VISHC at PsyDefDetect: Mitigating Data Scarcity in Psychological Defense Classification with Context-Aware Synthetic Augmentation

Hoang-Thuy-Duong Vu, Quoc-Cuong Pham, Huy-Hieu Pham


Abstract
Psychological defense mechanisms (PDMs) are unconscious cognitive processes that modulate how individuals perceive and respond to emotional distress. Automatically classifying PDMs from text is clinically valuable but severely hindered by data scarcity and class imbalance, challenges which generative augmentation alone cannot resolve without psychological grounding. In this work, we address these challenges in the PsyDefDetect shared task (BioNLP@ACL 2026) by proposing a context-aware synthetic augmentation framework combined with a hybrid classification model. Our hybrid model integrates contextual language representations with basic clinical features, along with 150 annotated defense items. Experiments demonstrate that definition quality in prompting directly governs generation fidelity and downstream performance. Our method surpasses DMRS Co-Pilot, reaching an accuracy of 58.26% (+40.25%) and a macro-F1 of 24.62% (+15.99%), thereby establishing a strong baseline for psychologically grounded defense mechanism classification in low-resource settings. Source code is available at: https://github.com/htdgv/CASA-PDC.
Anthology ID:
2026.bionlp-2.12
Volume:
Proceedings of the BioNLP 2026 (Shared Tasks)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Deepak Gupta, Dina Demner-Fushman
Venues:
BioNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
77–86
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.bionlp-2.12/
DOI:
Bibkey:
Cite (ACL):
Hoang-Thuy-Duong Vu, Quoc-Cuong Pham, and Huy-Hieu Pham. 2026. VISHC at PsyDefDetect: Mitigating Data Scarcity in Psychological Defense Classification with Context-Aware Synthetic Augmentation. In Proceedings of the BioNLP 2026 (Shared Tasks), pages 77–86, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
VISHC at PsyDefDetect: Mitigating Data Scarcity in Psychological Defense Classification with Context-Aware Synthetic Augmentation (Vu et al., BioNLP 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.bionlp-2.12.pdf
Supplementarymaterial:
 2026.bionlp-2.12.SupplementaryMaterial.txt