The Japanese journal of neuropsychology

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ArticleTitle	Cognitive and behavioral problems in Parkinson disease
Language	J
AuthorList	Masaru Mimura
Affiliation	Department of Neuropsychiatry, Showa University School of Medicine
Publication	Japanese Journal of Neuropsychology: 23 (3), 166-175, 2007
Received
Accepted
Abstract	Although Parkinson disease (PD) is primarily a condition of motor symptoms, an increasing amount of research has indicated that non-motor symptoms including cognitive and emotional deficits are observed even in the earliest stage of the disease. Individuals with PD may show various psychiatric and/or behavioural problems. The present review highlighted recent research topics on neuropsychological and neuropsychiatric problems of PD. Among various neuropsychiatric symptoms, psychotic features secondary to dopaminergic treatment may lead to most troublesome problems in clinical practice. Newly developed atypical antipsychotics partially improved such psychotic conditions in PD. Depressive state is the most frequently observed symptom. Prevalence of comorbid depression in PD has reportedly been 7-76%. Such marked differences in the prevalence is partially attributable to different diagnostic criteria. It is useful to make a diagnosis according to standardized semi-structured diagnostic interview following the DSM-IV or ICD-10. Based on such diagnostic criteria, prevalence of depression may approximate as 20-40%. A half of such individuals fulfill the criteria of major depressive disorder while remaining half may be diagnosed as having dysthymia, minor depression or apathy. Recent studies have revealed that individuals with PD may also exhibit impairments in a variety of social cognition tasks (ability to infer the mental states of other people in social contexts), including recognition of facial expressions and eye expressions. Interestingly, such impairment in social cognition in PD appears to be interlinked with impaired performance in the decision-making activities as indexed by the Iowa Gambling Task. In contrast, impairment in social cognition and decision-making could not be accounted by underlying executive dysfunction or working memory deficits. These findings offer a new perspective on the cognitive and behavioral impairments that affect social living and adaptive decisions for individuals with PD.
Keywords	Psychotic symptom, atypical antipsychotics, depression, social cognition, facial expression