Who benefits from mindfulness? The moderating role of personality and social norms for the effectiveness on psychological and physiological outcomes among police officers.

There is a growing interest to use mindfulness-based interventions (MBIs) for occupational health promotion. As most evidence for the beneficial effects comes from convenience samples in the social/education/health sector, it is still an open question if MBIs are effective in other contexts, or for whom MBIs are more effective. In addition, self-selection and sample characteristics may have biased previous findings. Theoretically and practically, it is important to know whether MBIs are also effective for nonselective samples outside the social and health sector, especially in agentic and male-oriented cultures. Therefore, this study investigates the effects of a MBI on physiological and psychological criteria in a nonselective sample of police officers. Moreover, this study examines whether effectiveness depends on participants' personality (neuroticism, openness, and conscientiousness) and on perceived social norms toward MBIs. Using a pre-post intervention design, N = 267 police officers were randomly assigned to an intervention group receiving a 6-week intervention and to a control group. Repeated-measures analysis of variance showed a positive effect on heart rate variability and a stronger reduction of psychological strain, health complaints, and negative affect, as well as more improvement of mindfulness and self-care in the intervention group in comparison with the control group. Additionally, participants higher in neuroticism and openness benefitted more, and the effectiveness was stronger for those who perceived a favorable social norm toward MBIs. Our findings provide evidence that participants with male-oriented occupations may also benefit from a MBI. The importance of individual differences and the social context is discussed. (PsycInfo Database Record (c) 2020 APA, all rights reserved).