Someone is dealing with co-occurring disorders if they have more than one mental or physical disorder at a time. There are certain co-occurring disorders that are common in people with eating disorders. One of these is borderline personality disorder.
Borderline Personality Disorder Definition
A personality disorder is a way of thinking, behaving, and feeling that is different than most people. It’s more than quirks or unique personality traits. These thought, feeling, and behavior patterns wreak havoc in someone’s life.
According to the DSM-5, which is the diagnostic manual that professionals use, someone with borderline personality disorder (BPD) struggles with at least five of the following:
- Intense, chaotic efforts to avoid real or perceived abandonment
- Pattern of unstable and intense interpersonal relationships characterized by alternating between extremes of idealization and devaluation
- Significantly unreliable sense of self or self-image
- Impulsivity in at least two areas. For example, impulsive spending, sex, substance abuse, reckless driving, binge eating
- Recurrent suicidal behavior, gestures, threats, or self-harm
- Unstable mood and drastic shifts in mood that lasts a few hours up to a few days
- Chronic feelings of emptiness
- Intense anger or difficulty controlling anger
- Stress-related paranoia or severe dissociation 
These symptoms begin by early adulthood and are present in several aspects of someone’s life.
BPD Symptoms Explained: Understanding the Signs
This section will further break down some of the symptoms described above. People with BPD have an intense fear of abandonment. It’s important to note that the fear of abandonment may be activated when a real abandonment is occurring or even when they suspect it may occur. There can be a big reaction to this, such as uncontrollable crying, inability to function at work or in school, or angry outbursts. This fear can get activated during normal times of separation, such as during the time between therapy sessions or when their partner travels for work.
Another key feature of borderline personality is the pattern of intense relationships. The intensity within these relationships tends to occur for a few reasons. One of the contributing factors is a borderline person’s tendency to idealize and devalue people. Idealization is when someone views someone else as perfect.
This is unrealistic and when the idealized person inevitably makes a mistake, they get devalued. Devaluing someone is when that person’s worth gets cut down and diminished. Simply put, this cycle of idealization and devaluation can be viewed as looking at things as black and white; people are either all good or all bad. This can lead someone with BPD to have intense relationships that start out intensely good and then get destroyed as that person gets devalued.
Borderline Personality Disorder Causes & Risk Factors
Research shows there are a few different things that can contribute to someone developing BPD. These are:
- Genetics: While there is no evidence of a gene for BPD, studies show that people who have relatives with BPD are more likely to also struggle with the disorder.
- Brain chemicals: One current thought is that people with BPD may have differences in their brain chemistry compared to people who don’t have this condition.
- Brain development: Some researchers have discovered that many individuals with BPD have differences in their brain structure. The three main areas that tend to be smaller or overactive directly influence someone’s ability to control their emotions, behavior, and make decisions.
- Environmental influences: Certain life experiences are linked with borderline personality disorder. These include:
- Experiencing emotional, physical, or sexual abuse
- Being a victim of childhood neglect
- Growing up with a family member who had a serious mental illness 
Co-Occurring BPD and Eating Disorders
Borderline personality disorder is one of the most common co-occurring disorders for people with eating disorders. These disorders are clearly different conditions with their own unique symptoms and consequences. That being said, they can feed into each other.
Anorexia and BPD
People with anorexia struggle with maintaining a healthy weight and an intense fear of gaining weight. This fear leads to a variety of disordered behaviors, such as restriction or compulsive exercise, in an attempt to lose weight.
Borderline personality may feed into someone’s anorexia in unique ways. There are a number of ways that this could manifest. For example, one of the identifying symptoms of BPD was an unstable sense of self.
For people with anorexia, their sense of self and worth is deeply dependent on their weight. Their already unstable identity may intensify their anxiety about their weight or losing weight may be an attempt to establish a secure identity.
Bulimia and BPD
Bulimia is an eating disorder characterized by cycles of binge eating and compensatory behaviors to avoid gaining weight from binging. There are a number of compensatory behaviors, such as purging, laxative use, compulsive exercise, or fasting.
Similar to people with BPD and anorexia, BPD can influence someone with bulimia in multiple ways. One example of this could be impulsively engaging in disordered eating behaviors due as a way to cope with rapidly shifting moods.
BPD and Binge Eating Disorder
Individuals with binge eating disorder (BED) deal with out of control episodes of binge eating. A binge is eating an amount of food that is larger than most people would eat in the same time frame. Just like with any other eating disorder, BPD can overlap with BED. One example could be binging as a way to emotionally comfort themselves after their fear of abandonment was triggered.
Borderline Personality Disorder Statistics
Here are some statistics about borderline personality disorder:
- About 75% of people diagnosed with BPD are women 
- Approximately 1.4% of US adults have borderline personality disorder
- 84.5% of people with personality disorders also have another mental illness 
- It’s estimated that 70% of people with BPD will make at least one suicide attempt in their lifetime 
- 8-10% of people with BPD will complete suicide 
BPD and Eating Disorder Treatment
Treatment is available for borderline personality disorder and eating disorders. It’s important for someone struggling with both of these conditions to receive treatment for both. This can help tackle anyways that the disorders feed into each other and can be an important relapse prevention technique. There are various aspects of treatment for BPD and eating disorders.
There aren’t medications that are used exclusively for BPD or eating disorders. Typically, the medications given to these individuals are for other mental health conditions or symptoms such as depression or anxiety.
People with borderline may also be prescribed medication that is typically given to people with bipolar disorder as a way to stabilize their mood .
There are certain therapeutic approaches that are designed specifically for the treatment of borderline personality and eating disorders. One overlapping therapy method that is known to be effective is dialectical behavioral therapy (DBT).
DBT was originally created to treat borderline personality, but is sometimes used in eating disorder treatment because of how effective it can be. DBT focuses on the following core skills:
- Relational skills
- Distress tolerance
- Emotional regulation
DBT may be taught in a group setting but may also be incorporated into individual therapy sessions. A therapist treating someone with co-occurring borderline personality and an eating disorder may use a variety of therapy approaches. Typically therapy is focused on helping a person stabilize and limit or stop any harmful behaviors. After a person is stable, a therapist may dive in deeper to help someone deal with any unresolved emotions or beliefs that negatively impact them.
Relapse Prevention and Aftercare Support
Given that impulsivity is a typical feature in BPD, having a solid relapse prevention plan is crucial. Setbacks are normal, but preventing a full-blown relapse can help keep someone from sliding too far back. A relapse prevention plan can include the following:
- A list of triggers and ways to cope with them
- Warning signs that you’re struggling
- List of names and numbers of people you can reach out to
There’s a wide variety of things that can serve as aftercare support. Some examples include attending therapy, remaining compliant with medication, joining a support group, having a regular self-care practice, or setting aside time for friends who cheer you up.
Dealing with borderline personality disorder and an eating disorder is a significant undertaking. It’s important to get treatment because these conditions can be life threatening and can significantly impact the someone’s quality of life.
Resources: American Psychiatric Association. (2013). Feeding and eating disorders. In Diagnostic and Statistical Manual of Mental Disorders. (5th edition, pp. 329-354). American Psychiatric Publishing.  NHS (n.d). Causes—Borderline personality disorder. Retrieved September 28th, 2021 from https://www.nhs.uk/mental-health/conditions/borderline-personality-disorder/causes/  National Institute of Mental Health. (n.d). Personality disorders. Retrieved September 28th, 2021 from https://www.nimh.nih.gov/health/statistics/personality-disorders  Salters-Pedneault, K. (2020, November 25). Borderline personality disorder. Verywell Mind. Retrieved September 28th, 2021 from https://www.verywellmind.com/borderline-personality-disorder-statistics-425481  NHS (n.d) Treatment—Borderline personality disorder. Retrieved September 28th, 2021 from https://www.nhs.uk/mental-health/conditions/borderline-personality-disorder/treatment/
Author: Margot Rittenhouse, MS, LPC, NCC
Page Last Reviewed and Updated on October 18th, 2021 by Jacquelyn Ekern MS, LPC