Yun Kwok Wing1, Siu Ping Lam2, Jihui Zhang2, Eric Leung2, Chi Lai Ho2, Sirong Chen2, Man Ki Cheung2, Shirley Xin Li2, Joey Wing Yan Chan2, Vincent Mok2, Joshua Tsoh2, Anne Chan2, Crover Kwok Wah Ho2. 1. 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. 2. 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.
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. CONCLUSION: 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.
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. CONCLUSION:Patients with comorbid RBD and MDD had presynaptic dopaminedysfunction 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.