Matthew Broome1, Gennaro Catone2,3, Guisi Moffa4,5, Jack Kuipers6, Elizabeth Kuipers7, Daniel Freeman8, Steven Marwaha9, Belinda Lennox8, Paul Bebbington4; 1Institute for Mental Health, School of Psychology, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK, 2Università della Campania Luigi Vanvitelli, Naples, Italy, 3Faculty of Educational Sciences, Suor Orsola Benincasa University, Naples, Italy, 4Division of Psychiatry, University College London, London, UK, 5Institute for Clinical Epidemiology and Biostatistics, University Hospital Basel and University of Basel, Basel, Switzerland, 6D-BSSE, ETH Zurich, Basel, Switzerland, 7Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK, 8Department of Psychiatry, University of Oxford, Oxford, UK., 9Unit of Mental Health and Wellbeing, Warwick Medical School, University of Warwick, Coventry, UK
Introduction Being bullied is an aversive experience with short- and long-term consequences. We used the 2000 and the 2007 British Adult Psychiatric Morbidity Surveys to test the hypothesis that bullying is associated with individual psychotic phenomena and with psychosis. Methods Respondents were presented with a card listing stressful events to identify experiences of bullying over the entire lifespan. We assessed associations with the dependent variables persecutory ideation, auditory and visual hallucinations, and diagnosis of probable psychosis. We used directed acyclic graphs (DAGs) to analyse data to assess putative mediators of the association between bullying victimization and psychosis. We compared results using DAGs and the Karlson-Holm-Breen (KHB) logistic regression commands in STATA. Results We used data for 8580 respondents from 2000 and 7403 from 2007. Bullying was associated with presence of persecutory ideation and hallucinations. Bullying was associated with a diagnosis of probable psychosis. If reported at baseline, bullying predicted emergence and maintenance of persecutory ideation and hallucinations during 18 months of follow-up in the 2000 survey. DAG analysis revealed a richer structure of relationships than could be inferred using the KHB commands. Bullying had direct effects on worry, persecutory ideation, mood instability, and drug use. Bullying led to hallucinations indirectly, via persecutory ideation and depression. Conclusion Bullying victimisation increases the risk of individual psychotic symptoms and of a diagnosis of probable psychosis. DAGs indicate the complex interactions seen in psychiatry, including the mechanisms underpinning psychiatric symptoms. It may consequently be used to optimize the choice of intervention targets.
