About 70% of those who are diagnosed with an eating disorder have experienced some type of trauma. This can include  “neglect, emotional, physical, or sexual abuse” (Newton, 2019). These types of events lead to self-harming behaviors, desire for control, emotional dysregulation, or hopelessness. All of which are common symptoms found in individuals diagnosed with BPD. Similarly, causes of BPD also tend to be sexual assault or abuse. In one study, researchers found that more than 90% of individuals with BPD reported both childhood abuse and neglect” (Sansone & Sansone, 2010).  As a result, these individuals may continue to gravitate to self-harm behaviors, whether they realize it or not, to either soothe their emotional pain or even continue what they had been accustomed to in childhood. That said, these self-harming behaviors are often impulsive and are a means to regulate the emotional instability and emptiness. That said, those with BPD might engage in purging, binging, or eating restrictions as a result of a trauma. Or those with an eating disorder may also develop more emotional dysfunction and impulsive behavior similar to that of BPD. 

Early Childhood Trauma as a Cause of BPD and ED

- Lee and Vaillancourt’s (2023) longitudinal study on the comorbidity of eating disorders and borderline personality disorder (BPD) identifies bullying as a significant environmental risk factor for the development of either or both disorders. Among 14 assessed risk factors, bullying stood out as the most potent: its elimination was projected to reduce the incidence of eating disorders by 66% and BPD by 38%.

- In addition to bullying, sociocultural and gender-based factors also play a significant role. Lee and Vaillancourt (2023) report that girls are more frequently diagnosed with eating disorders, whereas LGBTQ+ individuals are more likely to meet criteria for BPD—highlighting how identity-based vulnerabilities intersect with psychiatric risk.

- Other interpersonal contributors include personality traits such as impulsivity and emotional instability. These traits may not only predispose individuals to both conditions but also complicate diagnosis. For example, disordered eating behaviors may be misattributed to mood symptoms when in fact they are rooted in underlying personality pathology (Sansone & Sansone, 2010). Notably, these traits may arise from a complex interaction of genetic vulnerability and early relational experiences.--

Interpersonal & Environmental Effects as Causes of BPD and ED Comorbidity

Like many disorders, there are biological components in interplay with the environment, or past childhood experiences, that create foundations for a disorder to build from. Overlapping biological causes of BPD and EDs include the following:

- Neurochemical Effects
- Genetic Predispositions
- Neurobiological Effects

Biological Etiologies of Both BPD and EDs

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.

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

Costa, J., Marôco, J., Pinto-Gouveia, J., Ferreira, C., & Castilho, P. (2016). Validation of the Psychometric Properties of the Self-Compassion Scale. Testing the Factorial Validity and Factorial Invariance of the Measure among Borderline Personality Disorder, Anxiety Disorder, Eating Disorder and General Populations. Clinical Psychology and Psychotherapy, 23(5), 460–468. https://doi.org/10.1002/cpp.1974

Bozzatello, P., Garbarini, C., Rocca, P., & Bellino, S. (2021). Borderline Personality Disorder: Risk Factors and Early Detection. Diagnostics (Basel, Switzerland), 11(11), 2142. https://doi.org/10.3390/diagnostics11112142
Khosravi, M. Eating disorders among patients with borderline personality disorder: understanding the prevalence and psychopathology. J Eat Disord 8, 38 (2020). https://doi.org/10.1186/s40337-020-00314-3

Dyson Tori, Thomas Susan J., Townsend Michelle L., Finch Adam, South Alexandra, Barkus Emma, Walter Emma, Mendonca Carley, Grenyer Brin F. S., Pickard Judy A. (2023). Salivary testosterone and cortisol levels in borderline personality disorder before and after a 12-week group dialectical behavior therapy intervention. Frontiers in Psychology, 14(14). https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2023.1195187

Federici, A. (2009). Dialectical Behaviour Therapy for the Treatment of Eating Disorders. NEDIC, NEDIC Eating Disorders Bulletin.

Lee, K. S., & Vaillancourt, T. (2024). Trajectories, comorbidity, and risk factors for adolescent disordered eating and borderline personality disorder features. Development and Psychopathology, 36(4), 1546–1557. doi:10.1017/S0954579423000792

Lee, S. S. M., Keng, S.-L., & Hong, R. Y. (2024). Validating the biosocial model of borderline personality disorder: Findings from a longitudinal study. Development and Psychopathology, 36(4), 1752–1762. doi:10.1017/S0954579423001116

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

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

Navarro-Haro, M. V., Botella, C., Guillen, V., Moliner, R., Marco, H., Jorquera, M., Baños, R., & Garcia-Palacios, A. (2018). Dialectical Behavior Therapy in the Treatment of Borderline Personality Disorder and Eating Disorders Comorbidity: A Pilot Study in a Naturalistic Setting. Cognitive Therapy and Research, 42(5), 636–649. https://doi.org/10.1007/s10608-018-9906-9

Newton, J. R. (2019). Borderline personality disorder and eating disorders: a trans-diagnostic approach to unravelling diagnostic complexity. Australasian Psychiatry : Bulletin of the Royal Australian and New Zealand College of Psychiatrists, 27(6), 556–558. https://doi.org/10.1177/1039856219852297

Ni, X., Chan, D., Chan, K., McMain, S., & Kennedy, J. L. (2009). Serotonin genes and gene–gene interactions in borderline personality disorder in a matched case-control study. Progress in Neuro-Psychopharmacology & Biological Psychiatry, 33(1), 128–133. https://doi.org/10.1016/j.pnpbp.2008.10.022.

Ntshingila, N., Poggenpoel, M., Myburgh, C. P. H., & Temane, A. (2016). Experiences of women living with borderline personality disorder. Health SA = SA Gesondheid, 21(1), 110–119. https://doi.org/10.1016/j.hsag.2016.01.001

Sansone, R. A., & Sansone, L. A. (2007). Childhood Trauma, Borderline Personality, and Eating Disorders: A Developmental Cascade. Eating Disorders, 15(4), 333–346. https://doi.org/10.1080/10640260701454345

Sansone, R. A., & Sansone, L. A. (2010). Personality Disorders as Risk Factors for Eating Disorders: Clinical Implications. Nutrition in Clinical Practice, 25(2), 116–121. https://doi.org/10.1177/0884533609357563.

Steiger, H. (2004). Eating disorders and the serotonin connection: state, trait, and developmental effects. Journal of psychiatry & neuroscience: JPN, 29(1), 20–29.

Power, R. A., & Pluess, M. (2015). Heritability estimates of the Big Five personality traits based on common genetic variants. Translational psychiatry, 5(7), e604. https://doi.org/10.1038/tp.2015.96

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)

Cognitive Behavioral Therapy is a common form of treatment for individuals with both BPD and various eating disorders. Cognitive Behavioral Therapy, in this case, often involves first addressing the impulsive behaviors and urges of the individual by increasing awareness of what constitutes good and bad behaviors (Navarro-Haro et al., 2018). Then, researchers will begin restructuring the client's thinking pattern and work through a reward-based procedure, with the hope that the client will develop internal attribution and prevention strategies against relapse..  (Navarro-Haro et al., 2018)  DBT is primarily focused on crisis de-escalation and emotion regulation practices. There are four different stages, the first being regulating the self-harm/suicidal behaviors; the second is encouraging open communication, asking for help, and being involved in therapy (Navarro-Haro et al., 2018). The last two stages focus on developing healthier coping mechanisms and acquiring skills to manage certain impulses (Navarro-Haro et al., 2018). For example, if a CBT clinician were discussing purging behaviors with a client, they may ask what prompted these behaviors and the accuracy of the behavior. Whereas a clinician engaging with DBT might validate the pain the client was experiencing and then work through healthier management means for the next urge. Past research has established that DBT is useful in treating both ED and BPD independently, and Navarro-Haro et al. (2018) hypothesize that it will be more effective in treating both disorders at the same time rather than treatment as usual cognitive behavioral therapy (TAU CBT). 

Researchers Navarro-Haro et al. (2018) compared both methods of treatment with “a total of 118 women diagnosed with borderline personality disorders and eating disorders, who were assigned to one of two treatment groups in a naturalistic setting (DBT=71; TAU CBT=47)”  (Navarro-Haro et al., 2018). The researchers found that both methods of treatment create a decline in hospitalizations, suicide attempts, dysfunctional eating, and emotional suppression  (Navarro-Haro et al., 2018). That said, both treatments exhibit impressive outcomes, and one may not necessarily be superior to the other at this time. Thus, it is necessary to continue clinical trials to assess the transdiagnostic effectiveness of DBT. Additionally, CBT is usually not effective by itself in treating BPD and usually requires some of the foundations of DBT. Utilizing both CBT and DBT is a common means of treatment for clinicians because there is never one way to treat individuals with BPD or ED. For instance, when an individual with anorexia nervosa is admitted into a rehabilitation center, clinicians might resort to CBT treatment until they find that the individual exhibits borderline behaviors; then, the clinicians might turn to DBT approaches.

Transdiagnostic Treatment Approaches for BPD and ED's. 

Clinicians are attempting to both diagnose and treat clients accurately while working with the American Healthcare system to make sure 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. The goal of her research is to demonstrate the institutional expectations that clinicians must meet that are not necessarily realistic for patients struggling with BPD. For instance, eating disorder patients with BPD or BPD behaviors will often appear manipulative or inauthentic in their treatment process to the point that insurance companies will cut the resident’s treatment once they reach a healthy weight. This is because, at some point, insurance companies believe that this individual does not want to heal or improve, and so the remaining resources are better utilized elsewhere. It is for this reason that clinicians will avoid specific words or frame their BPD patients’ behaviors or progress more vaguely to promote the continued treatment of the patient  (Lester 2009). Unfortunately, pulling a client out of treatment early ultimately results in relapse, and even if the patients get a second chance at being put into a rehabilitation center, the results will remain the same if they cannot receive enough care. The clients will fall back into dysfunctional eating behaviors, suicidal ideation, or their bodies will not be able to keep up with this lifestyle and will shut down. Thus, clinicians have a difficult job, almost competing against the American healthcare system, so that their clients may fully recover. 


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

Causes to the Comorbidity Between Eating Disorders and Borderline Personality Disorder

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.

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