Organic Background of Restrictive-Type Anorexia Nervosa Suggested by Increased Serotonin1A Receptor Binding in Right Frontotemporal Cortex of Both Lean and Recovered Patients: [18F]MPPF PET Scan Study

Background Serotonin (5-HT) pathway abnormalities were demonstrated in anorexia nervosa (AN). Brain imaging studies on 5-HT receptors support this evidence. 4-(2-methoxyphenyl)-1-[2-(N-2-pyridinyl)-p-fluorobenzamido]-ethylpiperazine ([18F]MPPF) is a selective 5-HT1A receptor antagonist with an affinity close to that of endogenous 5-HT. Methods In 24 subjects including 8 lean restrictive-type AN patients, 9 recovered from restrictive-type AN subjects and 7 age-matched control subjects, we assessed in vivo brain [18F]MPPF binding by positron emission tomography and eating-related psychopathological traits. Inter-groups differences in [18F]MPPF binding were evaluated by voxel-based analyses. Results Restrictive AN patients presented increased [18F]MPPF binding in a selective area of the right cortex including part of the superior temporal gyrus, inferior frontal gyrus, parietal operculum, and temporoparietal junction. Striking regional similarities of increased [18F]MPPF binding were found in recovered from AN subjects. Most of the psychiatric scores were increased in restrictive AN patients, and elevated perfectionism and interpersonal distrust scores were noticed in subjects recovered from AN. Conclusions The persistent increased 5-HT1A receptor binding in frontotemporal region of recovered AN concomitantly with specific psychopathological traits support the hypothesis of an organic dysfunction of this area and corroborates with previous literature reports of AN cases induced by temporal lesions.