Treatment improves serotonin transporter binding and reduces binge eating

Rationale. Serotonin (5-HT) is involved in the control of eating behaviour by inhibiting food intake. Obese women with binge-eating disorder (OB-BED) were recently found to have reduced 5-HT transporter binding. Objectives. The aim of this study was to investigate the effect of a successful treatment on 5-HT transporters in OB-BED. Methods. The 5-HT transporter binding of seven OB-BED was measured by single-photon emission computed tomography (SPECT), by using iodine-123-labelled nor-beta-CIT as a tracer, before treatment and after successful treatment, when the OB-BED were asymptomatic. Treatment consisted of group psychotherapy and fluoxetine medication. The control subjects, six obese women without eating disorders, were also studied twice by using SPECT. Results. The 5-HT transporter binding of the symptomatically recovered OB-BED increased significantly (24+/-22%) after treatment, whereas in the control group, binding remained unchanged. Conclusions. The results tentatively suggest that 5-HT transporter binding in OB-BED is an adaptive mechanism, which can be affected by treatment. Furthermore, there seems to be a link between improved 5-HT transporter binding and reduced binge eating.