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February 2008

New Medicines for GAD: Duloxetine and Quetiapine
Duloxetine (Cymbalta) and quetiapine (Seroquel) are effective in treating generalized anxiety disorder.

In Brief
FDA Warns About Varenicline Psychiatric Adverse Effects; Index Ranks States on Prevalence of Depression and Suicide

Norepinephrine Uptake Inhibition
Atomoxetine (Strattera) inhibits norepinephrine uptake at lower doses than does venlafaxine (Effexor and others) or paroxetine (Paxil and others).

Rimonabant Causes Depression and Anxiety
Rimonabant works as a weight loss agent but may cause depression and anxiety.

Selegiline Augmentation for Negative Symptoms of Schizophrenia
Patients with schizophrenia who take selegiline (Eldepryl, Emsam) in addition to antipsychotic drugs may have greater improvement in negative symptoms.

Managing Psychosis in Parkinson's Disease and DLB
Psychosis in Parkinson’s disease or dementia with Lewy bodies is difficult to treat, and patients are sensitive to side effects of drugs used for these conditions.

Managing Psychosis in Parkinson's Disease and DLB

February 2008

Among neurodegenerative disorders, Parkinson's disease (PD) is second in prevalence only to Alzheimer's disease, developing in approximately 1% of elderly people.1 Up to 75% of patients with PD go on to develop dementia. In western countries, dementia with Lewy bodies (DLB) ranks second in frequency among dementing illnesses, also after Alzheimer's disease. An update by Weintraub and Hurtig is illuminating.1

PD with dementia and DLB may be hard to distinguish, and both are difficult to treat. When dementia occurs within a year after the first signs of parkinsonism, the diagnosis is DLB. Psychotic symptoms are rare in untreated patients with PD, but because antiparkinsonian drugs can cause psychosis, it may occur in up to 40% of treated cases. Roughly 75% of patients with DLB have hallucinations and more than half have delusions. Patients with DLB, as opposed to PD, characteristically experience visual hallucinations—even in the absence of dopamine-agonist treatments.

Treating psychosis in a patient with PD or DLB produces a "Catch-22": dopaminergic medications that control motor symptoms typically worsen psychosis, while many antipsychotic drugs exacerbate motor signs. Low doses of clozapine (Clozaril and others), however, are usually effective in treating psychosis in patients with PD, with relatively little effect on motor symptoms. Data are less positive with other second-generation antipsychotics, and first-generation antipsychotics are not recommended. Cholinesterase inhibitors, such as donepezil (Aricept) and rivastigmine (Exelon)—which are used to treat dementia—might have antipsychotic properties, but data are limited.

Cholinesterase inhibitors are the first-line treatment for DLB. Patients with DLB are very sensitive to antipsychotic medications, which are not recommended.

When psychosis occurs in PD, the authors suggest thoroughly evaluating antiparkinsonian medications and possibly withdrawing some of them. Clozapine is most effective for psychosis in PD, but quetiapine (Seroquel) is used more often because of its convenience and safety. Cholinesterase inhibitors might have antipsychotic properties in both PD with dementia and DLB.

PD and DLB are common conditions, and with the aging of the population, destined to become even more so. Psychosis is frequent in both disorders. Given the delicate balance required, and the sensitivity of these patients to adverse drug effects, treatment must be cautious and collaborative among the psychiatrist, neurologist, patient, and family members.

1Weintraub D, Hurtig HI: Presentation and management of psychosis in Parkinson's disease and dementia with Lewy bodies. Am J Psychiatry 2007;164:1491–1498.