BDNF levels in adolescent patients with anorexia nervosa increase continuously to supranormal levels 2.5 years after first hospitalization
Britta Borsdorf, Brigitte Dahmen, Katharina Buehren, Astrid Dempfle, Karin Egberts, Stefan Ehrlich, Christian Fleischhaker, Kerstin Konrad, Reinhild Schwarte, Nina Timmesfeld, Christoph Wewetzer, Ronald Biemann, Wolfgang Scharke, Beate Herpertz‐Dahlmann, Jochen Seitz
Abstract
BACKGROUND: Brain-derived neurotrophic factor (BDNF) influences brain plasticity and feeding behaviour, and it has been linked to anorexia nervosa in numerous studies. Findings in mostly adult patients point to reduced serum BDNF levels in the acute stage of anorexia nervosa and rising levels with weight recovery. However, it is unclear whether this increase leads to normalization or supranormal levels, a difference that is potentially important for the etiology of anorexia nervosa and relapse. METHODS: = 79). We analyzed associations with body mass index, eating disorder psychopathology and comorbidities. RESULTS: Serum BDNF was only nominally lower at admission in patients with anorexia nervosa compared to healthy controls, but it increased continuously and reached supranormal levels at 2.5-year follow-up. BDNF was inversely associated with eating disorder psychopathology at discharge and positively associated with previous weight gain at 1-year follow-up. LIMITATIONS: We compensated for attrition and batch effects using statistical measures. CONCLUSION: In this largest longitudinal study to date, we found only nonsignificant reductions in BDNF in the acute stage of anorexia nervosa, possibly because of a shorter illness duration in adolescent patients. Supranormal levels of BDNF at 2.5-year follow-up could represent a pre-existing trait or a consequence of the illness. Because of the anorexigenic effect of BDNF, it might play an important predisposing role for relapse and should be explored further in studies that test causality.