Children who were consistently victimized by peers were more likely to develop psychotic symptoms in early adolescence, according to a report in the May issue of Archives of General Psychiatry.

Some psychosis-like symptoms such as hallucinations and delusions are commonly experienced in childhood and even adulthood, according to background information in the article, though children with these symptoms are at increased risk of developing psychosis in adulthood.

So did bullying cause the psychosis or were the kids bullied because they had psychotic symptoms?

The risk of psychotic symptoms was approximately doubled among children who were victims of bullying at age 8 or 10, independent of other psychiatric illness, family adversity or the child's IQ. The association was stronger when victimization was chronic or severe. 

Andrea Schreier, Ph.D., of Warwick Medical School, University of Warwick, Coventry, England, and colleagues studied 6,437 individuals in early adolescence (average age 12.9) who were part of the Avon Longitudinal Study of Parents and Children (ALSPAC). Parents had completed regular mailed questionnaires about their child's health and development since birth, and the children underwent yearly physical and psychological assessments from age 7.

At each visit, trained interviewers rated the children on whether they had experienced psychotic symptoms (hallucinations, delusions or thought disorders) during the previous six months. Children, parents and teachers reported on whether the child had experienced peer victimization, defined as negative actions by one of more other students with the intention to hurt.

A total of 46.2 percent of participants were categorized as victims and 53.8 percent were not victimized at either ages 8 or 10. At follow-up, 13.7 percent had broad psychosis-like symptoms (one or more symptoms suspected or definitely present), 11.5 percent had intermediate symptoms (one or more of the symptoms was suspected or present at times other than going to sleep, waking from sleep, fever or after substance use) and 5.6 percent had narrow symptoms (one or more symptoms definitely present).

"A range of mechanisms has been proposed to explain the link between traumatic events, such as victimization, and psychotic symptoms," the authors write. For instance, chronic stress from bullying may act on a genetic predisposition to schizophrenia to trigger symptoms.

"Whether repeated victimization experiences alter cognitive and affective processing or reprogram stress response or whether psychotic symptoms are more likely due to genetic predisposition still needs to be determined in further research," the authors conclude. "A major implication is that chronic or severe peer victimization has non-trivial, adverse, long-term consequences. Reduction of peer victimization and of the resulting stress caused to victims could be a worthwhile target for prevention and early intervention efforts for common mental health problems and psychosis." 

Article: Arch Gen Psychiatry. 2009;66[5]:527-536.