Abi Rayner, MD, MPH, Buller Medical Service, Westport, New Zealand.

Hallucinations and delusions increase the risk of developing dementia, delirium, functional impairment, and of death. The differential diagnosis includes isolated hallucinations, delirium, depression with psychotic symptoms, late-onset schizophrenia, and unrecognized dementing disorder, including Lewy Body disease and frontotemporal dementia. Optimum management requires diagnosis, assessment of the goals of treatment, and understanding the risks and benefits associated with psychoactive medications. Atypical neuroleptics are appropriate first-line agents for most patients with dementia and psychotic symptoms. Response to medications is modest and a second agent (including acetylcholinesterase inhibitors, antidepressants, and anticonvulsants) may be necessary to reduce behaviour to acceptable levels. In addition, decline in cognitive status and increased risk of cerebrovascular events and death are associated with the use of antipsychotic medications. Change in functional status and time alter the impact of behavioural symptoms. Periodic reassessment and reduction of medication dosage over time appears safe, usually without re-emergence of symptoms.
Key words: psychotic symptoms, older adult, dementia, antipsychotics, behavioural disturbance.

Taresa Stefurak MSc, MD, FRCPC, Neuropsychiatry Fellow, Rotman Research Institute, Baycrest Centre for Geriatric Care, University Health Network, Department of Neurology, University of Toronto, Toronto, ON.

Introduction
Although Parkinson's disease (PD) is by definition a movement disorder, with a clinical diagnosis made by the presence of two out of three cardinal levodopa-responsive motor signs (tremor, rigidity, bradykinesia), both cognitive and neuropsychiatric symptoms are also important components. The clinical impact of these neurobehavioural symptoms is supported by a study in which the strongest predictor of quality of life perceived by PD patients was the presence of depression.¹ Cognitive impairment as well as postural instability and disability also contributed to poor quality of life. Behavioural disturbances and dementia are the primary reasons for nursing home placement in PD patients.²

Characterizing the nature of these symptoms in PD provides an important model to understand the underlying mechanisms of disease progression and brain function. Although psychosocial aspects may play a role in some of the behavioural and mood disturbances in PD, evidence suggests that the underlying mechanism for these symptoms arises from the biological dysfunction of anatomical and neurochemical substrates that occur in PD.