Chronic stress in relation to clinical burnout: an integrative scoping review of definitions and measurement approaches.

Background: Since its introduction, the definition and diagnosis of burnout remain controversial. Although the literature distinguishes between severe clinical burnout, characterized by debilitating symptoms and prolonged recovery, and milder burnout complaints in generally healthy employees, unclear diagnostic criteria hinder reliable differentiation. As clinical burnout is often framed as an outcome of chronic stress, clarifying how chronic stress is defined and measured is crucial to improve the understanding, diagnosis, and distinction of clinical burnout. Objective: This scoping review synthesizes results from systematic reviews using an integrative approach. It examines how chronic stress is defined and measured, from psychosocial, biological, and biopsychosocial perspectives. Additionally, it explores the discriminative value of these measurement approaches in identifying individuals at risk of chronic stress-related disorders and in diagnosing clinical burnout. Methods: A systematic search was performed on April 9th, 2024, and updated on July 8th, 2025 (PsychInfo, Embase, Medline and PubMed), following the PRISMA-ScR guidelines. The search identified 2,645 abstracts, 219 were included for full text screening, and 45 reviews were analyzed, covering over 2000 studies. Results: Across reviews, definitions of chronic stress varied, referring to either internal and external stressors or to stress responses. Measurements ranged from biomarkers and psychosocial scales to downstream health outcomes, such as burnout. In evaluating their discriminative value, chronic stress was consistently associated with HPA-axis dysregulation, immune impairment, autonomic imbalance, and elevated allostatic load, validating the biopsychosocial model of chronic stress. Sleep and cognitive deficits emerged as both causes, consequences, and maintaining factors of chronic stress. Among psychosocial instruments, the Burnout Assessment Tool (BAT) demonstrated the strongest psychometric properties, showing superior ability to distinguish individuals at risk of burnout from healthy controls. However, no single biomarker or questionnaire demonstrated sufficient accuracy to diagnose clinical burnout. Conclusion: No agreed-upon definition of chronic stress was found, nor is there consensus on how it should be measured. This lack of conceptual clarity hampers reliable diagnosis of clinical burnout. Progress in diagnosing and treating clinical burnout requires moving beyond single-cause diagnostics toward integrative biopsychosocial frameworks, such as system dynamics theory, that capture the complex, evolving nature of chronic stress and provide a foundation for more accurate diagnosis and treatment.