Psychological Capacity Compression: Reframing Common Mental Disorders as Symptoms of Overload-A Theory of Change for Primary Care

Mental health conditions are major contributors to global disability and are commonly encountered in primary care, often alongside chronic medical diseases. Despite their high prevalence, conditions such as depression and anxiety disorders are frequently under-recognised and treated as separate diagnostic entities, leading to fragmented care and suboptimal outcomes.1 This paper proposes psychological capacity compression as a unifying, transdiagnostic mechanism underlying depression and anxiety in primary care, conceptualising these conditions not as distinct diseases but as symptomatic expressions of a shared state of cumulative psychological overload, consistent with contemporary transdiagnostic models.2-4 Psychological capacity compression reflects reduced well-being-related neurobiological activity (often described as happiness-related pathways) with heightened stress-hormone activation (cortisol and adrenaline) due to chronic hypothalamic-pituitary-adrenal axis stimulation, explaining heterogeneous psychological and somatic presentations in primary care and their parallel improvement when neurobiological balance is restored.5,6 This conceptual model provides the theoretical foundation for the AlKhathami Five-Step Patient Interview Approach, reframing the traditional biopsychosocial perspective by replacing its psychosocial components with a biologically informed five-step clinical framework (the Bio-Five-Step Approach). By targeting psychological capacity compression as the core process, the approach supports early identification, rational clinical decision-making, and effective integration of mental healthcare into routine primary care practice.6,7 Restoration of psychological capacity re-establishes adaptive regulation across psychological and physiological systems and is commonly experienced as peace of mind.