Neuropsychiatric symptoms in Parkinson disease

Depression and anxiety are common in Parkinson disease, and are treated with standard pharmacotherapy (see advice: depression; anxiety).

Psychosis is common in Parkinson disease, especially in patients who are elderly, have cognitive disturbance or are taking anticholinergic drugs. Review antiparkinson treatment and possibly reduce levodopa dose or withdraw anticholinergic drugs and dopamine agonists.

If psychosis continues, low doses of second-generation antipsychotic drugs can be helpful. Clozapine is the most effective, and may improve motor function, but can have significant adverse effects and needs regular blood monitoring. Open-label studies have suggested low-dose quetiapine is beneficial, and it is often used empirically, but randomised controlled trials have not confirmed its efficacy.

Avoid using other second-generation antipsychotic drugs (eg olanzapine, risperidone, aripiprazole) because they are not as effective and can aggravate parkinsonism at higher doses. Avoid using first-generation antipsychotic drugs (eg chlorpromazine, haloperidol) as these often make parkinsonism worse.