Effect of Equine-assisted Biographical Work (EABW) in older adults with subclinical depression: a randomized controlled trial

Preventive approaches for depression in adults aged 50 years and older have received little attention, despite increasing needs arising from demographic changes. In particular, subclinical depression is often underdiagnosed and associated with anxiety, a poorer quality of life, and greater need for assistance from the healthcare system. This multicentre, randomised, controlled phase III trial investigated if Equine-Assisted Biographical Work (EABW) is effective to improve subclinical depression. Qualified sites in Germany enrolled 52 participants ≥ 50 years (Full Analysis Set (FAS), N = 50). The intervention received weekly sessions of EABW for 8 weeks. The control group was not treated. Follow-up was after 3 months. Participants in both groups had similar demographic and baseline characteristics. The primary endpoint was change in Beck Depression Inventory-II (BDI-II). Secondary target parameters included questionnaires, e.g., dealing with anxiety, behavioural avoidance, and state of health. The pre-test BDI-II score averaged 20.92 (SD 5.99) in the intervention group and 22.36 (SD 6.80) in the control group with a highly significantly greater improvement after treatment (F = 15.21, p < 0.001, Cohen’s d = 1.80) for intervention group. This difference was maintained until the follow-up period (F = 15.23, p < 0.001, d = 1.43). This outcome was supported by an improvement of secondary endpoints at week 8: Beck Anxiety Inventory (F = 8.38, p < 0.001, d = 0.93), Ego-Integrity Questionnaire (F = 19.60, p < 0.001, d = 1.32), Questionnaire for Positive and Negative Spontaneous Thoughts (F = 9.95, p < 0.001, d = 1.07), Gratitude Questionnaire (F = 12.71, p < 0.001, d = 1.09), Cognitive Behavioural Avoidance Scale (F = 18.26, p < 0.001, d = 1.50), Reminiscence Functions Scale (identity, F = 7.93, p < 0.001, d = 0.93; problem-solving, F = 5.88, p = 0.004, d = 0.85), Short Form Health Survey (36) (mental, F = 8.41, p < 0.001, d = 1.11), General Self-Efficacy Scale (F = 9.44, p < 0.001, d = 0.89), Multidimensional Mood State Questionnaire. For the Short Form Health Survey (36) (physical, F = 0.17, p = 0.84, d = 0.11) and other subgroups of the Reminiscence Functions Scale (death preparation, bitterness revival, boredom reduction, intimacy, conversation, and teach) no differences were observed. EABW was able to achieve a significant and lasting treatment success. This approach may represent an innovative concept to prevent worsening of depressive symptoms, improve anxiety and quality of life. The gentle use of the horse as a medium turned out to be very effective in achieving therapeutic results and acted as a kind of gateway for therapeutic processes. German Clinical Trials Register DRKS00017010. Registered on 01 April 2019.