The neuropsychiatry of Parkinson's disease and related disorders.

Parkinson's disease is associated with classical Parkinsonian features that respond to dopaminergic therapy. Neuropsychiatric sequelae include dementia, major depression, dysthymia, anxiety disorders, sleep disorders, and sexual disorders. Panic attacks are particularly common. With treatment, visual hallucinations, paranoid delusions, mania, or delirium may evolve. Psychosis is a key factor in nursing home placement, and depression is the most significant predictor of quality of life. Clozapine may be the safest treatment for psychotic features, but more research is needed to establish the efficacy of antidepressant treatments. Dementia with Lewy bodies, the second most common dementia in the elderly, may present in association with systematized delusions, depression, or RBD. Early evidence suggests the utility of rivastigmine, donepezil, low-dose olanzapine, and quetiapine in treating DLB. Parkinson-plus syndromes generally lack a good response to dopaminergic treatment and evidence additional features, including dysautonomia, cerebellar and pontine features, eye signs, and other movement disorders. MSA is associated with dysautonomia and RBD. SND (MSA-P) is associated with frontal cognitive impairments, but dementia, psychosis, and mood disorders have not been strikingly apparent unless additional pathological findings are present. In SDS (MSA-A), impotence is almost ubiquitous; urinary incontinence is frequent; depression is occasional, and sleep apnea should be treated to avoid sudden death during sleep. OPCA neuropsychiatric correlates await further definition. Progressive supranuclear palsy neuropsychiatric features include apathy, subcortical dementia, pathological emotionality, mild depression and anxiety, and lack of appreciable response to donepezil. CBD usually is recognized by early frontal dementia with ideomotor apraxia, often in the right upper extremity, attended later by poorly responsive unilateral Parkinsonism, with additional signs including cortical reflex myoclonus, limb dystonia, alien limb, oculomotor apraxia when asked to look horizontally, depression, personality changes, and, occasionally, Kluver-Bucy syndrome. The neuropsychiatry of FTDP-17 involves apraxia, executive impairment, personality changes, hyperorality, and occasional psychosis. Future research in these Parkinsonian disorders should target the characterization of neuropsychiatric sequelae and their treatment.