thoughts such as one's thoughts are being broadcast.
Professor Wolke said: "Our research shows that being victimised can have serious effects on altering perception of the world, such as hallucinations, delusions or bizarre thoughts where the person's insight into why this is happening is reduced"
"This indicates that adverse social relationships with peers is a potent risk factor for developing psychotic symptoms in adolescence and may increase the risk of developing psychosis in adulthood."