How does an English-language pop-psychology term become a commonly used mental health idiom in Japan, decades after its coinage? Based on twenty months of ethnographic fieldwork in Tokyo at Raku-no-Kai, a nonprofit supporting people navigating social withdrawal and related distress, this article traces the local uptake of “Highly Sensitive Person” (HSP) as a vocabulary for narrating vulnerability in everyday life. I argue that HSP functions as an emergent idiom of distress (Nichter, 1981, 2010): a flexible, morally workable language (Myers, 2015) through which people make sensitivity speakable, and at times care-able, without fully submitting to psychiatric diagnosis. Situating HSP within the infrastructures that enabled its spread—digital platforms, self-help publishing, and therapeutic media—I trace the conditions under which sensitivity became newly available as a personal disposition and socially legible form of suffering. The COVID-19 pandemic intensified this process by creating a rare public moment in which strain, withdrawal, and emotional overwhelm became broadly discussable rather than privately borne. Yet HSP’s very looseness also produces friction in clinical encounters, where it can draw people into care while failing to translate cleanly into diagnostic categories. In tracing HSP across peer spaces, media circuits, and the clinic, this article contributes to anthropological debates on idioms of distress, psychiatric legibility, and the contemporary social lives of psychological categories.
