2014 Volume 60 Issue 6 Pages 529-535
Parkinson’s disease (PD) is a neurodegenerative disorder caused by the loss of dopaminergic neurons. The major clinical features of PD include motor disabilities, such as rigidity, bradykinesia, impaired balance, and resting tremors, as well as non-motor symptoms, such as cognitive decline, psychosis, and autonomic dysfunction. Neuropsychiatric problems seriously affect the activities of daily living and quality of life of PD patients and are caused by a dysfunction not only in dopamine, but also other neurotransmitters, including noradrenaline, serotonin, acetylcholine, and glutamine. Choline esterase inhibitors may improve cognition and visual hallucinations, but not other psychotic symptoms. Although neuroleptics may improve psychiatric problems, these drugs have typically been associated with the deterioration of Parkinsonism. Therefore, the management of hallucinations is an intractable issue for the treatment of PD. Yokukansan, which contains the water extract of a mixture of seven crude drugs, may effectively improve cognition and ameliorate psychiatric problems, such as hallucinations, apathy, and anxiety. We here reviewed yokukansan therapy for and psychiatric problems associated with PD.