Do changes in coping mediate the effects of a psychological intervention on psychological morbidity in carers of people with dementia?

Background: Family carers of people with dementia report high levels of anxiety and depression. More emotion-focused and less dysfunctional coping appear protective against symptoms in observational studies, but no randomised controlled trial (RCT) has investigated emotion-focused coping as a mechanism of effective therapy. Method: We recruited 260 family carers of people with dementia (referred to services in past year) into a pragmatic RCT of 8-sessions manualised, individual-based coping skills intervention versus treatment-as-usual (TAU). Blinded raters measured carers’ psychological morbidity (Hospital Anxiety and Depression Scale, HADS-T) and coping (Brief COPE: emotion-focused, problem-focused, dysfunctional subscales) at 4 and 8 months. My hypothesis that increased emotion-focused coping mediated treatment effects in reducing symptoms was tested using regression. As baseline symptoms moderated treatment effects on coping, post-hoc subgroup efficacy analyses were performed in carers with different baseline morbidity levels. Finally moderated mediation was tested using regression models. Results: Emotion-focused coping did not mediate treatment effects in reducing psychological symptoms in the whole sample. It appeared to mediate such effects only in psychological morbidity cases (baseline HADS-T 16+). Increased emotion-focused coping over 4 months predicted reduced symptoms at 8 months regardless of treatment status (b = -0.24, p = 0.005). Intervention had no overall effects on coping, but more severe cases (HADS-T 20+) increased emotion-focused coping (b = 4.57 [95% CI: 1.83, 7.30]), and maintained dysfunctional coping while TAU decreased (b = 0.14 [95% CI: 0.02, 0.26]). Non-cases (HADS-T <8) in TAU increased dysfunctional coping versus intervention (b = -0.09 [95% CI: -0.17, -0.003], log). Conclusions: Emotion-focused coping appeared to mediate treatment effects on psychological morbidity only in carers with high baseline symptoms. The most distressed increased helpful coping strategies and improved; ...