Coping strategies as mediators of the effect of the START (strategies for RelaTives) intervention on psychological morbidity for family carers of people with dementia in a randomised controlled trial.

BACKGROUND

Family carers of people with dementia frequently become depressed or anxious. In observational studies, more emotion-focused and less dysfunctional coping predict fewer psychological symptoms, but no randomised controlled trial (RCT) has directly investigated emotion-focused coping as mediator of effectiveness of a successful psychological intervention. We hypothesised that emotion-focused coping would mediate the START psychological intervention׳s effects in an RCT. We tested whether mediated effects were moderated by severity of baseline symptoms.

METHODS

260 family carers from NHS dementia services were randomised to START (manualised coping skills intervention), or treatment-as-usual (TAU). Blinded raters administered the Hospital Anxiety and Depression Scale (HADS-T) and Brief COPE inventory at baseline, 4 and 8 months. HADS-T improved in the intervention group when compared to TAU at all levels of psychological distress. We tested whether coping was a mediator and for moderated mediation, and (post-hoc) subgroup treatment effects on coping.

RESULTS

Data were available for 187 carers (71.9%) for the mediation analysis. The reduced HADS-T score in the intervention group was mediated by increased emotion-focused coping only among carers with higher (16+) baseline HADS-T scores (mediated effect=-0.63 [-1.11, -0.15]; proportion of overall effect=33% [3%, 64%]).

LIMITATIONS: We did not measure plausible psychosocial treatment mechanisms other than coping.

CONCLUSIONS

START benefited family carers both in preventing and treating psychological morbidity, through different mechanisms of action. The most psychologically distressed carers increased their emotion-focused coping and did not decrease their dysfunctional coping, while others benefited but not through this mechanism.