824114b19c7a8265f620bf 20260221042305726 hyperscienceij@gmail.com:rcrl hyperscienceij@gmail.com WEB-FORM Hyperscience in Psychology & Social Science HPSS 31158625 03 2026 2 1 Independent Researcher, Tokyo, Japan H Nakamura The concept of mental disorder remains one of the most philosophically complex and clinically significant constructs in psychiatry. Although international classification systems such as ICD-11 and DSM-5-TR provide operational definitions, fundamental conceptual ambiguities persist regarding the distinction between pathology, cultural variation, and socially deviant behavior. In Japan, where psychiatric practice primarily follows the ICD system and cultural context plays a central role in shaping normative expectations, definitional clarity is particularly important. This article develops a strengthened conceptual framework grounded in three interdependent criteria: culturally contextualized deviation, harmfulness, and epistemic incomprehensibility requiring professional explanatory systems. Through theoretical analysis and integration of philosophy of psychiatry, cultural psychology, and Japanese sociocultural considerations, the study proposes a refined descriptive definition of mental disorder. The model clarifies the boundary between pathology and rationally intelligible misconduct while maintaining compatibility with contemporary psychiatric practice. 03 2026 1 4 10.55672/hpss2026pp16_23 https://hscience.org/index.php/hpss/article/view/189