Bullying by peers can contribute to psychotic symptoms - LA Times Bullying in childhood and adolescence is a scourge in sore need of effective solutions. Studies have already revealed the toll that bullying takes on kids' mental and physical health. Now new research suggests that bullying by peers can increase the risk of the victim developing psychotic symptoms later in life. The new study, published in the American Journal of Psychiatry, used valuable data from the Environmental Risk Longitudinal Twin Study, which follows 2,232 twin children and their families. Mothers of the children were interviewed and, at age 12, children were asked about bullying experiences and psychotic symptoms, such as hallucinations, delusions or paranoia. The presence of psychotic symptoms was verified by a doctor. Psychotic symptoms can develop into full-blown mental illness, the authors note. However, early treatment is thought to be important in curbing the extent and severity of the illness. Doctors who treat children with psychosis should look for evidence of bullying or maltreatment of the child, they said.