Bridging Ethology, Somatics, and Attachment: The Equine Post-Traumatic Stress, Somatic & Attachment Scale (EPTS-SA™) as a Clinical Diagnostic Framework

Conventional equine behavioral assessments frequently conflate neurobiological trauma responses with voluntary disobedience, leading to coercive interventions that exacerbate autonomic dysregulation. Domestic management practices—characterized by premature industrial weaning, spatial isolation, and mechanical restraint—routinely induce developmental attachment disruptions and chronic sympathetic or dorsal vagal states in equines. Existing clinical instruments, such as the Horse Grimace Scale (HGS), quantify acute nociceptive pain but fail to account for centralized affective trauma, attachment injuries, or dissociative shutdown. This paper introduces the Equine Post-Traumatic Stress, Somatic & Attachment Scale (EPTS-SA™), a multi-vector clinical diagnostic framework designed to quantify chronic stress, somatic holding patterns, and attachment neurobiology. Structured across six operationalized domains—(1) Developmental Trauma & Attachment Profile (DTA), (2) Autonomic Baseline & Recovery Dynamics (ABR), (3) Nociceptive Pain vs. Affective Trauma Differential (PDT), (4) Somatic Holding Patterns & Discharge Capacity (SHD), (5) Ethological Calming Signals & Signaling Flow (CSC), and (6) Interspecies Autonomic Resonance & Co-Regulation (ARC)—the EPTS-SA™ yields a cumulative score (0–24) mapped to five clinical severity tiers (Tiers 0–4). By integrating Jaak Panksepp’s subcortical affective neuroscience, Stephen Porges’ Polyvagal Theory, and somatic trauma paradigms, this framework provides veterinary clinicians, ethologists, and behavioral practitioners with a standardized, non-invasive methodology to differentiate acute pain from chronic nervous system trauma, assess developmental trauma, and guide neurobiologically informed rehabilitation.