Reduced serotonin transporter availability in patients with unipolar major depression reflect the level of anxiety

Central seronergic dysfunction has been implicated in negative mood states. Serotonin transporter (5-HTT) availability (binding potential BP sub(ND)), measured with positron emission tomography and the carbon-11-labelled serotonin transporter ligand [11C]DASB, was significantly reduced in the thalamus of unmedicated patients with unipolar major depression (region-of-interest analysis), surviving correction for genotype (5-HTTLPR), gender, smoking status and age. Voxelwise analysis revealed reduced BP sub(nd) in a cluster that extends from the midbrain/raphe area to the bilateral thalamus, as well as reductions in the striatum, cingular gyrus and insular cortex (colorcode: delta BP sub(nd) = absolute BP sub(ND) group difference). Across all investigated regions of interest (thalamus: P = 0.004; midbrain: P = 0.004; amygdala: P = 0.003) reduced BP sub(nd) was associated with higher anxiety scores (Spielberger's State-Trait Anxiety Inventory, STAI).