The protective effect of decentering on the links between internalising symptoms, functional impairment and wellbeing

• One’s internalising symptoms negatively influence wellbeing via functional impairment on a given month and over time. • Decentering reduces the effect of one’s internalising symptoms on functional impairment on a given month and overall, but decentering does not moderate the effect of impairment on wellbeing. • Individual differences in decentering also moderate the effect of internalising symptoms on impairment, but not the effect of impairment on wellbeing. • The relationship between internalising symptoms and wellbeing via functional impairment is bidirectional over time. • Decentering and functional impairment are important therapeutic targets for wellbeing promotion. There is a lack of longitudinal research examining the relationships between internalising symptoms and wellbeing via functional impairment. Decentering is a malleable and clinically relevant characteristic that may disrupt the links among these constructs over time, but this is yet to be explored . A community sample (N=386) completed monthly self-report surveys for 12 months, assessing internalising symptoms (depression, generalised anxiety, social anxiety, panic), impairment, wellbeing and decentering. Multilevel structural equation modelling was conducted to analyse the within-person association between symptoms and wellbeing mediated by impairment (in the same month and subsequent months), as well as a moderated-mediation model with decentering as the moderator (in the same month and as individual differences). Further, the mediation model was tested over time bidirectionally. Within a given month, higher levels of symptoms significantly predicted lower wellbeing via impairment, and prospective analyses revealed that these effects were bidirectional. Decentering significantly reduced the impact of one’s symptoms on impairment on a given month and throughout the study, but not the impact of impairment on wellbeing. Thus, decentering was supported as a protective factor that reduces the link between symptoms and impairment. Further research is needed to uncover different ways to protect wellbeing, particularly because low wellbeing also predicted elevated symptoms over time. These novel findings indicate that the inverse cycle between symptoms and wellbeing may be maintained by impairment, but the short-term and cumulative effects of symptoms on impairment could be reduced by decentering. As such, impairment and decentering may be important therapeutic targets when aiming to promote wellbeing in the context of symptoms.