Serotonin 5-HT2 receptor imaging in major depression: focal changes in orbito-insular cortex

Background Serotonin receptors may play an important role in the pathophysiology of affective disorders. We studied type-2 serotonin (5-HT 2 ) receptors in the brain of patients with major depression. Method Using positron emission tomography (PET) and the selective radioligand [ 18 F]altanserin, we investigated 5-HT 2 receptor distribution in eight drug-free unipolar depressed patients and 22 healthy subjects. Data were analysed using Statistical Parametric Mapping 95. Results In depressed patients, [ 18 F]altanserin uptake was significantly reduced in a region of the right hemisphere including the posterolateral orbitofrontal cortex and the anterior insular cortex. A trend to similar changes was found in the left hemisphere. No correlation was found between the uptake and the Hamilton rating scale score. Conclusions Pathophysiology of depression may involve changes in 5-HT 2 receptor in brain regions selectively implicated in mood regulation.