Causality in medical liability and he prevailing standard of probability: between absolute certainty, legal imputation and proof of the causal link in psychiatric pathologies

Abstract

Medical liability faces one of its greatest challenges in establishing causation, particularly in cases involving scientific uncertainty, multifactorial disease etiology, and the inherent complexity of clinical practice. These circumstances make it difficult to demonstrate a direct causal relationship between the healthcare professional's conduct and the patient's injury. This study aimed to analyze the evolution of causation in medical liability and to assess the relevance of the preponderance of the evidence standard as a criterion for evaluating causation within the Colombian legal framework. A systematic literature review was conducted following the PRISMA guidelines, using major scientific databases to identify studies addressing medical liability, causation, standards of proof, and tort law.

The findings indicate that medical causation has evolved from being considered a purely factual issue to becoming an interdisciplinary legal problem that integrates tort law, evidentiary law, forensic medicine, bioethics, patient safety, and healthcare risk management. The review also reveals a gradual transition from traditional approaches based on absolute certainty toward evidentiary models grounded in the preponderance of the evidence, rational inference, dynamic allocation of the burden of proof, and loss of chance, particularly in cases characterized by informational asymmetry, multiple concurrent causes, and significant evidentiary difficulties. Furthermore, psychiatric disorders, injuries that are inherently difficult to prove, and the increasing use of emerging healthcare technologies, including artificial intelligence, intensify the complexity of causal attribution and require more flexible evidentiary standards.

The study concludes that the preponderance of the evidence standard provides a legally sound approach for addressing the epistemic limitations of contemporary medical science while ensuring effective judicial protection. Its progressive incorporation into Colombian medical liability law could promote a more balanced assessment of causation, strengthening both victims' access to justice and legal certainty for healthcare professionals through a comprehensive, rational, and context-sensitive evaluation of the available evidence.