ABSTRACT
Background Older adults were more likely to be socially isolated during the COVID-19 pandemic, with risk of depression and loneliness. Behavioural Activation (BA) could feasibly maintain mental health in the face of COVID isolation. Methods We undertook a multicentre randomised controlled trial [BASIL+ ISRCTN63034289] of BA to mitigate depression and loneliness among older people. BA was offered by telephone to intervention participants (n=218). Control participants received usual care, with existing COVID wellbeing resources (n=217). Findings Participants engaged with 5.2 (SD 2.9) of 8 remote BA sessions. Adjusted mean difference (AMD) for depression (PHQ-9) at 3 months [primary outcome] was -1.65 (95% CI -2.54 to -0.75, p<0.001). There was an effect for BA on emotional loneliness at 3 months (AMD -0.37, 95% CI -0.68 to -0.06, p=0.02), but not social loneliness (AMD -0.05, 95% CI -0.33 to 0.23, p=0.72). Other secondary outcomes at 3 months were anxiety (GAD-7: AMD -0.67, 95% CI -1.43 to 0.09, p=0.08) and quality of life (SF12 mental component: AMD 1.99, 95% CI 0.22 to 3.76, p=0.03; physical component: AMD -0.50, 95% CI -2.14 to 1.10, p=0.53). BASIL+ trial results were incorporated into a living systematic review [PROSPERO CRD42021298788], and we found strong evidence of an impact of behavioural and/or cognitive strategies on depression [random effects pooled standardised mean difference -0.32, 95% CI -0.48 to -0.16, 10 studies, n=1,210 participants] and loneliness [random effects pooled standardised mean difference -0.44, 95%CI -0.64 to -0.24, 13 studies, n=1,421 participants] in the short-term (<6 months). Interpretation BA is an effective intervention that reduces depression and some aspects of loneliness in the short term. This adds to the range of strategies to improve population mental health, particularly among older adults with multiple long-term conditions. These results will be helpful to policy makers in preventing depression and loneliness beyond the pandemic. Funding NIHR RP-PG-0217-20006