New research in the UK has shown that being exposed to bullying during childhood will lead to an increased risk of psychotic experiences in adulthood, regardless of whether they are victims or perpetrators.

According to the study, children who were bullied over a number of years (chronic victims), but also the bullies themselves in primary school were up to four and a half times more likely to have suffered from psychotic experiences by the age of 18. Equally concerning is that those children who only experienced bullying for brief periods (e.g. at 8 or 10 years of age) were at increased risk for psychotic experiences.

Psychological Medicine
https://www.sciencedaily.com/releases/2013/12/131217104235.html