Evidence map›Paper›PMID 40948070›Full record

ArticleWorld psychiatry : official journal of the World Psychiatric Association (WPA)2025

Charting the evolution of artificial intelligence mental health chatbots from rule-based systems to large language models: a systematic review.

Yining Hua, Steve Siddals, Zilin Ma, Isaac Galatzer-Levy, Winna Xia, Christine Hau, Hongbin Na, Matthew Flathers, Jake Linardon, Cyrus Ayubcha and 1 more

Abstract read
In one paragraph

Article in World psychiatry : official journal of the World Psychiatric Association (WPA), 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 31 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
31citing papers in PubMed, 2 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

31 citing papers in PubMed, 2 syntheses or guidelines pooled it.

  1. Pooled it
  2. Pooled it
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  14. Ethical Considerations in Personal Health Large Language Models.Journal of medical Internet research · 2026
    Article
  15. Review
  16. Article
  17. A framework for clinical validation of generative artificial intelligence therapeutics.World psychiatry : official journal of the World Psychiatric Association (WPA) · 2026
    Article
  18. Exploring Student Perceptions of Generative AI Therapists and Their Benefits and Challenges in Schools.International journal of psychology : Journal international de psychologie · 2026
    Article
  19. Article
  20. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

11 authors.

Yining HuaDepartment of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Steve SiddalsBeth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Zilin MaIntelligent Interactive Systems Group, Harvard School of Engineering and Applied Sciences, Allston, MA, USA.
Isaac Galatzer-LevyDepartment of Psychiatry, New York University Grossman School of Medicine, New York, NY, USA.
Winna XiaBeth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Christine HauBeth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Hongbin NaAustralian Artificial Intelligence Institute, University of Technology Sydney, Sydney, NSW, Australia.
Matthew FlathersBeth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Jake LinardonSEED Lifespan Strategic Research Centre, School of Psychology, Faculty of Health, Deakin University, Geelong, VIC, Australia.
Cyrus AyubchaSEED Lifespan Strategic Research Centre, School of Psychology, Faculty of Health, Deakin University, Geelong, VIC, Australia.
John TorousBeth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The rapid evolution of artificial intelligence (AI) chatbots in mental health care presents a fragmented landscape with variable clinical evidence and evaluation rigor. This systematic review of 160 studies (2020-2024) classifies chatbot architectures - rule-based, machine learning-based, and large language model (LLM)-based - and proposes a three-tier evaluation framework: foundational bench testing (technical validation), pilot feasibility testing (user engagement), and clinical efficacy testing (symptom reduction). While rule-based systems dominated until 2023, LLM-based chatbots surged to 45% of new studies in 2024. However, only 16% of LLM studies underwent clinical efficacy testing, with most (77%) still in early validation. Overall, only 47% of studies focused on clinical efficacy testing, exposing a critical gap in robust validation of therapeutic benefit. Discrepancies emerged between marketed claims ("AI-powered") and actual AI architectures, with many interventions relying on simple rule-based scripts. LLM-based chatbots are increasingly studied for emotional support and psychoeducation, yet they pose unique ethical concerns, including incorrect responses, privacy risks, and unverified therapeutic effects. Despite their generative capabilities, LLMs remain largely untested in high-stakes mental health contexts. This paper emphasizes the need for standardized evaluation and benchmarking aligned with medical AI certification to ensure safe, transparent and ethical deployment. The proposed framework enables clearer distinctions between technical novelty and clinical efficacy, offering clinicians, researchers and regulators ordered steps to guide future standards and benchmarks. To ensure that AI chatbots enhance mental health care, future research must prioritize rigorous clinical efficacy trials, transparent architecture reporting, and evaluations that reflect real-world impact rather than the well-known potential.

Indexed as

Artificial intelligencechatbotsclinical efficacy testingfoundational bench testinglarge language modelsmachine learningmental health carepilot feasibility testingrule‐based systems

Identifiers

PMID40948070
PMCPMC12434366

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.