multiple guidelines in place for the administration of SDM addressed for nursing home managers, nursing home managers specialized for dementia, and adult guardians. MHLW. 2025. "Guidelines for Supported Decision-Making. "in Japanese. https: //www. mhlw. go. jp/stf/seisakunitsuite/bun-ya/0000202622₀0026. html. 6) Nakayama, Shigeki. 2024. "Consent and Intimate Relationships in Medical Care: From the constitutional perspective of 'respect for the individual' (1) " in Japanese. 34 3 (2026) 128 are subject to variation based on medical institutional practices and professional judgment. This inconsistency underscores the need for legal norms that offer clearer and more enforceable mechanisms for ethical healthcare decision-making. The adult guardianship system serves as the primary legal framework for substituted decision-making in Japan. Adult guardians are not legally authorized to make healthcare decisions on behalf of individuals deemed legally incapacitated. However, de facto coordination between adult guardians and healthcare providers may occur in practice, particularly in cases involving moderate decisions. 7) Informal consent is often obtained from family members who lack formal legal authority, creating ambiguity for both healthcare professionals and patients. Although this practice aligns with Japan's cultural emphasis on familial involvement, it risks undermining individual rights and may lead to conflicts of interest or coercion. 8) ADs and living wills have been proposed as mechanisms to preserve individual autonomy in anticipation of incapacity. These tools allow individuals to articulate treatment preferences, particularly concerning life-sustaining interventions. However, in Japan, their legal status remains vague, as there is no national legislation explicitly validating or enforcing ADs. Although some local governments and medical associations voluntarily promote their use, 9) the absence of legal clarity inhibits broader adoption, particularly in situations involving family opposition or institutional hesitancy. Japanese healthcare decision-making is further shaped by cultural norms that 7) Ito, Ayumi and Kae Ito.
幸男 櫻井 (Fri,) studied this question.