Do personality traits moderate the relations between bystanders and victims of bullying at work and mental health?

Aim: Workplace bullying is widespread and has negative healtheffects on victims as well as on witnesses of bullying, the so calledbystanders. Literature confirming that bullying is associated withvictims’ poor mental health is overwhelming, but research into theinfluence on mental health of bystanders is scarce. Starting fromthe Michigan Stress Model we investigated the relationshipsbetween victimization and witnessing bullying behavior, mentalhealth complaints and personality traits. We expected victimizationand witnessing bullying behavior to have a significant positiverelationship with mental health. Moreover, we expectedpersonality traits to moderate both relationships. Method: Data were obtained using an online survey with validatedself-report questionnaires which were distributed via the studentand alumni website of the Open University of the Netherlands,resulting in 182 respondents, of which 119 (65%) filled out thequestionnaires completely (mean age 42,9, 23.5 % male).Victimization and witnessing bullying behavior were measuredwith both the self-labelling method (a definition was provided) andthe behavioral experience method (a list with specific behaviorswas given, the Negative Acts Questionnaire, NAQ). The personalitytraits and mental health were measured with the NEO-Five FactorInventory (NEO-FFI) and the Hopkins Symptom Check List–25(HSCL-25). The Cronbach’s alpha’s of the questionnaires rangefrom acceptable to good (.64. to .90).Results and conclusions: Results differ depending on theoperationalization of bullying. Hierarchical regression analysis withthe NAC showed that contrary to our hypothesis both victimizationand witnessing bullying were not associated with mental healthand personality traits did not moderate this relationships but twoof the personality traits, neuroticism (β= .75) and agreeability (β. =-.18), influenced mental health directly.The analysis with the self-labeling method also showed no directrelations between victimization, witnessing bullying and mentalhealth. However, the moderation hypothesis was partly confirmed:agreeability moderated the relations between victimization andmental health (β. = -.36). As hypothesized the relation was weakerfor employees who score high on agreeability. For bystanders wefound no moderations.These findings illustrate the need for future studies into theinfluence of personality traits on the effects of bullying not only onvictims but also on bystanders and show the relevance ofmeasuring bullying with different types of questionnaires.