Eating disorders and the nine symptoms of borderline personality disorder: A systematic review and series of meta-analyses.

TLDR: This paper performed nine separate meta-analyses (one for each BPD symptom) to compare levels of symptoms in patients with eating disorders versus healthy controls, and found that affective instability was the most elevated symptom in individuals with versus without eating disorders.

Abstract: OBJECTIVE Eating disorders and borderline personality disorder have high rates of comorbidity. However, the extent to which individual BPD symptoms are elevated in patients with EDs is largely unknown. Meta-analyses examined: (1) which of the nine BPD symptoms are especially elevated in individuals with versus without EDs, (2) whether particular ED subtypes have elevated levels of certain BPD symptoms, and (3) which BPD symptoms remain unstudied/understudied in relation to EDs. METHODS We performed nine separate meta-analyses (one for each BPD symptom) to compare levels of symptoms in patients with EDs versus healthy controls. A total of 122 studies (range = 4-34 studies across symptoms) were included. RESULTS Affective instability was the BPD symptom most elevated, while anger was the BPD symptom least elevated, in patients with EDs compared to controls. When comparing effect sizes across ED subtypes, anorexia nervosa binge-eating/purging subtype had the largest effect sizes for the greatest number of BPD symptoms, while effect sizes for AN restrictive subtype were not significantly larger than those of other EDs for any BPD symptom. The least studied BPD symptoms were identity disturbance and interpersonal difficulties. DISCUSSION These meta-analyses suggest that certain symptoms of BPD play a more prominent role in the comorbidity between BPD and EDs than others. Targeting affective instability when treating cases of comorbid ED and BPD may be especially likely to ameliorate the negative outcomes related to this comorbidity. Future research should further investigate identity disturbance and interpersonal difficulties in the context of EDs. PUBLIC SIGNIFICANCE Having an eating disorder and borderline personality disorder is a common comorbidity associated with a severe clinical presentation. BPD is characterized by nine distinct symptoms. This research examined levels of individual BPD symptoms in patients with versus without EDs. Findings can guide researchers and clinicians towards studying and treating symptoms that may be most relevant for BPD-ED comorbidity and in turn, improve outcomes for these patients.