Eligible participants were licensed outpatient psychotherapists providing guideline-based psychotherapy for adults in Germany. Inclusion required a valid professional licensure and current or recent involvement in outpatient psychotherapy practice. Participants were excluded if they did not provide information on licensure status.

The final sample consisted of 296 outpatient German psychotherapists. Sociodemographic and professional characteristics, including age, gender, therapeutic orientation, and years of professional experience, are presented in the results section. Additional variables relevant to the study context included indicators of digital affinity (eg, private and professional internet use) and VBT usage patterns.

The study was conducted in 5 German federal states organized within the East German Psychotherapists’ Chamber (Ostdeutsche Psychotherapeutenkammer, OPK): Brandenburg, Mecklenburg-Western Pomerania, Saxony, Saxony-Anhalt, and Thuringia. A comprehensive sampling approach aimed at contacting all identifiable licensed outpatient psychotherapists in these regions. Data collection took place between July 2020 and January 2021 for the first survey wave (T1) and between March 2024 and May 2024 for the second survey wave (T2). Recruitment, recontact procedures, and sample composition are shown in Figure 1.

For T2, 1885 psychotherapists were contacted by postal mail, including T1 participants, previous respondents who had not declined recontact, previous nonrespondents, and newly identified practitioners. Of 1696 successfully delivered invitations, 299 questionnaires were returned (response rate: 17.6%), and 296 were retained after excluding 3 responses with missing licensure information. Of these, 117 participants had also participated in T1, forming the matched longitudinal subsample and corresponding to a retention rate of 31.5%.

The response rate is within the expected range for postal surveys of specific professional groups [50,51] and may reflect clinical workload, questionnaire length, and the longitudinal design [52]. The paper-based format was chosen to reduce digital-affinity-related selection bias. Participation was voluntary, resulting in a self-selected sample. T1 data have been reported previously [7]; the present study focuses on postpandemic T2 data and longitudinal changes. Potential attrition bias was assessed by comparing sociodemographic and professional characteristics between longitudinal participants and T1-only participants.

This study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of DIPLOMA University of Applied Sciences (reference number: 1104/2024). All participants provided informed consent before participation and were informed about the study’s purpose, procedures, voluntary nature, and their right to withdraw at any time without consequences. Participants from the first survey wave (T1) were informed about possible recontact for follow-up assessments and could explicitly consent to or decline future contact; only those who had not declined recontact were approached for the second survey wave (T2). The informed consent procedure also covered the use of data for longitudinal analyses.

To support recruitment, participants were offered a lottery-based incentive [53,54]. The prize draw included cash prizes of €3000, €2000, and three prizes of €1000 (EUR €1=US $1.0865 as of June 4, 2024), as well as training vouchers worth approximately €200‐250 each for participants ranked 6 to 10. The lottery-based format was chosen as a pragmatic alternative because individual fixed compensation proportionate to outpatient psychotherapists’ opportunity costs was not feasible within the study budget. To ensure transparency, the lottery date was announced in advance, the draw was conducted online, and participants received the link to the online draw together with the study information and questionnaire materials.

Confidentiality and data protection were ensured by collecting identifying information via a separate consent form returned in a different envelope from the survey responses. Survey data were stored separately in pseudonymized form. Longitudinal linkage was enabled through a self-generated pseudonymized identification code based on personal cues, which could not be reconstructed by the research team to identify individual participants [55]. No identifying information is included in this manuscript or supplementary materials, and all results are reported in aggregated form.

We aimed to contact all licensed outpatient psychotherapists within the selected federal states. Thus, no fixed a priori sample size was defined. Instead, the sampling approach approximated a census of the target population within the OPK regions. Given the observational nature of the study, sample size was primarily determined by feasibility and response rates, and no formal a priori sample size calculation was conducted. Sample size adequacy was evaluated based on conventional recommendations for statistical power. For within-subject analyses, a minimum sample size of 44 is required to detect medium effect sizes (d=0.5) at α=0.05 with a power of 0.9. For multiple regression analyses with up to 6 predictors, a minimum sample size of 98 is recommended, while larger samples (n≥150) are preferable for stable estimation of smaller effects. The sample size achieved 296 for cross-sectional analyses, and 117 for longitudinal analyses, was considered sufficient to detect medium effects and to conduct regression and subgroup analyses, including cluster analysis.

The study assessed VBT use, technology acceptance, perceived effectiveness, change mechanisms, and therapist-related characteristics using validated instruments and study-specific items. An overview of all measures, including operationalization and response formats, is provided in Multimedia Appendix 1.

Reflecting heterogeneous approaches to sustainability measurement in prior research [13], VBT sustainability was operationalized through usage persistence and usage intensity. Usage persistence was defined as postpandemic VBT usage status (user vs nonuser), based on self-reported VBT sessions and treated patients. Following established criteria [11], participants were classified as users if they had conducted at least 5 VBT sessions with at least 3 different patients. Usage intensity was captured using the total number of VBT sessions, the number of patients treated via VBT, weekly VBT session frequency, and the proportion of weekly sessions conducted via VBT.

Technology acceptance was assessed using the UTAUT-T framework [22], including the dimensions therapy quality expectation, ease of use, social influence, professional support, convenience, and behavioral intention. Items were rated on a 5-point Likert scale, reversed items were recoded before analysis, and mean scores were computed for each subscale. Perceived effectiveness of VBT compared to F2F psychotherapy was assessed using a single Likert-scale item. Evaluations of therapeutic processes based on Grawe’s general change mechanisms were assessed using multiple-response formats, with each response option coded as a separate dichotomous variable.

Additional variables included prepandemic and pandemic VBT use, digital affinity, awareness of VBT-related regulations, perceived regulatory restrictions, sociodemographic and professional characteristics, and contextual factors such as reasons for VBT use or nonuse. These variables were used as predictors, group comparison variables, or descriptive contextual indicators.

Data were collected using a structured, paper-based questionnaire distributed by postal mail and returned in prepaid envelopes. The paper-based format was chosen to ensure accessibility regardless of digital affinity. The questionnaire included closed-ended, open-ended, and filter questions, enabling differentiation between VBT users and nonusers. Data collection for T1 took place between July 2020 and January 2021; T2 was conducted between March 2024 and May 2024.

The questionnaire was originally developed for the first survey wave to assess psychotherapists’ experiences, attitudes, and use of VBT. Its development involved an expert panel of 5 practicing psychotherapists, some with prior VBT experience. For T2, items were revised or added to reflect the postpandemic context while retaining as many original items as possible to ensure comparability across time points and enable longitudinal analyses. The revised version was again reviewed by 5 experienced psychotherapists. The questionnaire used at T2 is provided in Multimedia Appendix 2.

As data were collected using a standardized self-report questionnaire, no training of data collectors or interrater reliability procedures were required. Measurement quality was supported by clearly defined items and response formats, expert review by practicing psychotherapists, and filter-questions tailored to participants’ VBT experience to reduce response burden and enhance response accuracy.

The questionnaire combined validated instruments and study-specific items. Study-specific items assessed VBT usage patterns, perceived effectiveness, disorder-specific applicability, and evaluations of therapeutic processes based on Grawe’s general change mechanisms [24,25]. Therapists rated whether VBT addresses these 5 mechanisms to a comparable extent as F2F therapy, reflecting subjective professional equivalence ratings. Filter questions were used to tailor item presentation to VBT users and nonusers.

Technology acceptance was assessed with the therapist version of the UTAUT [22], a 21-item self-report measure covering ease of use, pressure from others, therapy quality expectations, professional support, convenience, and behavioral intention. The instrument was translated into German using a forward translation procedure and reviewed by practicing psychotherapists to ensure conceptual equivalence with the original version.

Given the observational, nonexperimental design of the study, no masking procedures were used. Participants completed a self-report questionnaire and were fully aware of the study content. No experimental conditions or group assignments were implemented.

The UTAUT-T instrument [22] has demonstrated good psychometric properties in previous research, with reported internal consistency coefficients of Cronbach α=0.79 [32]. In the present sample (T2), internal consistency coefficients for the UTAUT-T subscales ranged from α=0.489 to α=0.973, with lower internal consistency observed for some subscales (see Table S1 in Multimedia Appendix 3). Items were aggregated to form scores for each dimension.

Study-specific items assessed perceived effectiveness of VBT, disorder-specific applicability, and evaluations of therapeutic processes based on Grawe’s general change mechanisms [24,25]. Given the exploratory nature of these measures, no composite reliability indices were calculated.

The study used a nonexperimental, observational survey design based on participants’ self-reported experiences and behaviors. It combined repeated cross-sectional and longitudinal elements. Psychotherapists were surveyed at two assessment waves (T1 and T2), allowing comparisons between survey waves. In addition, a matched subsample of participants completed both waves (n=117), enabling within-person analyses of change over time. Accordingly, analyses were conducted at two levels: cross-sectional analyses based on the full T2 sample and longitudinal analyses based on the matched subsample. Throughout the manuscript, T1 and T2 refer to assessment waves, whereas prepandemic, first pandemic phase, second pandemic phase, and postpandemic refer to time-related reference periods assessed within the survey. Comparisons across reference periods are described as longitudinal only when based on the matched subsample with data from both waves. Comparisons based on retrospective reports or nonidentical samples are interpreted as retrospective or repeated cross-sectional comparisons, respectively.

This study was reported in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines [56]. The completed checklist is provided as Checklist 1.

Before analysis, participants were excluded if eligibility for the target population could not be verified, particularly if information on licensure status was missing. The missing data assessment therefore refers to the eligible analytic sample. Complete-case analyses with listwise deletion were used as the primary analytic approach. Missing data were low across the analytic variables, ranging from 0% to 1.7% for sociodemographic variables, from 2.4% to 5.1% for items assessing usage frequency, and from 0% to 3% for UTAUT-T items. Little’s test of missing completely at random (MCAR) did not provide evidence against the assumption that data were MCAR (χ²₁₇₅=199.9; P=.10). Multiple imputation with 20 datasets was conducted as a sensitivity analysis for the main regression models using fully conditional specification and predictive mean matching for metric variables. The imputation models included all variables from the respective regressions, and pooled estimates were compared with complete-case results.

Data were screened for outliers using boxplots. No systematic or implausible extreme values requiring exclusion were identified. Descriptive analyses were conducted and nonparametric methods were applied where appropriate. For cluster analysis, variables were z-standardized.

The analytic strategy followed the study objectives and distinguished between cross-sectional, longitudinal, retrospective, and exploratory analyses. Cross-sectional T2 analyses examined postpandemic VBT use, group differences between users and nonusers, and determinants of technology acceptance. Group differences were analyzed using chi-square tests and Mann-Whitney U tests. Multiple linear regression examined UTAUT-T predictors of behavioral intention, and logistic regression analyses identified factors associated with postpandemic VBT usage status. Regression diagnostics were examined where applicable.

Secondary analyses examined within-person longitudinal changes in the matched subsample using McNemar tests for dichotomous outcomes and Wilcoxon signed-rank tests for ordinal or nonnormally distributed variables. Retrospective comparisons across prepandemic, pandemic, and postpandemic reference periods were based on self-reported T2 data and analyzed using Cochran Q tests followed by Bonferroni-adjusted McNemar tests for pairwise comparisons. The retrospective data were not interpreted as true longitudinal measurements. Contextual variables were analyzed longitudinally, where item formats allowed valid comparisons; items introduced only at T2 were reported descriptively.

Exploratory person-centered analyses used a 2-step cluster analysis combining Ward’s method and k-means relocation based on z-standardized UTAUT-T variables. Therapy quality expectation, ease of use, pressure from others, professional support, and behavioral intention were included; convenience was excluded because it was not predictive of behavioral intention in preliminary analyses. Cluster validity was examined using average silhouette width, the elbow method based on within-cluster sum of squares, and gap statistics. The final solution was selected based on internal validity indices and theoretical interpretability. Cluster differences were examined using ANOVAs or Welch ANOVAs and chi-square tests, with η² for ANOVAs and Cramér V for chi-square tests reported as effect sizes.

All analyses were conducted using SPSS 29.0 (IBM Inc) and R [57-69]. Statistical significance was defined as a 2-tailed P value of <.05.

Results are presented in 3 parts. First, sample characteristics and attrition patterns are described. Second, cross-sectional analyses based on the full T2 sample (n=296) provide a detailed picture of postpandemic VBT use, its determinants, and therapists’ evaluations. Third, longitudinal analyses based on the subsample of therapists who participated in both survey waves (n=117) examine how VBT use, underlying motivations, and perceived effectiveness evolved over time.

At T2, 296 outpatient psychotherapists participated. Of these, 117 also completed T1 and constituted the longitudinal subsample. Table 1 summarizes the sociodemographic and professional characteristics of the full T2 sample, stratified by postpandemic VBT user status. The sample was predominantly female (228/296, 77%), with a mean age of 50.5 (SD 9.2) years, an average of 15.7 (SD 9.2) years of professional experience and 12.6 (SD 8.0) years working in outpatient psychotherapeutic practice. Most participants reported a cognitive behavioral approach (227/296, 76.7%), followed by psychodynamic (70/296, 23.6%), psychoanalytic (12/296, 4.1%), and systemic (7/296, 2.4%) approaches. [In Germany, outpatient psychotherapists are typically trained and licensed in 1 or more of 4 guideline-based therapeutic approaches: cognitive behavioral therapy, psychodynamic therapy, psychoanalysis, and systemic therapy. Membership in one or more of these orientations is required for licensure and reimbursement within statutory health insurance.] Detailed information is provided in Table 1.

Attrition analyses indicated that retained participants were younger (t₃₆₈=2.95, P=.003, d=0.33), with a mean age of 47.56 (SD 8.59) years compared to 50.63 (SD 9.59) years among dropouts, reported fewer years of professional experience (mean 12.41, SD 8.75 vs mean 14.96, SD 9.86; U=12,450, P=.02, r=0.12), and indicated more positive prior experience with VBT (χ²₃=10.2, P=.02, V=.22). No significant group differences were found for pandemic VBT usage, private internet use, perceived VBT effectiveness, intended future VBT use and therapeutic approaches (all P>.05). Professional internet use also did not differ significantly between groups (χ²₄=7.5, P=.11). However, a significant linear-by-linear association was observed (χ²₁=4.5, P=.03), indicating that lower levels of professional internet use were associated with a higher likelihood of dropout. Detailed results are provided in Table S2 in Multimedia Appendix 3.

Cross-sectional analyses examined postpandemic VBT use at T2, including usage patterns, its determinants, therapists’ evaluations of clinical process quality, and person-centered profiles of technology acceptance. All analyses are based on T2 data; comparisons across time periods rely on retrospective self-reports.

Longitudinal analyses extend the cross-sectional findings by examining changes in VBT use, usage intensity, underlying motivations and barriers, and perceived effectiveness among therapists who participated in both survey waves (n=117).

This repeated cross-sectional, partially longitudinal survey study examined postpandemic VBT use among licensed outpatient psychotherapists in Germany. The findings indicate that VBT has become a sustained but selectively used component of outpatient psychotherapy. Use remained above prepandemic levels but declined from pandemic peaks, and motivations shifted from infection-control needs toward practical and patient-centered reasons. Within the UTAUT-T framework, therapy quality expectation was the strongest predictor of behavioral intention, which in turn predicted actual use. Prior VBT experience and regulatory awareness further explained postpandemic use. At the same time, many therapists rated VBT as less effective than F2F therapy and perceived limitations in core therapeutic change mechanisms, particularly the therapeutic relationship. The three identified acceptance profiles further show that postpandemic VBT use is shaped by therapist heterogeneity rather than a simple distinction between users and nonusers.

The findings suggest that VBT did not disappear after the pandemic but stabilized as a selectively used option rather than becoming a dominant treatment format. This pattern is consistent with international telehealth research showing that digital care remained above prepandemic levels but below pandemic peaks [5,70-74]. The present study extends this trajectory to German outpatient psychotherapy and suggests that postpandemic use is filtered through clinical judgment: therapists retain VBT when it is perceived as practically useful and clinically appropriate but reduce or discontinue it when perceived clinical fit is limited [4,6,43].

This selective sustainment must be understood within the German regulatory context. VBT became billable within statutory health insurance shortly before the pandemic, whereas pandemic-related quota suspensions temporarily facilitated broader use. The return to more regulated use after the pandemic likely contributed to the decline in usage intensity. National billing data and provider studies similarly indicate that reimbursement rules, certified platforms, data protection requirements, and billing conditions shaped VBT uptake and continuation [75,76].

The motivational pattern further supports this interpretation. During the pandemic, VBT was largely driven by external pressure and infection-control needs; postpandemically, patient demand, scheduling flexibility, and avoidance of missed appointments became more relevant [1,6,72,77-79]. However, patient demand does not imply universal suitability, as some patients cannot be reached through VBT or decline this format [80]. Practical barriers such as technical disruptions appear to decrease with experience, whereas broader concerns about effectiveness and therapeutic change mechanisms remain more stable [10,11,34,43,45,81].

The UTAUT-T findings provide evidence for the psychological determinants of sustained VBT use in a postpandemic context. The model explained a substantial proportion of variance in behavioral intention, and behavioral intention strongly predicted actual postpandemic VBT use, supporting the core UTAUT assumption that intention translates into use behavior [23]. This extends the original UTAUT-T framework by showing that the intention-behavior relationship persists when VBT use is no longer primarily driven by pandemic-related necessity [22]. Because postpandemic use reflects more voluntary clinical decision-making, this link may indicate genuine acceptance rather than situational compliance [72].

Therapy quality expectation emerged as the strongest predictor of behavioral intention, outweighing ease of use, social pressure, and professional support. This is consistent with the original UTAUT-T validation study by Békés et al [22], which conceptualized therapy quality expectation as the psychotherapy-specific equivalent of performance expectancy. In psychotherapy, perceived usefulness refers less to productivity or convenience than to clinical effectiveness and therapeutic quality. Similar findings by Zentner et al [12] and Békés et al [79] further support this interpretation. Sustained VBT integration therefore appears to depend primarily on perceived clinical meaningfulness rather than technical feasibility or convenience.

Ease of use, pressure from others, and professional support also contributed to behavioral intention, although their effects were smaller. This pattern is consistent with UTAUT, where effort expectancy, social influence, and facilitating conditions remain relevant but are often secondary to performance expectancy, particularly after users have gained experience [23]. The nonsignificant role of convenience further suggests that practical advantages alone do not drive VBT acceptance once clinical quality expectations are considered. Nevertheless, professional and social contexts remain important implementation conditions for VBT continuation [12,82].

Beyond behavioral intention, prior pandemic VBT use predicted postpandemic use, supporting a path-dependency interpretation. Pandemic-era exposure may have reduced uncertainty, supported skill development, and helped integrate VBT into professional routines [8,9,73]. However, this may reflect more than habituation: VBT mastery involves clinical competencies associated with therapeutic relationship quality and presence [32]. Regulatory awareness also predicted postpandemic VBT use, although causality remains unclear. Greater awareness may facilitate use or result from use itself, but in either case appears to mark practitioners more embedded in VBT implementation. Given that regulation, reimbursement rules, and unclear guidelines have been identified as recurring barriers to VBT diffusion, regulatory communication should target active users and potential adopters [72].

A central finding was the discrepancy between existing outcome evidence and therapists’ clinical process perceptions. Most therapists rated VBT as less effective than F2F therapy, and only about one-third perceived Grawe’s change mechanisms as equally supported. This skepticism is consistent with therapist-reported concerns in Germany and internationally [4,6,16], but contrasts with evidence indicating noninferiority of VBT for symptom reduction, satisfaction, alliance, and dropout across several disorders and treatment contexts [28,29,83-87]. This suggests that sustained VBT integration depends not only on outcome efficacy, but also on perceived process validity [10,32].

This perception-outcome gap may reflect different evaluative frameworks. Outcome studies typically assess symptom change or standardized alliance measures, whereas therapists evaluate moment-to-moment process quality, including therapeutic presence, nonverbal information, relational exchange, and intervention delivery. Prior studies similarly report uncertainty about sensory impressions, eye contact, nonverbal signals, and therapeutic presence in VBT, sometimes with more favorable patient than therapist evaluations [10,32,77,88]. Thus, VBT may not weaken therapeutic processes globally, but it changes the conditions under which they unfold.

This distinction is particularly relevant for Grawe’s change mechanisms. The therapeutic relationship was most often perceived as compromised, followed by problem activation and motivational clarification. These mechanisms rely on emotional engagement, embodied presence, and subtle feedback loops. Qualitative and systematic evidence suggests that VBT changes silence, corporeality, spatial dynamics, and nonverbal interaction, which may complicate the assessment of affective intensity, ambivalence, or highly emotional material [38,84,89-91]. At the same time, alliance and outcome studies show that relational quality can remain stable when therapists and patients adapt to the medium [10,32,84,88,92,93].

More favorable evaluations among VBT users may therefore reflect either acquired mastery or self-selection. Experience may support VBT-specific competencies, but therapists whose style, orientation, or patient groups fit the medium better may also be more likely to continue using it [11,29,32,89]. Because the present design cannot disentangle these mechanisms, implementation should address both possibilities: structured training and supervision are needed, but VBT should also be treated as a modality whose suitability depends on patient characteristics, therapeutic task, therapist competence, and professional fit [94-96].

The 3-cluster solution shows that postpandemic VBT acceptance cannot be reduced to a simple user/nonuser distinction. Tech-savvy optimists showed high acceptance and the highest actual VBT use, whereas skeptical traditionalists showed the lowest acceptance and use and perceived VBT as less able to support core therapeutic change mechanisms. Cautious neutrals, the largest group, used VBT more pragmatically and less intensively, suggesting that ambivalence rather than enthusiasm or rejection may characterize the dominant postpandemic stance among German outpatient psychotherapists.

These profiles indicate that sustained VBT implementation is shaped by different configurations of acceptance beliefs rather than by a single linear adoption pathway. Hoffmann’s qualitative typology of German providers offers a conceptual parallel: “pragmatists” viewed VBT as a results-oriented opportunity to improve care, whereas “conservatives” emphasized disruptions to professional routines, responsibilities, and care quality [97]. The present findings therefore suggest that VBT acceptance depends not only on perceived benefit or technological openness, but also on professional identity, therapeutic self-concept, and person-technology fit [97]. Cluster correlates further support this interpretation. Skeptical traditionalists tended to be older and less likely to use cognitive behavioral approaches, consistent with prior findings on stronger online-therapy acceptance among cognitive behavioral therapists [6]. The gradient in evaluations of Grawe’s change mechanisms further suggests that VBT acceptance is linked to perceived alliance quality, professional self-doubt, therapeutic presence, and the fit between video settings and therapists’ process orientation [47,98].

The absence of cluster differences in prior VBT training suggests that existing training may not sufficiently address these process-level concerns [32,99]. Prior research indicates that initially skeptical clinicians can become more positive after a supported VBT experience, and that teletherapy mastery involves clinical skills beyond technical proficiency, including compensating for reduced nonverbal information, managing disruptions, and adapting interventions to digital affordances [32,99].

Regulatory perceptions added a profile-specific layer. Regulatory awareness predicted postpandemic VBT use, whereas perceived restrictions were not simple deterrents: tech-savvy optimists reported stronger restrictions despite high use, while lower awareness among skeptical traditionalists may reflect limited engagement with VBT. Regulatory communication should therefore be profile-sensitive and combine practical clarity with clinically grounded explanations of responsible VBT use [75,76,100,101].

The findings have theoretical and practical implications. Theoretically, they support the UTAUT-T as a framework for explaining sustained VBT use beyond crisis-driven adoption [22,23], while also showing that technology acceptance in psychotherapy is not primarily a technical issue. Acceptance depends on whether VBT is perceived as clinically meaningful, therapeutically effective, and compatible with psychotherapeutic work [12,22,32]. The findings also extend technology acceptance models by showing that sustained VBT use is shaped by path-dependent experience [8,9,73] and therapist heterogeneity [47]. Future models of VBT adoption should therefore integrate therapist heterogeneity, professional identity, and perceived clinical process quality more explicitly.

Practically, implementation strategies should move beyond generic technical training. The longitudinal stability of clinical evaluations suggests that passive exposure alone may be insufficient for adaptation, consistent with evidence that teletherapy mastery involves clinical competencies beyond technical familiarity [32,38,88-91]. Training should target VBT-specific clinical competencies, including therapeutic presence, compensation for reduced nonverbal information, intervention adaptation, disruption management, and indication-specific decision-making [32,94-96,99]. Profile-sensitive approaches may be useful: highly accepting therapists may benefit from advanced guidance on indication and quality assurance, ambivalent therapists from case-based supervision, and skeptical therapists from evidence-informed engagement with clinical process concerns [47,97-99]. Therapists may benefit from examining how their own professional orientation and prior experiences shape their perception of VBT, and from distinguishing between concerns grounded in direct experience and concerns based primarily on assumptions [10,32,88,98].

Regulatory and organizational guidance should be clear, stable, and clinically actionable. Information about billing, certified platforms, data protection, quality standards, and appropriate indications should reach both active users and potential adopters [72,75,76,100,101]. Because VBT may not fit all therapeutic approaches, patient groups, or professional identities equally well [11,80,91,97,98], sustainable implementation should aim for flexible, evidence-informed, and clinically differentiated use rather than universal digital transformation. In practice, this requires shared decision-making that integrates empirical evidence, clinical judgment, and patient preferences [102,103].

Several limitations should be considered when interpreting these findings. First, the postal survey design with voluntary participation may have introduced self-selection bias, potentially overrepresenting psychotherapists with a greater interest in or experience with VBT.

Second, attrition in the longitudinal subsample may have biased longitudinal findings. Participants who completed both waves were younger and reported more positive VBT experiences at T1 than dropouts, potentially leading to an overestimation of positive trajectories. The longitudinal subsample was too small for more advanced modeling approaches, such as growth curve models or latent transition analyses.

Third, all outcomes were based on therapist self-report and were not validated against objective data. Patient outcomes, patient preferences, session recordings, behavioral observations, or standardized process measures were not assessed. Thus, therapists’ perceptions of VBT effectiveness and process quality may not correspond to patients’ experiences or objective outcomes.

Fourth, measurement limitations should be noted. Although the UTAUT-T is a validated instrument [22,23], some subscales showed limited internal consistency in the present sample, which may have weakened associations and affected regression and cluster-based findings. In addition, measures of perceived effectiveness and Grawe’s change mechanisms were developed for this study, limiting comparability with prior research and underscoring the need for validated instruments assessing clinical process quality in VBT.

Fifth, the cluster analysis was exploratory. The profiles depended on the selected UTAUT-T variables, and cluster validity indices indicated only moderate separation. Although the 2-cluster solution showed somewhat better internal separation, the 3-cluster solution was retained because it provided greater theoretical and clinical interpretability by identifying an ambivalent group between high acceptance and skepticism. This group reflected heterogeneity beyond a simple user versus nonuser distinction. The profiles should be understood as exploratory acceptance patterns rather than sharply separated natural groups and require replication in independent samples.

Sixth, the predominantly cross-sectional design limits causal inference. Although the longitudinal subsample allowed examination of within-person change, the study cannot determine whether attitudes drive behavior, behavior shapes attitudes, experience leads to adaptation, or self-selection explains user-nonuser differences. Similarly, regulatory awareness may either facilitate VBT use or result from using VBT.

Finally, the sample was restricted to psychotherapists in East German federal states, was predominantly female, and was largely cognitive behavioral therapy oriented. Findings may therefore not generalize to other countries with different health care and reimbursement systems, other therapeutic orientations, or more gender-balanced samples. The results should be interpreted within the specific context of postpandemic German outpatient psychotherapy and its regulatory conditions.

Future research should examine VBT as a clinically differentiated modality rather than as a uniform alternative to F2F therapy. Qualitative studies are needed to identify how psychotherapists adapt therapeutic techniques and clinical decision-making to VBT, while longitudinal studies should clarify whether acceptance profiles are stable orientations or change with experience, training, and regulation. Patient outcomes, preferences, satisfaction, and perceived process quality should be assessed with validated instruments. Finally, intervention studies should test whether competency-based VBT training improves acceptance, therapeutic presence, and clinical decision-making more effectively than generic technical training.

This study extends existing pandemic-era and cross-sectional VBT research by examining how technology acceptance, clinical process quality, and therapist heterogeneity shape postpandemic VBT sustainability under more voluntary routine-care conditions. This approach differs from prior studies that primarily focused on pandemic use or cross-sectional acceptance. The findings show that VBT has become a sustained but selectively used component of German outpatient psychotherapy rather than evidence of a comprehensive digital transformation or a universal replacement for F2F care.

The study contributes to the field by showing that sustained VBT use depends on perceived clinical meaningfulness, prior experience, regulatory familiarity, and therapist acceptance profiles. The identified heterogeneity indicates that implementation strategies should not assume a simple user versus nonuser distinction. Instead, VBT should be understood as a flexible modality whose value depends on indication, patient preference, therapeutic task, therapist competence, and organizational conditions.

In real-world practice, sustainable VBT implementation requires clinically differentiated and evidence-informed use. This includes profile-sensitive training, clear regulatory and organizational guidance, and shared decision-making that integrates empirical evidence, clinical judgment, and patient preferences. Further research should examine clinical process quality and identify when, for whom, and under which conditions VBT provides added value within routine outpatient psychotherapy.