Animal-Assisted Interventions in Custodial Settings: A Systematic Review of Psychological Wellbeing Outcomes

The use of animal-assisted interventions (AAIs) to support incarcerated individuals’ psychological wellbeing has expanded rapidly in recent years. However, research in custodial settings remains limited and is largely characterized by methodologically weak study designs that rely on small, self-selected samples from single institutions. This systematic review synthesized evidence on the effectiveness of AAIs in improving the psychological wellbeing of incarcerated individuals. Seven databases were searched: PsycINFO, PubMed, Medline, Web of Science, the Educational Resources Information Center (ERIC), the Criminal Justice Database, and the Applied Social Sciences Index and Abstracts (ASSIA). This was supplemented by hand-searching key journal articles, reference lists, and Google Scholar. The database searches yielded 152 records. A further 27 articles were identified from hand-searching. The database search was completed on 26 February 2025. In total, 18 articles met the inclusion criteria and were included in the qualitative narrative synthesis. Risk of bias was assessed using the Downs and Black quality appraisal tool for quantitative studies, and the Critical Appraisal Skills Programme (CASP) Qualitative Studies Checklist was used for qualitative studies. Findings from both self-reported and objective outcomes were examined and summarized in tables to describe study characteristics and intervention effects. Despite substantial heterogeneity in intervention approaches and methodologies, results indicated mostly positive outcomes. Reported improvements included reductions in anxiety, depression, post-traumatic stress disorder (PTSD), loneliness, symptom distress, and cortisol levels; improvements were also found in participants’ self-esteem, self-worth, mood, and emotional state. AAIs may therefore offer a promising approach to supporting psychological wellbeing in custodial settings; however, well-designed randomized controlled trials are needed to strengthen the evidence base and clarify effectiveness across outcomes and program models.