The Effects of Light Therapy on Sleep, Agitation and Depression in People With Dementia: A Systematic Review and Meta-analysis of Randomized Controlled Trials

ObjectiveTo evaluate the effects of light therapy on the alleviation of sleep disturbances, agitation and depression in people with dementia.MethodsA search was performed in PubMed, Medline, SCOPUS, Web of Science, EMBASE, CINAHL, Cochrane Library, for studies published between 2000 and 2021.ResultsA total of 4315 articles were screened. Sixteen articles were eligible for this review and 11 randomized controlled studies were included in the meta-analysis. Light therapy had a significant effect on reducing the number of awakenings in sleep (n = 4; 95% CI = -.56, -.05; I-2 = 0%; SMD = -.31) but was not significant in reducing the wake after sleep onset (n = 3; 95% CI = -.14, .59; I-2 = 0%; SMD = .23), agitation (n = 4; 95% CI = -1.02, .45; I-2 = 87%; SMD = -.28) and depression (n = 6; 95% CI = -.80, .40, I-2 = 85%; SMD = -.20).ConclusionLight therapy appeared to be more effective in terms of alleviating sleep disturbances, rather than reducing agitation and depression, but its long-term effects remain unclear.