We examined the prospective association between self-labeled and witness-reported bullying and the risk of newly onset of depression.
Employees were recruited from two cohorts of 3196 and 2002 employees, respectively. Participants received a questionnaire at baseline in 2006 to 2007 with follow-up in 2008 to 2009 and 2011. New cases of depression were diagnosed in the follow-up using Schedules for Clinical Assessment in Neuropsychiatry interviews and the Major Depression Inventory questionnaire.
We identified 147 new cases of depression. The odds ratio for newly onset depression among participants reporting bullying occasionally was 2.17 (95% confidence interval [CI]: 1.11 to 4.23) and among frequently bullied 9.63 (95% CI: 3.42 to 27.1). There was no association between percentage witnessing bullying and newly onset depression.
Frequent self-labeled bullying predicts development of depression but a work environment with high proportion of employees witnessing bullying does not.