Increased 5-HT 2A Receptor Binding in Euthymic, Medication-Free Patients Recovered From Depression: A Positron Emission Study With [ 11 C]MDL 100,907

Abstract

A previous positron emission tomography (PET) study reported increased serotonin 5-HT(2A) receptor binding in unmedicated depressed patients with high scores on the Dysfunctional Attitudes Scale. The purpose of the present study was to use the highly selective 5-HT(2A) receptor ligand [(11)C]MDL 100,907 in a PET imaging paradigm to assess 1) 5-HT(2A) receptor binding potential in euthymic subjects with a history of recurrent depression and 2) the relationship between receptor binding and scores on the Dysfunctional Attitudes Scale. Cortical 5-HT(2A) receptor binding was measured in 20 unmedicated, fully recovered unipolar depressed patients and 20 age- and gender-matched comparison subjects. Regional estimates of binding potential were obtained using a reversible plasma input function compartmental model and the cerebellum as a reference region to estimate the free and non-specifically bound [(11)C]MDL 100,907 in brain tissue. Relative to the comparison subjects, the recovered depressed patients demonstrated significantly higher 5-HT(2A) receptor binding potential in the frontal cortex (mean increase: 19%), parietal cortex (mean increase: 25%), and occipital cortex (mean increase: 19%). 5-HT(2A) receptor binding potential correlated negatively with age in both patients and comparison subjects and positively with the Dysfunctional Attitudes Scale in the recovered patients. These findings should be considered preliminary but suggest that recovered subjects with a history of recurrent major depression have elevated binding potential of cortical 5-HT(2A) receptors. The correlation of increased 5-HT(2A) receptor binding potential with increased scores on Dysfunctional Attitudes Scale supports earlier work suggesting that increased 5-HT(2A) receptor availability characterizes a group of depressed patients with high levels of dysfunctional attitudes.