Animal-Assisted Therapy for Reducing Anxiety in Vulnerable Clinical Populations: A Systematic Review

Background: Anxiety is highly prevalent among individuals living with disability, chronic illness, or hospitalisation, yet it often remains insufficiently addressed in healthcare settings. Animal-assisted therapy (AAT) has been proposed as a complementary intervention to reduce anxiety; however, existing evidence is fragmented across populations and methodologies. Methods: A systematic review was conducted following PRISMA 2020 guidelines. The review protocol was registered in PROSPERO (CRD42024494109); no amendments were made to the protocol after registration. Four databases (Scopus, APA PsycInfo, Web of Science, and PubMed) were searched for empirical studies (2013-2023) evaluating AAT delivered by trained professionals using domesticated species and reporting anxiety outcomes in individuals with disability, illness, or hospitalisation. Results: Thirty-one studies met eligibility criteria and were included in the review. Across heterogeneous designs, most interventions-primarily using dogs or horses-reported significant post-intervention reductions in anxiety. Randomised clinical trials consistently showed superior results compared with control conditions. AAT demonstrated beneficial effects across populations including PTSD, paediatric hospitalisation, chronic illness, disability, acute care, and trauma exposure. Long-term outcomes were mixed, and methodological variability limited comparability across studies. Conclusions: AAT appears to be a promising complementary intervention for anxiety management within clinical, psychosocial, and healthcare settings. Evidence supports short-term anxiolytic effects across diverse populations, although standardisation and long-term evaluations remain insufficient. Future research should establish optimal intervention parameters, mechanisms of action, and strategies for integrating AAT into multidisciplinary mental healthcare.