transformer_1376 at PsyDefDetect: A QLoRA-Based Generative Framework for Context-Aware Psychological Defense Mechanism Detection

Pritha Saha, Shuvodwip Saha, Anik Mahmud Shanto


Abstract
Psychological defense mechanisms play a cru-cial role in shaping human responses duringemotionally charged conversations, yet remainunderexplored in natural language processing.In this work, we address the PSYDEFCONVshared task, which involves classifying defensemechanisms in multi-turn dialogues using clin-ically grounded annotations based on the De-fense Mechanism Rating Scales (DMRS). Wepropose a generative supervised fine-tuningframework that reformulates the task as con-ditional text generation. A pre-trained causallanguage model (Gemma-2-2B) is adapted us-ing parameter-efficient fine-tuning (PEFT) with4-bit quantization, enabling efficient trainingunder limited computational resources. To han-dle class imbalance, we apply random oversam-pling, and we design a prompt-based input rep-resentation to incorporate conversational con-text effectively. Experimental results demon-strate that our generative approach is compet-itive with discriminative baselines while of-fering improved flexibility in modeling sub-tle and context-dependent defensive behaviors.The findings highlight the potential of genera-tive large language models for psychologicallygrounded dialogue understanding tasks.
Anthology ID:
2026.bionlp-2.15
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
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Publisher:
Association for Computational Linguistics
Note:
Pages:
99–103
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URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.bionlp-2.15/
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Cite (ACL):
Pritha Saha, Shuvodwip Saha, and Anik Mahmud Shanto. 2026. transformer_1376 at PsyDefDetect: A QLoRA-Based Generative Framework for Context-Aware Psychological Defense Mechanism Detection. In Proceedings of the BioNLP 2026 (Shared Tasks), pages 99–103, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
transformer_1376 at PsyDefDetect: A QLoRA-Based Generative Framework for Context-Aware Psychological Defense Mechanism Detection (Saha et al., BioNLP 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.bionlp-2.15.pdf
Supplementarymaterial:
 2026.bionlp-2.15.SupplementaryMaterial.txt