Childhood abuse and platelet tritiated-paroxetine binding in bulimia nervosa: implications of borderline personality disorder.

BACKGROUND: Co-occurrence of bulimia nervosa and borderline personality disorder has been attributed to shared factors, including childhood abuse and disturbances in central serotonin (5-hydroxytryptamine; 5-HT) mechanisms. To explore this notion, we conducted a controlled assessment of childhood abuse and 5-HT function in bulimics with and without borderline personality disorder.
METHOD: Forty patients with bulimia nervosa, confirmed with the Eating Disorders Examination interview (14 with borderline personality disorder and 26 without), and 25 normal-eater controls were assessed for clinical symptoms (eating disturbances, mood lability, impulsivity, and dissociation) and childhood sexual and physical abuse. We also conducted tests of platelet tritiated-paroxetine binding in blood samples from 27 of the bulimics (11 with borderline personality disorder and 16 without) and 16 of the controls.
RESULTS: Relative to normal eaters, bulimics showed greater affective instability, overall impulsivity, and a history of physical abuse. However, borderline bulimics alone showed elevated motor impulsivity, dissociation, and rates of sexual abuse. Paroxetine-binding tests indicated no differences attributable to comorbid borderline personality disorder, instead linking bulimia nervosa with or without borderline personality disorder to substantially reduced 5-HT transporter density.
CONCLUSION: Results suggest relatively autonomous pathologic entities: one, relevant to bulimia nervosa, being associated with abnormal 5-HT transporter function and affective instability, but relatively independent of childhood sexual abuse; another, relevant to borderline personality disorder, onto which sexual abuse, dissociative symptoms, and behavioral impulsivity converge. We propose that abnormal 5-HT function may, however, constitute one basis for the frequent co-occurrence of bulimic and borderline disturbances.