A detailed examination of the major neuropsychiatric syndromes of Parkinson's disease and a cognitive theory that accounts for their neurology and phenomenology. Patients with Parkinson's disease (PD) suffer most visibly with such motor deficits as tremor and rigidity and less obviously with a range of nonmotor symptoms, including autonomic dysfunction, mood disorders, and cognitive impairment. The neuropsychiatric disturbances of PD can be as disabling as its motor disorders; but they have only recently begun to be studied intensively by clinicians and scientists. In this book, Patrick McNamara examines the major neuropsychiatric syndromes of PD in detail and offers a cognitive theory that accounts for both their neurology and their phenomenology. McNamara offers an up-to-date review of current knowledge of such neuropsychiatric manifestations of PD as cognitive deficits, personality changes, speech and language symptoms, sleep disorders, apathy, psychosis, and dementia. He argues that the cognitive, mood, and personality symptoms of PD stem from the weakening or suppression of the agentic aspects of the self. McNamara's study may well lead to improved treatment for Parkinson's patients. But its overarching goal is to arrive at a better understanding of the human mind and its breakdown patterns in patients with PD. The human mind-brain is an elaborate and complex structure patched together to produce what we call the self. When we observe the disruption of the self structure that occurs with the various neuropsychiatric disorders associated with PD, McNamara argues, we get a glimpse into the inner workings of the most spectacular structure of the self: the agentic self, the self that acts.