Are Equine Assisted Interactions (EAI) a Dark Horse Bet? A Systematic Review on Measuring the Psychological and Physiological Effects of EAI on PTSD, Anxiety and/or Mood Disorders.
Abstract: Background: Conventional forms of trauma-focused psychological interventions seem to be less effective in military veterans with post-traumatic stress disorder (PTSD). Equine Assisted Interventions (EAI) have become increasingly popular as an additional treatment, resulting in increasing research on the effects of EAI. However, no systematic review on the effects of EAI has focused on PTSD, anxiety and/or mood disorders and whether the effects are reflected in psychological and physiological measures. This systematic review investigated the treatment effects, study design, population, intervention, and psychological and physiological measurements in EAI research. Methods: The search strategy yielded 1028 original articles from 3 electronic databases: PubMed, Scopus, and CAB Abstracts. These articles were screened by 2 individual blinded researchers with Rayyan according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and rendered 31 eligible studies. Results: Although all quantitative studies reported 1 or more positive treatment effects on symptoms of PTSD, anxiety and/or mood disorders, well-designed studies were sparse. This review demonstrated a lack of methodological information and few randomized controlled studies, in addition to a large heterogeneity in population characteristics, interventions, terminology, and questionnaires. Conclusion: Future studies should address these methodological considerations in order to advance the understanding of EAI and optimize their efficacy in treating PTSD, anxiety and/or mood disorders.
Publication Date: 2025-08-27 PubMed ID: 40865011PubMed Central: PMC12410245DOI: 10.5152/pcp.2025.24958Google Scholar: Lookup
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Summary
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Overview
- This research systematically reviewed existing studies on the use of Equine Assisted Interventions (EAI) for treating PTSD, anxiety, and mood disorders, focusing on both psychological and physiological outcomes.
- While many studies reported positive effects, the review highlights significant methodological limitations and variability, suggesting the need for more rigorous research to confirm and optimize the benefits of EAI.
Background
- Conventional psychological treatments targeting trauma, especially for military veterans with PTSD, often show limited effectiveness.
- Equine Assisted Interventions (EAI), therapy involving interactions with horses, are gaining popularity as an alternative or complementary approach for mental health treatment.
- Prior to this study, no comprehensive systematic review specifically examined EAI’s effects on PTSD, anxiety, and mood disorders by assessing both psychological symptoms and physiological measures.
Research Objectives
- To systematically review the treatment effects of EAI on PTSD, anxiety, and mood disorders.
- To analyze the study designs, populations involved, types of EAI interventions used, and the psychological and physiological outcome measures applied.
- To identify gaps and inconsistencies in the existing research literature.
Methods
- Database Search: Three electronic databases were searched—PubMed, Scopus, and CAB Abstracts—yielding 1028 original articles.
- Screening: Two independent, blinded researchers screened the articles using the Rayyan software following PRISMA guidelines.
- Inclusion: After screening, 31 studies met eligibility criteria to be included in the systematic review.
Key Findings
- Positive Effects: Every quantitative study included reported at least one positive treatment effect of EAI on symptoms of PTSD, anxiety, or mood disorders.
- Methodological Concerns: Despite positive findings, there was a scarcity of well-designed studies, especially randomized controlled trials (RCTs), considered the gold standard for clinical research.
- Heterogeneity: There was substantial variability in the characteristics of study populations (e.g., different demographics and clinical profiles), types of EAI interventions, terminology used across studies, and questionnaires/measurement tools.
- Physiological Measures: Fewer studies incorporated physiological outcomes alongside psychological assessments, limiting understanding of the full scope of EAI effects.
- Reporting Gaps: Many studies lacked detailed methodological information which hinders replication and thorough evaluation of study quality.
Conclusions and Recommendations
- Although EAI shows promise as a complementary therapy for PTSD, anxiety, and mood disorders, the current evidence base is limited by methodological weaknesses and inconsistency.
- Future research should prioritize:
- Conducting more randomized controlled trials to provide high-quality evidence.
- Standardizing intervention protocols and terminology to reduce heterogeneity.
- Incorporating both psychological and physiological outcome measures to fully capture treatment effects.
- Detailed reporting of study methodologies to improve reproducibility and allow for meta-analytic synthesis.
- Addressing these issues will help clarify the therapeutic potential of EAI and optimize its use in clinical settings, especially for populations where conventional treatments are less effective.
Cite This Article
APA
Kapteijn C, Reinders N, Hueting M, Van Huffelen RA, Vermetten E, Rodenburg B, Endenburg N.
(2025).
Are Equine Assisted Interactions (EAI) a Dark Horse Bet? A Systematic Review on Measuring the Psychological and Physiological Effects of EAI on PTSD, Anxiety and/or Mood Disorders.
Psychiatry Clin Psychopharmacol, 35(Suppl 1), S90-S112.
https://doi.org/10.5152/pcp.2025.24958 Publication
Researcher Affiliations
- Animals in Science & Society, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Animals in Science & Society, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Military Mental Health Care Ministry of Defense, Utrecht, The Netherlands.
- Mentrum Psychiatric Hospital, Amsterdam, The Netherlands.
- Department of Psychiatry, Leiden University Medical Centre, Leiden, The Netherlands.
- Animals in Science & Society, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
- Adaptation Physiology Group, Wageningen University and Research, Wageningen, The Netherlands.
- Animals in Science & Society, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Conflict of Interest Statement
Eric Vermetten is an Associate Editor at Psychiatry and Clinical Psychopharmacology, however, his involvement in the peer-review process was solely as an author. The other authors have no conflict of interest to declare.
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