title: Reduced striatal dopamine transmission in REM sleep behavior disorder comorbid with depression.
abstract: OBJECTIVE
  To investigate dopamine transmission in patients with comorbid REM sleep behavior disorder (RBD) and major depressive disorder (MDD).
  
  
  METHODS
  This is a case-control study including 11 medicated patients with comorbid RBD and MDD (mean age 47.5 ± 8.2), 8 medicated patients with MDD only (mean age 47.9 ± 8.4), and 10 healthy participants (mean age 46.5 ± 10.6 years). They underwent clinical assessment, video-polysomnography, olfactory tests, and neuroimaging studies ((18)F-DOPA, (11)C-raclopride, and (18)F-FDG PET neuroimaging).
  
  
  RESULTS
  Compared with the 2 control groups, patients with comorbid RBD and MDD had significantly lower (18)F-DOPA uptake at 60 minutes in the putamen and caudate after controlling for age and sex effect (p < 0.05). There were no significant differences for the (11)C-raclopride and (18)F-FDG-PET. The (18)F-DOPA uptake in putamens had significant inverse correlation with severity of RBD symptoms (p < 0.01) and REM-related tonic muscle activity (p < 0.01). The comorbid RBD and MDD group had more impairment in olfactory function.
  
  
  CONCLUSIONS
  Patients with comorbid RBD and MDD had presynaptic dopamine dysfunction and impaired olfactory function. There is a distinct possibility that the development of RBD symptoms among patients with MDD may represent an early phase of α-synucleinopathy neurodegeneration instead of a merely antidepressant-induced condition.
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital. ykwing@cuhk.edu.hk.
authors.forename: Yun Kwok
authors.initials: YK
authors.lastname: Wing
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Siu Ping
authors.initials: SP
authors.lastname: Lam
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Jihui
authors.initials: J
authors.lastname: Zhang
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Eric
authors.initials: E
authors.lastname: Leung
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Chi Lai
authors.initials: CL
authors.lastname: Ho
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Sirong
authors.initials: S
authors.lastname: Chen
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Man Ki
authors.initials: MK
authors.lastname: Cheung
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Shirley Xin
authors.initials: SX
authors.lastname: Li
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Joey Wing Yan
authors.initials: JW
authors.lastname: Chan
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Vincent
authors.initials: V
authors.lastname: Mok
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Joshua
authors.initials: J
authors.lastname: Tsoh
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Anne
authors.initials: A
authors.lastname: Chan
authors.affiliation: From the Department of Psychiatry (Y.K.W., S.P.L., J.Z., S.X.L., J.W.Y.C., J.T., C.K.W.H.) and the Department of Medicine and Therapeutics (V.M., A.C.), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; and Nuclear Medicine & PET (E.L., C.L.H., S.C., M.K.C.), Hong Kong Sanatorium & Hospital.
authors.forename: Crover Kwok Wah
authors.initials: CK
authors.lastname: Ho
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D015331:Cohort Studies; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D020187:REM Sleep Behavior Disorder / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D004298:Dopamine