Implementation, Adoption, and Perceptions of Telemental Health During the COVID-19 Pandemic: Systematic Review

1Since the onset of the COVID-19 pandemic in the first few months of 2020, most countries have experienced a severe disruption of mental health service delivery in its usual forms. Community-based outpatient, day and home treatment programs, prevention and mental health promotion programs, and services for specific age groups, such as older adults, children, and adolescents and people with substance misuse problems, have been among those severely affected at a time of potentially increased demand due to the adverse mental health consequences of the pandemic.

2Mental health care providers around the world responded to the disruption of services in many ways, including the significant and widely documented shift to remote delivery of mental health services to replace in-person consultations. Telemental health, defined as “the provision of behavioral and/or mental health care services using technological modalities in lieu of, or in addition to, traditional face-to-face methods”, including video conferencing, telephone, email or text messaging, has been central to continuing assessment and support in the community. Additionally, technological innovations are helping to address isolation and service disruption in hospital and residential settings.

3Multiple research studies conducted both before and during the pandemic have reported evidence of the effectiveness of telemental health in reducing treatment gaps and improving access to care for a range of service users. Findings from studies, often of telemental health programs established for purposes of research, have suggested that, overall, synchronous modalities such as video conferencing are comparable to face-to-face delivery in terms of quality of care, reliability of clinical assessments, and treatment outcomes and adherence. Good levels of service user acceptance and satisfaction with telemental health services have also been reported. Successful adoption of telemental health has been described across a wide range of populations (adult, child and adolescent, older people, ethnic minorities), settings (hospital, primary care, community), and conditions. For certain populations, including some with autism and severe anxiety disorders, and those with physical disabilities or geographical barriers to accessing services, telemental health can be preferable for some service users, although individuals experiencing significant social disadvantage or severe mental health problems, such as psychosis, have been found to benefit less. Research suggests that telemental health can also work for group interventions. The attitudes of clinicians who have delivered care via synchronous telemental health appear to be largely positive, with professionals finding it both effective and acceptable and recognizing its potential to enhance communication within and between mental health teams. There is also some positive health economic evidence, with several studies suggesting telemental health is no more expensive than face-to-face delivery and tends to be more cost-effective. This approach also appears to be a viable and inexpensive treatment option where access to emergency services is limited, and associations have been found with reduced psychiatric admissions.

4However, despite this evidence base, integration of telemental health approaches into routine mental health care or the widespread adoption of remote working across whole systems has rarely been reported. Even during the pandemic, adoption of such technologies has been piecemeal, with utilization varying substantially both between and within countries. Technological barriers to the wider adoption of telemental health include (1) the risk of digital exclusion of some service users, such as those facing significant social disadvantage or with limited technological access and expertise, and (2) the lack of technological infrastructure and clear protocols within services, impeding the integration of telemental health with face-to-face care. Other barriers include difficulty in establishing and maintaining therapeutic relationships and in conducting high-quality assessments; service users who lack private space or find participating in sometimes intimate and distressing discussions from home intrusive. A range of other ethical, regulatory, technological, cultural, and organizational barriers have also been identified, both before and during the pandemic.

5The widespread emergency adoption of telemental health since the onset of the pandemic has generated a substantial literature. Numerous commentaries, service evaluations and reports of telemental health innovations, and service user, carer and staff experiences, in addition to a growing number of research studies addressing effectiveness and implementation issues have been published internationally. Clinical guidelines have been rapidly produced in a number of countries.

6A synthesis of the relevant empirical evidence gathered during the pandemic is therefore timely and informative for planning by generating evidence of effects of adopting telemental health across whole populations and service systems rather than in the context of relatively small-scale research studies involving volunteer participants. Capturing the learning and experiences gained through the rapid shift to telemental health will help optimize remote health care in a population that presents unique relational challenges associated with mental distress. It will also help to understand and overcome implementation barriers and inform strategies for improving the flexibility, effectiveness, and efficiency of mental health services through the sustained integration into routine care of telemental health approaches, to ensure that it brings the greatest benefits for patients, carers, and staff.

7The aim of this review is to synthesize the international literature specific to remote working in mental health services (as a replacement for or in conjunction with face-to-face service delivery) in the context of early stages of the COVID-19 pandemic. The paper complements our previous umbrella review (systematic review of reviews) of literature on telemental health prior to the COVID-19 pandemic: focusing on the literature from the pandemic period allows us to identify specified learning from the very wide implementation that occurred during this period. Our research questions are as follows:

8What evidence has been obtained during the COVID-19 pandemic regarding the effectiveness and cost-effectiveness of telemental health and regarding its safety (including adverse events due to breaches of privacy and safety)?

9What coverage has been achieved through telemental health adoption in the pandemic (including extent of adoption by services and reach among clinical populations in which it is adopted); in which groups and for which service settings is telemental health more or less likely to be implemented successfully; what are potential risks associated with digital exclusion for those not reached; and what barriers and facilitators influence success in implementation?

10How acceptable are telemental health approaches to service users, carers, and staff as applied during the pandemic, including perceived impacts on therapeutic relationships, communication, and privacy?

11What innovations and improvements have been introduced to make clinical care via telemental health more effective and acceptable, achieve greater coverage, and address barriers to delivering care in this way? (This includes descriptions and evaluations of specific strategies designed to make telemental health work better than usual delivery, and of adaptations of telemental health to specific settings, such as inpatient wards and crisis services).

12A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The protocol for this review was registered with PROSPERO (CRD42021211025).

13Four electronic databases (PubMed, PsycINFO, CINAHL, and Web of Science), preprint servers medRxiv, PsyArXiv, Wellcome Open Research, and JMIR were searched for research relating to COVID-19, mental illness, and remote working from January 1 to December 9, 2020. An example search strategy can be found in Multimedia Appendix 1.

14This search was supplemented by searching the references listed in included studies for any additional studies that met our inclusion criteria.

15The resulting list of articles was deduplicated using Endnote and all references were imported into Rayyan for title and abstract screening. Full texts were sourced for articles deemed relevant for inclusion, and these were screened against the full review eligibility criteria. To establish consistency in study selection, title and abstract screening was conducted by 4 reviewers (MS, ZH, JH-S, and LSR), with 100% of included and 25% of excluded references checked by another reviewer (RA). Full texts were screened by 3 reviewers (RA, MB, and MS), with 100% of included and 25% of excluded papers checked by another reviewer (task divided between LG, HJ, JW, PB, and LSR). Any disagreements were resolved through team discussion.

16Staff working within the field of mental health, people receiving organized mental health care for any condition (including addictions, dementia, and intellectual disability), family members or carers of people receiving mental health care (regarding their views on the impact of remote working on the service user, and interventions aimed at reducing carer distress). There are no age restrictions on participants in this review.

17Any form of spoken or written communication carried out between mental health professionals or between mental health professionals and service users/family members/unpaid carers or peer support communications using the internet, the telephone, text messaging platforms, or hybrid approaches combining different platforms.

18Any mental health communication delivered face-to-face, digitally or remotely, waitlist control, or placebo. Studies comparing different modes of delivery during the pandemic, and those comparing care delivery and outcomes during the pandemic with those before the pandemic were included. Relevant studies with no comparator were also included.

19Qualitative and quantitative outcomes describing implementation effectiveness (including process evaluations) and barriers and facilitators to digital engagement, clinical effectiveness, cost-effectiveness, acceptability (including service user, carer, and staff satisfaction), impacts on communication and therapeutic relationships, coverage and impacts of digital exclusion, interventions to improve quality or coverage, improvements in quality of life, and economic impacts.

20Any papers that present qualitative or quantitative data from study designs of any type (including relevant service evaluations and case series). If the focus of the study was not solely remote working but the results section contained substantial data relevant to our research questions, these were also included. Any relevant reviews identified in the searches were checked for included research which met our inclusion criteria.

21We excluded studies that were (1) not specific to the pandemic response; (2) reporting on interventions with patients with primary sleep disorders; (3) reporting on those with subclinical symptoms (unless combined with another included mental health problem); (4) focused on digital interventions such as apps, websites, and virtual reality tools, except where the sole purpose of the digital intervention was to facilitate direct spoken or written communication; (5) focused on interventions aimed at improving the mental health or well-being of health care professionals; and (6) editorials, opinion pieces, guidance documents, protocols, conference abstracts, and letters, with the exception of editorials or letters which contained primary research findings.

22No language or location restrictions were applied in this review.

23Data extraction was supported by well-established implementation science frameworks. A data extraction form was developed based on a brief version of the Consolidated Framework for Implementation Research (CFIR) and the taxonomy of implementation outcomes. We used the higher-level CFIR constructs (see Table 2 in section Barriers and Facilitators to Telemental Health for a brief definition of each one of the implementation facets that CFIR constructs capture) to extract data on factors influencing implementation success, and the taxonomy of implementation outcomes including acceptability, adoption, and feasibility. We also extracted information deemed relevant based on previous studies conducted by the research team, including an umbrella review of pre-COVID-19 systematic reviews on telemental health and a qualitative study. Data extracted consisted of study details, including design and focus of study; gender, ethnicity, age; diagnosis of participants; details of staff occupation; setting and context of study; intervention details, implementation outcomes (including acceptability, adoption, appropriateness, feasibility, fidelity, cost effectiveness, penetration, and sustainability); barriers and facilitators to implementation; and clinical and safety outcomes. The full data extraction form can be viewed in Multimedia Appendix 1.

24Data extraction was completed by 9 reviewers (AP, JW, MS, ER, RA, MT, JM, SS, HJ, approximately 8 studies each) using EPPI-Reviewer 4. All reviewers were trained on how to extract data to ensure consistency, and extracted data were checked by a second reviewer (RA & NVSJ). The extraction form was first piloted on 9/77 (12%) of included studies to assess usability and content, with amendments made before completing extraction for the whole data set.

25Given the diversity of the included article types and methods, 2 quality appraisal tools were used. Primary research studies were assessed with the Mixed Methods Appraisal Tool (MMAT). Commentaries and service evaluations were assessed using AACODS (authority, accuracy, coverage, objectivity, date, significance) tool, which appraises the veracity, clarity, acknowledgement of bias, and relevance of the contribution to the field. Study quality was assessed by RA and verified by NVSJ. Disagreements were resolved through discussion.

26We conducted a framework synthesis of study characteristics and outputs. Study outcomes were tabulated by applying existing implementation science frameworks, that is, the CFIR framework, Proctor et al’s taxonomy of implementation outcomes; and also by relevant topics/themes that emerged during data extraction. This table-based synthesis of the study outcomes combined a deductive and inductive approach to data analysis by using existing frameworks, while identifying emerging themes. Results reported in this paper include a narrative synthesis of the study characteristics and quantitative study outputs and the tabulated results.

27A total of 3956 references were identified through searching databases of published papers. medRxiv was the only preprint database where included papers were found (n=10); 1 more relevant paper was identified by a member of the research team and a further paper was found through reference searching of included studies.

28A PRISMA flow diagram of the screening and selection process is presented in Figure 1.

29The quality of included primary research studies was moderate to high: 23 out of 48 studies appraised using the MMAT met above 80% of quality criteria, whereas 21 out of 48 met between 50% and 79%. The quality of included service evaluations or audits was generally high: 27 out of 29 studies appraised using the AACODS met at least 4 out of the 6 quality criteria assessed. These include being written by recognized experts; including reference lists; having a clear aim; stating details such as date, location, and limitations; and making a meaningful contribution to the research literature.

30Of the 77 studies which were eligible for inclusion in the review (Table 1), 45 were primary research studies, 24 were service evaluations or audits, and 8 were editorials or letters that included data. Thirty-three were conducted in the United States, 9 in the United Kingdom, and 5 each in Australia, Canada, and Spain. Five were conducted across more than 1 country.

31Of the 45 primary research studies, 32 involved staff and 9 involved service users. The remaining 4 analyzed service use data (3 evaluated contacts with hotlines and 1 evaluated service use in 1 UK National Health Service [NHS] service provider).

32Most studies were conducted in services that worked with people with mixed psychiatric diagnoses (n=30), although we also found studies conducted with groups with a single diagnosis (eg, dementia or eating disorders). Studies could include more than 1 service type, the most commonly studied being community mental health teams (CMHTs) or outpatient settings (n=39), followed by psychology or psychotherapy services (n=17). Inpatient or residential services were included in 15 studies, while 12 included general hospitals. Eight studies included private hospitals or clinics, while 4 explored telemental health use in helplines, voluntary sector services, crisis teams, or veterans’ health services, respectively. Five studies did not report any specific setting.

33The aims of most studies were either a description of changes made due to the pandemic, new services set up because of the pandemic, or an evaluation of the impact of the pandemic on either staff or service users. The descriptions of changes either focused specifically on the move to telemental health or were wider descriptions of changes to services including the use of telemental health. The characteristics of each of the included studies are shown in Table 1, with a more detailed summary in Multimedia Appendix 2.

34Implementation barriers and facilitators were categorized using a condensed version of the CFIR framework (see Table 2, where definitions of the CFIR constructs are also provided). The key findings are summarized below.

35Video and phone calls were the most common modalities used for remote care; studies also reported the use of emails, instant messaging services, apps, prerecorded videos and forums (further details about the modality used in each study can be found in Table 1).

36When comparing remote care with traditional face-to-face settings, studies identified advantages for both methods. Benefits for remote care included being more convenient (for both staff and service users), making care more accessible to groups who may previously have been excluded, reducing travel (resulting in both time and cost savings), and helping clinicians understand more about the service user, as they had more insight into their home lives. A further benefit is that more family members were readily able to attend family therapy or family education sessions since care was moved online (eg,). However, clinicians reported difficulties in picking up on nonverbal cues in remote compared with face-to-face care, and that remote care could sometimes require more concentration.

37Services commonly implemented remote methods of working due to “stay at home” orders or national lockdowns, or due to a high level of cases in their local area. Overall, all settings described in papers had sufficient capacity to make a rapid shift to remote forms of care. Several studies in the United States in particular mentioned the impact of health insurance regarding uptake of telemental health (eg,), as not all insurance providers covered remote care. However, this did change during the course of the pandemic as telemental health delivery was eased by the relaxation of policy and billing reimbursements. The change from face-to-face to remote delivery of care was also facilitated by professional societies who posted guidelines on their websites to assist clinicians.

38Enablers for clinician uptake included supporting clinicians by ensuring supervision, supportive leadership, clear communication, keeping track of clinicians’ needs, optimizing physical space for comfort and privacy (eg, using headphones or ergonomic seating), and arranging times away from the computer.

39However, staff in several studies reported a lack of initial training for telemental health, and therefore identified training needs regarding the use of online platforms and meeting privacy regulations in particular. In some studies, having no previous experience with telemental health was also found to be associated with higher anxiety and lower uptake of remote care. However, others found that previous experience did not impact clinicians’ views of telemental health during the pandemic.

40As telemental health was not commonly used in most services before COVID-19, staff had to rapidly adjust to a new way of working. Several studies discussed the training which was put in place for staff, which included training courses, shadowing, or observing senior colleagues; discussion within clinical teams’ facility-level telehealth coordinators and clinical champions providing training; webinars; and checking official guidelines. New workflows also had to be developed to allow staff to access patient records remotely, and service users had to be informed about the transition to telemental health.

41In addition to the needs of staff, service users also identified certain needs and resources to enable them to effectively transition to telemental health care. A commonly reported issue was access to technology, particularly among service users with diagnoses such as schizophrenia (eg,), older adults (eg,), and service users from lower socioeconomic backgrounds (eg,). Service users also reported problems having a stable internet connection to allow for uninterrupted communication, which could negatively impact the therapeutic relationship. Concerns were also raised by both clinicians and service users regarding privacy and confidentiality, and in some cases service users had difficulties concentrating on remote care. Several studies (eg,) mentioned the need for an agreed “Zoom etiquette” for service users, including attire, audio/visual set up, and background distractions.

42Outcomes of the implementation of telemental health have been summarized below using Proctor et al’s taxonomy of implementation outcomes. Further information can be found in Table 3.

43Remote care was seen as satisfactory by the majority of clinicians and service users in most studies in the context of the pandemic. A number of studies also reported that telemental health enabled some groups to access care who found it difficult to engage with face-to-face support (eg,). Some clinicians reported that they would also be willing to continue with some aspects of remote care in the future (eg,). However, it is important to note that while acceptability was high overall, this was not the case for all groups; for example, Grover et al reported acceptability rates of around 45% for both clinicians and service users using services in a range of settings in India. Further details of satisfaction and acceptability outcomes are presented in Table 4.

44Telemental health services were acceptable to people during the pandemic as a way of continuing their treatment; however, findings from several studies also indicated that participants wanted at least some appointments to be face-to-face once restrictions on in-person contact had loosened.

45Adoption rates were relatively high across studies, with most services or clinicians moving their appointments to remote methods. Rates of adoption of telemental health for service users who were already receiving care at the start of the pandemic ranged from 48% to 100%. Some studies reported face-to-face appointments still took place if necessary, for example, for initial assessments or for medication reviews (eg,). Most studies that examined impact on attendance reported no adverse effects on attendance rates after introducing telemental health: there was either no difference in missed appointments when comparing remote with face-to-face care, or nonattendance after adoption of telemental health decreased. Further details about adoption of telemental health across studies can be found in Table 5.

46While most studies reported high adoption rates, a few studies reported a decrease in attendance: for example, Erekson et al (though possibly because of the university setting) and Dores et al identified challenges in retention due to low client adherence, lack of privacy, interruptions at home, lack of appropriate technology, or simply preference for face-to-face contact.

47There was also evidence to indicate that adoption rates of telemental health fell as COVID-19 cases decreased (eg,).

48There were some concerns raised over the appropriateness of remote care, for example, studies reported difficulties managing medication (eg,) and concerns around engaging and assessing new patients (eg,). Clinicians also found it harder to assess some physical indicators of mental health status (eg, hygiene, eye contact, physical symptoms of opioid withdrawal) without being able to see the service user in person. However, by contrast, remote methods of working felt safer for clinicians who worked with service users at risk for violence and behavioral dysregulation (eg,). Online care was also not necessarily appropriate for patients with auditory or visual impairments, or with conditions such as migraines.

49Staff reported concerns around the management of risk and safeguarding of service users when using remote methods of care (eg,). Some helpful features of platforms which were thought to improve safety were using the waiting room function, being able to remove call participants, renaming participants (to protect anonymity), and using the private chat function.

50In general, all studies reported good feasibility, at least for the short-term emergency response during the pandemic. However, some studies reported that telemental health is not suitable for all types of therapy, for example, those that require a physical presence (exposure therapy, role play, collaborative models; eg,). Telemental health may also be less suitable for treating trauma; clients with severe anxiety, learning difficulties or autism; children; and clients with cognitive impairment.

51There was limited information about costs of implementation of remote care in the included studies and no actual costs of telemental health were reported in the papers. However, initial evidence suggests remote care is not a costly intervention, with 1 paper stating that telemental health is “cost-effective”, while another mentions the use of “low-cost technologies” by clinicians.

52There was widespread penetration (the extent to which telemental health was integrated into mental health services) of remote methods of care delivery due to the COVID-19 pandemic, despite few services utilizing telemental health previously. Services were able to rapidly adapt to this new way of working, with the majority of appointments conducted remotely after the first few weeks of “stay at home” orders.

53The sustainability of telemental health cannot be completely determined from the included studies, as they present data mostly from the early stages of the COVID-19 pandemic. However, there was some indication that although remote working was widely accepted as a necessity, once restrictions loosened, rates of telemental health use declined (corresponding with the drop in cases in Europe in summer 2020). This correlates with findings that not all staff and service users would want to continue using remote methods of care after the pandemic ends. However, there are some aspects of remote working that both clinicians and service users would like to keep in the future in combination with face-to-face care (eg,), as this approach has benefits such as being more efficient, flexible, and enabling access for certain groups (eg,).

54Comparing the clinical outcomes of face-to-face and remote care using quantitative measures indicated that telemental health approaches could be as effective as face-to-face care (eg,), although it should be noted that most studies were on a small scale. Several studies also reported no psychiatric decompensations after switching to remote care (eg,). However, it is important to note that clinical outcomes for telemental health were not comparable for all service users; for example, Dores et al found that a quarter of psychiatrists reported poorer clinical outcomes after switching to remote care. Another study also indicated that only one-third of clinicians felt as though telemental health consultations were comparable to prepandemic sessions. A full presentation of the clinical outcomes reported in included studies is shown in Table 6.

55Although the quality of therapeutic relationships reported by studies was generally good, clinicians reported problems reading patients’ emotions (eg,) or feeling less connected to the service user compared with face-to-face sessions (eg,). Clinicians also reported difficulties regarding feeling and expressing empathy remotely. Other challenges to therapeutic relationships when using remote care included a lack of client engagement, possible misunderstandings due to lack of nonverbal signals, common context, or not having a clear idea of patients’ physical state (alongside reduced privacy).

56One study compared social outcomes in a trial comparing telephone-only care with caregivers of older adults with neurocognitive disorder, with supplementary video care to both carers and service users. Findings indicated that those who received both telephone and video support had greater resilience, better cognitive functioning, and a higher quality of life.

57Improved communication was noted between staff when using telemental health when compared with traditional face-to-face care, as the use of online file sharing or discussion platforms facilitated communication between staff (eg,). The use of online methods also facilitated staff training and some staff reported that remote working resulted in a better work–life balance (eg,).

58This review collated evidence regarding the implementation and outcomes of remote working in mental health services in the context of the COVID-19 pandemic. Most studies indicate a relatively high level of activity, suggesting that at least in the services studied in higher-income countries, much mental health care can be shifted to telemental health in a crisis. Services mainly reported using a mixture of phone and video calls, with both service users and clinicians varying in their preference for these modalities. There were some indicators of reduced numbers of missed appointments, potentially due to the greater convenience of remote care, which may make access to services easier for some service users.

59There was reasonable acceptability across the studies, at least in conditions where the alternative may have been no contact with services at all. However, there were situations where telemental health may be less acceptable, including for new patients, physical health aspects of care, and for service users without a private space at home to use for therapy. Telemental health also may not be as feasible for certain types of support, including support which needs a physical presence such as exposure therapy or role play. This finding reflects those in a systematic review by Turgoose et al, which found that service users had concerns around managing emotions during exposure tasks without the physical presence of a clinician. There was also evidence that telemental health may not be feasible for some clinical presentations, including some service users with psychosis, learning difficulties, or autism. Clinicians also reported a decrease in their ability to develop and maintain a strong therapeutic relationship with service users, due to being unable to pick up on nonverbal cues and a lack of connectedness, something which was also identified in a review conducted prior to the pandemic. The acceptability levels found in this study are not dissimilar to previous studies (eg,), even though the participants in the current studies are less likely to be volunteering to pilot a new type of care and more likely to be using telemental health because they have no alternative.

60Few formal investigations of how to improve implementation were identified in this review, which may reflect the rapid nature of research conducted during the pandemic. However, some strategies for improving adoption/penetration/acceptability may include staff training, the use of telemental health champions, strategies for introducing service users to technology, and providing some simple guidance on how to use it best, identifying situations or populations when telemental health is not a good idea and those where it might be better. There was also a lack of fidelity assessments when therapies had to be adapted to fit telemental health delivery formats; therefore, little is known about the consequences of these adaptations.

61Our interpretation of this pattern of findings is that the successful delivery in a pandemic of telemental health should not necessarily be seen as confirmation that people are happy with this mode of delivery long-term, as some of the identified problems may become more serious over time, and reports of being satisfied may have reflected awareness that at the time of the study, it was difficult to offer care by any other means. The longevity of these changes will ultimately turn not only on information technology, safety, and quality, but also on whether policy changes will support the reimbursements and regulatory adjustments implemented during the current crisis.

62There was a lack of reporting in included studies of trying to identify and reach those patients who are at increased risk of digital exclusion (Textbox 1). The needs of those at risk of digital exclusion are still largely underreported in both pre-COVID-19 and COVID-19–specific literature and should be made a priority for future research. Studies also included little information regarding the cost-effectiveness of telemental health implementation. Further research is needed to explore the differences in cost (both to the service and to the service user) between face-to-face and telemental health care. Further research can also formally compare (rather than simply observe) different delivery support strategies that can improve the implementation and potentially also the clinical effectiveness of telemental health, including for specific conditions and service user groups.

63Lived experience commentary by Karen Machin and Raza Griffiths, members of the NIHR Mental Health Policy Unit's Lived Experience Working Group.

64Systematic reviews aim to give an overview of research findings around a particular topic, although, as in this review, they may find that many of the primary studies are of moderate to low quality. At times of intense pressure, such as those presented by the COVID pandemic, overviews may be welcomed, and researchers may feel a need to respond promptly. This urgency creates a potential for gaps to be overlooked.

65The main concern for us is around service user involvement, which has been acknowledged as key to good quality research, but has still not become the default for research teams. Participatory approaches are largely absent from the reviewed studies, with service user and carer views “reported by clinicians” ignoring the likelihood of misunderstandings and service user views being skewed by unequal power dynamics. There is no statement about the involvement of lived experience researchers in the review itself either. While some researchers may not wish to expose their personal experiences, it is important to be clear about the level of involvement within all studies.

66Service users can shine a spotlight on aspects of mental health support of importance to people who rely on services which may otherwise be missed. Their lack of involvement in this review may be one reason why only one out of 41 primary research studies reviewed looks at the voluntary sector, and none at peer support or social care. It is unclear if this is a result of the review process itself or a lack of evidence. Had service users been involved, this fundamental gap might have been explored at an earlier stage.

67The review does identify some factors that can help determine how useful or accessible telemental health is for different groups of people. However, an analysis linking these factors to broader underlying factors such as poverty would be more helpful.

68Further research is needed to ensure future service planning can more accurately assess which elements of telemental health work well, why, and for whom, and to have service user involvement integral to the whole process from beginning to end.

69Finally, there is scope to conduct big data studies to identify who is not accessing remote care or those at risk of disengaging, and potential comparisons for matched groups to try to compare effectiveness across a range of settings, as this could be done more quickly than in clinical trials while respecting patient preference.

70The studies included in this review identified outcomes across different settings and health care systems, which may help findings generalize to different settings. This review also captured recent findings on the use of telemental health during the COVID-19 pandemic, allowing findings to be used to improve both existing and future models of remote mental health care.

71However, it is also important to take some limitations into account when interpreting the findings from this review. First, the results from quality assessment indicated that while around half of primary research studies and the majority of the service evaluations were high quality, around half of primary research studies were scored as moderate to low. This reflects the short nature of studies and often quick turnaround from data collection to publication. Some studies were also published in preprint form and therefore had not undergone peer review. The majority of studies used cross-sectional data, rather than more rigorous methods. Second, there was a lack of high-quality quantitative evidence for the clinical effectiveness of telemental health care. Clinical effectiveness outcomes were only reported in 9/77 included studies, with some of these findings only based on qualitative evidence or a small number of service users. It is also important to note that the voices of those who dropped out of care may not be included.

72The short time scale for data collection and assessment of changes in practice in included studies could also be viewed as a limitation of this research, as it is not clear if changes will be sustained over time or in other contexts (eg, lower-income countries). We also recognize that the search dates do not cover the whole of the pandemic to date; however, as plans for the medium- to long-term adoption of telemental health are currently being made in several countries, we think it best to make the findings from this research available promptly. Research was also not inclusive of those not accessing or using remote technologies, meaning there is a risk of those at risk of digital exclusion being forgotten when taking the findings of this review into consideration.

73We also designed this review to be conducted rapidly to ensure results would be relevant and quickly available, therefore we chose to search 4 databases and not all studies were independently double screened by blinded researchers. Although quality assessment was conducted by 2 reviewers independently, they were also not blinded to the previous decision. However, we are confident that the rigor of our searches and inclusion of preprint servers meant that the papers included are representative of the literature on this topic.

74Telemental health was a largely effective method to enable continuation of mental health support during the COVID-19 pandemic. While most reported outcomes were positive, telemental health was not feasible for all types of support and may not be acceptable to all service user groups. A blended approach combining face-to-face and telemental health care may be the most desirable service model for future care. The need remains for higher-quality evidence regarding the clinical effectiveness of telemental health and how uptake can be improved for groups at risk of digital exclusion.