Previous studies have shown that women with anorexia nervosa (AN), when ill and after recovery, have alterations of serotonin (5-HT) neuronal activity and core eating disorder symptoms, such as anxiety.
To further characterize the 5-HT system in AN, we investigated 5-HT1A receptor activity using positron emission tomography imaging because this receptor is implicated in anxiety and feeding behavior.
Design, Setting, and Participants
To avoid the confounding effects of malnutrition, we studied 13 women who had recovered from restricting-type AN (mean age, 23.3 ± 5.2 years) and 12 women who had recovered from bulimia-type AN (mean age, 28.6 ± 7.3 years) (>1 year normal weight, regular menstrual cycles, no bingeing or purging). These subjects were compared with 18 healthy control women (mean age, 25.1 ± 5.8 years).
The 5-HT1A receptor binding was measured using positron emission tomography imaging and a specific 5-HT1A receptor antagonist, [carbonyl-11C]WAY-100635.
Main Outcome Measure
Specific 5-HT1A receptor binding was assessed using the binding potential measure. Binding potential values were derived using both the Logan graphical method and compartmental modeling. The binding potential in a region of interest was calculated with the formula: binding potential = distribution volume of the region of interest minus distribution volume of the cerebellum.
Women recovered from bulimia-type AN had significantly (P<.05) increased [11C]WAY-100635 binding potential in cingulate, lateral and mesial temporal, lateral and medial orbital frontal, parietal, and prefrontal cortical regions and in the dorsal raphe compared with control women. No differences were found for women recovered from restricting-type AN relative to controls. For women recovered from restricting-type AN, the 5-HT1A postsynaptic receptor binding in mesial temporal and subgenual cingulate regions was positively correlated with harm avoidance.
We observed increased 5-HT1A receptor binding in women who had recovered from bulimia-type AN but not restricting-type AN. However, 5-HT1A receptor binding was associated with a measure of anxiety in women recovered from restricting-type AN. These data add to a growing body of evidence showing that altered serotonergic function and anxiety symptoms persist after recovery from AN. These psychobiological alterations may be trait related and may contribute to the pathogenesis of AN.