Dementia is a chronic condition which progressively affects memory and other cognitive functions, social behaviour, and ability to carry out daily activities. To date, no treatment is clearly effective in preventing progression of the disease, and most treatments are symptomatic, often aiming to improve people’s psychological symptoms or behaviours which are challenging for carers. A range of new therapeutic strategies has been evaluated in research, and the use of trained animals in therapy sessions, termed animal‐assisted therapy (AAT), is receiving increasing attention.
To evaluate the efficacy and safety of animal‐assisted therapy for people with dementia.
We searched ALOIS: the Cochrane Dementia and Cognitive Improvement Group’s Specialised Register on 5 September 2019. ALOIS contains records of clinical trials identified from monthly searches of major healthcare databases, trial registries, and grey literature sources. We also searched MEDLINE (OvidSP), Embase (OvidSP), PsycINFO (OvidSP), CINAHL (EBSCOhost), ISI Web of Science, ClinicalTrials.gov, and the WHO’s trial registry portal.
We included randomised controlled trials (RCTs), cluster‐randomised trials, and randomised cross‐over trials that compared AAT versus no AAT, AAT using live animals versus alternatives such as robots or toys, or AAT versus any other active intervention.
Data collection and analysis
We extracted data using the standard methods of Cochrane Dementia. Two review authors independently assessed the eligibility and risk of bias of the retrieved records. We expressed our results using mean difference (MD), standardised mean difference (SMD), and risk ratio (RR) with their 95% confidence intervals (CIs) where appropriate.
We included nine RCTs from 10 reports. All nine studies were conducted in Europe and the US. Six studies were parallel‐group, individually randomised RCTs; one was a randomised cross‐over trial; and two were cluster‐RCTs that were possibly related where randomisation took place at the level of the day care and nursing home. We identified two ongoing trials from trial registries.
There were three comparisons: AAT versus no AAT (standard care or various non‐animal‐related activities), AAT using live animals versus robotic animals, and AAT using live animals versus the use of a soft animal toy. The studies evaluated 305 participants with dementia. One study used horses and the remainder used dogs as the therapy animal. The duration of the intervention ranged from six weeks to six months, and the therapy sessions lasted between 10 and 90 minutes each, with a frequency ranging from one session every two weeks to two sessions per week. There was a wide variety of instruments used to measure the outcomes. All studies were at high risk of performance bias and unclear risk of selection bias. Our certainty about the results for all major outcomes was very low to moderate.
Comparing AAT versus no AAT, participants who received AAT may be slightly less depressed after the intervention (MD –2.87, 95% CI –5.24 to –0.50; 2 studies, 83 participants; low‐certainty evidence), but they did not appear to have improved quality of life (MD 0.45, 95% CI –1.28 to 2.18; 3 studies, 164 participants; moderate‐certainty evidence). There were no clear differences in all other major outcomes, including social functioning (MD –0.40, 95% CI –3.41 to 2.61; 1 study, 58 participants; low‐certainty evidence), problematic behaviour (SMD –0.34, 95% CI –0.98 to 0.30; 3 studies, 142 participants; very‐low‐certainty evidence), agitation (SMD –0.39, 95% CI –0.89 to 0.10; 3 studies, 143 participants; very‐low‐certainty evidence), activities of daily living (MD 4.65, 95% CI –16.05 to 25.35; 1 study, 37 participants; low‐certainty evidence), and self‐care ability (MD 2.20, 95% CI –1.23 to 5.63; 1 study, 58 participants; low‐certainty evidence). There were no data on adverse events.
Comparing AAT using live animals versus robotic animals, one study (68 participants) found mixed effects on social function, with longer duration of physical contact but shorter duration of talking in participants who received AAT using live animals versus robotic animals (median: 93 seconds with live versus 28 seconds with robotic for physical contact; 164 seconds with live versus 206 seconds with robotic for talk directed at a person; 263 seconds with live versus 307 seconds with robotic for talk in total). Another study showed no clear differences between groups in behaviour measured using the Neuropsychiatric Inventory (MD –6.96, 95% CI –14.58 to 0.66; 78 participants; low‐certainty evidence) or quality of life (MD –2.42, 95% CI –5.71 to 0.87; 78 participants; low‐certainty evidence). There were no data on the other outcomes.
Comparing AAT using live animals versus a soft toy cat, one study (64 participants) evaluated only social functioning, in the form of duration of contact and talking. The data were expressed as median and interquartile ranges. Duration of contact was slightly longer in participants in the AAT group and duration of talking slightly longer in those exposed to the toy cat. This was low‐certainty evidence.
We found low‐certainty evidence that AAT may slightly reduce depressive symptoms in people with dementia. We found no clear evidence that AAT affects other outcomes in this population, with our certainty in the evidence ranging from very‐low to moderate depending on the outcome. We found no evidence on safety or effects on the animals. Therefore, clear conclusions cannot yet be drawn about the overall benefits and risks of AAT in people with dementia. Further well‐conducted RCTs are needed to improve the certainty of the evidence. In view of the difficulty in achieving blinding of participants and personnel in such trials, future RCTs should work on blinding outcome assessors, document allocation methods clearly, and include major patient‐important outcomes such as affect, emotional and social functioning, quality of life, adverse events, and outcomes for animals.
Plain language summary
Animal‐assisted therapy for people with dementia
Do therapy sessions that involve live animals help people with dementia?
Dementia is an increasingly common condition across the world. People with dementia have progressive loss of the ability to think, remember, and communicate; to manage their daily activities; and to mix successfully with other people. Many people with dementia also develop depression and related problems. To date, no treatment has proven able to cure the disease or stop it from getting worse. However, many treatments are in use which aim to improve the well‐being of people with dementia and the people who look after them. Animal‐assisted therapy (AAT) is one of the types of treatment that has been studied. It is thought that animals could help people with dementia by providing companionship and support in daily activities and that this might lead to improvements in physical and mental health, including better mood and fewer problematic behaviours.
We searched medical databases to September 2019.
Key characteristics of included studies
We included nine randomised controlled trials (clinical studies where people are randomly put into one of two or more treatment groups), involving 305 people with dementia, which compared AAT to a control treatment (either usual care or an alternative treatment). All studies took place in Europe or the US. Seven studies compared AAT to usual care or to another activity which had nothing to do with animals. Two studies compared AAT (using live animals) to the use of robotic animals. One study compared AAT to the use of a soft toy cat. There were some features of the studies which could have biased the results. Study participants and care staff knew what treatment a person was receiving and this might have affected some results. Also, it was not always clear that the randomisation to treatments had been done as well as possible.
The studies received funding from various sources, including research grants (four studies), personal donation (one study), and support from an institute that promotes AAT (two studies). Two studies did not describe how they were funded.
We found evidence from two studies with 83 participants that people with dementia who had AAT were possibly slightly less depressed at the end of treatment than people who had standard care or other interventions not related to animals. We also found evidence from three studies with 164 participants that people who received AAT had no clear difference in their quality of life compared to those who did not. However, we found no evidence of an effect on social functioning (interactions with their environment and families), behaviour, agitation, activities of daily living, self‐care ability or balance. There were no clear differences when AAT was compared with the use of a robotic animal in two studies with 156 participants (in social functioning, behaviour, and quality of life), or with the use of a soft toy cat in one study with 64 participants (in social functioning). There were no data on harmful effects of the treatment on the participants and nothing was reported about the effect on the animals in any study.
Certainty of the evidence
We took several factors into account when deciding how certain we could be of our results. In this review, two main factors reduced our level of certainty. First, for all the outcomes we looked at, there was only a small number of studies and participants. Second, we thought there was a significant risk that all of the results could have been biased by the way the studies were designed or conducted. For a few outcomes, our confidence was also reduced by inconsistent results between studies. Overall, our certainty about the results ranged from very low to moderate.
AAT may slightly reduce depressive symptoms. Otherwise, no conclusions can yet be drawn on whether AAT is beneficial or safe for people with dementia. The small size of the included studies, and the diversity of outcomes and outcome measures, were major issues. We recommend further well‐conducted studies with the inclusion of important outcomes such as emotional and social well‐being, quality of life, side effects, and effects on the animals.