title: [123I]-beta-CIT SPECT imaging shows reduced brain serotonin transporter availability in drug-free depressed patients with seasonal affective disorder.
abstract: BACKGROUND
  Numerous findings indicate alterations in brain serotonin systems in seasonal affective disorder (SAD). [(123)I]-2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane ([(123)I]-beta-CIT) labels serotonin transporters (5-HTTs) in the midbrain. We performed a [(123)I]-beta-CIT single photon emission computer tomography (SPECT) study under the hypothesis of lower [(123)I]-beta-CIT binding reflecting reduced central 5-HTT availability in depressed SAD patients.
  
  
  METHODS
  Depressed SAD patients and healthy control subjects were investigated using [(123)I]-beta-CIT SPECT 4 hours and again 24 hours after tracer injection. Subjects had either never used psychotropic medication or had been drug-free for at least 6 months prior to the investigation. Specific-to-nondisplaceable partition coefficient (V(3)") was calculated for the thalamus-hypothalamus and the midbrain-pons; the cerebellum served as a reference region.
  
  
  RESULTS
  Patients showed a reduction in V(3)" in thalamus-hypothalamus (2.41+/-0.3 vs. 2.84+/-0.4; p = .026) 24 hours post tracer injection (p.i.). No difference between patients and control subjects was found in midbrain-pons (1.31+/-0.2 vs. 1.42+/-0.2; p = .39). No differences were detected in the SPECT acquisitions 4 hours p.i.
  
  
  CONCLUSIONS
  Depressed SAD patients showed lower specific-to-nondisplaceable [(123)I]-beta-CIT binding in the region of interest (ROI) thalamus-hypothalamus. The small size of the midbrain-pons ROI may have contributed to the failure to show a difference in this ROI as well. Similar to reduced midbrain 5-HTT availability in nonseasonal depression, depression in SAD seems to be associated with reduced 5-HTT availability to the thalamus-hypothalamus.
authors.affiliation: Department of General Psychiatry, Vienna University, Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Willeit
authors.forename: N
authors.initials: N
authors.lastname: Praschak-Rieder
authors.forename: A
authors.initials: A
authors.lastname: Neumeister
authors.forename: W
authors.initials: W
authors.lastname: Pirker
authors.forename: S
authors.initials: S
authors.lastname: Asenbaum
authors.forename: O
authors.initials: O
authors.lastname: Vitouch
authors.forename: J
authors.initials: J
authors.lastname: Tauscher
authors.forename: E
authors.initials: E
authors.lastname: Hilger
authors.forename: J
authors.initials: J
authors.lastname: Stastny
authors.forename: T
authors.initials: T
authors.lastname: Brücke
authors.forename: S
authors.initials: S
authors.lastname: Kasper
mesh_terms: D000328:Adult; D001692:Biological Transport; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism*; D003042:Cocaine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D003865:Major Depressive Disorder / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016574:Seasonal Affective Disorder / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D012701:Serotonin; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine