Combining AI and human support in mental health: a digital intervention with comparable effectiveness to human-delivered care

Background Escalating global mental health demand exceeds existing clinical capacity. Scalable digital solutions will be essential to expand access to high-quality mental healthcare for everyone. This study evaluated a structured, evidence-based digital program for mild, moderate and severe anxiety that combined an Artificial Intelligence (AI) driven conversational agent to deliver content with human clinical oversight and user support to maximize outcomes.

This study aimed to measure engagement, clinical effectiveness, acceptability and safety of this digital intervention in comparison to externally generated comparator groups.

All prospective participants (N=299) were given the digital intervention to use for up to 9 weeks. Endpoints for effectiveness, engagement, acceptability, and safety were collected before, during and after the intervention, and at one-month follow-up. Adherence and effectiveness were compared to three propensity-matched real-world patient comparator groups: i) waiting control; ii) face-to-face cognitive behavioral therapy (CBT); and iii) remote typed-CBT.

Participants used the program for a median of 6 hours over 53 days. There was a large clinically meaningful reduction in anxiety symptoms for the intervention group (per-protocol (PP; n=169): change on GAD-7 = –7.4, d = 1.6; intention-to-treat (ITT; n=299): change on GAD-7 = –5.4, d = 1.1) that was statistically superior to the waiting control (PP: d = 1.3; ITT: d = 0.8), non-inferior to human-delivered care, and was sustained at one-month follow-up.

By combining AI and human support, the digital intervention achieved clinical outcomes comparable to human-delivered care while significantly reducing the required clinician time by up to 8 times. These findings highlight the potential of technology to scale effective evidence-based mental healthcare, address unmet need, and ultimately impact quality of life and economic burden globally. Competing Interest Statement Chief Investigator (EMa) and other investigators (CEP, EMi, GW, MPE, EC, SL, AS, CH, JY, MB, LM, SM, RC, VT, AC, AW, AB) are employees of ieso Digital Health Limited (the company funding this research) or its subsidiaries. None of these authors had a direct financial incentive related to the results of this study or the publication of the manuscript. Clinical Trial ISRCTN ID: 52546704 Funding Statement This research was funded by ieso Digital Health Ltd. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: NHS Research Ethics Committee (REC) West of Scotland REC 4 gave ethical approval for this research (IRAS ID: 327897) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes Table 3 updated to include between-subject effects; Discussion revised to increase clarity around limitations; Supplementary table 3 updated to include more details around statistical findings; Supplementary table 6 expanded into two tables and post-hoc chi-squared tests added