Mental Disorder as Constraint Dysregulation: A Constraint-Theoretic Account of Psychopathology, Nosology, and Therapeutic Change

The philosophy of psychopathology faces a foundational problem: no existing account provides a principled, unified characterisation of what mental disorder is that is neither purely biological, purely normative, nor purely statistical, while remaining applicable across the full range of diagnostic categories and integrating the biological, psychological, and social levels at which mental disorder manifests. Wakefield’s harmful dysfunction analysis correctly identifies dysfunction as central but cannot ground the concept of natural function without circularity. The biopsychosocial model correctly identifies the multi-level character of psychopathology but lacks a unifying structural principle. The DSM and ICD classification systems provide operationally useful symptom clusters but rest on no coherent ontological foundation. This paper proposes that Constraint Theory (CT) — the thesis, established by transcendental argument, that constraint is the ontological primitive constitutive of determinate existence as such — provides that foundation. Mental health, on the CT account, is the condition of appropriate constraint calibration: the maintenance of constraint structures at cognitive, affective, behavioural, and interpersonal levels that are sufficiently determinate to constitute a coherent self and enable goal-directed action, yet sufficiently flexible to respond adaptively to novel constraint environments. Mental disorder is constraint dysregulation: systematic deviation from appropriate constraint calibration in the direction of either excess constraint (rigidity, repetition, foreclosed possibility) or constraint insufficiency (dissolution, disorganisation, loss of coherent selfhood). This account dissolves the demarcation problem by providing a structural criterion for dysfunction that does not depend on contested notions of natural function or statistical norms. It unifies apparently heterogeneous diagnostic categories under a single structural principle. It integrates biological and psychological levels through structural homology rather than reductive identity. It connects naturally to the predictive processing account of psychopathology, interpreting prediction-error dysregulation as a specific form of constraint propagation failure. And it provides a principled foundation for dimensional rather than categorical psychiatric nosology. The paper develops each of these contributions in detail and addresses the principal objections.