LLMs as Standardised Patients for Motivational Interviewing: How Faithful Are They?

Van Hoang, Eoin Rogers, Robert Ross


Abstract
Recent advances in large language models (LLMs) have enabled the creation of highly realistic digital patients across a broad range of clinical scenarios, yet systematic evaluation of such simulations remains challenging due to a lack of standardised methodology. This paper investigates the faithfulness of LLM-simulated patients within motivational interviewing contexts. We directly compare the properties of data generated by simulated and human patients given identical profiles, rather than relying on subjective user experiences. Our findings reveal that while simulated and human patients produce semantically similar content and engage with comparable topics, their modes of expression differ substantially. LLM-simulated patients struggle to reproduce the full complexity of human behaviours and attitudes. While human patients exhibit a mix of positive and negative responses, LLM patients skew toward uniformly ones.
Anthology ID:
2026.clpsych-1.21
Volume:
Proceedings of the 10th Workshop on Computational Linguistics and Clinical Psychology (CLPsych 2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Aya Zirikly, Kfir Bar, Sean MacAvaney, Molly Ireland, Yaakov Ophir, Dana Atzil-Slonim, Vasudha Varadarajan, Steven Bedrick, Bart Desmet
Venues:
CLPsych | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
258–270
Language:
URL:
https://aclanthology.org/2026.clpsych-1.21/
DOI:
Bibkey:
Cite (ACL):
Van Hoang, Eoin Rogers, and Robert Ross. 2026. LLMs as Standardised Patients for Motivational Interviewing: How Faithful Are They?. In Proceedings of the 10th Workshop on Computational Linguistics and Clinical Psychology (CLPsych 2026), pages 258–270, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
LLMs as Standardised Patients for Motivational Interviewing: How Faithful Are They? (Hoang et al., CLPsych 2026)
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PDF:
https://aclanthology.org/2026.clpsych-1.21.pdf