AI-generated vs. human therapist feedback in internet-based CBT for social anxiety disorder: A six-arm randomized controlled trial with deception design
In brief
In 263 adults, AI and human feedback showed similar anxiety reductions
In this trial, psychologist-reviewed AI feedback and human therapist feedback were not statistically different in reducing social anxiety, while active treatment produced large improvements compared with waitlist. The study did not establish that AI feedback was non-inferior, so the results do not prove the approaches are interchangeable; participants initially rated treatment as more credible when they expected human feedback.
- Journal
- Internet interventions (Q1)
- Published
- 16 October 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Jón Ingi Hlynsson, Gerhard Andersson, Per Carlbring
- PMID
- 42935939
- DOI
- 10.1016/j.invent.2026.101012
Why clinicians should know about it
- Picked for Health Informatics (paper of the day, 29 October 2026): AI‑generated vs human therapist feedback in internet CBT
Abstract
INTRODUCTION: Guided internet-delivered cognitive behavioral therapy (ICBT) is effective for social anxiety disorder (SAD), but therapist-delivered feedback limits its scalability. Whether AI-generated feedback can match human feedback, and whether patients' expectations about the source shape outcomes is unknown. METHOD: In a six-arm randomized controlled trial, 263 adults with SAD received psychologist-reviewed AI-generated or human feedback. They were told it came from a human or an AI which was correct or incorrect information (four fully crossed feedback arms), or were allocated to unguided self-help or a waitlist. The Social Phobia Inventory (SPIN) was analyzed using linear mixed models, complemented by Bayesian estimation. Secondary outcomes included therapeutic alliance, treatment credibility, negative effects, depression, and anxiety. RESULTS: Active treatment yielded large reductions in social anxiety relative to waitlist (d = -1.23). Before treatment, participants rated it as more credible when they expected feedback from a human rather than AI. AI and human feedback did not however statistically differ in symptom reduction (d = 0.10, 95% CI [-3.62, 5.91]); non-inferiority was not established. Neither the actual source, participants' beliefs, nor their congruence influenced symptoms or alliance. Depression, anxiety, and negative effects did not differ by source. Stronger alliance predicted subsequent symptom reduction, but not the reverse. CONCLUSIONS: Psychologist-reviewed AI-generated feedback yielded reductions in social anxiety symptoms that did not differ significantly from human feedback, without greater harm, and despite participants' initial expectation that AI would be less credible. The barrier to AI-supported ICBT may therefore lie in expectations rather than outcomes. TRIAL REGISTRATION: ISRCTN11343758.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.