Animal-Assisted Therapy in Adolescents with Mental Health Disorders: Effects on Depression, Self-Perception, and Mindfulness

Background and objectives: Animal-assisted interventions have been introduced in adolescent mental health care, but evidence for their added benefit in inpatient treatment remains limited. This study examined animal-assisted group psychotherapy across three assessment intervals: 1) the individual sessions, 2) the five-week intervention period, 3) the full inpatient stay.Methods: This controlled study included 276 adolescents aged 12–18 years receiving inpatient psychosomatic treatment. The intervention group (n = 108) participated in five weekly 150-minute animal-assisted group psychotherapy sessions alongside standard multimodal treatment, whereas the control group (n = 168) received standard treatment alone. Group allocation was determined by the treating clinicians based on predefined clinical indications and safety criteria. Linear mixed-effects models examined 1) immediate pre–post session changes in depressive symptoms and mindfulness, 2) change in depressive symptoms, self-esteem, self-concept, and mindfulness across the intervention period, and 3) admission-to-discharge changes in depressive symptoms by group.Results: Depressive symptoms decreased (b = −2.53 to −3.04, all p < .001) and mindfulness increased (b = 4.88 to 6.36, all p ≤ .001) immediately after individual sessions. Across the intervention period, depressive symptoms decreased, while self-esteem, self-concept, and mindfulness increased significantly (all p ≤ .031). Although depressive symptoms decreased substantially from admission to discharge in both groups, no significant time × group interactions were found for the BDI-II (b = 1.36, p = .371) or PHQ-9 (b = 0.65, p = .394).Conclusions: The findings suggest that animal-assisted group psychotherapy may provide short-term psychological benefits for adolescents receiving inpatient mental health care, potentially supporting readiness, attention, and therapeutic engagement. However, these immediate benefits do not necessarily translate into additional improvements in depressive symptoms over the course of inpatient treatment.