Self-Stigma Is Not a Monolith, but Generic Empathy Is: Persona-Conditioned LLM Support for People Who Use Drugs

A proof-of-concept study presents a persona-aware approach to LLM support for people who use drugs (PWUD), based on a four-persona typology derived from Latent Profile Analysis of self-stigma expressions on Reddit. The study demonstrates that sequential Bayesian and recurrent neural classifiers can effectively identify these personas, achieving a macro-F1 score of 0.74 with only 30 posts, outperforming traditional LLM baselines. The findings highlight a tension between persona-matched responses that drive behavioral change and the preference for generic empathy in evaluations, indicating the need for nuanced assessment rubrics in LLM-based stigma support.