Anonpsy: A Graph-Based Framework for Structure-Preserving De-identification of Psychiatric Narratives

Kyungho Lim, Byung-Hoon Kim


Abstract
Psychiatric narratives encode patient identity not only through explicit identifiers but also through idiosyncratic life events embedded in clinical structure. Existing de-identification approaches, including PHI masking and LLM-based synthetic rewriting, operate at the text level and offer limited control over which semantic elements are preserved or altered. We introduce Anonpsy, a de-identification framework that reformulates the task as graph-guided semantic rewriting. Anonpsy (1) converts each narrative into a semantic graph encoding clinical entities, temporal anchors, and typed relations; (2) applies graph-constrained perturbations that modify identifying context while preserving clinical structure; and (3) regenerates text via graph-conditioned LLM generation. Evaluated on 90 clinician-authored psychiatric case narratives, Anonpsy preserves diagnostic fidelity while achieving consistently low re-identification risk under expert, semantic, and GPT-5-based evaluations. Compared with a strong LLM-only rewriting baseline, Anonpsy yields substantially lower semantic similarity and identifiability. These results demonstrate that explicit structural representations combined with constrained generation provide an effective approach to de-identification for psychiatric narratives.
Anthology ID:
2026.findings-acl.963
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
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Findings
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Publisher:
Association for Computational Linguistics
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Pages:
19288–19311
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.963/
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Cite (ACL):
Kyungho Lim and Byung-Hoon Kim. 2026. Anonpsy: A Graph-Based Framework for Structure-Preserving De-identification of Psychiatric Narratives. In Findings of the Association for Computational Linguistics: ACL 2026, pages 19288–19311, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Anonpsy: A Graph-Based Framework for Structure-Preserving De-identification of Psychiatric Narratives (Lim & Kim, Findings 2026)
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