Decreased levels of serum brain-derived neurotrophic factor in female patients with eating disorders. 
Several lines of evidence suggest that brain-derived neurotrophic factor (BDNF) plays a role in the regulation of eating behavior.  Because of its role in eating behavior, which is especially relevant to eating disorders, BDNF is an attractive candidate for investigation of potential biological markers of eating disorders such as bulimia nervosa (BN) and anorexia nervosa (AN).  We enrolled 18 female patients with BN, 12 female patients with AN, and 21 age-matched female normal control subjects in this study.  Eating-related psychopathology and depressive symptoms were evaluated using the Bulimic Investigatory Test, Edinburgh (BITE) and the Hamilton Depression Rating Scale (HDRS).  Serum BDNF levels were measured by a sandwich enzyme-linked immunosorbent assay.  Serum levels of BDNF in the patients with AN or BN were significantly (p<.0001) decreased compared with those of normal control subjects, and serum BDNF levels in the patients with AN were significantly (p=.027) lower than those in patients with BN.  A significant positive correlation (r=.378, p=.006) between serum BDNF levels and body mass index in all of the subjects was detected.  Furthermore, there was a significant positive correlation (r=.435, p=.015) between the BITE symptom scale score and HDRS in these patients.  The present study suggests that BDNF may play a role in the pathophysiology of eating disorders.