All of the researchers' participants believed that their ED was merely an outlet for their BPD. Since BPD makes one feel out of control, the ED, one said, “gives you drive, it gives you… a goal… With BPD, you feel like you're so out of control all the time” (Miller et al. 2025). Not only does this provide a priori evidence for individuals who may struggle with both BPD and ED–BPD is more likely to arrive first–but it also suggests that BPD is often a force that is very far outside of their control. It is not that they wish to struggle with emotional regulation, indecision, or self-destruction.

Perception of BPD in ED maintenance and treatment. 

Miller, A. E., Hotte-Meunier, A., Bain, T., Macdonald, E. P., Steiger, H., & Racine, S. E. (2025). A Qualitative Study of the Lived Treatment Experiences of Women With an Eating Disorder and Comorbid Borderline Personality Disorder. The International journal of eating disorders, 58(5), 860–867. https://doi.org/10.1002/eat.24390


A Qualitative Study of the Lived Treatment Experiences of Women With an Eating Disorder and Comorbid Borderline Personality Disorder.

One common theme of participants struggling with both BPD and EDs was working in an environment with several others. They were easily irritated and had several interpersonal conflicts (Miller et al. 2025). On the other hand, participants also highly valued their relationship with their therapists. Thus, as often is the case with BPD, if they placed their trust in their therapist and the therapist did not meet their expectations or made a mistaken promise, there was turmoil in the relationship, but also in the participant’s recovery (Miller et al., 2025). 	

Relational dynamics faced by patients with both BPD and ED during treatment.

Currently, there are several ethical concerns regarding care for participants with both eating disorders and BPD and pathology. For instance, there is a high relapse rate for these individuals, who will often struggle with ED behaviors on and off for the remainder of their lives. The Miller et. al. (2025) research offers qualitative insight into the why behind these relapses. All 14 of their participants express their fear of relapse after treatment and acknowledged that they will likely resort to ED behaviors because, without the safety net a therapist provides, they begin to feel hopeless and out of control, so the ED behaviors comfort them (Miller et al. 2025). One participant stated, “I see myself relapsing… so that I'll get referred back to the [ED Clinic] because like I can't be without, like, anything at all… my brain can't compute that, like to just be completely on my own… I don't feel safe.” (Miller et al., 2025). This research shows that there needs to be a change in either the treatment process or the accessibility to treatment. 

A feeling that treatment was “never enough.”

Lester, R. J. (2009). Brokering Authenticity: Borderline Personality Disorder and the Ethics of Care in an American Eating Disorder Clinic. Current Anthropology, 50(3), 281–302. https://doi.org/10.1086/598782

Brokering Authenticity: Borderline Personality Disorder and the Ethics of Care in an American Eating Disorder Clinic. Current Anthropology

Current research on the comorbidity between both disorders agrees that the eating disorders' pathologies are often a means to cope with emotional distress, and Miller et al. (2025) find this to be true in their research as well. However, they also add that targeting these emotions is critical to treatment. 
One participant interestingly emphasized that binging, purging, or restricting are the only methods that ever provided some form of comfort. Other emphasized the importance of exploring emotions and appreciated the days they had Dialectical Behaviorial Therapy. The aspect they enjoyed the most was the fact that they were able to understand and related to others through DBT, finding a sense of comfort and confidence in emotion regulation. Additionally, one participants discussed how other ED focused treatment did not use emotion focusd langage and instead said, “you eat your lunch” rather than what this participants thought to be more helpful “what are you living or what are you feeling right now” (Miller et al. 2025).


The central role of emotions in the relationship between EDs and BPD.

Similar to Lester's (2009) research, Miller et al. (2025) found that it is essential to target both BPD and ED if the patient is to make a full recovery. These researchers found that by shifting focus to and from both disorders consistently, recognizing the BPD pathology, and holding the belief that recovery means resolving both disorders, improves their chances of recovery. One participant described her experience as that of a whack-a-mole; she would take down an ED symptom, but then another BPD symptom pops up, encouraging certain coping mechanisms (Miller et al., 2025). Lastly, participants emphasized that if one symptom that coexists in both disorders is treated, that does not necessarily mean that there will be improvement in both disorders, especially if you are only looking at the symptoms from one perspective, such as an ED perspective.

The importance of addressing ED and BPD symptoms simultaneously. 


Miller et al. (2025) published a fascinating article on their research, which included qualitative data from 14 of the participants who were diagnosed with both borderline personality disorder (BPD) and an eating disorder (ED). Before discussing their findings, they elaborate on the fact that hospitalization, self-harm, and suicide attempts occur more often in patients with both disorders rather than one or the other. As a result, it is beneficial for clinicians to gain insight into their experiences, thereby expanding treatment options in an eating disorder rehabilitation center. 

They found five central themes throughout their qualitative data collection:

- The central role of emotions in the relationship between EDs and BPD.
- Perception of BPD in ED maintenance and treatment. 
- Relational dynamics faced by patients during treatment. 
- A feeling that treatment was “never enough.” 
- The importance of addressing ED and BPD symptoms simultaneously.

Saint Olaf College

There is significant overlap between Borderline Personality Disorder (BPD) and Eating Disorders (specifically bulimia and binge eating) symptoms, suggesting that they may stem from similar environments, events, or chemistry. Additionally, learning more about the similarities and effects of each disorder on the other can lead to the development of new, effective treatment protocols. The intersection of BPD and EDs brings up deep psychological questions: Is disordered eating a form of affect regulation in those who can’t tolerate intense emotions? Does controlling food become a substitute for controlling unstable identity, a core issue in BPD? This makes the comorbidity a rich area for exploring self-concept, autonomy, and emotional survival strategies.

Comorbidity of BPD and ED

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Miller, A. E., Hotte-Meunier, A., Bain, T., Macdonald, E. P., Steiger, H., & Racine, S. E. (2025). A Qualitative Study of the Lived Treatment Experiences of Women With an Eating Disorder and Comorbid Borderline Personality Disorder. The International journal of eating disorders, 58(5), 860–867. https://doi.org/10.1002/eat.24390

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Reference List: Comorbidity of Borderline Personality Disorder and Eating Disorders

According to the DSM-5 criteria (American Psychiatric Association, 2013), the overlapping symtons consist of:

- Impulsivity
- Affective instability
- Mood regulation
- Disturbed self-image

Other sources notice various symptoms that the DSM-5 does not include. Newton (2019) found in his research that the two disorders also overlap in the following:

- Self-harm (cutting)
- Suicidal ideation
- Difficulty differentiating between hunger or anger
- Negative Coping behavior to prevent further distress-*

Overlapping Criteria in DSM-5 of BPD and EDs (specifically Bulimia Nervosa)

The comorbidity is a result of the shared cognitive distress that both disorders build off of. This includes:

- Interpersonal/Environmental Effects
- Biological Effects
- Emotion Dysregulation
- Early Childhood Trauma

Additionally, eating disorders, specifically anorexia nervosa as well as bulimia nervosa tend to act as a form of coping and self-harm (symptomology) for BPD.

Causes to the Comorbidity Between Eating Disorders and Borderline Personality Disorder

Lived Treatment experiences: The Complexity and Clinical Impact of having both an Eating Disorder and Borderline Personality Disorder.

Clinicians are attempting to both diagnose and treat clients accurately while working within the American Healthcare system to ensure that their clients receive continued care. One researcher, Lester (2009), found that they worked in an eating disorder clinic and observed the difficulties that their clinicians faced. 

Some challenges include:

- The resident needs to be sick enough but also appear genuine in their recovery for insurance companies to provide continued support. 
- Having enough resources to continue care even when at a healthy weight.
- Documenting behaviors so that they appear less borderline.

Ethical Concerns of Care and the Impact of Clinical Diagnostics for BPD Patients with Eating Disorders

The two approaches in treating comorbid BPD and ED:

- Cognitive Behavioral Therapy
- Dialectical Behavioral Therapy

Cognitive Behavioral Therapy (CBT) and Dialectical Behavior Therapy (DBT) are both widely used to treat comorbid Borderline Personality Disorder (BPD) and Eating Disorders (EDs), but they approach symptom management differently.

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