title: Serotonin transporter binding is reduced in seasonal affective disorder following light therapy.
abstract: To investigate the effects of light therapy on serotonin transporter binding (5-HTT BPND), an index of 5-HTT levels, in the anterior cingulate and prefrontal cortices (ACC and PFC) during winter in seasonal affective disorder (SAD). 5-HTT BPNDfluctuates seasonally to a greater extent in SAD relative to health. We hypothesized that in SAD, 5-HTT BPNDwould be reduced in the ACC and PFC following light therapy.
  
  
  
  Eleven SAD participants underwent [11C] DASB positron emission tomography (PET) scans to measure 5-HTT BPNDbefore and after 2 weeks of daily morning light therapy.
  
  
  
  The primary finding was a main effect of treatment on 5-HTT BPNDin the ACC and PFC (repeated-measures manova, F(2,9)= 6.82, P = 0.016). This effect was significant in the ACC (F(1,10)= 15.11 and P = 0.003, magnitude of decrease, 11.94%) and PFC (F(1,10)= 8.33, P = 0.016, magnitude of decrease, 9.13%). 5-HTT BPNDalso decreased in other regions assayed following light therapy (repeated-measures manova, F(4,7)= 8.54, P = 0.028) including the hippocampus, ventral striatum, dorsal putamen, thalamus and midbrain (F(1,10)= 8.02-36.94, P < 0.0001-0.018; magnitude -8.83% to -16.74%).
  
  
  
  These results demonstrate that light therapy reaches an important therapeutic target in the treatment of SAD and provide a basis for improvement of this treatment via application of [11C]DASB PET.
authors.affiliation: CAMH Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
authors.forename: A E
authors.initials: AE
authors.lastname: Tyrer
authors.affiliation: CAMH Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
authors.forename: R D
authors.initials: RD
authors.lastname: Levitan
authors.affiliation: CAMH Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Houle
authors.affiliation: CAMH Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
authors.forename: A A
authors.initials: AA
authors.lastname: Wilson
authors.affiliation: CAMH Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.|Behavioural Neurobiology Laboratory and Campbell Family Mental Health Research Institute, Departments of Psychiatry, Pharmacology and Toxicology, and Psychology, University of Toronto, Toronto, ON, Canada.
authors.forename: J N
authors.initials: JN
authors.lastname: Nobrega
authors.affiliation: CAMH Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
authors.forename: P M
authors.initials: PM
authors.lastname: Rusjan
authors.affiliation: CAMH Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Departments of Psychiatry, Pharmacology and Toxicology, Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada. jeff.meyer@camhpet.ca.
authors.forename: J H
authors.initials: JH
authors.lastname: Meyer
mesh_terms: D000328:Adult; D005260:Female; D006179:Gyrus Cinguli / Q000378:metabolism; D006801:Humans; D008297:Male; D010789:Phototherapy / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods; D017397:Prefrontal Cortex / Q000378:metabolism; D011485:Protein Binding; D016574:Seasonal Affective Disorder / Q000378:metabolism / Q000628:therapy*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*; D016896:Treatment Outcome
chemical_list: C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins
keywords: light therapy; neuroimaging; prefrontal cortex; seasonal affective disorder; serotonin