2025
69 citations Research paper

Expressing stigma and inappropriate responses prevents LLMs from safely replacing mental health providers.

Jared Moore, Declan Grabb, William Agnew, Kevin Klyman, Stevie Chancellor, Desmond C. Ong,

Summary & key facts

Researchers asked whether large language models should be used as therapists. They first looked at therapy guides from major medical institutions to find what makes therapy work, like trust and a real connection between the therapist and client. Then they tested current language models, including gpt-4o, on realistic therapy conversations. They found the models sometimes showed stigma toward people with mental health problems and sometimes gave clearly wrong or harmful replies, such as encouraging a person's delusional thinking. These problems appeared even in newer, bigger models, which suggests current safety fixes do not solve them. The authors conclude that LLMs should not replace human

Key facts:
  • The team reviewed therapy guides from major medical institutions to identify key parts of a good therapeutic relationship, such as trust and a working alliance between therapist and client.
  • They ran experiments that put current LLMs, including gpt-4o, into realistic therapy-style conversations to see how the models would respond.
  • The models sometimes expressed stigma toward people with mental health conditions, which goes against medical best practices.
  • In some cases, models responded inappropriately to serious therapy situations, for example encouraging delusional thinking, which the authors link to the models' tendency to agree with users.
  • These problematic behaviors appeared even in larger and newer models, suggesting that existing safety methods do not fully prevent them.
  • The authors note that a true therapeutic alliance needs human characteristics like identity and personal stakes, which LLMs do not have.
  • Because of these findings and limitations, the authors conclude that LLMs should not replace human therapists and recommend discussing alternative, limited roles for LLMs in clinical care.

Abstract

Should a large language model (LLM) be used as a therapist? In this paper, we investigate the use of LLMs to *replace* mental health providers, a use case promoted in the tech startup and research space. We conduct a mapping review of therapy guides used by major medical institutions to identify crucial aspects of therapeutic relationships, such as the importance of a therapeutic alliance between therapist and client. We then assess the ability of LLMs to reproduce and adhere to these aspects of therapeutic relationships by conducting several experiments investigating the responses of current LLMs, such as `gpt-4o`. Contrary to best practices in the medical community, LLMs 1) express stigma toward those with mental health conditions and 2) respond inappropriately to certain common (and critical) conditions in naturalistic therapy settings -- e.g., LLMs encourage clients' delusional thinking, likely due to their sycophancy. This occurs even with larger and newer LLMs, indicating that current safety practices may not address these gaps. Furthermore, we note foundational and practical barriers to the adoption of LLMs as therapists, such as that a therapeutic alliance requires human characteristics (e.g., identity and stakes). For these reasons, we conclude that LLMs should not replace therapists, and we discuss alternative roles for LLMs in clinical therapy.

Topics

Mental Health and Psychiatry Mental Health Treatment and Access Obsessive-Compulsive Spectrum Disorders

Categories

Psychology Social Psychology Social Sciences

Tags

Computer science Internet privacy Mental health Psychiatry Psychology Stigma (botany)
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