Introduction
NHS Talking Therapies for anxiety and depression
In England, free psychological therapies within primary mental health care are provided through NHS Talking Therapies for Anxiety and Depression (TTad). Formerly known as Improving Access to Psychological Therapy (IAPT), this programme focuses on delivering evidence-based psychological interventions for individuals with depression or anxiety disorders (NHS Digital, n.d.).
Launched in 2008 to address the shortage of evidence-based therapies for common mental health conditions like anxiety and depression (Clark, Reference Clark2011), the initiative has since expanded, aiming to enhance access to and streamline the delivery of psychological treatments (National Collaborating Centre for Mental Health, 2024). To date, the programme has trained thousands of therapists across England, treated millions of clients, improved therapy accessibility, integrated outcome measures, and served as a model for mental health care worldwide (Clark, Reference Clark2018).
These services operate under a stepped care model, offering a range of NICE recommended evidence-based psychological therapies (Clark, Reference Clark2018). Services are typically delivered in out-patient settings by trained therapists and may involve in-person, remote, or hybrid formats. One treatment offered is Step 3 cognitive behavioural therapy (CBT), which is a high-intensity, evidence-based psychological treatment for individuals with moderate to severe presentation of common mental health conditions such as depression and anxiety disorders. Delivered by CBT therapists, Step 3 CBT involves structured, collaborative interventions that target maladaptive thought patterns and behaviours to promote emotional and psychological recovery. This level of therapy often includes treatment for more complex or persistent issues, such as generalised anxiety disorder (GAD), obsessive compulsive disorder (OCD), post-traumatic stress disorder (PTSD), and social anxiety. Sessions are typically conducted one-on-one, although group-based interventions may also be offered depending on clinical need. CBT should emphasise a tailored approach, with interventions customised to the client, their individual experience, their identity, specific symptoms and goals (Fenn and Byrne, Reference Fenn and Byrne2013).
Disparity in access and outcomes within TTad
Despite efforts to improve access, clients from diverse backgrounds often experience lower access rates and poorer treatment outcomes within TTad compared with White British clients (Baker and Kirk-Wade, Reference Baker and Kirk-Wade2024). Ahmad et al. (Reference Ahmad, McManus, Cooper, Hatch and Das-Munshi2022) found that White British clients were more likely to complete treatment and show improvement than clients from other ethnic groups during 2018–2019. People from ethnic minority backgrounds were less likely than White British people to access TTad, either through self-referral or GP referral, and were also less likely to receive CBT (Kapadia et al., Reference Kapadia, Zhang, Salway, Nazroo, Booth, Villarroel-Williams, Becares and Esmail2022). Additionally, Harwood et al. (Reference Harwood, Rhead, Chui, Bakolis, Connor, Gazard and Hatch2023) found that individuals from Black Caribbean, Black other, and White other groups were more likely to be referred to other services instead of receiving treatment within TTad. Kapadia et al. (Reference Kapadia, Brooks, Nazroo and Tranmer2017) found that Pakistani women in the UK experience high levels of mental health problems but have lower access rates. A ‘one size fits all’ approach in some TTad services fails to meet the linguistic, cultural, and religious needs of Pakistani, Somali, and Yemeni patients resulting in barriers to access and engagement, emphasising the need for culturally and linguistically adapted interventions, diverse workforce representation, and community informed practices to improve equity and therapy outcomes (Arafat, Reference Arafat2021).
Such disparity is exacerbated when clients request or require an interpreter to engage with therapy (Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025). Although formal data on interpreter-mediated treatment outcomes within TTad is scarce, anecdotal reports suggest that the challenges of accessing therapy in a non-English language worsen the already limited access and outcomes for clients. The low uptake of psychological therapies by clients from diverse groups is often tied to language barriers, which act as a significant barrier to accessing care (Department of Health, 2005). Delays in assessments and appointments due to the availability of interpreters further exacerbate this issue, negatively impacting both access to care and treatment outcomes (Harwood et al., Reference Harwood, Rhead, Chui, Bakolis, Connor, Gazard and Hatch2023). Such delays can also lead to disengagement from treatment (Costa and Briggs, Reference Costa and Briggs2014), with some clients eventually abandoning therapy altogether. In some cases, delays in booking interpreters, particularly for less commonly spoken languages, can be costly and time-consuming (Transformation Partners in Health and Care, n.d.), contributing to frustration for both clients and practitioners. Furthermore, many therapists are reluctant to work with interpreters, especially when only a few are trained and available to handle interpreter-mediated sessions (Costa, Reference Costa2022a). Without adequate training and support, practitioners report difficulties in expressing empathy and maintaining a smooth therapeutic relationship in a three-way dynamic with the client and interpreter (Tutani et al., Reference Tutani, Eldred and Sykes2018). Additionally, issues with interpreter competency and adherence to best practices, such as attempts to steer the conversation, can further create an additional barrier (Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025). Challenges during the preparation phase, including inefficient booking systems for interpreters and insufficient therapist preparation, also create barriers that undermine the effectiveness of therapy (Costa, Reference Costa2022a; Costa, Reference Costa2022b; Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025).
Efficacy of interpreter-mediated CBT
There is a limited breadth of research exploring the efficacy of interpreter-mediated CBT either within trial conditions or routine practice. Several studies highlight the potential of interpreter-mediated therapy, particularly for refugee populations. For example, Quiroz Molinares (Reference Quiroz Molinares2024) and d’Ardenne et al. (Reference d’Ardenne, Ruaro, Cestari, Fakhoury and Priebe2007) both found no significant differences in PTSD symptoms or treatment outcomes between clients who received therapy with or without interpreters. In fact, some evidence points to slight improvements for clients who received interpreter-mediated therapy, suggesting that interpreters may not hinder therapeutic progress and could even enhance treatment outcomes for some individuals. Schulz et al. (Reference Schulz, Resick, Huber and Griffin2006) found that cognitive processing therapy (CPT) was effective for refugees whether an interpreter was used or when delivered in the client’s native language, demonstrating its strong clinical utility when unable to delivery therapy in the client’s language. Furthermore, Woodward et al. (Reference Woodward, Orengo-Aguayo, Stewart and Rheingold2020) demonstrated significant reductions in PTSD and depression symptoms in a Spanish-speaking Latina woman undergoing prolonged exposure therapy, further supporting the feasibility and effectiveness of interpreter-mediated trauma therapy.
However, the evidence is not entirely conclusive. Sander et al. (Reference Sander, Laugesen, Skammeritz, Mortensen and Carlsson2019) found that interpreter-mediated CBT was associated with less improvement in PTSD symptoms compared with sessions where no interpreter was used. This suggests that while interpreter-mediated therapy can be effective, there may be instances where the presence of an interpreter could complicate treatment, possibly due to communication barriers or other logistical challenges. Overall, while the research provides a strong case for the use of interpreters in CBT for trauma, it also indicates that more research is needed to understand the factors that may influence the effectiveness of interpreter-mediated therapy.
Diversity of language in England and Wales
The diversity of languages spoken within England and Wales increased between 2011 and 2021, with English (or English or Welsh in Wales) remaining the primary language, spoken by 90.8% of the population (Office for National Statistics, 2022). Other than English, the main spoken languages were Polish (1.1%), Romanian (0.8%), Panjabi (0.5%), and Urdu (0.5%), with the largest increase seen in those speaking Romanian (Office for National Statistics, 2022). The concentration of language speakers varies across regions within England, with London having the greatest diversity of spoken languages (Office for National Statistics, 2022). The majority of respondents who did not report English as their main language reported speaking English either very well or well (Office for National Statistics, 2022). However, proficiency in English should not necessitate therapy in English. Rolland et al. (Reference Rolland, Dewaele and Costa2017) reported that clients speaking English as a learned language can feel a sense of detachment and be less able to express themselves. Where possible, clients were shown to favour their first language in therapy, even when speaking in English was possible (Rolland et al., Reference Rolland, Dewaele and Costa2017), indicating the importance of offering TTad in spoken languages other than English.
Rationale for the current study
Despite the growing use of interpreters in psychological therapy, there is limited research examining its potential impact on key outcomes, such as waiting times and treatment efficacy. Although the use of interpreters within healthcare is common practice, to the authors’ knowledge, this is the first paper of its kind to explore waiting times and outcomes for interpreter-mediated CBT within TTad. This gap in the literature highlights the need for further investigation into how interpreters influence therapeutic waiting times and outcomes, which could provide valuable insights for improving service delivery and treatment efficacy.
Method
Routine outcome data in TTad
Standard practice is to routinely collect outcome measures at every therapeutic contact (National Collaborating Centre for Mental Health, 2024), which includes validated measures such as the Patient Health Questionnaire-9 (PHQ-9; Kroenke et al., Reference Kroenke, Spitzer and Williams2001) for assessing depressive symptoms, the Generalized Anxiety Disorder-7 (GAD-7; Spitzer et al., Reference Spitzer, Kroenke, Williams and Löwe2006) for anxiety symptoms, the Work and Social Adjustment Scale (WSAS; Mundt et al., Reference Mundt, Marks, Shear and Greist2002) for functional impairment, and the IAPT Phobia Scale for specific phobias (National Collaborating Centre for Mental Health, 2024). In addition to the above measures, clients routinely complete Anxiety Disorder Specific Measures (ADSM) tailored to their unique presenting issues and the symptoms associated with their primary presenting problem. These measures are used to define ‘caseness’ where scores on the above measures are severe enough to be of a clinical level, >9 on the PHQ-9 and >7 on the GAD-7. Once initially assessed with TTad, clients are given a problem descriptor to identify the main symptoms they are presenting with for support, e.g. depression. The PHQ-9, GAD-7 and ADSM, where relevant, are used to calculate recovery, reliable improvement, and reliable recovery when matched with the problem descriptor (National Collaborating Centre for Mental Health, 2024). Recovery is defined as outcome scores moving from caseness at the start of their treatment to below caseness at the end. Reliable improvement is where outcome measures show a significant improvement between their first and last scores, without worsening on other measures. Reliable recovery is where clients meet both recovery and reliable improvement criteria (NHS Digital, 2025; Porter et al., Reference Porter, Franklin, De Vocht, d’Apice, Curtin, Albers and Kidger2024). Within TTad there are lower rates of reliable recovery, compared with recovery or reliable improvement (NHS Digital, 2025).
It is worth noting that while routinely collected data contains a large amount of information about patient characteristics, data on preferred language are not available in the dataset (National Collaborating Centre for Mental Health, 2023).
Data
Given that data on access and outcomes of interpreted mediated therapy is not typically reported for TTad, a Freedom of Information (FOI) request was submitted, seeking five years of Step 3 CBT data with and without interpreter support, which was rejected due to cost limits. After refinement, an amended request for the 2022–2023 period was submitted. NHS England provided national aggregated data on waiting times and treatment outcomes, grouped by interpreter support, withholding some details of demographic information.
According to the note on methodology provided by NHS England with the FOI, the data covered referrals in England between 1 April 2022 and 31 March 2023. It included only those with a discharge date within this period who had completed a course of treatment, where at least half of the attended treatment appointments were Step 3 CBT. Internet enabled therapies and employment advisor appointments were excluded from the definition of attended treatment sessions. The presence of an interpreter was identified using the ‘Interpreter present at care contact’ code recorded during the first attended treatment appointment. As the data were provided in aggregated form by NHS England, we were unable to modify these parameters or access further details.
NHS England uses specific categories to document interpreter support during care contacts, indicating whether and how communication assistance was provided (NHS Digital, 2024). The category ‘Yes – a professional interpreter was used for the purposes of communication’ denotes the presence of a qualified interpreter to facilitate communication. ‘Yes – a family member or friend was used for the purposes of communication’ indicates that a relative or friend acted as an interpreter, while ‘Yes – another PERSON was used for the purposes of communication’ refers to someone other than a professional interpreter, family member, or friend, such as a staff member or ad hoc interpreter. The category ‘No – an interpreter was not used for the purposes of communication as an interpreter was not required’ reflects that the client could communicate effectively without assistance. Lastly, ‘No – an interpreter was not used for the purposes of communication as the interpreter was required but did not attend’ relates to instances where interpreter support was needed but an interpreter did not attend.
Data from version 1.5 of the IAPT dataset were excluded, as this version did not include the required ‘Interpreter present’ field. Treatment outcomes were assessed based on the first and last valid scores recorded for each referral during the reporting period.
Sample
The sample consisted of 177,340 clients who accessed TTad services and received Step 3 CBT. Whilst it is best practice to report demographic and identity information in full to support clarity, relevance, and to avoid homogenising the sample, neglecting nuance and making imprecise generalisations (Kunorubwe et al., Reference Kunorubwe, John, Molina, Davies, Gait, John, Roderique-Davies and Lancastle2024), on this occasion, we are unable to do so, as demographic details were not shared. Consequently, it is not possible to report on key factors such as age, ethnicity, presenting problems, languages spoken, or the severity of clients’ mental health issues. Given the context, it is assumed that the sample consists of adults presenting with common mental health problems, such as depression and anxiety disorders, which are typically within the remit of NHS Talking Therapies.
Results
Data were provided for 177,340 clients. Of these, interpreter status was not recorded for 127,877 clients, representing 72.1% of the data provided. Of the clients with interpreter status recorded, 98% of this represented those who did not require an interpreter. The remaining 2% of data, representing 873 clients, were split across four groups, indicating who interpreted (a professional, a family member or friend, another person), and a fourth group where an interpreter was required but did not attend (see Fig. 1). This figure is broadly in line with that reported in the 2021 Census (Office for National Statistics, 2022) where 1.8% of the total England and Wales population do not speak English well (1.5%) or at all (0.3%).
Pie charts indicating full data sample (a) split by interpreter status (Interpreter required, Interpreter not required, Interpreter requirement not known), and Interpreter required group (b) split by who provided interpretation (Professional interpreter, Family member or friend, Another person, Interpreter did not attend).

Waiting time data indicated that across all groups, 91.5% of clients were seen within 6 weeks or less, 7.1% were seen over 6 weeks and less than 18 weeks, and 1.4% were seen 18 weeks or more following referral. Across groups, 69.05% showed reliable improvement and 44.29% showed reliable recovery. Frequency and percentage data are reported for each group in Table 1.
Frequency and percentage data for the five interpreter groups for the full sample, recovery and improvement, and waiting times

Table 1. Long description
The table presents frequency and percentage data for five interpreter groups across various waiting times and outcomes. It includes columns for sample size, reliable improvement within six weeks or less, reliable recovery within six to eighteen weeks, and waiting times of eighteen weeks or more. The rows categorize the data by interpretation status: professional interpreter, family member or friend, another person, interpreter not required, and interpreter required but did not attend. Notable trends include a high percentage of clients showing reliable improvement and recovery within six weeks or less, with the ‘interpreter not required’ group having the highest percentages. Waiting times of eighteen weeks or more are relatively low across all groups.
Waiting times
A chi-squared analysis was performed to compare waiting times for those needing an interpreter to those not needing an interpreter, which showed a significant association (χ2=136.69, p < .001), with those using an interpreter having a higher proportion of clients waiting 6–18 weeks (15.9%) or 18+ weeks (3.4%) compared with those not using an interpreter (6.9% and 1.3%, respectively). In other words, clients using an interpreter waited longer than those not using an interpreter (see Fig. 2). However, it is worth noting that around 80% of clients using an interpreter were seen within 6 weeks, adhering to NHS Talking Therapies access targets. To explore if there were differences between the different interpreter-needed groups, we ran a chi-squared analysis on these groups only comparing waiting times up to 6 weeks and over 6 weeks, given the low cell counts for one group. There was no significant association found (χ2=3.06, p=.38).
Bar chart demonstrating percentage of those using or not using an interpreter in three waiting time categories: under 6 weeks, between 6 and 18 weeks, and more than 18 weeks.

Figure 2. Long description
The bar chart compares the percentage of groups using or not using an interpreter across three waiting time categories: under 6 weeks, 6 to 18 weeks, and over 18 weeks. The x-axis represents the waiting time categories, while the y-axis shows the percentage of the group. There are two sets of bars for each category: one for groups using an interpreter and one for groups not using an interpreter. The bars for groups using an interpreter are dark gray, while the bars for groups not using an interpreter are light gray. In the under 6 weeks category, approximately 80 percentage of the group used an interpreter, and approximately 90 percentage did not. In the 6 to 18 weeks category, approximately 10 percentage of the group used an interpreter, and approximately 5 percentage did not. In the over 18 weeks category, approximately 2 percentage of the group used an interpreter, and approximately 1 percentage did not. All values are approximated.
Reliable improvement
We then looked at those using an interpreter compared with not using an interpreter on reliable improvement, and found a significant relationship (χ2=45.95, p < .001). Percentages demonstrated that 58.5% of those using an interpreter showed reliable improvement, with 69.2% of those not using an interpreter showing reliable improvement. When looking at interpreter groups, there were no significant relationships between reliable improvement and type of interpreter (χ2=5.06, p=.17).
Reliable recovery
Finally, we looked at relationships between interpreter use and reliable recovery. Chi-squared analysis showed a significant association (χ2=49.78, p < .001), with 32.5% of those using an interpreter showing reliable recovery compared with 44.5% of those not using an interpreter. A chi-squared analysis of interpreter groups showed a significant association (χ2=13.97, p=.003), with the highest percentage of reliable recovery in the friends and family group (n=17, 58.8%), those using another person (n=88) and those for whom the interpreter did not attend (n=182) having around 41% showing reliable recovery (41% and 40.8%, respectively). Those using professional interpreters (n=586) had the lowest percentage to reliable recovery at 29.6% (see Fig. 3).
Bar chart illustrating reliable recovery rates for those using and not using interpreters, and the different types of interpreter used.

Figure 3. Long description
The bar chart compares reliable recovery rates for individuals using and not using interpreters, as well as the different types of interpreters used. The chart features two sets of vertical bars. The first set compares recovery rates between those who used interpreters and those who did not. The second set breaks down the types of interpreters used: professional interpreters, family members or friends, and other persons, along with those who did not attend. The y-axis represents the percentage of recovery rates, ranging from 0 to 70 percentage. The x-axis categorizes the data into two main groups: interpreter used versus interpreter not used, and types of interpreters used. The bars for interpreter usage show that a higher percentage of individuals recovered when interpreters were not used, approximately 45 percentage, compared to around 35 percentage when interpreters were used. Among the types of interpreters, family members or friends have the highest recovery rate at around 60 percentage, followed by other persons at approximately 40 percentage, and professional interpreters at about 30 percentage. Additionally, around 40 percentage of individuals who did not attend are included in the data. All values are approximated.
Discussion
Summary findings
Firstly, the finding that 72.1% of clients lacked recorded interpreter status highlights a significant gap in capturing relevant data. However, this is not a problem limited to TTad as it is apparent that there are issues in recording interpreter need or use in mental health care assessments (Young et al., Reference Young, Vicary, Tipton, Rodríguez Vicente, Napier, Hulme and Espinoza2023) or maternity care (MacLellan et al., Reference MacLellan, McNiven and Kenyon2024). Moreover, this practice is contrary to existing guidance that recommends recording a patient’s language and interpreting needs in their healthcare record and passing this information on when referring them to other health professionals (Office for Health Improvement and Disparities, 2021).
Of those that reported, the analysis identified a statistically significant association between clients’ waiting times and the use of an interpreter, with those utilising an interpreter experiencing longer waits than those who did not. We also identified significant associations between using an interpreter and outcome measures.
Although approximately 80% of clients who utilised an interpreter were seen within the TTad target of 6 weeks, this is notably lower than the 92% for clients who did not utilise an interpreter. The disparity suggests a potential inequity in timely access to care for clients with language support needs, with concomitant inequities in treatment outcomes. This delay likely reflects the service and organisational level barriers to interpreter-mediated therapy within TTad, including challenges with booking interpreters, sourcing interpreters for specific languages, and interpreter non-attendance reported by Kunorubwe et al. (Reference Kunorubwe, O’Leary and Wynne2025). Such disparities may not be limited to TTad; as clients have shared, they regularly wait longer than average to access an appointment or even to arrange an appointment across healthcare services (Brennan and Seymour, Reference Brennan and Seymour2024).
The analysis also indicates that clients who used an interpreter had lower recovery rates than those who did not. This finding stands in contrast to previous research, which has generally shown that interpreter-mediated therapy can be effective when appropriately delivered (Quiroz Molinares, Reference Quiroz Molinares2024; d’Ardenne et al., Reference d’Ardenne, Ruaro, Cestari, Fakhoury and Priebe2007; Schulz et al., Reference Schulz, Resick, Huber and Griffin2006; Woodward et al., Reference Woodward, Orengo-Aguayo, Stewart and Rheingold2020). These earlier studies have reported comparable or in some cases improved outcomes for clients receiving interpreter-mediated therapy, particularly when interpreters are professionally trained and integrated effectively into the therapeutic process. However, a key difference may lie in the context and population studied. Many of the aforementioned studies were conducted within specialist services, where therapists often have greater experience working cross-culturally and are more accustomed to collaborating with interpreters (Kunorubwe, Reference Kunorubwe2025). In contrast, the findings presented here reflect interpreter-mediated therapy within standard TTad services, where the infrastructure, training, and time required to support such work may be more limited. Importantly, in many of the prior studies showing equal or improved outcomes, participants may have received timely access to treatment as part of the research, potentially minimising delays between referral and treatment initiation. In routine practice in TTad, however, delays associated with arranging interpreter-mediated therapy may themselves contribute to poorer outcomes.
A particularly interesting finding involved the very small subset of clients (0.03% of the sample) who used friends or family members as interpreters, who proportionally showed higher than expected improvement rates. With such a small sample, we need to be mindful interpreting such data. It is therefore entirely possible that this is a statistical artefact, but future research might explore whether there are scenarios in which family and friend interpreters could lead to improved outcomes for some clients in certain circumstances. The use of family as informal interpreters is typically not advised in therapy due to concerns about limiting disclosure, communication errors, and the impact of personal biases (Bauer and Alegría, Reference Bauer and Alegría2010; Costa, Reference Costa2022a; Hadziabdic et al., Reference Hadziabdic, Albin, Heikkilä and Hjelm2014; Leanza et al., Reference Leanza, Miklavcic, Boivin, Rosenberg, Kirmayer, Guzder and Rousseau2013; Tribe and Morrissey, Reference Tribe and Morrissey2004). With healthcare interactions where there may be issues around domestic violence, child protection, mental health or sexual matters, communicating through family members may be counterproductive at best and, at worst, dangerous (Fazil and Beavan, Reference Fazil and Beavan2015). This is also compounded when considering that clients have expressed how the lack of access meant that they were more likely to have to rely on family members or children across healthcare, reliance creates risks interpreting sensitive or complex medical contexts, and may lead to poorer patient safety, miscommunication, missed appointments, or inappropriate care (Brennan and Seymour, Reference Brennan and Seymour2024).
The lower recovery rates observed could reflect delays in starting therapy due to issues with waiting times, or may be related to barriers to interpreter-mediated therapy in TTad, such as challenges associated with a change in the traditional therapy dynamic, lack of therapist training in working with interpreters, time pressures due to inflexible caseloads, and a reluctance or resistance to interpreter-mediated therapy (Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025). More broadly, this might be linked to wider inequalities in outcomes and a general absence of co-produced models of culturally adapted care. The NHS Race and Health Observatory (National Collaborating Centre for Mental Health, 2023) reported that clients from minoritised ethnic groups often present with greater symptom severity at the point of assessment and wait longer for assessment and treatment. Ethnic minority status is also linked to multiple disadvantages, with some outcome disparities reflecting structural factors experienced more acutely in these groups (Amati et al., Reference Amati, Green, Kitchin, Watt, Jones, AlRubaye, McCann and Greenfield2023). Clients from minority ethnic groups are less likely to complete treatment and show improvement (Ahmad et al., Reference Ahmad, McManus, Cooper, Hatch and Das-Munshi2022; Baker and Kirk-Wade, Reference Baker and Kirk-Wade2024), a trend that appears to be compounded when the clients have limited English proficiency (Njeru et al., Reference Njeru, DeJesus, St Sauver, Rutten, Jacobson, Wilson and Wieland2016). It is plausible that there is some overlap between minority ethnic status and need for interpretation in this sample, and poorer outcomes might therefore be partly due to the factors listed above. These delays and poorer outcomes are consistent with earlier studies (Costa and Briggs, Reference Costa and Briggs2014; Harwood et al., Reference Harwood, Rhead, Chui, Bakolis, Connor, Gazard and Hatch2023), which noted that interpreter-related delays and barriers can lead to disengagement and reduced therapeutic effectiveness. This is also of importance as increased duration of the waiting time has been associated with less favourable treatment outcome (van Dijk et al., Reference van Dijk, Meijer, van den Boogaard, Spijker, Ruhé and Peeters2023) and predicts drop-out (Carter et al., Reference Carter, Pannekoek, Fursland, Allen, Lampard and Byrne2012) more generally. Longer waiting times, especially those over 3 months, were associated with declines in outcomes for patients (Reichert and Jacobs, Reference Reichert and Jacobs2018). A qualitative study exploring young adults’ experiences of waiting lists found that participants reported relying on alternative support, experiencing impaired functioning, and developing negative beliefs and emotions, highlighting the broad psychological and practical impact of treatment delays (Punton et al., Reference Punton, Dodd and McNeill2022); 182 clients were recorded as Interpreter Didn’t Attend. While it is unclear from the data whether these clients were subsequently able to access interpreter-mediated therapy or how their care was managed following this disruption, the presence of such a sizeable group underscores a known barrier to equitable access. This aligns with broader concerns raised in Kunorubwe et al. (Reference Kunorubwe, O’Leary and Wynne2025), which identified interpreter non-attendance as a recurring issue that disrupts care, delays treatment, contributes to therapists’ frustration and may lead to disengagement from services.
Finally, to provide some context, it is helpful to consider the use of interpreters across other areas of healthcare. However, data on interpreter need and usage across NHS settings is limited. Young et al. (Reference Young, Vicary, Tipton, Rodríguez Vicente, Napier, Hulme and Espinoza2023) noted that it is not known how many people undergo mental health assessment with the use of an interpreter. MacLellan et al. (Reference MacLellan, McNiven and Kenyon2024) found that within maternity trusts, an average of 9% of people required an interpreter, compared with Gill et al. (Reference Gill, Beavan, Calvert and Freemantle2011) who found in a Birmingham Trust that 29% of consultations involved the use of an interpreter. Therefore, more research is needed to understand rates of interpreter use.
Clinical implications
The clinical implications of these results highlight several key areas for improvement and consideration in service delivery for clients requiring interpreters in mental health and therapeutic contexts.
The finding that clients utilising an interpreter tend to experience longer waiting times than those not utilising one underscores a potential barrier to timely access to therapy. This delay could have significant implications for client outcomes, particularly in mental health services where timely intervention is critical, supported by the poorer outcomes seen in these data. Importantly, this dataset only includes wait times to the initial assessment appointment, not to the start of treatment. As the assessment is typically used to determine the appropriate therapeutic intervention, clients are often placed on additional waiting lists thereafter. As such, potential further delays including between treatment sessions are not captured. This is relevant as waiting time targets for treatment are seen as too long by service users, which exacerbates distress, and increases drop-out and disengagement from treatment (Punton et al., Reference Punton, Dodd and McNeill2022). Therefore, clinicians, supervisors, services, and strategic leadership need to consider expanding interpreter services or adjusting scheduling practices to reduce waiting times for those needing interpreters, thereby improving the overall efficiency and accessibility of services.
The significant associations between rates of reliable improvement and reliable recovery between clients’ use of interpreters point to potential disparities in treatment outcomes, with 58.5% of those with an interpreter showing reliable improvement compared with 69.2% of those without an interpreter, and only 32.5% of those with an interpreter showing reliable recovery compared with 44.5% of those without an interpreter. The analysis also revealed that clients using professional interpreters had lower rates of reliable recovery (28.8%) compared with those using friends/family (38.6%) or other persons (39%). Interestingly, the group using friends or family as interpreters showed higher improvement rates than expected, despite literature advising against this practice due to concerns over dual roles, potential bias, and increased communication errors. This highlights how clinicians, interpreters, interpreting agencies, TTad services and strategic leadership need to assess the quality of the interpretation process, including ensuring that interpreters are adequately trained in the nuances of mental health terminology and therapy-related conversations.
While the majority of clients using an interpreter were seen within 6 weeks, the data suggest that targeted interventions are needed to ensure that those who wait longer are not disproportionately affected. Clients in the 6–18 weeks and 18+ weeks categories may experience deterioration in mental health, exacerbating the difficulty of treatment. It is important to acknowledge, however, that data on clients’ initial symptom severity are not available, which limits conclusions about the true impact of waiting times on outcomes and reliable change from this sample.
Clinical teams might consider implementing strategies to address the longer waits for those who utilise interpreters, such as offering additional resources or adjusting how appointments are scheduled to ensure quicker access. However, for these strategies to be successful, they would require robust support and resourcing from strategic leadership, including adequate funding for interpreter services, sufficient staffing to manage increased demand, and organisational buy-in to prioritise equity in access to timely care. Effective implementation of these changes would rely on collaboration between clinical teams and leadership to ensure that adequate resources are allocated and that systems are put in place to meet the needs of clients requiring interpreters.
Providing therapy in a client’s primary language is critical, particularly in mental health contexts where emotional nuance, cultural meaning, and identity are deeply embedded in language. Language is not merely a conduit for communication; it plays a central role in how individuals access, process, and express emotional experiences. Therapy in a non-primary language can disrupt this process and impose an additional cognitive burden on clients, whereas using a first language supports more accurate self-expression, emotional regulation, and therapeutic engagement (Tannenbaum and Har, Reference Tannenbaum and Har2020).
The lack of recording of interpreter status for 72.1% of clients in the dataset (n=127,877) has significant clinical implications. When such a fundamental aspect of service access is not routinely recorded, it becomes difficult to assess whether clients’ language needs are being identified and met. This data gap raises concerns about the visibility of linguistically minoritised groups within services and suggests that language support may be under-recognised or inconsistently documented in routine practice. Issues with inconsistent recording of language and interpreter use are also found in other areas such as Mental Health Act Assessments (Young et al., Reference Young, Vicary, Tipton, Rodríguez Vicente, Napier, Hulme and Espinoza2023) and within Maternity Trusts (MacLellan et al., Reference MacLellan, McNiven and Kenyon2024).
Moreover, the absence of these data hampers efforts to monitor equity, evaluate outcomes accurately, and implement service improvements. Without reliable recording, it is impossible to determine whether interpreter services are being offered consistently, declined, unavailable, or simply overlooked. Importantly, acknowledging and addressing language-based discrimination in healthcare is critical to shifting the culture away from the widespread yet often unacknowledged acceptance of substandard care for linguistically diverse clients (Tomkow et al., Reference Tomkow, Prager, Drinkwater, Morris and Farrington2023). Improving data quality and embedding routine assessments of language needs are necessary steps towards ensuring that language is not a hidden barrier to accessing equitable and effective mental health care.
This is not just limited to recording of language, but also the recording and use of information on the dialect spoken, given that errors in interpreter booking due to dialect mismatches are common within TTad, leading to missed appointments, ineffective communication, and impact on continuity of care (Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025). Such errors not only prolong waiting times but also risk further disengagement, particularly for clients already experiencing long delays. By consistently recording and reporting on dialects, services could reduce inefficiencies, ensure more appropriate interpreter matching, and ultimately support stronger therapeutic alliances. Better recording would also enable a full language/dialect analysis across TTad services, ensuring an evidence-based provision of spoken word interpreters. This simple adjustment to recording practices could have significant implications for treatment accessibility, engagement, and outcomes for linguistically minoritised clients.
Interpreter-mediated CBT should be embedded within training pathways rather than relegated to CPD. At present, many therapists receive little or no structured training on how to work effectively with interpreters (Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025), despite growing evidence that therapeutic processes and outcomes are significantly shaped by the quality of interpreter-mediated communication. A strategic approach from NHS England, accrediting bodies such as the BABCP (or others outside of the UK), and training institutions such as universities, would be to review core curricula and incorporate interpreter-related competencies into mandatory training requirements. This could include structured teaching, demonstrations, simulation-based learning, and, wherever possible, opportunities for trainees to engage with case studies specifically involving interpreter-mediated CBT. Embedding such training within the core curriculum would ensure that therapists enter the workforce equipped to deliver equitable care to linguistically diverse populations, while also aligning with recommendations that emphasise the role of organisations such as accrediting bodies and training institutions in creating optimum conditions for therapists and interpreters to work effectively together (Kunorubwe, Reference Kunorubwe2025).
In addition, it would be beneficial to address the lack of translated CBT materials that can act as a barrier to interpreter-mediated therapy with TTad (Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025). Therapists often rely on interpreters to directly translate English-language questionnaires during sessions, which raises concerns about the consistency and validity of such measures (Tutani et al., Reference Tutani, Eldred and Sykes2018). At a minimum, translated materials and resources in the client’s primary language should be shared with the interpreter prior to the session (d’Ardenne et al., Reference d’Ardenne, Ruaro, Cestari, Fakhoury and Priebe2007; Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025; Villalobos et al., Reference Villalobos, Orengo-Aguayo, Castellanos, Pastrana and Stewart2021).
Moreover, there is consideration as to what constitutes improvement. Williams (Reference Williams2015) argues that the IAPT framework is underpinned by positivist epistemological assumptions which emphasise quantifiable symptom change as the primary indicator of recovery. This emphasis on numerical outcome data shapes not only what is valued as ‘evidence’, but also what forms of experience are recognised, often ignoring more idiosyncratic, subjective, or contextually grounded meanings of recovery. Moreover, the outcome measures used are developed predominant in English speaking and Western contexts and may not fully capture expression of symptoms in linguistically diverse populations, and responses may be influenced by cultural norms, potentially limiting the comparability and accuracy of outcomes for some patients. For example, the PHQ-9 and GAD-7 have shown cultural biases, with certain items functioning differently across groups and potentially misrepresenting symptom severity; notably, the PHQ-9 item ‘psychomotor problems’ appeared culturally biased among Surinam Dutch males (Baas et al., Reference Baas, Cramer, Koeter, van de Lisdonk, van Weert and Schene2011), and Black/African American participants with high anxiety symptoms scored lower on the GAD-7 than other groups with comparable symptom levels (Parkerson et al., Reference Parkerson, Thibodeau, Brandt, Zvolensky and Asmundson2015). Therefore, there is a need for practitioners to carefully review psychometric data for accuracy and be mindful of how the interpretation process may have impacted client responses (Kunorubwe, Reference Kunorubwe2025) and in the longer term there is the need for the development and routine use of more culturally attuned routine outcome measures. Without culturally responsive outcome measures and translated therapeutic resources, services may unintentionally reinforce barriers to engagement and recovery, as clients are required to navigate therapy in frameworks that do not adequately reflect their cultural or linguistic contexts.
Strengths and limitations
A key strength of this study is its use of a large, routinely collected dataset from TTad services, allowing for the analysis of interpreter-mediated therapy in the context of everyday NHS clinical practice. Unlike many previous studies that have focused on smaller samples, often in specialist settings, this analysis reflects the real world. By focusing on routine care, the study enhances ecological validity and offers insights that are directly relevant to current service provision. Furthermore, the findings contribute to the broader discourse on healthcare inequities by highlighting how language needs intersect with other forms of structural disadvantage. This is particularly important given the longstanding under-representation of linguistically minoritised groups in mental health research. In addressing this significant evidence gap, the study offers an important first step towards better understanding interpreter-mediated therapy within TTad and sets the foundation for future research and targeted service improvements.
Despite the valuable insights provided by this study on interpreter-mediated therapy within the TTad program, several limitations must be acknowledged.
A significant challenge arises from the categorisation of interpreter use by NHS England. The available classifications: ‘Yes – Professional interpreter’, ‘Yes – Family member or friend’, ‘Yes – Another person’, ‘No – Interpreter not required’, ‘No – Interpreter was required but did not attend’, and ‘Not known (not recorded)’ lack specificity. The broad category of ‘Yes – Another person’ is particularly problematic, as it remains unclear whether this refers to another staff member, an ad hoc interpreter, or an unqualified individual. Additionally, ‘Not known (not recorded)’ represents the largest proportion of recorded data, 72.1% of the overall dataset, raising concerns about data quality, routine data collection practices, the visibility of language needs in service delivery and the potential under-reporting of interpreter needs. This gap limits the ability to assess the impact of different types of interpreters on therapeutic outcomes. As such, reported outcomes should be interpreted with caution.
Furthermore, there is no information on the quality of interpretation provided, which could significantly affect the therapeutic process. While best practice guidelines exist (Beck, Reference Beck2016; Beck et al., Reference Beck, Naz, Brooks and Jankowska2019; Costa, Reference Costa2022a; Kunorubwe, Reference Kunorubwe2025; Leanza et al., Reference Leanza, Miklavcic, Boivin, Rosenberg, Kirmayer, Guzder and Rousseau2013; Tribe and Lane, Reference Tribe and Lane2009; Tribe and Thompson, Reference Tribe and Thompson2017; Tribe and Thompson, Reference Tribe and Thompson2022), it is unclear whether these were followed by either the interpreter or the therapist. The reliance on informal interpreters, such as family members or untrained staff, is not recommended, as it may introduce biases or compromise confidentiality. However, the dataset does not allow for an analysis of these factors.
Another limitation is the lack of specificity regarding the CBT interventions delivered within TTad. The dataset does not provide details on the quality, structure, or supervisory processes involved when an interpreter was present. Additionally, information on the number of sessions attended is unavailable, making it difficult to assess engagement levels, treatment adherence, or other factors influencing treatment outcomes.
Importantly, there is no indication of whether treatments were culturally adapted or simply delivered with an interpreter in a manner that is not idiosyncratic, formulation driven or collaborative. Delivering CBT in a ‘copy and paste’ manner through an interpreter may be perceived as ineffective due to language barriers, when the underlying issue may be a lack of cultural adaptation (Kunorubwe, Reference Kunorubwe2025). This is particularly relevant, as culturally adapted interventions have been shown to improve acceptability, engagement and outcomes for diverse populations (Kunorubwe et al., Reference Kunorubwe, John, Molina, Davies, Gait, John, Roderique-Davies and Lancastle2024). Without this information, it is unclear whether interpreter-mediated therapy was tailored to meet the cultural and linguistic needs of service users.
The one-year time frame of the dataset also restricts the ability to analyse long-term trends or determine whether engagement with interpreter-mediated therapy and its effectiveness have changed over time. A broader timespan would allow for a more comprehensive understanding of patterns in service use and treatment outcomes. As the data included only patients who attended at least half of their Step 3 CBT appointments, we were unable to examine outcomes for those who dropped out or attended fewer sessions. This may bias the findings towards patients who completed a larger portion of treatment and limits the generalisability of the results to all referrals.
Additionally, the dataset lacks demographic information, making it impossible to account for other factors that may influence engagement and outcomes, such as socioeconomic status, migration history, or previous mental health treatment. This absence of data limits the ability to explore potential disparities in access to interpreter-mediated therapy.
Another key limitation is the absence of information on the range of languages represented in the dataset. Beyond English, there are approximately 7000 spoken languages worldwide (Leben, Reference Leben2018), some of which share historical and structural similarities. While certain widely spoken languages may be more readily interpreted, others may face interpreter shortages. A common barrier is the lack of available interpreters for some languages or dialects (Kunorubwe et al., Reference Kunorubwe, O’Leary and Wynne2025), which can leave some linguistic groups under-served, ultimately affecting access to and the quality of therapy. It remains unclear whether certain languages are better accommodated within TTad services or if some linguistic groups experience greater barriers to accessing interpreter-mediated CBT.
As no information is provided about the therapists, we are unable to offer any detailed report or analyse whether factors such as location, service structure, therapist experience, or other variables influence wating times or treatment outcomes. However, it is expected that therapists delivering therapy should be appropriately trained and supported, adhering to the best practice guidelines (National Collaborating Centre for Mental Health, 2024).
As no information was provided about the interpreters, we cannot report on their involvement or analyse factors such as interpreter experience, competence, amount of supervision, or whether the professional interpreter adhered to best practices. However, it is expected that interpreters involved in therapy are appropriately trained and supported, adhering to the best practice guidelines (National Collaborating Centre for Mental Health, 2024).
Additionally, there is a lack of data on patients’ initial symptom severity across different groups, which likely impacted on measures of reliable change and recovery. Without this information, we have limited ability to determine whether observed differences in outcomes are due to treatment effects, waiting times, or baseline differences in clinical need.
Finally, the dataset does not provide details on the specific disorders treated or whether disorder-specific measures were used to assess treatment outcomes. This limits the ability to determine whether certain mental health conditions are more amenable to interpreter-mediated therapy. Some disorders may be more responsive to interpreter-mediated CBT, whereas others may pose additional challenges.
Addressing these limitations would require improved data collection practices, including more precise categorisation of interpreter roles, quality measures, session level details, disorder specific outcomes, and cultural adaptations. Expanding the dataset beyond a single year and incorporating demographic and linguistic information would allow for a more nuanced understanding of interpreter-mediated therapy within TTad and its impact on patient outcomes.
Research recommendations
Service development and future research should focus on improving data collection and classification by ensuring more precise categorisation of interpreter roles within NHS frameworks and reducing the use of vague classifications like ‘Not known (not recorded)’. Assessing the quality of interpretation is also crucial, as interpreter training, adherence to best practice guidelines, and interpretation accuracy can significantly impact therapeutic outcomes.
Additionally, studies should examine whether CBT interventions delivered with interpreters are culturally adapted, as culturally tailored therapies have been shown to improve engagement and effectiveness. Longitudinal research is needed to track interpreter-mediated therapy trends over time, allowing for a better understanding of long-term engagement and treatment success. Incorporating demographic and linguistic factors into research would help identify disparities in access and effectiveness, particularly for under-served language groups. It would also be interesting to examine the impact of interpreter-mediated therapies of other modalities that are delivered in TTad.
Further investigation is also required to determine whether certain mental health conditions, such as anxiety and depression, are more responsive to interpreter-mediated CBT compared with disorders like PTSD or personality disorders. Best practices for interpreter-mediated therapy, including the role of pre-session briefings, post-session debriefings, and therapist–interpreter collaboration, should be explored to enhance service delivery. Additionally, studies should analyse the specific CBT interventions provided with an interpreter and the role of supervision in maintaining therapy quality. Research on language availability and accessibility would help address interpreter shortages for certain languages and dialects, ensuring equitable access to mental health services. Alternative language support methods, such as digital translation tools, multi-lingual therapy workbooks, and bilingual therapy models, should be investigated as potential solutions to barriers to interpreter-mediated therapy.
Finally, future research should also incorporate data on patients’ initial symptom severity and baseline needs, as these factors may influence both engagement with interpreter-mediated therapy and treatment outcomes. Studies examining reliable deterioration could help identify which patient groups are most at risk during waiting periods or therapy, informing targeted interventions and service planning to prevent worsening of mental health symptoms.
Addressing these research gaps will contribute to a more comprehensive understanding of interpreter-mediated therapy and its impact on mental health outcomes for linguistically diverse populations.
Conclusion
This study reveals clear and concerning disparities in both access to and outcomes from Step 3 CBT within TTad for clients requiring or requesting interpreters. While it is encouraging that the majority of these clients are still seen within national waiting time targets, some nonetheless experience longer delays than those not requiring interpreters, delays that may compound psychological distress and reduce engagement. More critically, those requiring interpreters also demonstrate significantly lower rates of reliable improvement and reliable recovery, suggesting deeper systemic issues in the provision of equitable care. The notably poorer outcomes among clients supported by professional interpreters raise important questions about the quality and consistency of interpreter-mediated therapy, as well as the training and preparedness of both interpreters and therapists to work effectively in this triadic therapeutic model. To deliver on the promise of equitable mental health care for all, there is a pressing need for targeted interventions at the practitioner, service and organisational levels.
Without acknowledging and addressing the role of language in shaping therapeutic experiences, TTad risks perpetuating the very inequalities they aim to redress and longstanding invisibility of language-based inequity in healthcare and the widespread tolerance of substandard care for linguistically diverse clients.
Important note on terminology
In this report, the term interpreter refers specifically to spoken language interpreters, those who facilitate verbal communication between speakers of different languages. This should not be confused with translators, who work with written text (Costa, Reference Costa2022a).
Also, when referring to individuals receiving psychological therapies, we use a range of commonly accepted terms such as patients, clients, service users, and others. These terms are used interchangeably throughout the report.
This approach follows the guidance of Kunorubwe (Reference Kunorubwe2023), who emphasises the importance of being conscious of the language we use. Terminology can significantly influence those we support, our colleagues, the services we provide, and broader policy decisions. It is therefore essential to continuously reflect on our language choices, clearly explain how terms are used, and acknowledge that no single term will be appropriate for all contexts or individuals.
Key practice points
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(1) Recognise that language can be a barrier to timely access to care. Clients who request or require interpreters can experience longer waiting times before accessing treatment. CBT therapists should remain mindful of how these delays may affect engagement and psychological wellbeing and, where possible, advocate for timely interpreter bookings and appropriate prioritisation of these clients.
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(2) Monitor outcomes and reflect on how interpreter use may impact therapy. Lower rates of reliable improvement and reliable recovery among clients who use interpreters suggest that language mediation could affect engagement and intervention delivery. Therapists, interpreters, services and strategic leadership should ensure adherence of best practice recommendations and adapt their processes and practices to the needs of the client, the interpreter and therapist.
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(3) The poor outcomes for clients who use interpreters within TTad, contrary to some of the other research, suggests issues with the quality of interpreter-mediated CBT delivered within TTAd. This links with research that identified some of the barriers relate to the lack of training for therapist and interpreters. Therefore, training should be provided for therapists and interpreters that covers not only the mechanics of working with interpreters, but also how to foster a collaborative, supportive, and culturally sensitive dynamic.
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(4) Further research should move beyond Step 3 CBT in TTad, to explore the nuanced interplay of language, culture, and identity in therapy. Therapists and researchers should advocate for studies that examine how linguistic diversity intersects with cultural background, migration experiences, and mental health diagnoses across all levels of care. This includes investigating the effectiveness of interpreter-mediated therapy across all the modalities offered within TTad, and even across all mental health provision.
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(5) Supervision provides a key space for therapists and supervisors to collaboratively reflect on the impact of language barriers on therapeutic work. Supervisors should proactively ask about interpreter use, explore its impact on formulation and treatment, and support therapists in advocating for clients’ needs. Issues identified in supervision such as long waits for interpreters, inconsistent interpreter quality, or lack of cultural safety should be escalated to service leads or leadership forums and inform service development and funding priorities.
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(6) Supervisors, Service Leadership, Commissioners, NHS Strategic Leadership and all individuals in positions of power hold a shared responsibility to ensure equitable access to mental health care for clients using interpreters. This includes actively addressing delays in service, ensuring interpreter quality, shaping inclusive service design, influencing policy, and holding systems accountable for reducing linguistic barriers. Equity in language access is not an optional add-on, it is a fundamental component of ethical and effective mental health care.
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(7) High-quality, complete data is essential for monitoring equity and ensuring appropriate care. Front-line staff have a key responsibility to accurately and consistently record critical demographics, including interpreter need. This should be embedded as a core part of routine practice, not seen as optional or secondary. At the same time, strategic leadership must ensure that systems support this process through adequate training, monitoring, and infrastructure. Strategic leaders are also accountable for the central collation, analysis, and use of these data to inform service planning, identify disparities, and drive improvements. Without shared responsibility and system-wide commitment, poor data quality will continue to obscure inequalities and limit progress.
Data availability statement
The data that support the findings of this study are available on request from the corresponding author, T.K.
Acknowledgements
None.
Author contributions
Taf Kunorubwe: Conceptualization (lead), Data curation (lead), Formal analysis (supporting), Investigation (lead), Methodology (supporting), Project administration (lead), Writing – original draft (joint), Writing – review & editing (joint); Natalie Meek: Formal analysis (supporting), Investigation (supporting), Methodology (supporting), Project administration (supporting), Writing – original draft (joint), Writing – review & editing (joint); Rachel E. Pye: Formal analysis (lead), Methodology (lead), Project administration (supporting), Writing – review & editing (supporting).
Financial support
This research received no specific grant from any funding agency, commercial or not-for-profit sectors.
Competing interests
The authors declare no competing interests with respect to this publication.
Ethical standards
All research conducted in this study adhered to the Ethical Principles of Psychologists and Code of Conduct as outlined by the British Association for Behavioural and Cognitive Psychotherapies (BABCP) and the British Psychological Society (BPS). This study used publicly available, anonymised data, which does not contain identifiable personal information and does not require additional ethical approval under the guidelines of the authors’ institutional review board. All procedures contributing to this work comply with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008.



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