ABSTRACT
INTRODUCTION James Parkinson in his original observations on Parkinson’s disease (PD) commented mainly on tremor and gait abnormality (1); however, it has become increasingly evident that PD patients can have cognitive and behavioral changes, and that these changes, most notably psychosis and dementia, can affect motor function. Furthermore, pharmacotherapy of psychosis and dementia can limit optimal treatment of the motor symptoms through dopamine antagonism and can even contribute to cognitive and behavioral dysfunction in PD. This makes it complicated to differentiate which features are medication side effects and which are intrinsic to PD.
