Borderline personality disorder (BPD) is marked by significant fluctuation in emotions, self-perception, and relationships with others. It is notably prevalent in psychiatric settings and is associated with a high frequency of self-harming behaviours, including suicidal attempts, self-injury, and pervasive feelings of emptiness. Given its severe implications, including a high rate of healthcare utilization and increased suicide mortality, BPD, along with its associated comorbidities, garners substantial attention from the medical research community.
The coexistence of BPD with substance abuse, mood disorders, anxiety, and other personality disorders is common. Research indicates that the co-occurrence of mood disorders with BPD could reach up to 29.4%. Anxiety disorders are also frequently seen alongside BPD, with a comorbidity rate of 21.5%, and substance abuse disorders appear in about 14.1% of BPD cases.
Eating disorders are significantly more prevalent among individuals diagnosed with personality disorders compared to the general populace, with an estimated 30 to 38% of those with eating disorders also qualifying for a diagnosis of an Axis II disorder, indicating a substantial number of people with dual diagnoses potentially facing compromised long-term outcomes.
About 25% of those with anorexia nervosa also exhibit borderline personality traits. The co-presence of anorexia nervosa and BPD stands at around 25%, while bulimia nervosa and BPD show a comorbidity rate of 28%. These figures surpass the general prevalence of personality disorders within the broader population, which is estimated to be between 5 and 10%.
The Diagnostic and Statistical Manual of Mental Disorders-IV characterizes anorexia nervosa as an unwillingness to maintain a minimally average body weight, with patients often maintaining a weight less than 85% of what is considered normal for their age and height. Individuals with this disorder exhibit a profound fear of gaining weight despite being underweight and often minimize the seriousness of their low body mass. Additionally, the DSM-IV notes that amenorrhea, defined as the absence of menstruation for at least three consecutive cycles, is a criterion for diagnosis, provided estrogen has been administered.
Gender differences are apparent in the comorbidity of disorders, with males with BPD more prone to substance abuse disorders. At the same time, females with BPD are more susceptible to eating disorders and may also be more likely to suffer from mood, anxiety, or posttraumatic stress disorders. Personality disorders are generally identifiable during adolescence or early adulthood, with temperament being largely hereditary but also influenced by environmental factors and life stressors. It is believed that personality disorders precede the development of eating disorders, making the understanding of their interrelationship crucial for accurate diagnosis and effective treatment.
Although not necessarily causal, there’s speculation about a potential partial causal link between these conditions, with several biological and psychological risk factors for eating disorders identified. These include familial modelling of disordered eating, negative life experiences, a child’s distress tolerance level, societal ideals regarding physique, and exposure to weight-related teasing or criticism.
It’s hypothesized that the specific nature of a personality disorder may influence the manifestation of eating disorders. The characteristics of BPD, such as fear of abandonment, identity confusion, and quasi-psychotic symptoms under stress, may inform the type of eating disorder that develops. For instance, BPD’s impulsivity might manifest as binge eating. Moreover, self-harming behaviours, like self-induced vomiting and laxative misuse, are seen as manifestations of self-injury through disordered eating. Binge eating may serve to mitigate feelings of emptiness characteristic of BPD, while purging can provide temporary relief from emotional turmoil and anger, suggesting a complex interplay between BPD traits and disordered eating behaviours.
