Effectiveness of animal-assisted therapy and pet-robot interventions in reducing depressive symptoms among older adults: A systematic review and meta-analysis

Background: Systematic reviews suggest that animal-assisted therapy (AAT) and pet-robot interventions (PRI) achieve a reduction in mental health variables such as depressive symptoms. However, these systematic reviews include both randomised and non-randomised studies, which prevents an adequate assessment of the effect of confounding variables. Objective: This systematic review and meta-analysis aimed to evaluate the comparative effectiveness of AAT and PRI through randomized controlled trials (RCTs) in reducing depression in older adults. Methods: Our study is a systematic review. We searched three databases of scientific articles: SCOPUS, Web of Science and PubMed. We included studies that their population was older adults, aged 65 years or older, with or without a clinical condition, clinical diagnosis based on mental examination/test or documentation from medical records, accredited by the facilities' staff. We included trials in which the comparator was a passive intervention or an active intervention. We used the Cochrane risk-of-bias tool for randomised trials (RoB 2) to assess the risk of bias for each study. Our study was registered in PROSPERO (CRD42023393740). Results: Twenty-three studies were included in this systematic review. However, only 19 trials were included in the meta-analysis. At the overall risk of bias level, 78.9% of the studies were at high risk of bias (n = 15). We found that AAT (g= −0.72; 95%CI −1.13 to −0.31; p = 0.001) has a moderate and statistically significant effect as an intervention to reduce depressive symptoms in older adults. However, the PRIs do not show a significant effect on reducing depressive symptoms in older adults. In addition, a sub-analysis based on dog-assisted therapy (g= −0.65; 95%CI −1.21 to −0.08; p = 0.025), a specific type of AAT, showed a modest effect on reducing depressive symptoms. Conclusions: Our study concluded that AAT and DAT had a moderate and statistically significant effect as interventions to reduce depressive symptoms in older adults. On the other hand, PRI did not show a significant effect in reducing depressive symptoms.