Adherence to online psychotherapy during the COVID-19: a scoping review

Abstract Evidence suggests that changes in online psychotherapy adherence factors occurred during the COVID-19 pandemic. Thus, this study aimed to review the perception of patients and psychotherapists regarding factors associated with adherence to online psychotherapy during the pandemic. Thus, 18 articles remained for analysis after searches in five databases and 25 factors associated with adherence to online psychotherapy were identified. The main factors for psychotherapists were confidence in professional skills and connection stability. For the patients, basic informatics skills and finding an adequate setting to participate in sessions. Furthermore, the factors fear of contagion, tiredness and the impossibility of face-to-face meetings emerged during the pandemic. Modifications of factors associated with pre-pandemic adherence were identified and strategies to overcome barriers related to online sessions were presented and discussed. The pandemic has increased adherence to online psychotherapy, although not everyone intends to follow this modality in the post-pandemic.


Introduction
The period between 2020 and 2021 was marked by the COVID-19 pandemic and its effects on physical and mental health in the population.Infections and deaths resulting from COVID-19 are events with great traumatic potential.Furthermore, measures of social distancing, although extremely necessary, can result in serious mental health impairments, such as emotional deregulation and exhaustion, insomnia, feelings of loneliness, anger, or impotence (Brooks et al., 2020).
As a result of the pandemic, the world population started to access the internet more, with a growth of 316 million (7.3%) in the number of users in 2020 (We Are Social, 2021).This growth contributed to the increased demand for online care with several specialties in the health area (Almathami et al., 2020).Regarding psychology, online psychotherapy (i.e.synchronous therapy via the internet) is one of the alternatives to the traditional care model (i.e.face-to-face).In synchronous therapy, psychologist and patient are positioned in different physical environments, communicating by video call simultaneously (Rodrigues & Tavares, 2016).
However, even with efficacy evidence (Langarizadeh et al., 2017), online psychotherapy is still being discussed, especially regarding therapeutic bonding.Many therapists believe that the bond formed during face-to-face care has higher quality compared to the online environment.This difficulty in establishing a good bond is often one of the main criticisms of online psychotherapy.On the one hand, some psychologists believe that non-verbal communication can be compromised in the virtual environment, hindering the development of the therapeutic relationship (Almathami et al., 2020;Zeren, 2017).On the other hand, some psychotherapists report that some patients are more comfortable in the virtual environment, especially shy patients, or patients with anxiety symptoms, which may favor the development of the therapeutic relationship (Poletti et al., 2020;Zeren, 2017).
The opinion of patients about online psychotherapy is also not consensual, some show resistance (Almathami et al., 2020), and others are satisfied with the online setting and with the established therapeutic bond (Poletti et al., 2020).In addition, many patients opt for online psychotherapy, reporting benefits compared to face-to-face therapy such as no travel cost and reduced expenses (Stoll et al., 2020).
Although some factors have not changed during the COVID-19 pandemic, such as no travel cost and reduction of expenses, some studies have reported the emergence of new factors that facilitate (e.g.fear of being contaminated with  or hinder (e.g.excessive tiredness) the adherence to online psychotherapy during COVID-19 (Frayn et al., 2021;Sampaio et al., 2021).There is also evidence that factors that hindered online psychotherapy, in the pre-pandemic period, intensified during the pandemic.One of these factors is the difficulty in finding an adequate/confidential setting, which intensified mainly due to the social distancing measures implemented by governments, such as the closure of schools and companies (Sampaio et al., 2021).On the other hand, some authors reported that during the COVID-19 pandemic, many psychotherapists who were resistant to the online modality, due to the possible impairment of the therapeutic relationship due to the loss of nonverbal communication, started to search for strategies to overcome this difficulty (Simpson et al., 2020).
Considering such changes in pre-existing factors and/or the emergence of new ones, some authors recommend that new studies investigate the factors associated with the adherence of patients and psychotherapists to the virtual environment during the COVID-19 pandemic (Boldrini et al., 2020;Weinberg, 2020).As far as is known, there are no integrative, systematic, or scope reviews that have addressed this issue.Thus, this study aims to review the perception of patients and psychotherapists regarding the factors associated with adherence to online psychotherapy during the COVID-19 pandemic.The results found are compared and discussed with the factors reported in the pre-pandemic period.

Method
A scope review was conducted following the steps proposed by Tricco et al. (2018).The online searches for scientific articles were conducted by two independent researchers in March 2021.Searching for the main national and international scientific productions, five databases were consulted: Virtual Health Library (VHL), Web of Science, Scopus, American Psychological Association database (PsycINFO), and US National Library of Medicine and National Institutes of Health (PubMed).The only filter used in the databases was "document type", which varies in each of the databases: in the VHL, Scopus, and Web of Science the filter "article" was used in the PubMed and PsycINFO "journal".
The string used in the databases were: "Online Therapy" or "Online Psychotherapy" or "E-Therapy" or "Teletherapy" or "Cybercounseling" or "Internet Counseling" and COVID-19.All descriptors were selected based on the descriptors dictionaries Thesaurus (PsycINFO) and Medical Subject Headings (MeSH/PubMed).The articles located in the databases were imported to the "Rayyan" website where the selection and eligibility steps were conducted.Rayyan is a tool that helps researchers perform integrative, systematic, or scope reviews more quickly and with a lower risk of selection bias, as it allows each evaluator to conduct their blind assessment (i.e.similar to the peer-review process).At the end of the article selection process, the website allows the removal of blind mode, showing how many articles were included by each researcher and if there are any differences of opinion (Ouzzani et al., 2016).
The inclusion criteria used for the selection of articles were: I) empirical articles; II) who went through the peer review process; and III) who investigated the perception of psychotherapists and/or patients about performing online psychotherapy during the COVID-19 pandemic (i.e. 2020 and2021).Exclusion criteria were: I) duplicated articles; II) protocols or articles that aimed only to provide suggestions on how to perform online psychotherapy; III) studies with an exclusive focus on online clinical supervision; IV) articles with samples composed exclusively of physicians, occupational therapists, speech and/or language therapists.
In order to cover all the literature on online psychotherapy published during the COVID-19 pandemic, there were no restrictions on the language of publications or the age of the participants.After the exclusion of the duplicated articles, the titles and abstracts were analyzed.First, articles that did not present in the title or abstract at least one of the used keywords were excluded.During the full reading, studies that were not related to the theme of this review or presented incompatible methodological aspects were excluded.

Results and Discussion
Initially, 546 articles were found in the five databases.After the selection process, 18 studies remained to inclusion in the results.Figure 1 illustrates in detail the steps followed during the selection of articles.The analysis of the included articles was performed by extracting the main characteristics of the studies.This synthesis is presented in three results tables.Table 1 presents the main characteristics of the articles included and the psychotherapeutic treatments used.Each article received a number in ascending order (1, 2, 3...).This numbering is used to mention the studies throughout the results.
Most of the studies were conducted in the USA (n = 8; 44.5%) and Europe (n = 6; 33.4%), no studies were found investigating the perception of Brazilian patients and psychotherapists.Regarding the theoretical approach of psychotherapists, psychoanalytic therapy was the most prevalent (n = 7; 38.9%), followed by cognitive-behavioral therapy (n = 5; 27.8%).Regarding the duration of treatments, considering that each psychotherapist interviewed attended multiple patients and that the duration of treatment was different for each patient, many studies (n = 12; 66.6%) did not evaluate  and/or present the mean duration of treatment (i.e.number of sessions).In addition, 13 studies (72.3%) did not report the number of weekly sessions (i.e.studies flagged as NR).Among the articles that reported the duration of treatment (n = 7; 38,9%), the mean duration observed was 17 sessions that occurred once or twice a week over 60 or 90 minutes.Table 2 presents the characteristics and perceptions of patients regarding factors that contribute and/ or hinder the adherence to online psychotherapy.Table 3 presents the characteristics and perceptions of psychotherapists regarding these same factors.Articles with samples composed exclusively of psychotherapists (Studies 2,3,(5)(6)(7)(8)10,15,and 18) were omitted from Table 2, and articles with samples composed exclusively of patients from Table 3 (Studies 12 and 17).
Regarding the characteristics of the participants, the samples of the analyzed studies were composed predominantly of psychotherapists.A total of (n = 134) patients and approximately (n = 2330) psychotherapists were reached in all samples.Moreover, among the nine studies that included patients in their samples, seven had samples composed mostly of women (≥ 57%), only in Study 1 most of the sample was composed of men (63%) and Study 13 did not report the sex of the patients.Among the 16 studies that included psychotherapists, eight had samples composed mostly of women (≥ 66.8%), and eight other studies did not report the sex of psychotherapists.
Female patients combined with female therapists usually report higher therapeutic alliance scores than male patients and psychotherapists.Dyad with a female psychotherapist and male patient also report a larger alliance than male dyad (Bhatti, 2014).Another study adds that this influence of sex occurs both in the faceto-face and online environment (Zeren, 2017).In this sense, the absence of information about the sex of psychotherapists may represent a research bias, especially in the factor "Difficulties in communication and emotional connection" which may be influenced by the difference in sex between patient and psychotherapist.The same applies to the age variable since half of the studies included did not report the mean age of the participants and there is evidence that when the psychotherapist is younger than the patient, the therapeutic alliance tends to develop more rapidly during the initial sessions (Behn et al., 2017).
Regarding the symptoms and/or psychopathologies of the participants, there was no predominance of a disorder or symptom.Regarding the experience with online psychotherapy before the COVID-19 pandemic, in five of the included articles, patients reported not having participated in sessions before the pandemic, another four studies did not report this variable.Regarding psychotherapists, the participants reported not having previous experience with online psychotherapy in five of the included articles, four other studies presented mixed results, with approximately 50% of the samples reporting previous experience, the remaining seven articles did not evaluate or report this variable.
Regarding the perceptions of patients and psychotherapists about the factors that may facilitate or hinder the access to online psychotherapy, after the careful analysis of the 18 included articles, two categories were elaborated for the presentation and discussion of the results: I) Factors that facilitate adherence to online psychotherapy; II) Factors that hinder adherence to online psychotherapy.The factors reported by at least 33.3% (n = 6) of the included articles were transformed into subcategories inside categories I and II.Some articles reported more than one factor and investigated both the opinion of psychotherapists and patients.Therefore, some studies can be mentioned multiple times in each subcategory.

Factors that facilitate online psychotherapy
This category presents the perceptions of patients and psychotherapists.Thus, all the included articles reported at least one factor that facilitates the adhering of patients and/or psychotherapists to online therapy.The factors that were reported by less than six studies were grouped inside some of the subcategories according to thematic proximity.

Feeling confident or competent (n = 8; 44.5%)
Trusting their professional skills was the main factor reported by psychotherapists as a possible facilitator of online care 8,13,and 18).This finding corroborates a recent study, which suggested that psychotherapists tend to feel more confident and competent when they receive some type of training, supervision, or protocol for performing online psychotherapy during the pandemic (Sherbersky et al., 2021).In this sense, the factors training/structuring of the sessions (Studies 10, 13, 14, and 18) and the influence of peers (i.e.colleagues or supervisors) (Studies 2, 3, and 6), were indicated by psychotherapists as possible facilitators of online psychotherapy during the pandemic.Although receiving training and/or supervision is already associated with increased confidence of Table 2.   psychotherapists during online consultations in the prepandemic period, recent studies highlighted the need to develop specific training and protocols for conducting online psychotherapy during the COVID-19 pandemic, even for professionals who attended online in the prepandemic (Boldrini et al., 2020;Stoll et al., 2020).

Patients characteristics and perceptions
Positive opinions or experiences with online psychotherapy (n = 8; 44.5%)Among the studies that suggest that positive opinions or experiences with online psychotherapy before or during the pandemic result in greater adherence, seven refer to the opinions of therapists (Studies 2,3,6,10,13,15,and 18), and one of the patients (Study 12).Thus, this factor was the second most reported by psychotherapists.One of the studies evaluated the opinions of Chinese and American psychoanalysts, showing that the Chinese had more positive opinions before and during the pandemic.This may indicate that the perceptions of psychotherapists are influenced by cultural differences (Study 10).This hypothesis had already been raised before the pandemic (Stoll et al., 2020), however, seems to have become more evident with the increase in the demand for online psychotherapy during the pandemic (Weinberg, 2020).
Another factor associated with the positive experiences of psychotherapists during the pandemic was the possibility of obtaining additional information on patients' home environments (Studies 7,13,and 15).Although this information could be obtained in person or the virtual environment in the pre-pandemic (Friedlander et al., 2018), as a result of social distancing measures (e.g.lockdown), psychotherapists began to obtain a new type of information.Especially since family members spent more time at home and did not always respect the moment of psychotherapy (e.g.background noises, talking to the patient during the sessions), which contributes to the understanding of family dynamics and boundaries (Studies 13 and 15).

Impossibility of face-to-face meetings (n = 7; 38.9%)
Seven studies indicated that the social distancing generated by the pandemic contributed to psychotherapists (Studies 4, 8, 15, and 16) and patients (Studies 4, 9, 11, and 17) adherence to online psychotherapy.This factor was the second most reported by the patients.However, many patients and psychotherapists reported that they do not intend to follow online after the pandemic.This result does not seem to be influenced by the type of therapeutic approach, as this information is from psychotherapists from six different approaches.Other studies partially corroborate this finding, reporting divergent opinions about the adherence to online psychotherapy due to the lockdowns established during the COVID-19 pandemic (Boldrini et al., 2020;Probst et al., 2020).
A survey with 1.547 Austrian psychotherapists found that although there was a mean reduction of 81% in the face-to-face sessions during the lockdown period, there was a mean increase of 979% in the sessions provided via telephone and 1561% via the Internet.However, this increase was not enough to compensate for the reduction in the number of faceto-face patients (Probst et al., 2020).On the other hand, 306 Italian psychotherapists reported that a mean of 42.1% of the treatments performed before the pandemic were interrupted during the national lockdown period, without migration to the virtual environment or increased demand for online psychotherapy.The main reasons for this reduction were the lack of experience of psychotherapists with online sessions and the difficulty of patients finding a confidential place in their homes (Boldrini et al., 2020).

Less resistance to addressing sensitive topics (n = 7; 38.9%)
Among the seven studies that suggest that lower resistance to addressing sensitive topics can facilitate adherence to online psychotherapy, four refer to the opinions of psychotherapists (Studies 1, 11, 15, and 16) and three of the patients (Studies 12-14).The reports of both groups are similar since the psychotherapists reported the perception that their patients found it easier to address issues that were commonly avoided in face-to-face sessions (Studies 1,11,15,and 16).On the other hand, patients reported less anxiety in the online modality, being more comfortable to address sensitive topics .This finding corroborates the prepandemic literature, which indicates that an advantage of online psychotherapy is the ease of approaching sensitive issues (e.g.sexuality, moral values).In this sense, some authors highlighted that less resistance favors the strengthening of the therapeutic bond and adherence to psychotherapy, especially for patients with symptoms of anxiety and depression (Almathami et al., 2020;Stoll et al., 2020).

Schedules flexibility (n = 6; 33.3%)
Six studies indicated that greater flexibility in scheduling sessions can contribute to patients (Studies 12, 13, and 16) and psychotherapists (Studies 1, 7, and 15) adherence to online psychotherapy.According to patients, it is easier to reconcile therapy with other daily obligations, especially considering that many psychotherapists began to provide hours at night or on weekends (Studies 12,13,and 16).On the other hand, psychotherapists report that online sessions allowed better use of time, increased productivity, and reduced the number of patient absences (Studies1, 7, and 15).Another factor associated with schedules flexibility was the no need to travel, three studies suggest that this factor may facilitate the adherence of patients (Studies 12, 13, and 16) and two of the psychotherapists (Studies 7 and 15) to online therapy.Moreover, the reduction of travel expenses also facilitates the adherence of patients (Study 16) and psychotherapists (Study 15).
Before the pandemic, both the schedules flexibility, no need to travel, and reduction of expenses were already factors commonly reported as facilitators of online psychotherapy adherence by patients and psychotherapists who preferred the convenience of performing psychotherapy in their homes (Stoll et al., 2020).The only difference during the pandemic was the emergence of fear of contagion, which seems to contribute to the adherence of patients to online psychotherapy (Studies 12 and 17).This finding is corroborated by Peng et al. (2020) who indicated the inevitable reduction in the search for face-to-face psychological treatments is due to the fear of being contaminated and/or stigmatized for being contaminated.
Patients provide positive feedback (n = 6; 33.3%) Receiving positive feedback from patients was the third factor most reported by psychotherapists, as a possible facilitator of adherence to online psychotherapy (Studies 2,6,10,(13)(14)(15).Although this factor was already described before the pandemic, it was common that even when patients reported a preference for online therapy, psychotherapists still preferred face-toface psychotherapy (Vaart et al., 2014).However, during the pandemic, there was an increase in the availability of online sessions by psychotherapists (Probst et al., 2020), especially when patients reported a preference for this modality, being suggested that the agreement and satisfaction of patients with the performance of online psychotherapy should always be considered by psychotherapists (Chherawala & Gill, 2020;Stoll et al., 2020).These data support the finding that providing positive feedback can facilitate the adherence of psychotherapists to online therapy (Studies 2, 6, 10, 13-15).
Basic informatics knowledge (n = 6; 33.3%)Among the six studies that suggest that basic informatics knowledge may contribute to greater adherence to online psychotherapy, five refer to the opinions of patients (Studies 4,9,11,13,and 14) and one of the psychotherapists (Study 15).Therefore, having knowledge related to the functioning of online service platforms and/or devices (e.g.computer, smartphone) was the main facilitator reported by the patients.The pre-pandemic literature partially corroborates this finding, since the need for basic computer knowledge, especially regarding the use of online psychotherapy platforms (e.g.Zoom, Google Meet), used to be frequently referred as a possible facilitator of adherence to online psychotherapy by patients and psychotherapists (Etzelmuller et al., 2018).On the other hand, concerns about the need for basic informatics knowledge seems to have increased among researchers during the COVID-19 pandemic (Earle & Freddolino, 2021).These data corroborate that the basics of informatics can contribute to the adherence of patients adherence to online psychotherapy (Studies 4,9,11,13,and 14).

Factors that hinder online psychotherapy
This category presents the perceptions of patients and psychotherapists, all the included articles reported at least one factor that hinders the adhering of patients and/or psychotherapists to online therapy.The factors that were reported by less than six studies were grouped inside some of the subcategories according to thematic proximity.(n = 15; 83.4%)Most of the included articles showed that issues with the Internet connection or with the functioning of the computer or smartphone hinder the adherence of patients (Studies 11,12,14,and 16) and psychotherapists (6)(7)(8)(9)(10)(11)(13)(14)(15)(16)and 18) to online psychotherapy.This factor was the most reported by psychotherapists and the second most reported by patients.Since the emergence of synchronous internet sessions, there is a concern about the connection and/ or technical problems associated with the use of communication technologies (e.g.computer, smartphone, tablet - Gros et al., 2013).However, these concerns seem to have increased during the pandemic.Some studies support the outcome of this review, indicating connection and/or technical problems as one of the main factors that hinder adherence to online psychotherapy (Earle & Freddolino, 2021;Probst et al., 2020).

Connection/technical issues
Developing countries are often more impacted by connection/technical problems (We Are Social, 2021).(n = 11; 61.2%) Difficulties in finding an adequate and confidential place were also one of the main factors that hinder the adherence to online therapy by patients (Studies 4, 12-14 and 16) and psychotherapists (Studies 2 and 13).However, this factor was observed as the most reported by patients.Most of the evidence that corroborates this finding is reports from reports of psychotherapists, in other words, psychotherapists reported that in their experiences, patients report fear of adhering to online psychotherapy due to the difficulty in finding adequate/confidential setting (Studies 2,3,6,8,15,and 18).Furthermore, both patients (Study 13) and psychotherapists (Studies 3 and 15) reported concern about confidentiality, especially regarding the possibility of data being stored or used by online platforms.

Difficulty of the patient or psychotherapist finding adequate setting
The concern with the security of data has existed since the emergence of synchronous internet sessions (Gros et al., 2013).However, seems to have intensified during the pandemic, mainly due to the security gaps and data leakage of platforms used for the sessions (e.g.Zoom) (Chherawala & Gill, 2020;Stoll et al., 2020).A recommended alternative to reduce the chances of data leakage is the use of platforms developed specifically for health care or that provide a license or special access to health professionals (Chherawala & Gill, 2020).
Regarding the difficulty of finding an adequate or confidential setting, a systematic pre-pandemic review corroborates our findings by showing that privacy problems were one of the factors most reported by patients, second only to connection/technical issues and resistance (Almathami et al., 2020).Another review study suggests that it is common for psychotherapists to report a concern about the ability of their patients to find an adequate setting for participation in online sessions (Stoll et al., 2020).Although this concern precedes the pandemic, this factor was intensified during COVID-19, especially during the periods of lockdowns where most families were at home all day 6,8,(12)(13)(14)(15)(16)and 18).There are reports of patients who performed psychotherapy inside their cars to achieve privacy (Study 8).Some researchers suggest the use of the mute button, headphones, and/or images as a virtual background to preserve confidentiality and privacy during sessions held in the home environment (Simpson et al., 2020).

Difficulties in communication and emotional connection (n = 10; 55.6%)
Among the ten studies that suggest that the difficulty in communicating and connecting emotionally can hinder the adhering to online psychotherapy, nine refer to the opinions of psychotherapists (Studies 1-3, 5-8, 13 and 15) and one of the patients (Study 12), being the second factor most reported by psychotherapists.A systematic pre-pandemic review corroborates this finding by analyzing 45 studies and finding that in only two, patients reported difficulty in connecting emotionally in the virtual environment (Almathami et al., 2020).Although before the pandemic therapists already reported feeling less connected with their patients during online psychotherapy (Almathami et al., 2020;Zeren, 2017), this difficulty may have intensified during the pandemic (Studies 1-3, 5-8, 13, and 15).
Moreover, in the pre-pandemic there were reports that communication difficulties and emotional connection were associated with the absence or reduction of body language reading in the virtual environment (Almathami et al., 2020).Due to the absence of body language, some psychotherapists reported impairment in their ability to feel or express empathy in online sessions (Studies 2 and 6).In order to strengthen the emotional connection and the feeling of intimacy, some researchers recommend that psychotherapists should familiarize themselves with the functionalities of the online platforms, thus adapting its techniques to the virtual environment and transferring the knowledge about the platform's operation to patients.Adjustments in the centering and image size (e.g. at eye height) are suggested to provide improvement in eye contact, expression of body language, and consequently a greater feeling of emotional connection between patient and psychotherapist (Simpson et al., 2020).
Perceive the therapeutic relationship as less authentic or genuine (n = 6; 33.3%) Among the six studies that suggest that perceiving the therapeutic relationship as less authentic or genuine may hinder adherence to online psychotherapy, five refer to the opinions of psychotherapists (Studies 2, 5, 6, 8, and 15) and one of the patients (Study 17).Psychotherapists who had already established a good therapeutic relationship in person before the pandemic were able to maintain in the virtual environment, reporting difficulties only with new patients (Studies 5 and 6).
The literature corroborates this finding by suggesting that in cases in which the therapeutic bond was established in the face-to-face sessions, the therapeutic relationship usually remains identical in online psychotherapy (Kooistra et al., 2020).There are also studies indicating that compared to patients, psychotherapists usually report lower satisfaction with the therapeutic relationship in the virtual environment both before (Shulman et al., 2017) and during the COVID-19 pandemic (Humer et al., 2020).Thus, the perception of deterioration of the therapeutic relationship in the virtual environment remains a concern among psychotherapists (Studies 2,5,6,8,and 15).
A possible explanation for this prevalence is related to the formality of the therapeutic setting, which is often impaired in online sessions and can contribute to psychotherapists feeling uncomfortable.On that line, the psychotherapists of five studies reported the factor "difficulty maintaining professional boundaries" as a possible obstacle to adherence to online psychotherapy (Studies 1-3, 13, and 15).Some researchers emphasize the importance of imposing limits during the performance of online psychotherapy (i.e.similar to those of face-to-face sessions), aiming to reinforce the authenticity of the psychotherapeutic process to ensure greater patient support and attention (Simpson et al., 2020;Weinberg, 2020).Establishment through a good therapeutic contract is also suggested thus therapeutic limits are established, which include issues related to the duration, value of care, and clarification on the functioning of the platform used for virtual care, especially regarding the security and confidentiality provided.Lastly, there are recommendations for psychotherapists to maintain the same level of professionalism performed in person, either during video calls or even sending SMS (Simpson et al., 2020).
Resistance to online psychotherapy (n = 6; 33.3%)Although resistance to the virtual environment has been identified as a factor that can hinder the adherence to online psychotherapy in the report of patients (Studies 4 and 9), this factor was more reported by psychotherapists (Studies 1, 7, 9, 10, and 13).In addition, psychotherapists who did not perform online sessions before the pandemic showed greater resistance (Studies 10 and 13).Although the findings suggest that the resistance factor was more frequent among psychotherapists, a systematic pre-pandemic review found 11 studies discussing patients' resistance, and it was suggested that fear of the unknown and lack of technological/informatics knowledge increased resistance to different types of online consultations (e.g. medical, nutritional, psychotherapeutic -Almathami et al., 2020).Even during the pandemic, there are studies suggesting resistance to online psychotherapy both by patients (Levy et al., 2021;Weinberg, 2020) as psychotherapists (Weinberg, 2020).Once the patient's resistance is identified, it is recommended that this should be the first topic addressed in the sessions since this manifestation may only reflect the concerns and mistrusts of the therapeutic process (Levy et al., 2021).
Another factor that hinders the adherence to online psychotherapy, reported only by psychotherapists, was the difficulty in increasing the engagement and/or motivation of some patients (Studies 8 and 15).Some authors corroborate this finding and suggest that efforts to increase patient involvement may contribute to reducing resistance to online psychotherapy (Levy et al., 2021;Simpson et al., 2020).The first sessions held in the virtual environment are recommended to be focused on the use of engagement strategies and the establishment of a safe environment for patients (Levy et al., 2021).In addition, psychotherapists who are working from home should organize an adequate space that is not used for other purposes, for the performance of online sessions.This recommendation aims to develop the perception of being in your work environment (Simpson et al., 2020).
Furthermore, the psychotherapists from four studies suggest that compared to face-to-face consultations, tiredness is usually higher after online sessions, which can hinder the adherence to online psychotherapy (Studies 2,5,15,and 17).Some professionals reported that tiredness in online sessions during the pandemic is higher than in the pre-pandemic period (Study 2).However, the main cause of this excessive tiredness remains unclear.Some authors suggest that it may be associated with the pandemic and social distancing, especially considering that quarantined health professionals tend to present more symptoms of posttraumatic stress compared to the general population (Brooks et al., 2020).There is also the possibility that excessive tiredness is caused by increased screen time and the use of online platforms.In this sense, during the pandemic the phenomenon known as "Zoom Fatigue" (i.e.exhaustion caused by the prolonged use of communication technologies) began to be widely disseminated and studied.This exhaustion may occur since it takes greater cognitive effort to process, interpret and interact with information in the virtual environment (Nadler, 2020).

Risk of the patient or psychotherapist being distracted (n = 6; 33,3%)
The increase in distractions in the virtual environment was suggested by six of the studies as a factor that can hinder adherence to online psychotherapy.Both patients (Study 13) and psychotherapists (Studies 1-3, 6 and 15) reported difficulty in maintaining focus throughout the session.Pre-pandemic studies corroborate this finding by showing that connection/technical problems can contribute to the distraction of patients and psychotherapists (Stoll et al., 2020).Moreover, the home environment usually contributes to the increase of distractions, from background noises to concerns related to the possibility of some family member listening the conversations (Almathami et al., 2020).
Problems associated with distraction, especially of patients, were also commonly reported by psychotherapists in online sessions during the COVID-19 pandemic.There were reports of patients who painted their nails, answered messages, or browsed the internet (Studies 1-3, 6, and 15).In this sense, some psychotherapists indicated that although the performance of online psychotherapy during the pandemic brings benefits to patients, the possibility of establishing a good therapeutic bond and maintaining the focus of patients during sessions are questionable and tend to be impaired due to the numerous distractions available in the family and virtual environment (Weinberg, 2020).
Establishing rules and limits in the first sessions held online is one of the ways to avoid distractions.The sessions are suggested to occur whenever possible on the same day and time, to be part of the routine of the patient and their family members.In addition, considering that during the pandemic most patients are working from home, it is recommended that patients adapt a space that provides privacy and especially that is different from their workplace or where other activities are performed (Simpson et al., 2020).

Conclusion
This article reviewed 18 studies that investigated the factors of adherence to online psychotherapy reported by patients and psychotherapists.This review contributes to the scientific literature by demonstrating the existence of at least 25 factors associated with adherence to online psychotherapy, and by presenting and discussing which of these factors arose during the COVID-19 pandemic, which ones existed in the pre-pandemic period and remained unchanged or underwent changes during the pandemic.
The main findings suggest that the factors most cited as facilitators of psychotherapists adherence to online sessions were: 1) Feeling confident or competent (n = 8); 2) Positive opinions or experiences with online psychotherapy (n = 7); and 3) Patients provide positive feedback (n = 6).The main factors that hinder adherence were: 1) Connection/technical problems (n = 14); and 2) Difficulties in communication and emotional connection in therapy (n = 9).Regarding the patients, the most cited facilitator was: 1) Basic informatics knowledge (n = 5).The main hinderer was: 1) Difficulty in finding adequate/confidential setting (n = 5).
Among the factors associated with online psychotherapy, those that already existed in the pre-pandemic and remained unchanged during the COVID-19 pandemic were: Positive opinions and experiences with online psychotherapy; Less resistance to addressing sensitive topics; Schedules flexibility; travel absence; Reduction of expenses; Basic informatics knowledge; Connection/technical issues; Perceive the therapeutic relationship as less authentic or genuine; difficulty in maintaining professional boundaries; Resistance to online psychotherapy; Risk of the patient or psychotherapist being distracted.The main factors that existed in the pre-pandemic but underwent changes during the pandemic were: Feeling confident or competent; Training/structuring of sessions; Patients provide positive feedback; Difficulty of the patient or psychotherapist finding adequate setting; Difficulties in communication and emotional connection in therapy.In addition, three factors emerged during the pandemic: Impossibility of face-to-face meetings; Fear of contagion; Excessive tiredness associated with online sessions.
These findings indicate that just as many companies needed to readjust during the COVID-19 pandemic and discovered the possibility of working remotely, many patients and psychotherapists sought ways to bypass barriers related to online psychotherapy, which contributed to some patients and psychotherapists adapting to the virtual environment.On the other hand, the "impossibility of face-to-face meetings" factor, indicates that many individuals intend to resume face-to-face meetings as soon as possible, which suggests that for some patients and professionals, there is so much resistance to online psychotherapy that the factors that facilitate online psychotherapy are not enough to replace face-to-face sessions.
Data extracted from the studies included in this review are not predictive.Therefore, the fact that some factors have been less reported does not necessarily mean that they are less important than those reported by several studies.In this sense, it is recommended that further studies use predictive analyses to investigate the influence of the 25 factors on the decision to adhere to online psychotherapy during or after the pandemic.In addition, the studies analyzed asked participants to report which factors facilitated or hindered online psychotherapy during the pandemic.However, none of the included studies requested that participants assign an order of importance to the factors reported, which reinforces the need for predictive studies.
Furthermore, except for connection problems and difficulty in finding an adequate setting, the other factors that hinder the adherence to online psychotherapy can be mitigated or eliminated through dialogue between patient and psychotherapist, and/or training related to the use of digital platforms to perform online psychotherapy.In addition to training and dialogue, it is recommended the development of both protocols that serve as a guide to psychotherapists in the sessions performed during pandemics, as well as protocols and even online platforms that aim to mitigate the factors that hinder adherence reported throughout this review.A possible technological alternative to reduce the impacts of some hindering factors (e.g.resistance) is the use of virtual reality platforms that have patient and psychotherapist avatars, which provide the feeling of immersion.
Moreover, although this review does not aim to evaluate the efficacy of online psychotherapy, all included articles reported that online therapy benefited patients in some way.Therefore, it emphasizes the importance of greater adherence by psychotherapists to the online psychotherapy model, especially during the COVID-19 pandemic, both due to the increase in people in psychological distress and due to the risk of contagion in face-to-face sessions.
Regarding the limitations of this review, although searches for scientific articles have been conducted in five of the main databases in the health area, other relevant studies may be indexed in other databases.Another possible limitation is associated with the fact that some of the included studies are experience reports, which are inserted in the lower levels of the scientific evidence pyramid.However, considering the COVID-19 pandemic is a recent event, the opinions of health professionals who are acting during this global crisis are of great value.Finally, considering that none of the studies included in this review was conducted with Brazilian participants, it is recommended to conduct national studies that investigate the opinions and experiences of patients and psychotherapists with online psychotherapy during the COVID-19 pandemic.

Figure 1 .
Figure 1.Article selection flowchart of face-toface meetings; 2) Fear of being contaminated with COVID-19 1) Perceiving the therapeutic relationship as less authentic or genuine Note.*Most participants reported more than one factor; ¹Before pandemic; BD -Bipolar disorder; ED -Eating disorder; F -Female; M -Male; NR -Not reported; OPD -Other psychotic disorders; PD -Personality disorder; SD -Standard deviation.

Table 1 .
Characteristics of the included studies and psychotherapeutic treatments Note. * -Some participants reported more than one approach.;ACT -Acceptance and commitment therapy; CBT -Cognitive behavioral therapy; DBT -Dialectical behavioral therapy.NR -Not reported.

Table 3 .
Psychotherapists characteristics and perceptions