What works for whom with telemental health? A rapid realist review
Authors: Schlief Merle , Saunders Katherine R K , Appleton Rebecca , Barnett Phoebe , Vera San Juan Norha , Foye Una , Olive Rachel Rowan , Machin Karen , Shah Prisha , Chipp Beverley , Lyons Natasha , Tamworth Camilla , Persaud Karen , Badhan Monika , Black Carrie-Ann , Sin Jacqueline , Riches Simon , Graham Tom , Greening Jeremy , Pirani Farida , Griffiths Raza , Jeynes Tamar , McCabe Rose , Lloyd-Evans Bryn , Simpson Alan , Needle Justin J , Trevillion Kylee , Johnson Sonia 
Published: March 2022

Background: Telemental health (delivering mental health care via video calls, telephone calls or text messages) is increasingly widespread. Telemental health appears to be useful and effective in providing care to some service users in some settings, especially during an emergency restricting face-to-face contact such as the COVID-19 pandemic. However, important limitations have been reported, and telemental health implementation risks reinforcing pre-existing inequalities in service provision. If it is to be widely incorporated in routine care, a clear understanding is needed of when and for whom it is an acceptable and effective approach, and when face-to-face care is needed.
Objective: The aim of this rapid realist review was to develop theory about which telemental health approaches work, or do not work, for whom, in which contexts and through what mechanisms.
Methods: Rapid realist reviewing involves synthesising relevant evidence and stakeholder expertise to allow timely development of context-mechanism-outcome (CMO) configurations in areas where evidence is urgently needed to inform policy and practice. The CMOs encapsulate theories about what works for whom, and by what mechanisms. Sources included eligible papers from (a) two previous systematic reviews conducted by our team on telemental health, (b) an updated search using the strategy from these reviews, (c) a call for relevant evidence, including "grey literature", to the public and key experts, and (d) website searches of relevant voluntary and statutory organisations. CMOs formulated from these sources were iteratively refined, including through (a) discussion with an expert reference group including researchers with relevant lived experience and front-line clinicians and (b) consultation with experts focused on three priority groups: 1) children and young people, 2) users of inpatient and crisis care services, and 3) digitally excluded groups.
Results: A total of 108 scientific and grey literature sources were included. From our initial CMOs, we derived 30 overarching CMOs within four domains: 1) connecting effectively; 2) flexibility and personalisation; 3) safety, privacy and confidentiality; and 4) therapeutic quality and relationship. Reports and stakeholder input emphasised the importance of personal choice, privacy and safety, and therapeutic relationships in telemental health care. The review also identified particular service users likely to be disadvantaged by telemental health implementation, and a need to ensure that face-to-face care of equivalent timeliness remains available. Mechanisms underlying successful and unsuccessful application of telemental health are discussed.
Conclusions: Service user choice, privacy and safety, the ability to connect effectively and fostering strong therapeutic relationships, need to be prioritised in delivering telemental health care. Guidelines and strategies co-produced with service users and frontline staff are needed to optimise telemental health implementation in real-world settings.

MS and KRKS are joint first authors.