Examining the foundational assumptions of the hierarchical taxonomy of psychopathology

The Hierarchical Taxonomy of Psychopathology (HiTOP) emerged to address critical shortcomings inherent to traditional psychiatric classification systems such as the Diagnostic and Statistical Manual of Mental Disorders and International Classification of Diseases, notably their categorical structure, high comorbidity across categories, and within-diagnosis heterogeneity. HiTOP adopts an empirically derived, dimensional, and hierarchical approach, organizing psychopathological phenomena based on their patterns of observed covariation. This paper explores essential conceptual and philosophical considerations around HiTOP, examining its theoretical assumptions about dimensionality and hierarchy, the nature and interpretation of latent variables, the notion of psychopathology, considerations around validity, and the role of epistemic and non-epistemic values in shaping scientific objectivity. HiTOP is a descriptive model based on quantitative evidence (such as taxometric and factor-analytic approaches), but it is also a nosological project that exists within a particular sociocultural and historical context. As an illustration of the role of values, the applicability of HiTOP to marginalized minority populations is discussed, highlighting ongoing efforts toward ensuring inclusivity and representational equity. By addressing these conceptual foundations, this paper lays groundwork essential for future philosophical inquiry, empirical research, and practical applications of the HiTOP framework.