Understanding the mechanisms by which psychotherapy improves outcomes for individuals with mental health conditions is crucial for the continuous advancement of treatments. One proposed mechanism is mentalizing, which refers to the human ability to comprehend intentional mental states, such as goals, desires, feelings, and wishes, of both oneself and others (Luyten & Fonagy, 2015). Mentalizing is multidimensional and is fundamental to navigating our species-specific social environment, and the ongoing development of social relationships and sense of self (Fonagy et al., 2002).

Deficiencies in mentalizing are observed in various psychopathologies, including psychosis and personality disorders (Johnson et al., 2022), and developmental conditions, like autism (Chung et al., 2014), making it a transdiagnostic concept. Understanding the role of mentalizing in psychological treatment is crucial for improving outcomes across diagnoses.

Luyten et al. (2024) explain that reviews have typically centred upon the association between psychopathology and deficits in mentalizing. In this systematic review, the authors instead synthesised the current research on the role of mentalizing, as a concept which applies across different diagnoses, and how it may play a role in psychological interventions.

The authors explored four main research questions:

1. Does mentalizing, prior to psychological interventions, predict outcomes?
2. Are outcomes predicted by changes in mentalizing throughout psychological interventions?
3. Does adhering to principles of mentalization-based treatment (MBT) predict outcomes?
4. Does enhancing mentalizing during psychotherapy influence the therapeutic process by improving the therapeutic alliance, reducing symptoms, or enhancing interpersonal functioning?

Methods

In their pre-registered review, Luyten and colleagues (2024) identified studies from three electronic databases. The databases were systematically searched, and the authors established criteria for study inclusion. The criteria included papers that explored mentalizing, or reflective functioning, using validated measures created to assess these concepts, or assess compliance with mentalization-based techniques, examining both of these as mechanisms of change in treatments in adult populations. Criteria also stipulated that interventions were on an individual basis, or a combination of individual and group treatment. Studies were written in English, had a sample size greater than 10, and were published in a peer-reviewed journal.

In the included studies, researchers used either the Reflective Functioning Scale (Fonagy et al., 1998), the Reflective Functioning Questionnaire (Fonagy et al., 2016), and the Mentalising Questionnaire (Hausberg et al., 2012), to measure mentalizing/reflective function.

Two coders assessed study quality using the Effective Public Health Practice Project (EPHPP) tool. EPHPP was chosen for its adaptability. Studies were assessed on five different domains and matched with a rating of strong, moderate or weak.

Results

The authors identified 3,080 papers once duplicate records had been excluded. After titles and abstracts were screened, inclusion criteria were met, and full text screening had been completed, 26 papers were identified. The authors retrieved an additional 7 papers through citation searching. Overall, the review comprised of 33 studies, which included 3,124 participants. Over 50% of the studies used or reported findings from single-armed designs or reported secondary findings from these studies.

A meta-analysis could not be conducted due to the heterogeneity of studies in terms of design, sample diagnosis, and treatment intervention. The study followed systematic narrative review design, which did not did not combine quantitative data. The review included all papers, including those where overlap in datasets was present. Regarding the quality assessment, the majority of studies included in the review were assessed to be moderate or strong.

Does pre-treatment mentalizing predict outcome?

Results demonstrated that pre-treatment mentalizing showed slightly ambiguous outcomes. Half of the studies included reported a positive relationship between patients’ ability to mentalize and outcomes, such as symptom improvement. The other half had mixed findings; for instance, some studies found a positive link with therapeutic alliance in treatment, but not treatment outcome. However, the authors did state that only one study found no association between concepts (p.8).

Do changes in mentalizing predict outcome?

The authors elucidated that a large proportion of the studies included in the review did indicate that changes in mentalizing throughout an intervention were associated with changes in treatment outcome. For some studies, changes in reflective functioning throughout treatment led to improvements in symptom severity. Although the authors noted that some papers reported negative results and found no correlation between change in reflective functioning and symptom severity (p.11).

Does adherence to the MBT model or MBT prototype predict outcome?

There was evidence that fidelity to the MBT model was associated with improved outcomes, like improvements in reflective functioning and symptom outcome. Additionally, in two studies, it was found that therapist mentalizing positively influenced patient outcomes; one study found that therapists with high levels of reflective functioning indicated better therapist effectiveness, and therefore these therapists managed better client outcomes in terms of symptom improvement (Cologon et al., 2017). The authors did stipulate, however, that there was only a small number of studies explored for this research question (p.11).

Proximal outcomes: does improving (in-session) mentalizing predict the therapeutic process in terms of improvements in process or symptomatic outcome?

Unfortunately, the authors stated that not enough studies were available to be included in the review, and the studies that were included were too heterogeneous to clearly answer this research question. The authors stipulated that there were some positive initial findings, including a study that found if therapists frequently encouraged patients to reflect on their mental state, this was associated with lower emotional arousal (Kivity et al., 2021).

Conclusions

The authors conclude:

Results suggest that mentalising might be a mediator of change in psychotherapy and may moderate treatment outcome. However, the relatively small number of studies (n = 33 papers based on 29 studies, totalling 3,124 participants) that could be included in this review, and the heterogeneity of studies in terms of design, measures used, disorders included, and treatment modalities, precluded a formal meta-analysis and limited the ability to draw strong conclusions (Luyten et al., 2024; p. 1).

Strengths and limitations

In their systematic review, Luyten et al (2024) advanced research by reviewing studies that explored the role of mentalizing as a moderator and mediator of change in psychotherapy; a topic not previously examined in a systematic review. The review comprehensively summarised available evidence and clearly presented the results of all papers. The review was also clearly focused around four research questions, with a defined population, intervention and outcome.

The authors completed a comprehensive search of three databases, and supplemented with citation searching to ensure identification of relevant studies. The authors excluded papers written in non-English, which could increase bias. Nevertheless, the paper was pre-registered, which is important for transparency and bias reduction (Stewart et al, 2012). Additionally, regarding quality assessment, the authors used the EPHPP, which is a validated tool for assessing study quality. A large proportion of the studies were rated moderate to strong, which aids in minimising bias.

However, there were limitations. The authors themselves asserted that mentalizing encompasses different dimensions that must be used flexibly. Many of the studies have explored the concept in a simplified manner; this is important as distinct dimensions of mentalizing may relate differently to different therapeutic outcomes. Future studies should measure how different aspects of mentalizing, like recognising differences between one’s own and others’ mental states, and whether mentalizing is automatic or controlled (Luyten et al., 2020), may differently impact therapeutic outcomes.

Additionally, although the measures used in the studies to assess mentalizing were validated and demonstrated good reliability, they included self-report measures which can increase risk of bias. As the population samples included in the review were diverse in relation to the psychopathologies experienced, this could have further impacted the results on the self-report measures and caused difficulty in capturing nuances of mentalizing across conditions.

Generally, papers included in the review had a significant amount of heterogeneity across many dimensions. Regarding study design, a large proportion of the studies were single-armed, which can increase bias, especially in comparison to randomised controlled trials, which have control groups (Cucherat et al., 2020). Furthermore, lack of consistency across the interventions used makes it difficult to draw clear inferences about the role of mentalizing in psychological treatment. Although the authors specifically included papers that used MBT, further reviews should standardise treatment type to clarify the role of mentalizing across clinical interventions.

Despite the limitations, the evidence-base for MBT is still growing, especially for application beyond borderline personality disorder (BPD), and, therefore, the authors provided valuable insights regarding the role of mentalizing in various psychopathologies and interventions. The authors have also identified key areas for further research. Overall, the paper provided significant food for thought regarding clinical practice.

Implications for practice

Due to the limitations of the study, the role of mentalizing in psychological interventions should be interpreted tentatively. However, as the authors stated there was evidence to suggest pre-treatment mentalizing may impact outcomes (findings were strongest in this area); mixed evidence that changes in mentalizing may impact outcomes; and some evidence to suggest that fidelity to an MBT model/prototype may impact outcomes, it is important to consider the role of mentalizing in clinical practice.

Considering fidelity to an MBT model, there is evidence to suggest that mentalization-based techniques have clinical utility in symptom reduction for people experiencing BPD (Vogt and Norman, 2018) and can continue to have a positive impact over time (Bateman and Fonagy, 2008). MBT is an evidence-based treatment for BPD and, therefore, secondary care or tertiary mental health services could consider, or continue to use MBT for this population. There is also some evidence to suggest that mentalization could be impaired in other psychopathologies, including posttraumatic stress disorder and obsessive-compulsive disorder (Sloover at al., 2022). Although research in this area appears more limited, it is important to begin to consider the MBT model across different psychopathologies, although further research would be needed before treatments can be implemented and standardised across the system.

The study also generally highlighted key elements of treatment that must be considered for people receiving psychological intervention. Clinicians can encourage mentalizing in treatment through existing structures, like psychoeducation or using language and questioning that promotes mentalizing, by encouraging people to reflect on their own mental states, or the mental states of others. Therapies that exist at all levels of the mental health system, such as cognitive behavioural therapy, can be used to practice mentalizing (Björgvinsson & Hart, 2006) and clinicians should make a conscious effort to continue to promote this element of therapy to improve therapeutic outcomes.

In the spirit of aligning our actions with our principles, the present study can also serve as a helpful reminder to continually consider our own mentalizing as clinicians. In busy clinical practice, it is important to take time to understand the actions of ourselves and others in terms of feelings, goals, and desires to reflect and improve interventions. It has been found that an effective therapist is one that can mentalize well (Cologon et al., 2017), so as we explore the implications for those we support, it is important to consider the implications for ourselves.

Statement of interests

There are no conflicts of interests to declare.

Relevant Mental Elf video

If you want to learn more about mentalizing and MBT in relation to ‘personality disorders’, check out this in-depth discussion with Anthony Bateman recorded as part of the 2024 BIGSPD Podcast.

Links

Primary paper

Luyten, P., Campbell, C., Moser, M., & Fonagy, P. (2024). The role of mentalizing in psychological interventions in adults: Systematic review and recommendations for future research. Clinical Psychology Review, 102380–102380. https://doi.org/10.1016/j.cpr.2024.102380

Other references

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