title: Altered serotonin transporter binding potential in patients with obsessive-compulsive disorder under escitalopram treatment: [11C]DASB PET study.
abstract: BACKGROUND
  Obsessive-compulsive disorder (OCD) is a chronic, relapsing mental illness. Selective serotonin reuptake inhibitors block serotonin transporters (SERTs) and are the mainstay of treatment for OCD. SERT abnormalities are reported in drug-free patients with OCD, but it is not known what happens to SERT levels during treatment. This is important as alterations in SERT levels in patients under treatment could underlie poor response, or relapse during or after treatment. The aim of the present study was first to validate a novel approach to measuring SERT levels in people taking treatment and then to investigate SERT binding potential (BP) using [11C]DASB PET in patients with OCD currently treated with escitalopram in comparison with healthy controls.
  
  
  METHODS
  Twelve patients and age- and sex-matched healthy controls were enrolled. The patients and healthy controls underwent serial PET scans after administration of escitalopram and blood samples for drug concentrations were collected simultaneously with the scans. Drug-free BPs were obtained by using an inhibitory E max model we developed previously.
  
  
  RESULTS
  The inhibitory E max model was able to accurately predict drug-free SERT BP in people taking drug treatment. The drug-free BP in patients with OCD currently treated with escitalopram was significantly different from those in healthy volunteers [Cohen's d = 0.03 (caudate), 1.16 (putamen), 1.46 (thalamus), -5.67 (dorsal raphe nucleus)].
  
  
  CONCLUSIONS
  This result extends previous findings showing SERT abnormalities in drug-free patients with OCD by indicating that altered SERT availability is seen in OCD despite treatment. This could account for poor response and the high risk of relapse in OCD.
authors.affiliation: Department of Neuropsychiatry,Seoul National University Bundang Hospital,Gyeonggi-do,Korea.
authors.forename: E
authors.initials: E
authors.lastname: Kim
authors.affiliation: Psychiatric Imaging,Medical Research Council Clinical Sciences Centre,Imperial College London,Hammersmith Hospital Campus,London,UK.
authors.forename: O D
authors.initials: OD
authors.lastname: Howes
authors.affiliation: Department of Psychiatry,Seoul National University College of Medicine,Seoul,Korea.
authors.forename: J W
authors.initials: JW
authors.lastname: Park
authors.affiliation: Department of Psychiatry,Seoul National University College of Medicine,Seoul,Korea.
authors.forename: S N
authors.initials: SN
authors.lastname: Kim
authors.affiliation: Department of Biomedical Sciences,Seoul National University,Seoul,Korea.
authors.forename: S A
authors.initials: SA
authors.lastname: Shin
authors.affiliation: Department of Clinical Pharmacology and Therapeutics,Kyung Hee University College of Medicine and Hospital,Seoul,Korea.
authors.forename: B-H
authors.initials: BH
authors.lastname: Kim
authors.affiliation: King's College London, Institute of Psychiatry,London,UK.
authors.forename: F E
authors.initials: FE
authors.lastname: Turkheimer
authors.affiliation: Department of Nuclear Medicine,Seoul National University College of Medicine,Seoul,Korea.
authors.forename: Y-S
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Psychiatry,Seoul National University College of Medicine,Seoul,Korea.
authors.forename: J S
authors.initials: JS
authors.lastname: Kwon
mesh_terms: D000328:Adult; D001596:Benzylamines; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D002250:Carbon Radioisotopes; D016022:Case-Control Studies; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism; D015283:Citalopram / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D009771:Obsessive-Compulsive Disorder / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000378:metabolism; D049268:Positron-Emission Tomography; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use; D013788:Thalamus / Q000000981:diagnostic imaging / Q000378:metabolism; D055815:Young Adult
chemical_list: D001596:Benzylamines; D002250:Carbon Radioisotopes; D015283:Citalopram; D050486:Serotonin Plasma Membrane Transport Proteins; D017367:Selective Serotonin Reuptake Inhibitors; C420885:N,N-dimethyl-2-(2-amino-4-cyanophenylthio)benzylamine
keywords: Anxiety disorder; SSRI; molecular imaging; obsessive-compulsive disorder; serotonin transporter