Table 2.

Study results.

Quantitative
Authors, year	Population	Measure(s) used	Measure target	Change, effect size	Outcome type	Assessment time point
Cumella et al., 2014	Inpatient adult women with AN, BN and EDNOS	Eating Disorder Inventory-2 (EDI-2)	Eating disorder	+Δ, N/A	Primary	Admission and discharge
		Beck Depression Inventory-II (BDI-II)	Depression	+Δ, N/A	Secondary	Admission and discharge
		Beck Anxiety Inventory (BAI)	Anxiety	+Δ, N/A	Secondary	Admission and discharge
Lutter, 2008 Lutter, & Smith-Osborne, 2011	Inpatient records or women with a length of stay ≥30 days and a primary diagnosis of AN, BN or EDNOS	Eating Disorder Inventory (EDI-2)	Eating disorder	+Δ (AN and BN), METS r2 = 0.25 − (EDNOS), N/A	Primary	Admission and discharge
		Beck Depression Inventory (BDI-II)	Depression	+Δ, METS r2 = 0.14	Secondary	Admission and discharge
		Compendium of Physical Activities	Intensity of physical activity	N/A - predictor	Primary	Admission and discharge
Schenk et al., 2009	Young adult women with AN, BN, or EDNOS	Symptom Checklist (SCL-90-R)	Psych symptoms	+Δ (time), η2 = 0.39, − (group), N/A +Δ (time × group), η2=0.13	Primary	Baseline and 3-month follow-up
Subscales:		Somatization, Obsessive Compulsive, Depression, Hostility, Paranoid Ideation, Psychoticism		+Δ (psych dimension × time), N/A
		Interpersonal Sensitivity, Anxiety, Phobic Anxiety		− (Psych dimension × time), N/A
		Eating Disorder Inventory (EDI-2)	Eating disorder	+Δ (Time), η2 = 0.34 − (Group), N/A − (Time × Group), N/A	Primary	Baseline and 3-month follow-up
Stefanini et al., 2015	Children and adolescents with psychiatric diagnoses (64.7 % EDs, 20.6 % mood disorders, 8.8 % schizophrenia, 5.9 % anxiety disorders)	Children Global Assessment Scale	Social and psychiatric functioning	+Δ, N/A	Primary	Beginning of intervention (T0) and the end of AAT (3 months later; T1).
		Format of hospital care	Clinical severity	+Δ, N/A	Primary	Beginning of intervention (T0) and the end of AAT (3 months later; T1).
		Ordinary school attendance	Type of school attendance (reflects level of impairment)	+Δ, N/A	Primary	Beginning of intervention (T0) and the end of AAT (3 months later; T1).
		Observation of AAT	Behavior patterns during AAT	+Δ for all, N/A	Primary	Beginning of intervention (T0) and the end of AAT (3 months later; T1).
		• Participation • Interaction with animal • Socialization with peers • Socialization with adults • Withdrawal behaviors • Affection towards the animal
Stefanini et al., 2016	Children and adolescents with psychiatric diagnoses (67.5 % EDs, 25 % mood disorders, 5 % anxiety disorders, 2.5 % schizophrenia)	Children Global Assessment Scale	Social and psychiatric functioning	+Δ, η2 = 0.3	Primary	Beginning and end of 3 month AAT programme
		Youth Self Report	Emotional-behavioral symptoms		Primary	Beginning and end of 3 month AAT programme
		Subscales: Internalizing Problems		+Δ, η2 = 0.14
		Externalizing Problems		−, N/A
		Total Competence		+Δ, η2 = 0.25
		Global Functioning		+Δ, η2 = 0.3
		Observation of AAT	Behavioral patterns during AAT	+Δ for all, N/A	Primary	Beginning and end of 3 month AAT programme
		• Participation • Interaction with the animal • Socialization with peers • Socialization with adult • Withdrawal behaviors • Affection towards the animal
Qualitative
Authors, year	Population	Method	Themes	Reported effects
Kingston, 2008	Therapists who use EAP with EDs	Qualitative study utilizing a twenty-question structured open-ended interview. Data was analyzed using thematic analysis	Structure and boundaries, changes observed in the client (although not sure if only due to EAP), therapeutic process and team approach.	Particularly effective in increasing motivation and lowering resistance to change in clients with eating disorders
Lutter, 2008 Lutter, and Smith-Osborne, 2011	Inpatient adult women with AN, BN, EDNOS, staying 30+ days	A mixed method approach using a retrospective examination of patient records	Identifying contributing factors to the eating disorder, asking for help, problem solving, thinking positively, and verbalizing feelings of frustration. Patients wanted alternatives for those who couldn’t ride (i.e. for medical reasons), input on activities, and to have been treated more as adults.	Physical activity involved in equine therapy is safe and plays a role in eating disorder symptom improvements
Sharpe, 2013	Adult woman with AN, BN, and OSFED	Hermeneutic phenomenology. Interviews and journal excerpts	Mindfulness or attunement to the present moment that occurred between the women and their horses, touch and movement, trusting another and trusting in oneself, as well as a giving up or sharing of control.	They felt safe and accepted being with their horses and many of the women became closer to them as they learned to move together
Træen et al., 2012	ED therapists using group-based EAP	Semi-structured interview assessed via qualitative content analysis about their experiences with Horse-Assisted Relationship Therapy (HART)	The horse’s therapeutic properties are related to how its physical properties affect the emotional response of patients, how the horse stimulates attachment and almost becomes a model for communicating directly and clearly.	The actual horse-assisted intervention was perceived by the therapists as useful for practicing the mastery of psychological skills
Case studies
DeZutti, 2013	Female adolescents and adults at eating disorder inpatient	Author’s personal observation of the interaction between horses and patients	Thinking outside of the box to create unique solutions for their problems.	Group cohesion, established trust
Helm, 2009	Adult women with AN and BN	A combination of documentary analysis, semi-structured interviews with open-ended questions, and observation	A renewed feeling of hope, power and control over a disease that once had complete control over them, re-telling of their experience involving EAP was not only fulfilling but also very freeing.	Positive responses to EAP in the treatment of eating disorders. Significant benefits in treating the psychological issues found in women with ED
Lac, 2017	16-year-old with AN, just out of inpatient	Equine Facilitated Psychotherapy from an Existential Integrative approach	Increasing presence/taking up space, emotional and physical safety, feeling belonging, place to feel emotions.	Found her place in the herd in an embodied way. This sense of belonging alleviated some of her constricted ways of being in the world

Note: METs = Metabolic Equivalent of a Task (a measure of exercise), controlled for length of stay; AN = anorexia nervosa; BN = Bulimia nervosa; ED = eating disorder; EDNOS = eating disorder not otherwise specified; +Δ = symptoms significantly better, less pathology; −Δ = symptoms significantly worse, more pathology; − = symptoms not significantly different

Note: AN = anorexia nervosa, BN = bulimia nervosa, EAP = equine assisted psychotherapy, ED = eating disorder, OSFED = other specified feeding and eating disorder.