Borderline Personality Disorder and Eating Disorders

Comorbidity is the existence of two mental health disorders in one individual. With clinical comorbidity, these syndromes are categorically distinct, yet one syndrome may influence the outcome, course and treatment response of the other disorder.

Borderline personality disorder (BPD) is characterized by instability in emotion and impulse regulation, self-image, and interpersonal relationships. In clinical settings, it is the most prevalent disorder. Self-harm behavior such as suicidal gestures, self-mutilation and chronic feelings of emptiness are also characteristic of this disorder. With high rates of treatment utilization and mortality by suicide, BPD and its co-occurring disorders are of intense interest to researchers.

BPD is comorbid with substance use and mood, anxiety and other personality disorders. One study found mood disorders and BPD prevalence to be as high as 29.4 percent. In the same study, anxiety disorder comorbidity with BPD was at 21.5 percent, and substance use disorder with co-occurring BPD was at 14.1 percent.

The rates of eating disorders amongst those with personality disorders are much higher than the general population. Interestingly, some 30 to 38 percent of patients with eating disorders have an axis II disorder that is diagnosable. This represents a large number of individuals with co-occurring disorders who may have impaired long-term functioning.

Approximately 25 percent of individuals with anorexia nervosa have borderline personality. Borderline personality disorder and co-occurring anorexia nervosa has a prevalence of 25 percent. Bulimia nervosa and BPD have a 28 percent prevalence rate, and these are higher than the overall rate of personality disorders in the general population, which ranges from 5 to 10 percent.

The Diagnostic and Statistical Manual of Mental Disorders-IV defines anorexia nervosa as a refusal to maintain body weight at or above the normal weight for the patient’s age and height. Other criteria include either a loss of weight or the maintenance of weight that is less than 85 percent of the normal weight.

Individuals with anorexia nervosa have an intense fear of weight gain despite being under-weight, and typically deny the seriousness of having a low body weight. According to the DSM-IV, amenorrhea for at least three cycles in a row will also be present in the individual. Amenorrhea is defined as a period that occurs only after estrogen has been taken.

It is clear that co-occurring disorders vary along gender lines. While men with BPD are more likely to have a co-occurring substance abuse disorder, women with BPD are more likely to have eating disorders. Females with BPD are also more likely to have mood, anxiety or posttraumatic stress disorders.

Personality disorders are recognizable during adolescence or early adulthood. Temperament is largely inherited, and shaped by upbringing and life stressors. From what researchers know about personality disorders, they gather that these disorders develop before eating disorders. Because of this, understanding the relationship between the two is vital in order to properly diagnose and treat them.

While the relationship is not a causal association, some researchers purport there may be a partially causal relationship at work. There are a number of biological and psychological risk factors for the development of eating disorders. Parents may model eating disordered behavior by commenting on the child’s size or weight, life events that were negative, the child’s level of tolerance for distress, and the media’s idealization of thin body types. In addition, exposure to teasing or criticism regarding weight can be a stressor.

Some researchers hypothesize that personality pathology may shape the type of eating pathology that is expressed in an individual. Because borderline personality is characterized by intense fears of abandonment, identity disturbance and stress related quasipsychotic symptoms, these features are likely to shape the co-occurring eating disorder. For example, the impulsivity inherent in BPD may be displayed in binge eating episodes. Self-induced vomiting and the abuse of laxatives are damaging behaviors that demonstrate self-harm.

Researchers view eating-disordered behaviors in those with BPD as attempts to modify food intake, and thus alter body shape; and as behaviors through which individuals with BPD act out self-injurious tendencies using food issues as a platform. Binging fills an individual, and thus quells the chronic feelings of emptiness that typify this disorder. Purging causes fatigue, which combats affective swells and the anger experienced by those with BPD. It is clear that BPD could readily manifest in disordered eating given the traits inherent in the disorder.