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. 2025 Mar 3;58(5):917–925. doi: 10.1002/eat.24397

Toward Integrated Treatment for Co‐Occurring Borderline Personality Disorder and Eating Disorders: A Clinician Perspective

Charlotte Cunningham 1, Jillian H Broadbear 2,3,4,✉, Janani Rajaram 4, Sathya Rao 2,3,5, Richard Newton 6,7, Roslyn Galligan 1
PMCID: PMC12067518  PMID: 40028771

ABSTRACT

Objective

It is common practice in Australia for co‐occurring borderline personality disorder (BPD) and eating disorders (ED) to be treated separately. The objective of this research was to review features these disorders share, evidence‐based approaches used for treating these disorders in isolation, clinicians' experiences of delivering treatment for co‐occurring BPD and ED, and finally to explore integrated approaches to treating this dual diagnosis.

Method

A qualitative approach was used to examine interview transcripts of 10 clinicians employed at specialist outpatient services for severe BPD or severe ED. Interview transcripts were analyzed using thematic analysis.

Results

Nominated features shared by BPD and ED were emotion dysregulation, impulsivity, and interpersonal difficulties. Clinicians endorsed a range of therapeutic approaches for this dual diagnosis patient group, as well as an eclectic approach utilizing a combination of treatment features. Most clinicians proposed an ideal program duration of 6–12 months, with group and individually focused therapy complementing one another to address underlying behavioural drivers and confer lasting clinical benefits.

Discussion

This study distills the importance of adopting integrated treatments for people with this dual diagnosis to optimize treatment outcomes. Future research could include soliciting client perspectives on using an integrated treatment approach for this dual diagnosis and trials of this approach to assess acceptability, feasibility, and longer‐term outcomes.

Public Significance Statement

This study highlights the merit of concurrently addressing the complex interplay between EDs and BPD via an integrated treatment approach. Streamlining the therapeutic approach can address underlying features of these disorders, improve clinical formulation, and optimize patient outcomes.

Keywords: acceptance and commitment therapy, affective instability, anorexia nervosa, borderline personality disorder, bulimia nervosa, cognitive behavior therapy, dialectical behavior therapy, eating disorders, holistic treatment, mentalisation‐based therapy

1.

Summary.

  • Borderline personality disorder and eating disorder frequently co‐occur and share some diagnostic features.

  • Their co‐occurrence leads to greater complexity and severity, requiring involvement of specialist services that may not work in a coordinated manner.

  • Clinicians familiar with treating both disorders considered emotion dysregulation and distress intolerance to be core shared components.

  • Treatments with proven effectiveness for treating either disorder may be combined in a holistic approach to address the shared psychopathology of co‐occurring BPD and ED.

2. Introduction

Borderline personality disorder (BPD) is a severe mental health condition causing significant functional impairment and frequent co‐occurrence with other psychiatric conditions (Leichsenring et al. 2011). Primary features of BPD include a pervasive pattern of emotional instability, impulsivity, and interpersonal difficulties (Miller et al. 2022), along with a high incidence of deliberate self‐harm and death by suicide (Liakopoulou et al. 2023). BPD is highly relevant to the diagnosis and treatment of eating disorders (ED). Prevalence varies by subtype, with BPD co‐occurring in 25% of people with anorexia nervosa (AN) binge‐eating purging type and in 24.8% of people with bulimia nervosa (BN) (Sansone and Sansone 2011). It is notable that BPD and ED share some diagnostic features, with impulsivity (Newton et al. 1993) and affective instability thought to give rise to chronically disturbed eating behaviors and weight preoccupation (Lavender and Mitchell 2015). Bingeing and purging are particularly common in people with a borderline personality structure (Miller et al. 2022).

The co‐occurrence of these disorders significantly heightens psychopathology, hospitalizations, and commensurate challenges for consumers and mental health workers alike (Hessler et al. 2019; Trull et al. 2018; Vivarini et al. 2022). Critically, treatment for co‐occurring ED and BPD is usually siloed for each of these disorders, despite the overlap in their underlying clinical features. A recent network analysis suggests that although ED symptoms and BPD symptoms cluster independently, several direct relationships may occur (De Paoli et al. 2020). For example, BN symptoms were linked with BPD symptoms of impulsivity and suicidality, and body dissatisfaction prevalent in BN is reportedly associated with identity disturbance and emotional instability, both characteristic of BPD (De Paoli et al. 2020). Despite this, there is limited capacity for services treating either BPD or ED to identify and implement evidence‐based treatments specifically for this dual diagnosis. Research suggests that attending solely to ED symptoms can result in therapy‐interfering behaviours if BPD is present and not treated (Bankoff et al. 2012; Federici et al. 2012). Likewise, treating BPD without targeting ED symptoms may limit treatment efficacy due to dysregulated eating intensifying BPD features such as mood lability (McDonald 2019). Furthermore, the medical and psychological stability of a person with ED can impact the viability and timing of BPD treatment (Weigel et al. 2019). It is therefore essential to explore ways in which treatment can be integrated most effectively for this clinical group and streamline its provision across BPD and ED treatment services.

Specialist psychological treatments may assist people with co‐occurring BPD and ED. Dialectical behavior therapy (DBT) is the most widely utilized treatment for BPD, targeting emotion regulation, distress tolerance, and suicidality (Linardon et al. 2018; Navarro‐Haro et al. 2018). Cognitive behavioral therapy (CBT) demonstrates high efficacy in weight restoration and cognitive reappraisal of factors that perpetuate EDs (Fairburn et al. 2003). Acceptance and commitment therapy (ACT)‐based approaches target distress tolerance and incorporate mindfulness principles (Beatson et al. 2010), while mentalisation‐based therapy (MBT) focuses on understanding others' and one's own emotional and cognitive processes to improve symptom expression and interpersonal functioning (Bateman and Fonagy 2013).

Evidence regarding strategies for treating co‐occurring BPD and ED is scarce and inconclusive. When these disorders co‐occur, their symptom severity tends to be positively correlated, with concurrent symptom reduction when treated together (Denning et al. 2023; Liakopoulou et al. 2023). Liakopoulou et al. (2023) evaluated the effectiveness of a DBT intervention, augmented with CBT strategies, for nutritional and weight restoration among 17–35‐year‐olds admitted to an ED treatment facility. They found that improvement in coping skills was related to a significant reduction of both ED and BPD symptomatology. The long‐term effectiveness of treatment for this clinical group was also explored in research comparing DBT with treatment‐as‐usual CBT (Navarro‐Haro et al. 2021). Results indicated that significant symptom reduction persisted at 4‐ and 6‐years post‐treatment for outpatients who had received either treatment. Further support for DBT has been demonstrated in an adult ED‐BPD cohort from a partial hospital program for EDs, wherein patients received a program of individual, family‐based, and group therapy (Denning et al. 2023). Greater BPD symptomatology at admission led to steeper declines in ED symptomatology, such as fasting, bingeing, and parasuicidality, compared with people with milder BPD symptoms (Denning et al. 2023). Despite the clear need to integrate treatment for this clinical group, the evidence‐base is still developing, with more studies needed to investigate the benefits of integrated treatments.

Qualitative research investigating consumer perspectives on the treatment of BPD and co‐occurring psychiatric conditions also underscores the value of synthesizing therapeutic modalities. For instance, while some consumers endorsed CBT for helping them to identify and restructure their thought patterns, others felt that the emphasis DBT places on understanding their behaviours and emotional states, prior to adopting behaviour change, was more aligned with their needs (Mooney et al. 2023). Similarly, consumers affected by BPD with co‐occurring trauma disorder desired a balance between emphasis on change and maintaining stability, an approach they thought was exemplified by MBT and DBT styles of therapy (Woodbridge et al. 2023). Therefore, conceptualizing a treatment approach that incorporates key disorder‐specific treatment features is a necessary step toward providing more targeted and tailored clinical care for people with this dual diagnosis. Clinicians who have experience treating both disorders are well placed to contextualize these consumer experiences, providing clinical insights that can inform future treatment design.

The present study addresses specific gaps in the BPD‐ED literature. First, despite the presence of established therapies for BPD or ED, treatment integration for co‐occurring disorders is less explored in research and clinical practice. Given the mutually reinforced chronicity of this dual diagnosis, treatments that can effectively attenuate symptoms of both disorders may have greater and longer‐lasting efficacy. Second, while the efficacy of BPD and ED treatments has been investigated quantitatively, qualitative data are comparatively scarce, particularly from a clinician perspective. Consulting with clinicians experienced in the treatment of BPD and ED may capture nuances reflecting different settings, treatment modalities, and clinical challenges associated with therapy provision. Thus, the aim of this study was to explore therapeutic approaches used when BPD and ED co‐occur, based on clinicians' experiences of delivering treatment to this population. Additionally, the researchers investigated clinicians' recommendations regarding an integrated approach to the treatment of co‐occurring BPD and ED. This study constitutes the first known attempt to study clinicians' perspectives on the treatment of co‐occurring BPD and ED.

3. Method

3.1. Participants

Recruitment for this study used purposive sampling and was therefore by invitation only. Clinicians employed at either a specialist outpatient service for severe personality disorder or a specialist inpatient/outpatient service for severe ED were invited. As such, they worked within different service models (i.e., evidence‐based psychotherapy versus the medical model of ED management, primarily AN). Neither service routinely provided treatment outside of its remit. They did, however, have some patients in common, who received interventions from both services. All who were invited—a total of 10 clinicians, five from each service—agreed to participate in this study. A key criterion for participation was that clinicians have substantive experience in delivering therapeutic interventions for BPD and ED to people with this dual diagnosis. Years of clinical experience varied, self‐reported as between 5 and 30 years, with an average of 13 years. The clinical director of the BPD service (Spectrum) and the medical director of the ED service (Austin Mental Health) were well‐placed to nominate clinicians on the basis of their clinical experience.

Treatment teams in both study settings were drawn from a range of professional disciplines; all were trained in delivering psychological treatments. Participants were senior clinicians who were knowledgeable about treatment approaches that were individually and experience‐based. Participants were psychiatrists (n = 3), psychologists (n = 4), psychiatric nurses (n = 2), and an occupational therapist (n = 1). Participants ranged from 30 to 55 years old (mean age 35.5) with 80% identifying as female. This study received ethical and governance approval from Eastern Health (LR52/2016), Austin Health (LNR/16/Austin/320), and Swinburne University (LNR/16/Austin/320) Human Ethics and Research Committees.

3.2. Procedure

The lead author was introduced via email to five clinicians from each specialist service (n = 10) by that service's clinical director. Participation involved a single 20 to 30‐minute individual interview with the lead author, a female Master of Clinical Psychology student completing a research thesis, who had previously interned at a BPD treatment facility. Interviews were conducted between August and October 2016, in person or over the phone, and were digitally recorded and manually transcribed. Transcripts were not returned to clinicians for review.

3.3. Design and Data Analysis

Thematic analysis was used to interpret the qualitative data from the interviews, identifying repeating patterns of responses to derive substantive themes. A six‐step approach recommended by Braun and Clarke (2006) was followed: (i) familiarize oneself with the data; (ii) generate initial codes; (iii) search for themes; (iv) review themes; (v) define and name themes; and (iv) produce the report. The lead author noted initial impressions and features of the transcribed interviews and coded these across the entire data set. The coded responses were collated into emerging themes that were clearly defined and addressed the research questions. Finally, vivid and compelling interview extracts representative of the themes were selected.

The major coding frame and themes were shaped by the interview questions (see Supporting Information). The finer grade categories (subthemes) emerged from the data during analysis. Any issues that arose during the coding process were resolved in discussion with the senior author. Considering the specific research aims, the current study was characterized by dense sample specificity, an established theoretical underpinning, and elaborate, insightful clinician responses. From this, it was determined that data obtained and analyzed from 10 interviews was sufficient to address the research aims in accordance with recommendations by Malterud et al. (2015).

4. Results

4.1. Comorbidity

4.1.1. Proportion of Clients With Co‐Occurring BPD and ED

When participating clinicians were asked about the prevalence of co‐occurring BPD and ED among clients they knew (current and retrospective), 2/10 clinicians estimated 20%, 3/10 estimated 30%, 4/10 estimated 50%, and 1/10 estimated 60%–70%. There were no clear differences in estimates across services. Estimates from clinicians in the primary ED service ranged from 20% to 70%, and clinicians in the specialist personality disorder service ranged from 20% to 50%.

4.1.2. ED Subtypes Most Frequently Associated With BPD

ED subtypes co‐occurring with BPD varied according to the specialist service participants worked for. Clinicians working at the specialist BPD service were more likely to report EDs defined by binge eating, either BN or binge eating disorder (BED). For example, Clinician 3 noted that “bulimia nervosa would be one of the main, or binge eating.” However, clinicians working within the specialist ED service reported a predominance of clients with AN, as highlighted by Clinician 7, who observed that ED treatment settings see “a lot of people with anorexia nervosa and some people with bulimia.” Clinician 8 from the specialist ED service highlighted that “people with anorexia binge type or people who have bulimia often, not always, but often have borderline personality structure as well.”

4.1.3. Shared Symptoms of BPD and ED

Many participants reported emotion regulation/dysregulation as a prominent feature of both disorders. Clinician 5 stated that, for clients, “bingeing is a way of regulating themselves and feeling good.” Clinician 8 also highlighted the “regulatory function in bingeing and purging, as a way of reducing emotional distress.” Elements of control and impulsivity were also identified, with Clinician 7 suggesting that “often people with borderline personality disorder do struggle emotionally… eating disorders can provide a way of being under control.” Similarly, clinician 5 surmised that ED may arise due to “lack of control, impulsivity.” Participants also observed interpersonal difficulties associated with the dual diagnosis, Clinician 6 noting “really poor interpersonal function.” Finally, themes of self‐harm and suicidality were also noted by clinicians across both clinical settings. Participants understood bingeing behavior to be a form of self‐harm. Clinician 5 described it thus: “there is an aspect of self‐punishment, sort of the spectrum of self‐harm behaviour, suicidal urges… some of that is met by the eating disorder.” Clinician 1 noted that “treatment is pretty much aimed at reducing their risk of suicidality and deliberate self‐harm… quite a long history of self‐destructive behaviour… lots of presentations to ED.” Clinician 6 corroborated this notion, stating that within this clinical population, “you're targeting both the restricted eating and the self‐harm… it's hard work, in a way, balancing those different targets.”

4.2. Current Treatment for BPD and ED—What Makes It Effective?

4.2.1. Features of Effective BPD Treatment

Clinicians employed by the BPD treatment service unanimously endorsed DBT and ACT as effective for relieving BPD symptoms. Many specifically noted that the chain analysis component of DBT helped clients understand the underlying causes of their behavior. Clinician 2 described this as “analysing step‐by‐step what leads up to the problem… that quite detailed behaviour chain… breaking problems down into just little steps that actually they can make changes on.” ACT's utility was summarized by Clinician 5: “Mindfulness—a different way of living… not focused on judgement or evaluation… Defusion—a different way to relate to their inner thoughts that are often precursors to dysfunctional behaviours… Values—considering what it is they might be doing with that time and energy.” Distress tolerance, core to both DBT and ACT, was also thought to be effective in clinical settings, described as “trying to bring the client back to the primary feeling that's at the origin… trying to help the person to learn to tolerate that feeling” (Clinician 2). Discussion of the value of MBT centered around the ‘not knowing stance’. For example, Clinician 1 defined this as to “try and not stamp [my] assumptions of what [I] think they're thinking or doing… actually ask them,” and “trying to help a person not just focus on their behaviour but try and understand the thoughts, feeling, and emotions in a curious and reflective way” (Clinician 4). Finally, all participants referred to the central importance of validation for the treatment of BPD, with Clinician 5 emphasizing “first and foremost, the experience of being acknowledged… their internal experience validated and reflected, understood, communicated.”

4.2.2. Features of Effective ED Treatment

Participants from the specialist ED service emphasized the importance of allowing the client to own the process of weight restoration. Clinician 10 expanded on this: “assisting them to accept the need for health restoration… being supported in taking control of that themselves.” Similar to BPD clinicians, ED clinicians discussed the value of distress tolerance. Clinician 9 stated, in relation to those who received BPD treatment prior to treatment for their ED: “there seems to be strong evidence that [DBT] has equipped them to be able to deal with inpatient admission in a more adaptive way, with less self‐harming behaviours and more distress tolerance. That seems to be a really important intervention.” Regarding CBT, specific elements such as food and thought diaries were perceived as foundational for improving clients' understanding of their behaviour. For example, Clinician 7 shared that “there's a grade of exposure with a CBT food and thought diary to help people understand and stay on track,” which was corroborated by Clinician 10, who noted “self‐monitoring of food intake” as an important treatment element. ACT was also regarded as effective for this group, particularly “how they can live their life in a way consistent with their values… we'll look at awareness of their thoughts and cognitive defusion” (Clinician 6). Emphasis on trust and rapport was also expressed, with Clinician 8 indicating that “if they don't even have that basis, you know, there'll be no commitment to any of this.” Clinician 7 reinforced this notion of consistency: “having regular appointments, having clear boundaries.” Finally, the inherent risk associated with severe ED was emphasized, as was the importance of “finding a way of monitoring risk… finding a way to keep people safe” (Clinician 8).

4.3. Current Treatment for Co‐Occurring BPD and ED—What Makes It Effective?

4.3.1. Eclectic Approach

Several participants referred to the benefits of using an eclectic approach to treat the dual diagnosis, that is, combining aspects of DBT, ACT, CBT, and MBT. For example, Clinician 1 stated “they allow for a targeting of both disorders because in some ways they're addressing a common factor like emotion dysregulation… relevant to BPD but also [to] why someone can't restrict their intake [in the context of ED].” Clinician 6 highlighted a diversity of therapeutic modalities: “emotion focused work can be quite helpful… cognitive reframing can be helpful or some cognitive work, CBT work can be helpful… motivational interviewing when they first come in, that's kind of been most effective at the start. ACT can be very effective as well.” The use of an eclectic approach that compensates for strengths and weaknesses of individual therapies was also discussed: “I think it requires the integration of all these techniques in one program… ACT and DBT don't adequately address the eating disorder part of it, but do address some of the common elements and maintaining factors of the personality component, whereas I think you also need some specific CBT to address the eating disorder, although ACT and DBT also help with some of that too… if they could learn in parallel or [in] an integrated program… you could cover most of the issues” (Clinician 8). Specific features of therapeutic approaches suggested by participants are listed in Table 1.

TABLE 1.

Therapeutic process and characteristics.

Theme Aspect Quotes
Process Group therapy C1: “Sometimes I've seen group programs get a bit too dominant on teaching things… as opposed to having a balance of providing skills but also as a group finding a way of processing emotions”
C6: “That's where the learning comes from… reflecting on things they say and how they behave… group dynamics can be incredibly intense”
Group and individual therapy C2: “The stabilization stuff, the distress tolerance, the distractions and self‐soothing skills… works quite well, in terms of teaching the skills in a group setting… in individual therapy that goes alongside the group, you can focus on any particular issue the client might have… relate [treatment targets] to the client and how their personality symptomatology and eating disorder affects them”
C7: “The DBT model where people have individual sessions and also group skills training… maybe adding in some meal support and psychoeducation around that”
Characteristic Compassion C5: “Supportive outpatient programs… a very accepting, understanding, compassionate, non‐pathologising relationship”
C4: “Setting them up to value more, the connection and relationships… making that maybe a stronger value than the need to have a perfect body… taking that self‐compassion attitude has been shown to be really positive in breaking that cycle”
Empowerment C7: “I have to empower the client as much as possible and meet them where they're at, so not trying to go at a pace that's ahead of them”
C6: “I like to approach the client as the expert in their own life. Even though there is a power imbalance inherently there, there has to be as much equality as possible”
Collaboration C10: “A strong emphasis on mutual collaborative conceptualisation of what the issues are. Carefully delineated, done actively together over a period of time rather than rushing into change… addressing regularization of eating patterns”
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Note: Representative quotes from clinicians with suggestions concerning the therapeutic process (group therapy, individual therapy) and characteristics (compassion, empowerment, collaboration) for integrating BPD and ED treatment.

4.4. Proposed Program Structure for Co‐Occurring BPD and ED

Participants were asked what they would regard as the ideal structure of an integrated treatment program, and what level of commitment they anticipated would be required from clinicians to deliver this. Their recommendations regarding treatment duration varied considerably, as did ideas regarding structural features (Table 2).

TABLE 2.

Participant suggestions regarding structure and duration of treatment programs for co‐occurring BPD and ED.

Duration Quotes
6–12 weeks C1: “Between 2 and 3 months would perhaps be a minimum… a core that teaches all the basic things that people need… but then with other options after that to continue with different modalities like MBT”
C7: “It would be ideal that they would have one‐on‐one concurrently with the group. I'd probably say twice a week… two group sessions as well as one‐to‐one… maybe about 6 or 8 weeks”
6–12 months C3: “I think both those conditions are chronic conditions and so I guess I'm thinking about the DBT structure in my mind—it was designed originally as a year, but I know that, like, in the hospital I work in privately, they run it for 6 months… it can be enough for some”
C4: “You start with 6 months and see what happens, but with maybe contact up until a year or two afterwards, with three sessions every second day. Three‐hour sessions. Or even a day thing”
C6: “I would wonder about it being set up in a block kind of way, so people commit to asix‐month block and then we review things…. You'd hope that people would be engaged for at least 6 months. And I think it would be good then if they could continue with the individual therapist for a prolonged period of time as well, so somebody is carrying them through”
C10: “The individual therapy needs to be the journey and the groups need to be the skills… so, it's going to need to be 6 months at least”
12–24 months C2: “12–18 months. Unless you address the underlying maintaining factors, you get a relapse. I think the only way to do that is to have people in treatment for longer… whether it's group or individual therapy my experience is a lot of these patients have all kinds of attachment difficulties”
C5: “A 12‐month program. And if money wasn't an object, three times a week”
C9: “Something like a day program where you have 4 days a week of treatment where eating's also supervised, for at least a few meals a day, and there's lots of incorporated challenges… So, 12 months to 2 years but possibly with a kind of step‐down approach”
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Note: Representative quotes from clinicians concerning nominated treatment durations for integrating BPD and ED treatment.

5. Discussion

The purpose of this study was to explore clinician impressions concerning the shared underlying etiology of co‐occurring BPD and ED, treatment features most effective in addressing the symptomology of these disorders, and how these might be delivered concurrently. Ten clinicians participated in this study, each of whom had expertise in the treatment of both disorders. The qualitative findings of this research revealed consistent perspectives in relation to the etiology and treatment of people with a dual diagnosis of BPD and ED.

Prior research highlights the prevalence of co‐occurring BPD and ED (Miller et al. 2022). Participants in the current study estimated that 20%–70% of clients having a known or suspected dual diagnosis of ED and BPD. This is consistent with previous estimates that co‐occurring ED is present in 10%–54% of people with BPD (Sansone et al. 2011). Participants from the specialist BPD service reported that clients with this dual diagnosis experienced EDs defined by binge eating, including BN and BED, while within the specialist ED service, participants reported co‐occurring AN (binge‐purge type) in association with BPD. These responses generally corroborate previous findings related to co‐occurring BPD and ED, where binge‐purge behaviour is present as either AN (binge‐purge type) (25%) or bulimia (28%) (Sansone et al. 2005).

Many participants in the present study referenced emotion dysregulation and distress intolerance as core components of both disorders, supported by previous research suggesting that dysregulated eating behaviors may arise from fluctuations in negative affect and difficulty tolerating negative emotions (Miller et al. 2022). Moreover, several participants perceived binge/purging behaviors as comparable to self‐harming behaviours prevalent among people with BPD, consistent with the concept that self‐harm serves an emotion‐regulating function (De Paoli et al. 2020; O'Loghlen et al. 2023). There was a clear perception among participating clinicians that disordered eating behavior and self‐harm are not only related but provide a similarly soothing effect for people in this clinical group.

Participants' endorsement of specific techniques across the frontline treatment modalities for BPD and ED (DBT, CBT, ACT, MBT) highlights the merit in combining treatment approaches for this dual diagnosis. For instance, DBT's chain analysis and the mentalisation focus in MBT emerged as important ways to encourage reflective exploration of clients' own and others' emotions. In generating a thorough understanding of clients' emotional and behavioral precursors such as self‐harm or bingeing (Rizvi and Ritschel 2014), and utilizing mentalisation‐ and mindfulness‐based strategies to assist with emotion recognition (Preece et al. 2022), streamlining these processes may alleviate shared symptoms, like self‐disgust, within the dual diagnosis (Ille et al. 2014). Additionally, several clinicians drew on food and thought diaries to suggest CBT strategies that may be best placed to address certain ED‐specific symptomatology, proposing that drawing on emotion‐focused strategies from range of modalities can assist in alleviating features of both disorders. This is reflected in existing literature, highlighting CBT's role in attaining nutritional restoration and medical stability for further psychological treatment (Fairburn et al. 2013; Weigel et al. 2019). Furthermore, studies suggest that a combination of emotion‐focused techniques such as distress tolerance and mindfulness can facilitate sustained improvement for this clinical group (Hessler et al. 2019; Liakopoulou et al. 2023). Given the efficacy of techniques drawn from various modalities to address the shared psychopathology of co‐occurring BPD and ED, synthesizing these into individualised treatment may assist in alleviating the unique psychopathology underlying this clinical group, and importantly, reduce relapse.

It is increasingly evident in ED research that personality dimensions may explain meaningful variance in several areas of clinical assessment, symptomatic expression, and treatment (Farstad et al. 2016; Liakopoulou et al. 2023; Miller et al. 2022). Therefore, further investigation is warranted to conceptualize an integrated and tailored treatment for this clinical population. Transdiagnostic approaches may provide an avenue towards conceptualizing such treatment. Transdiagnostic approaches such as CBT “Enhanced” (CBT‐E) incorporate modules targeting a broader range of psychological vulnerabilities, including clinically relevant perfectionism and low self‐esteem (Thompson‐Brenner et al. 2016). CBT‐E may facilitate sustained treatment benefits for people with this dual diagnosis, highlighting the potential advantage of including therapeutic content that targets mood states and interpersonal functioning (Thompson‐Brenner et al. 2016). The Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders also takes a broad‐spectrum approach. It acknowledges that personality features may drive BPD and co‐occurring conditions and targets these simultaneously (Sauer‐Zavala et al. 2016). This sentiment is corroborated in the current research, with participating clinicians emphasizing the importance of matching treatment to client personality difficulties. Therefore, clinicians familiar with different treatment modalities could selectively incorporate features of specialized treatments (i.e., using transdiagnostic approaches) to maximize treatment effectiveness.

Aside from specific therapeutic modalities, most participants spoke about the importance of the therapeutic alliance, observing that clients report the collaborative process of developing and sharing a formulation to be empowering and validating. These findings are thoroughly supported in the literature, particularly among clients with these complex disorders (Flückiger et al. 2018; Graves et al. 2017). Moreover, participant discussions on the importance of compassion are consistent with research suggesting that mindful self‐compassion may serve as a protective factor against ED pathology, such as body image disturbance (Braun et al. 2016; Hessler‐Kaufmann et al. 2020), as well as being an effective emotion regulation strategy for BPD clients (Warren 2015). This is regarded as essential for assisting clients to experience secure relationships and self‐acceptance, both of which are impaired in this clinical group (Beatson et al. 2010; Donald et al. 2019).

When asked to propose a treatment regime suited to people with this dual diagnosis, there was surprising variability among participant responses, with suggestions regarding treatment duration ranging from 6 weeks to 2 years. Despite this, most clinicians endorsed a 6–12 month duration, with some suggesting that 6 months may serve as an initial period, contingent upon client improvement and commitment. This is consistent with previous 6‐month effectiveness trials for co‐occurring BPD and ED, with significant symptom reduction persisting at 4‐ and 6‐years post‐treatment for outpatients who had received either standard DBT or CBT (Navarro‐Haro et al. 2021). Participants also suggested that group programs be offered 2–5 times a week, each for 90 min, particularly in an inpatient setting. However, participants also noted that clients with less severe symptoms would benefit from less intense and lengthy interventions. This is consistent with research indicating that brief interventions, such as a 3‐week self‐compassion intervention for ED, can lead to positive outcomes such as reduced body dissatisfaction and body shame, and improved body image (Braun et al. 2016). Importantly, one clinician noted potentially shortening a 12‐month treatment program to 6 months within a hospital setting. This mirrors existing feasibility studies exploring the clinical effectiveness of shorter treatment durations within certain healthcare settings, identifying promising results in relation to BPD treatment (McMain et al. 2018).

Despite areas of alignment between the services, there were also distinctions in participant perspectives according to the service from which they were recruited. Clinicians from the BPD service tended to focus more on addressing pervasive emotional dysregulation and trauma‐related behaviours, whereas clinicians from the ED service prioritized the management of physical and medical risks associated with ED. These perspectives shaped their approaches to formulating an ideal treatment program for people with this dual diagnosis. While clinicians from the ED service emphasized the interplay of one‐on‐one and group therapy, BPD clinicians reflected more on the utility of specific modalities like DBT or MBT to address latent interpersonal and emotional nuances linked to personality structure.

Some limitations in interpreting the findings of the current study are important to note. Conclusions from this study may be restricted given that the recruitment of participants was limited to specialist services for the treatment of BPD and ED, respectively. A further limitation is the absence of consumer lived experience perspectives from these same services. Furthermore, confirmation bias may have emerged during the interviews, with participants selectively favoring the treatment approaches that they use in their own work. Therefore, this research cannot be used to ascertain the utility of other evidence‐based treatments for BPD and/or ED, which may also have utility for the treatment of this co‐occurring disorder. This is offset in part by the broad range of treatments that individual participants were experienced in administering.

Future research could consult people with lived experience of this dual diagnosis about features of clinical interventions that they find effective, and what they believe would be beneficial in a group or individual program. It would also be advantageous to recruit clinicians who have training in other therapeutic approaches not mentioned in the present study. This includes common factors‐based approaches that have emerged as effective and practical alternatives to specialist treatments for the treatment of BPD, through combining effective therapeutic features shared by specialist treatments to provide a more flexible approach (Gunderson et al. 2018; Weinberg et al. 2011). Further research is also needed to investigate different treatment approaches, specifically their effectiveness for managing persistent symptoms in cases where one of the disorders has remitted.

The dual diagnosis of BPD and ED represents a major challenge to clients, caregivers, and treatment services. Given the suboptimal clinical outcomes when these co‐occurring disorders are treated in isolation, it is imperative that treatment services be guided by the overlap in underlying features of these disorders. Based on the clinical perspectives reported in the current study, there is a clear mandate for services to coordinate care of both disorders concurrently. Specifically, adopting client‐centered approaches in the delivery of holistic, tailored care, using a synthesis of manualized and flexible therapeutic modalities. The capacity of services to coordinate concurrent treatment for BPD and ED has the potential to address features underlying and perpetuating both disorders, alleviating strain on carers, more efficient utilization of mental health resources, and ultimately facilitating long‐lasting treatment efficacy for people with this complex clinical presentation.

Author Contributions

Charlotte Cunningham: conceptualization, data curation, formal analysis, investigation, methodology, project administration, writing – original draft. Jillian H. Broadbear: conceptualization, investigation, methodology, project administration, resources, supervision, writing – review and editing. Janani Rajaram: writing – review and editing. Sathya Rao: conceptualization, project administration, resources, supervision, writing – review and editing. Richard Newton: data curation, supervision, writing – review and editing. Roslyn Galligan: conceptualization, formal analysis, investigation, methodology, project administration, supervision, validation, writing – original draft, writing – review and editing.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Data S1. Supporting Information.

EAT-58-917-s002.docx (18.7KB, docx)

Data S2. COREQ checklist.

EAT-58-917-s001.docx (18.7KB, docx)

Acknowledgments

Open access publishing facilitated by Monash University, as part of the Wiley ‐ Monash University agreement via the Council of Australian University Librarians.

Action Editor: Tracey Wade

Funding: The authors received no specific funding for this work.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Data S1. Supporting Information.

EAT-58-917-s002.docx (18.7KB, docx)

Data S2. COREQ checklist.

EAT-58-917-s001.docx (18.7KB, docx)

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Articles from The International Journal of Eating Disorders are provided here courtesy of Wiley

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