In this first part of a review on drug-induced psychosis in Parkinson's disease, the etiology, the clinical features and the therapeutic strategies will be discussed. The drugs used in the therapy of Parkinson's disease may lead to non-motor complications, such as delirium or hallucinations. Especially anti-cholinergics, respectivily dopaminometics, play an important role. Lowering the dose or even discontinuing the medication is the main therapeutic measure. The use of an atypical antipsychotic drug (clozapine) may be indicated.
