What is major depressive disorder?

Major depressive disorder (MDD) is a common mental health problem characterised by persistent feelings of sadness, hopelessness, and loss of interest in activities that were once enjoyable. Symptoms of MDD can vary from person to person but may include a persistent sadness, loss of energy, difficulty sleeping, changes in appetite or weight, feelings of guilt or worthlessness, difficulty concentrating or making decisions, and thoughts of suicide or self-harm. To meet the diagnostic criteria, a person must experience five or more symptoms for at least 2 weeks. See Table 1 for the diagnostic criteria for MDD from the DSM-V (American Pyschiatric Association, 2013).

Table 1.

DSM-V criteria for major depressive disorder

From American Psychiatric Association (2013; p. 161).

Estimates of prevalence in 2000 were approximately 16 per 100,000 per year for men and 25 per 100,000 per year for women worldwide (Üstün et al., Reference Üstün, Ayuso-Mateos, Chatterji, Mathers and Murray2004). The Global Burden of Disease (GBD, 2019) reported that depressive disorders accounted for the largest proportion of mental disorders in 2019 (approximately 37.3%). In addition, Santomauro et al. (Reference Santomauro, Herrera, Shadid, Zheng, Ashbaugh, Pigott, Abbafati, Adolph, Amlag, Aravkin, Bang-Jensen, Bertolacci, Bloom, Castellano, Castro, Chakrabarti, Chattopadhyay, Cogen, Collins and Ferrari2021) estimated a further 27.6% increase in MDD due to the COVID-19 pandemic. In terms of impact, MDD is associated with significant burdens including decreased quality of life, functional impairment, suicide, cardio/cerebral mortality, disability, and economic and family burdens (Lepine and Briley, Reference Lepine and Briley2011).

CBT as an effective treatment for MDD

In randomised control trials (RCTs), cognitive behavioural therapy (CBT) for the treatment of MDD has demonstrated efficacy compared with control/waitlist groups (Beltman et al., Reference Beltman, Voshaar and Speckens2010; Van Straten et al., Reference Van Straten, Geraedts, Verdonck-de Leeuw, Andersson and Cuijpers2010) and is as effective as other forms of psychological therapy (Barth et al., Reference Barth, Munder, Gerger, Nüesch, Trelle, Znoj, Jüni and Cuijpers2013; Cuijpers et al., Reference Cuijpers, Muñoz, Clarke and Lewinsohn2010; Cuijpers et al., Reference Cuijpers, Berking, Andersson, Quigley, Kleiboer and Dobson2013; Hofmann et al., Reference Hofmann, Asnaani, Vonk, Sawyer and Fang2012). CBT is more effective than relaxation (Jorm et al., Reference Jorm, Morgan and Hetrick2008) or psychodynamic therapy (Tolin, Reference Tolin2010). This is not only true within study conditions; more recently, a systematic review and meta-analysis by Öst et al. (Reference Öst, Enebrink, Finnes, Ghaderi, Havnen, Kvale, Salomonsson and Wergeland2023) found that CBT for MDD is an effective treatment when delivered in routine clinical care, with outcomes comparable to those obtained in efficacy studies.

Although CBT is sometimes considered a monolith, it is more akin to a family of therapies with similarities and differences. Even within the treatment of MDD, there is cognitive therapy (CT) based on Beck (Reference Beck1979) and behavioural activation (BA) based on Martell et al. (Reference Martell, Addis and Jacobson2001) and Lejuez et al. (Reference Lejuez, Hopko and Hopko2001). In England, the National Institute for Health and Care Excellence (NICE) recommends these as front-line treatments delivered either individually or in groups. According to NICE guidelines, these CBT-based treatments should be considered first before exploring other modalities such as group exercise, mindfulness, interpersonal therapy, SSRI anti-depressants, counselling, and short-term psychodynamic psychotherapy (NICE, 2022).

Group delivery of CBT for MDD

Initially developed as an individual therapy (Beck, Reference Beck1979), CBT delivered in a group format has been found to be effective, with meta-analyses of RCTs of group CBT for MDD reporting good efficacy (Cuijpers et al., Reference Cuijpers, van Straten, Andersson and van Oppen2008; Feng et al., Reference Feng, Chu, Chen, Chang, Chen, Chou, Chang and Chou2012; Huntley et al., Reference Huntley, Araya and Salisbury2012). A more recent network meta-analysis by Cuijpers et al. (Reference Cuijpers, Noma, Karyotaki, Cipriani and Furukawa2019) highlighted that the efficacy of individual, group, telephone, and guided self-help CBT formats did not differ significantly. In addition, individual and group formats were more acceptable to clients.

In England, the majority of CBT for mild to severe MDD is delivered through the NHS Talking Therapies Programme (formerly known as Improving Access to Psychological Therapies or IAPT). This national initiative aims to improve access to evidence-based psychological therapies for individuals with common mental health disorders such as anxiety and MDD. Group CBT is a commonly offered treatment option within the NHS Talking Therapies programme, with a total of 23,868 clients receiving group CBT between 2021 and 2022 in England (NHS Digital, 2022). The data further indicate that group CBT for MDD yields promising results, reducing PHQ-9 scores from an average baseline score of 12.2 to an average final score of 9.2 over the same period (NHS Digital, 2022). The prevalence of group CBT in the NHS Talking Therapies programme is consistent with the NICE guidelines for MDD (NICE, 2022), which recommend group CBT as a second-line intervention.

In terms of benefits, group CBT provides frequent and varied opportunities for mutual reinforcement and peer modelling (Wolgensinger, Reference Wolgensinger2015), which is much more powerful than reinforcement by a therapist alone (Rose, Reference Rose, Price, Hescheles, Rae Price and Price1999). Group CBT is considered cost and time efficient for treating many patients (Kwon and Oei, Reference Kwon and Oei2003; Oei and Dingle, Reference Oei and Dingle2008). Therefore, given the need to improve access to talking therapies and meet targets, many services use group treatments (Wykes, Reference Wykes2013). The NICE guidelines for MDD (NICE, 2022) note benefits of connecting with others who are having similar experiences.

However, this is not to say that group CBT has no disadvantages. These may include possible confrontations between participants, the development of sub-group/cliques, and participants talking over each other (Tucker and Oei, Reference Tucker and Oei2007). Group CBT may not be suitable for people with recurrent MDD, co-morbidity, or those who need reasonable adjustments (e.g. language or accessibility). Finally, when reviewing the NHS Talking Therapies data from NHS Digital (2022), it is unclear what constitutes group CBT, as it is described as ‘psychoeducational peer support’ but it is not clear whether all services have a shared understanding of what this entails. For instance, do they all use the same interventions? Is there any difference in the intensity or number of sessions? Is there consensus about group size? Do they all involve rigorous quality assurance?

Influence of culture on the presentation and treatment of MDD

Culture can be described as the behaviours, norms, ideas, attitudes and traditions that exist within groups of people and are typically explicitly/implicitly communicated. Examples include whether one takes their shoes off or keep them on within the house, eating etiquette, rules around personal space, communication styles, greeting customs, and family structures. Whatever it is, if one has a typical pattern of behaviour; where did they learn this norm? Are there any explicit messages or implicit meanings that have been conveyed? If one has a typical pattern of behaviour, one’s culture helps to understand the origins of such norms and their associated meanings.

In the context of healthcare, culture inevitably impacts every aspect of illness and adaptations, such as responses to symptoms, explanations of illness, patterns of coping, help-seeking behaviour, adherence to treatment, and even emotional expression (Helman, Reference Helman2007).

This is also true with MDD, as culture influences the expression of symptoms, illness explanation, and pathways to care (Patel, Reference Patel2001). In many cultures, physical symptoms are the most common presenting feature, and they are more likely to be expressed than psychological symptoms (Aichberger et al., Reference Aichberger, Schouler-Ocak, Rapp and Heinz2008; Bhugra and Mastrogianni, Reference Bhugra and Mastrogianni2004; Desjarlais et al., Reference Desjarlais, Eisenberg, Good and Kleinman1995). Culturally bound descriptions are more likely to be used; for instance, clients from Iraq may be more likely to describe ‘oppression in the chest’ or ‘hunger for air’ than depression (Al-Krenawi and Graham, Reference Al-Krenawi and Graham2000). Some clients from Arabic backgrounds are more likely than Western clients to describe aches, pains and weakness (Sulaiman et al., Reference Sulaiman, Bhugra and de Silva2001).

In terms of the explanation of illness, this also varies too. With culturally specific presentations and understanding resulting in culturally specific syndromes such as ‘Brain Fag’, ‘Ode-ori’, ‘Hwa-byung’ or ‘Neurastheni’ (Kirmayer, Reference Kirmayer2001). Kleinman et al. (Reference Kleinman, Anderson, Finkler, Frankenberg and Young1986) reported that 30% of clients attending out-patient clinics in Hunan, China were diagnosed as ‘neurathenic’ (meaning having neural weakness) as this was more common and acceptable than depression. A more recent example comes from Taiwan, where Chen (Reference Chen2021) reported on the emergence and increasing prevalence of ‘Zilushenjin shitiao’ (自律神經失調 or autonomic imbalance). Autonomic imbalance is not a formal diagnosis but refers to a wide range of physical and mental symptoms that are medically unexplained (Chen, Reference Chen2022)

In terms of pathways to care, there is variation due to patterns of help-seeking behaviour ranging from traditional to informal, or semi-formal routes. This leads to variation between seeking help from religious leaders, family members and even internet forums (Markova et al., Reference Markova, Sandal and Pallesen2020). GPs face challenges in supporting clients from other cultures due to a lack of knowledge of past experiences/norms, culturally based differences, e.g. understanding of the aetiology, and even misunderstandings in communication (Lehti et al., Reference Lehti, Hammarström and Mattsson2009).

The influence on the presentation and treatment of MDD is not just limited to cultural differences but is also influenced by geopolitical events and historical processes. Considering the differences alone risks a simplistic, ahistorical, and decontextualised view. For instance, Okazaki et al. (Reference Okazaki, David and Abelmann2008) warn against the tendency in psychology to ascribe observed group differences to East–West binaries such as individualism–collectivism or Judaeo-Christian versus Confucian. Rather, it is necessary to be open to complex, multi-factorial influences and narratives. Due to historical and societal factors, some clients from diverse backgrounds face adversity, which may relate to an increased risk of mental health problems and is compounded by barriers to accessing mental healthcare (Lawton et al., Reference Lawton, McRae and Gordon2021).

In summary, all of this highlights the importance of clinicians gaining the necessary understanding of the client, their culture, and wider context to reach a shared understanding of the presenting problem and agree on a treatment approach (Kirmayer et al., Reference Kirmayer, Narasiah, Munoz, Rashid, Ryder, Guzder, Hassan, Rousseau and Pottie2011).

Poorer access and outcomes for clients from diverse backgrounds

Discourse is increasingly focused on how CBT may be less effective and less acceptable to clients from diverse backgrounds when delivered in a generic manner (Bennett et al., Reference Bennett, Flett and Babbage2016). It may not be appropriate for individuals from non-Western backgrounds due to the significant role that culture plays in the conceptualisation of difficulties and the ethnocentric nature of psychosocial interventions, developed based on Western cultural values (Naeem et al., Reference Naeem, Phiri, Rathod and Ayub2019).

In the NHS Talking Therapies programme, many clients receive CBT, accounting for 46.3% of all treatment episodes in 2020–2021 (NHS Digital, 2022). Despite this large proportion receiving CBT, clients from diverse backgrounds tend to have lower access rates and poorer outcomes than their White British counterparts (Baker and Kirk-Wade, Reference Baker and Kirk-Wade2023). This trend is true across the years as individuals who identified as White British were more likely to complete treatment and improve than those from any other background between 2018 and 2019 (Ahmad et al., Reference Ahmad, McManus, Cooper, Hatch and Das-Munshi2022). Poorer outcomes were reported for clients from Yemeni, Pakistani and Somali background (Arafat, Reference Arafat2021) and women of Pakistani background (Kapadia et al., Reference Kapadia, Brooks, Nazroo and Tranmer2017). In addition, clients from Black Caribbean, Black other, and White other groups were more likely to be referred to other services than to be treated within NHS Talking Therapies (Harwood et al., Reference Harwood, Rhead, Chui, Bakolis, Connor, Gazard and Hatch2023). Bhavsar et al. (Reference Bhavsar, Jannesari, McGuire, MacCabe, Das-Munshi, Bhugra and Hatch2021) noted that individuals residing in the UK for less than 10 years are less likely to engage with NHS Talking Therapies, even after accounting for factors such as English proficiency or reason for moving.

Poorer outcomes are also true in relation to engagement and completion. NHS Talking Therapies data highlights lower completion rates for clients from diverse backgrounds than White British counterparts (Baker and Kirk-Wade, Reference Baker and Kirk-Wade2023). However, whether this is solely associated with not receiving culturally adapted or sensitive psychological interventions or other factors is unclear. Rathod et al. (Reference Rathod, Kingdon, Pinninti, Turkington and Phiri2015) warn of the potential risk of clients disengaging if CBT is continually delivered in a generic way as it creates a perception or experience that their culture or they themselves are not understood.

Generic application of CBT could also obstruct the process of change, especially if the therapists’ explanations are contradictory or not acceptable to the client’s cultural model (Jameel et al., Reference Jameel, Munivenkatappa, Arumugham and Thennarasu2022). For example, when providing psychoeducation about the fight-or-flight response in practice, many therapists link this with the theory of evolution. However, this may contradict some clients’ beliefs or cultural models. Similarly, when implementing BA, there is a risk of focusing solely on generic activities or those that are the norm for the majority, such as going for a night out, drinking, socialising between genders, or engaging in certain recreational activities. However, these activities may not align with those preferred by clients from diverse backgrounds and may even directly conflict with their cultural models, obstructing the process of change.

This highlights significant issues with access and outcome rates for clients from diverse cultural backgrounds. Historically, this trend was not fully acknowledged, and the explanation reinforced problematic narratives. Clients from diverse backgrounds tended to be portrayed as being ‘hard to reach’ (Naz et al., Reference Naz, Gregory and Bahu2019).

There is a significant need to ensure that the delivery of CBT is not done in a copy-and-paste manner. It is worth noting that the author has chosen to use the term ‘generic’ rather than ‘standard’ as such copy-and-paste work is not consistent with CBT standards. Greenberger and Padesky (Reference Greenberger and Padesky1995) warn against such an approach in the 1990s:

If anything, CBT offers opportunities to ensure that psychological therapies are accessible and acceptable to clients from diverse backgrounds. Bhardwaj (Reference Bhardwaj2016) argues CBT has strengths lending itself to cultural adaptation, such as the flexibility to meet the needs of the individual, the focus on client empowerment, and attention to conscious processes and specific behaviours which are more appropriate.

Implicit cultural assumptions within CBT

CBT has been developed and studied predominantly with participants from the racial and cultural majority in Western countries, leading to criticism for being overly Western-centric and founded solely on cultural assumptions that align with Western societies (Summerfield and Veale, Reference Summerfield and Veale2008). Some aspects of CBT may be contradictory or incompatible with the values and cultural assumptions of individuals from non-Western cultures or those from marginalised backgrounds (Jameel et al., Reference Jameel, Munivenkatappa, Arumugham and Thennarasu2022). Therefore, it can be helpful to consider inherent, implicit assumptions when considering CBT in diverse cultures.

One of the key assumptions of CBT is that thoughts and beliefs are the primary drivers of emotions and behaviour. However, some individuals and cultures may be less likely to attribute their emotions and behaviour to internal factors, and more likely to attribute them to external factors such as social context and relationships (Heine et al., Reference Helman2007). Thus, CBT’s focus on changing internal thought patterns invariably influences the acceptability and efficacy of CBT.

The degree to which a culture or individual is individualistic or collectivistic is worth considering. Guo and Hanley (Reference Guo and Hanley2015) outline the challenges and opportunities for adapting CBT for Chinese clients and describe how CBT was developed based on the Western individualistic worldview. Such a worldview promotes the autonomy of the individual. It also emphasises the individual’s need for self-development. However, such values may not be relevant in the Chinese collectivist culture, where the needs of the community are placed before the needs of the individual, and the individual’s locus of control is often externalised.

Another culturally based assumption within CBT, rooted in Western cultural values, is a prioritisation of personal responsibility. Based on this cultural context, it is sometimes assumed that individuals are solely responsible for change, so much so, that personal responsibility for change is considered an indicator of suitability for CBT (Myhr et al., Reference Myhr, Talbot, Annable and Pinard2007). However, this assumption may not apply to individuals from collectivistic cultures, which emphasise interdependence, cohesion, and social harmony (Friedman et al., Reference Friedman, Rholes, Simpson, Bond, Diaz-Loving and Chan2010; Heine et al., Reference Heine, Lehman, Markus and Kitayama1999). Individuals from collectivistic cultures may be more likely to prioritise the family or community needs.

Another culturally based assumption within CBT is that individuals clearly understand the content of their thoughts and beliefs and are comfortable expressing them. However, this assumption may not apply to individuals from cultures where expressing emotions and thoughts is not encouraged or is even discouraged. For example, in some Asian cultures, there is a strong emphasis on emotional control and suppression (Matsumoto and Yoo, Reference Matsumoto and Yoo2006). Individuals from these cultures may be less likely to express their emotions and thoughts in a therapy session, which could influence the acceptability or effectiveness of CBT.

In CBT, there is an underpinning principle that early life experiences can significantly impact an individual’s beliefs, attitudes and behaviours. Specifically, negative early life experiences can lead to the development of maladaptive thought patterns and coping strategies that persist into adulthood. However, what constitutes a negative experience often carries assumptions influenced by norms based on the Western majority, and the assumption may not apply equally to individuals from different cultures. For instance, in CBT, there can be an assumption of a norm about attachment and family dynamics. However, research has shown that attachment styles may vary across cultures, with some cultures emphasising secure attachment, while others may value more autonomous and independent attachment styles (Grossmann and Grossmann, Reference Grossmann and Grossmann1991; Rothbaum et al., Reference Rothbaum, Weisz and Snyder1982). Research has shown that the impact of early life experiences on mental health may vary depending on cultural factors such as collectivism, individualism, and the importance of interdependence (Kirmayer, Reference Kirmayer2001).

There may be cultural differences in the types of early life experiences that are most likely to lead to negative outcomes in adulthood. For example, in some collectivist cultures, interpersonal stressors such as conflicts with family members or social ostracism may be more common and have an impact on mental health more than in cultures where individualism is prioritised (Kirmayer, Reference Kirmayer2001).

While CBT has been shown to be an effective treatment for many individuals, it is important to recognise that it is founded on culturally based assumptions that may not apply to everyone. Culture influences an individual’s life experiences, beliefs and responses, which can influence the development and maintenance of psychopathology, shaping their beliefs about health and illness, pathways into care, and trust in mental health services (Rathod et al., Reference Rathod, Phiri and Naeem2019).

It is important to acknowledge that the criticisms about being overly Western and the implicit assumptions noted above are applicable to CBT and most psychological therapies. As most psychological therapies and their underlying theories are rooted in Euro-American culture (Guo and Hanley, Reference Guo and Hanley2015), they have primarily been tested on individuals within Western countries. These therapies are also predominantly delivered in services that lack diversity and representation (Hays, Reference Hays, Iwamasa and Hays2019). Furthermore, the institutions and departments responsible for training therapists often do not reflect the broader diversity of society (Hays, Reference Hays, Iwamasa and Hays2019).

Addressing these issues requires a concerted effort from all, regardless of whether therapists, researchers and educators promote inclusivity within the field of psychological therapy, moving beyond the copy-and-paste delivery of Western-centric approaches to actively incorporate clients’ diverse cultural perspectives into existing therapeutic frameworks. This involves recognising inherent assumptions, adapting therapeutic techniques to suit different cultural contexts, and fostering a diverse and inclusive community of therapists who can effectively cater to the needs of a multi-cultural clientele. It also progresses to a point where psychological therapies are developed, tested and disseminated by and for clients from diverse backgrounds. By embracing these changes, the field can progress towards a more equitable and effective practice of psychological therapy for all.

Culturally adapted CBT

Culturally adapted CBT (CA-CBT) involves adjustments to how therapy is delivered without compromising the theoretical underpinning of CBT. The adjustments are informed and achieved through developing awareness, knowledge, and skills related to a given culture (Naeem, Reference Naeem2012a). This may include integrating the distinctive and culturally influenced aspects of how mental health issues are expressed and comprehended (Beck, Reference Beck2016). It also integrates the complex and multi-dimensional ways in which people conceptualise their identities (Hays, Reference Hays2016). It acknowledges and integrates cultural factors, values, beliefs and norms into the therapeutic process to enhance the effectiveness of treatment and improve outcomes for individuals from diverse cultural backgrounds.

Depending on the presenting problem and the client’s cultural background, different aspects of the delivery of CBT may be adjusted. Therefore, it is not a one-size-fits-all approach. While it is not feasible to outline all the different examples of adaptations, a range of examples are offered below:

One focus of modification is the integration of the client’s cultural values, in understanding and resolving psychological issues. An example of this is a case study by Diaz-Martinez et al. (Reference Diaz-Martinez, Interian and Waters2010), integrating Latino values of ‘marianismo’ (selfless sacrificing for the family), ‘respecto’ (respect), ‘familismo’ (value of the family), and ‘ser bien educado’ (parents’ responsibility for the behaviour of their children). Another example is the inclusion of Taoist principles of collective benefit, non-competition, moderation, acceptance, humility, flexibility, effortless action, and harmony with the laws of nature into cognitive therapy (Chang et al., Reference Chang, Hung, Ng, Ling, Chen, Cao and Zhang2016). Such integration of values enables greater sense making, provides context for thoughts/beliefs, becomes a central component of the formulation, and influences the interventions.

There may also be focus on modifying the typical assessment process by gaining a greater understanding of the client through discussions about their culture, religion and ethnicity. For instance, discussions about cultural identity, acculturation, religious/spiritual orientation, and difficulties in cultural adjustments can help understand the levels of cultural adjustments and religious orientation (Naeem et al., Reference Naeem, Phiri, Munshi, Rathod, Ayub, Gobbi and Kingdon2015). For other clients, once trust is established, there may be a need to enquire about experiences of racism or micro-aggressions and the impact these may have on the client and on their mental health (Beck, Reference Beck2019).

Another focus is the use of culturally originating or appropriate metaphors, stories, proverbs and lessons to describe key aspects of the client’s experience or principles within CBT. An example with Mauri clients is the metaphor of a house (Māori word – ‘whare’) to describe a formulation, with the foundation representing early childhood experiences. The first floor are the core beliefs, the next floor being rules for living and the roof being the coping strategies, which may or may not be helpful (Bennett et al., Reference Bennett, Flett and Babbage2016). Another example is Washington (Reference Washington2012) who used the metaphor of the trickster coyote with Native American clients. This was useful for explaining how cognitive distortions can trick people and mislead them, but also described cognitive restructuring as knowing the names of the coyotes, which brought them out of the dark and into the light.

Modification may also focus on the therapy process or interventions to ensure they are congruent or originate from the client or their culture. For example, the greater involvement of family members or significant others in therapy can improve communication and share learning (Berry et al., Reference Berry, Day, Mulligan, Seed, Degnan and Edge2018). Another example relates to whether to utilise cognitive or behavioural interventions, as some clients may encounter difficulties discussing thoughts due to cultural norms and a fear of being judged. Therefore, there may be a need to pick an intervention that aligns with a perceived cultural preference for behavioural work (Guo and Hanley, Reference Guo and Hanley2015). Alternative modifications may be focused on homework, whereby some may benefit more from writing in their native language, using symbols with less writing, regular reminders, audio, culturally bound counting (using beads), and involving the family (Naeem et al., Reference Naeem, Phiri, Munshi, Rathod, Ayub, Gobbi and Kingdon2015).

Such adjustments are not ad hoc; instead, they are systematic modifications of various research-based interventions to ensure that they are compatible (Bernal et al., Reference Bernal, Jiménez-Chafey and Domenech Rodríguez2009).

Several conceptual models have been developed and published to inform the systematic approach to adapting psychological therapies. However, within the scope of this review, it is not feasible to outline all of these. Rather, encourage the reader to consult Naeem et al. (Reference Naeem, Sajid, Naz and Phiri2023) who summarises existing frameworks and provide guidance on the processes and elements involved in culturally adapting therapies. The Southampton Adaptation Framework (Naeem et al., Reference Naeem, Ayub, Gobbi and Kingdon2009) was considered for this review. This involves a process of gaining awareness of relevant issues beforehand (through literature, experts, and community engagement), adapting assessment and engagement (assessing not just the presenting problem but the influence of culture, using culturally relevant formulations and modifying engagement approaches) and adjusting therapy processes or techniques (such as style of therapy, structural factors and even focus of interventions).

This field is gradually expanding and is beginning to address the lack of research on the effectiveness of CBT for MDD with clients from diverse backgrounds. However, there are only a few noteworthy systematic reviews in the current literature. Horrell (Reference Horrell2008) reviewed the literature on the use of CBT with ethnic minority clients living in the United States of America (USA) across a range of psychological disorders (including MDD). Six studies reported findings on the effectiveness of CBT as a treatment for ethnic minority adults with MDD. The findings suggest that CBT is an effective intervention for Hispanic and Latina women and has promising results for African American women, but no definitive conclusions were drawn for other communities. Kalibatseva and Leong (Reference Kalibatseva and Leong2014) reviewed existing culturally adapted treatments for MDD across multiple modalities (including CBT) and found that the majority involved practical adaptations, e.g. translating materials.

However, there were some issues within these reviews, such as a small number of appropriate studies, an unclear assessment of quality or a lack of details on methodology within the reviews, appearing to be more critical reviews rather than fully systematic reviews.

Lehmann and Bördlein (Reference Lehmann and Bördlein2020) reviewed culturally adapted BA to examine the methods and outcomes of cultural adaptations. Adaptations were found in different dimensions, including language, content, methods and context. The results indicate the effectiveness of BA and its cultural adaptations across the studies. Anik et al. (Reference Anik, West, Cardno and Mir2021) conducted a systematic review and meta-analysis on the efficacy of culturally adapted face-to-face psychological treatments (including CT and BA). Their findings highlighted how CT and BA were often selected because of their strong evidence base for effectiveness. While both contribute to the literature, there remains a gap in examining culturally adapted CBT specifically and a much larger gap in culturally adapted CBT groups for MDD.

In general, these studies recognised the shortage of research in this area, emphasise the need for continued efforts to incorporate ethnic minorities into research, and provided recommendations for future studies.

Rationale

Despite the literature exploring culturally adapted psychological therapies, there is a gap in research that examines whether CA-GCBT for MDD is effective. Okumura and Ichikura (Reference Okumura and Ichikura2014) were the closest to answering this question, and explored the efficacy and acceptability of group CBT for depression generally. Their findings highlighted that group CBT had a superior efficacy with a standardised mean difference (SMD=−0.68) and similar acceptability compared with non-active controls. However, this had a large proportion of studies that were focused on clients from the racial majority and were not specifically focused on CA-GCBT.

To the researcher’s knowledge, no systematic review has examined the effectiveness of CA-GCBT for depression in adults from diverse backgrounds.

Aim of the current study

The aim of this review is to systematically identify, evaluate, and integrate the findings of the existing empirical literature on the benefits of CA-GCBT for depressed clients from diverse backgrounds.

This systematic literature review explores whether group CBT is an effective treatment for clients from diverse backgrounds if culturally adapted.

It attempts to answer the following research questions: Are culturally adapted CBT groups beneficial for depressed clients from diverse backgrounds? What modifications have been made to make it culturally adapted group CBT?