Serotonin transporter availability in patients with schizophrenia: A positron emission tomography imaging study with [¹¹C]DASB

Background: Postmortem studies have reported several alterations in serotonin transporter (SERT) binding parameters in patients with schizophrenia. The aim of this study was to compare SERT availability in vivo in patients with schizophrenia and matched control subjects. Methods: Ten medication-free patients with schizophrenia and 10 healthy subjects underwent positron emission tomography (PET) scans for 90 min after ¹¹C-3-amino-4-(2- dimethylaminomethylphenylthio)benzonitrile ([¹¹C]DASB) injection. Metabolite-corrected arterial input function was measured. Regional distribution volumes (mL/g) were derived with a two tissue compartment kinetic model. Outcome measures for SERT availability included binding potential (BP) and the specific-to-nonspecific equilibrium partition coefficient (V₃″) . Ten brain regions with high density of SERT and where SERT availability can be reliably quantified with [¹¹C]DASB were included in the analysis. Results: No significant differences were observed in regional BP or V ₃″ between patients and control subjects. No significant relationships were observed between regional SERT availability and severity of positive, negative, and depressive symptoms. Conclusions: This study failed to detect alterations of SERT availability in patients with schizophrenia; however, this study does not rule out the possibility that schizophrenia might be associated with alterations of SERT density in the cortical regions, where the [¹¹C]DASB-specific binding signal is too low for reliable quantification of SERT.