title: Why psychosis is frequently associated with Parkinson's disease?
abstract: Psychosis is a common non-motor symptom of Parkinson's disease whose pathogenesis remains poorly understood. Parkinson's disease in conjunction with psychosis has been shown to induce injury to extracorticospinal tracts as well as within some cortical areas. In this study, Parkinson's disease patients with psychosis who did not receive antipsychotic treatment and those without psychosis underwent diffusion tensor imaging. Results revealed that in Parkinson's disease patients with psychosis, damage to the left frontal lobe, bilateral occipital lobe, left cingulated gyrus, and left hippocampal white-matter fibers were greater than damage to the substantia nigra or the globus pallidus. Damage to white-matter fibers in the right frontal lobe and right cingulate gyrus were also more severe than in the globus pallidus, but not the substantia nigra. Damage to frontal lobe and cingulate gyrus white-matter fibers was more apparent than that to occipital or hippocampal fiber damage. Compared with Parkinson's disease patients without psychosis, those with psychosis had significantly lower fractional anisotropy ratios of left frontal lobe, bilateral occipital lobe, left cingu-lated gyrus, and left hippocampus to ipsilateral substantia nigra or globus pallidus, indicating more severe damage to white-matter fibers. These results suggest that psychosis associated with Par-kinson's disease is probably associated with an imbalance in the ratio of white-matter fibers be-tween brain regions associated with psychiatric symptoms (frontal lobe, occipital lobe, cingulate gyrus, and hippocampus) and those associated with the motor symptoms of Parkinson's disease (the substantia nigra and globus pallidus). The relatively greater damage to white-matter fibers in psychiatric symptom-related brain regions than in extracorticospinal tracts might explain why chosis often occurs in Parkinson's disease patients.
authors.affiliation: Department of Neurology, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Jingmei
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Department of Neurology, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Shaoyuan
authors.initials: S
authors.lastname: Wu
authors.affiliation: Department of Magnetic Resonance Imaging, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Neurology, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Neurology, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Naiwei
authors.initials: N
authors.lastname: Zhao
authors.affiliation: Department of Neurology, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Kunwen
authors.initials: K
authors.lastname: Zheng
authors.affiliation: Department of Neurology, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Neurology, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Wenli
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Magnetic Resonance Imaging, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Magnetic Resonance Imaging, First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China.
authors.forename: Kunhua
authors.initials: K
authors.lastname: Wu
keywords: Parkinson's disease; brain injury; cingulate gyrus; diffusion tensor imaging; extracorticospinal tract; fractional anisotropy; frontal lobe; functional magnetic resonance; grants-supported paper; hippocampus; neural regeneration; neuroregeneration; occipital lobe; psychosis