Effects of Animal-Assisted Therapy in Individuals with Mental Disorders: A Systematic Review and Exploratory Meta-Analysis

Animal-assisted therapy (AAT) is increasingly used as a complementary intervention in mental health care, but its effectiveness for individuals with mental disorders remains uncertain. This systematic review synthesized randomized controlled trials (RCTs) published between 2014 and 2024; an exploratory meta-analysis was conducted only for outcome domains with sufficiently comparable data. Eligible studies evaluated structured AAT against a comparison condition in participants with diagnosed mental disorders; studies focused on dementia, neurodevelopmental disorders, or severe physical or neurological illness were excluded. PubMed/MEDLINE, CENTRAL, APA PsycINFO, and Google Scholar were searched. Thirteen studies met the eligibility criteria. In the systematic review, favorable findings were reported for subjective well-being-related outcomes, whereas findings for social functioning, depressive symptoms, behavioral problems, and other outcomes were mixed across populations, interventions, comparators, and measures. Seven studies contributed eight comparisons to the exploratory meta-analysis. The pooled estimate for subjective well-being-related outcomes was favorable (SMD = 0.87, 95% CI 0.37–1.37), with substantial heterogeneity. Estimates for social functioning, depressive symptoms, and behavioral problems did not reach statistical significance. The evidence suggests a preliminary signal for subjective well-being-related outcomes, but remains insufficient for firm conclusions about broader clinical effectiveness.