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Retrieval-Augmented Generation in Mental Health: A Systematic Review

Fransson E

2026

Abstract

Abstract Background: Retrieval-augmented generation (RAG) grounds large language model outputs in external knowledge. Systematic reviews have examined RAG in healthcare and generative AI in mental health as separate topics.

Objective:: To systematically identify and synthesize empirical studies applying RAG to mental health, stress, anxiety, depression, psychological assessment, and digital therapeutics.

Methods:: Searches followed PRISMA 2020 reporting guidelines.20 PubMed was searched on 4 July 2026 (56 records). Additional records were identified through IEEE Xplore, ACM Digital Library, Scopus, Web of Science, and forward/backward citation tracking. One reviewer (E.F.) screened records, extracted data, and assessed study quality using a structured LLM-RAG framework adapted from prior reviews, with verification steps described in Methods. Outcomes were too heterogeneous for valid quantitative pooling; synthesis was qualitative.

Results:: Fifteen studies met inclusion criteria (2022–2026). Naïve RAG was reported in 5 studies, advanced RAG in 7, and modular RAG in 3. Depression and general psychological distress were the most common conditions. Six studies reported direct RAG-versus-baseline comparisons with published metrics; in each, RAG or knowledge-augmented configurations outperformed the stated comparator on the study's primary reported outcome. Crisis-management documentation appeared in 2 studies. No included study indexed multimodal behavioral, VR, or wearable…

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