Psychiatric complications of drug treatment of Parkinson's disease

Summary

Drug-induced psychiatric conditions are a common and severe problem in the treatment of patients with Parkinson's disease. Psychotic symptoms are the most frequent reason for nursing home placement of patients with Parkinson's disease. The psychotic symptoms seem to present themselves in a continuum where alterations in dreaming patterns often precede visual hallucinations, which often progress into delusional syndromes and, finally, into confusional organic syndromes. When evaluating a patient on dopaminergic treatment, it is important to inquire systematically about abnormal sleep related phenomena, for these are important clues in the early detection of psychotic symptoms. The pathogenesis of the psychotic symptoms is not yet fully understood but complex adaptations of various neurotransmitter systems seem to be involved. In the treatment of these drug-induced psychotic symptoms, the atypical antipsychotic drug clozapine plays an important role. Drug-induced mania, hypersexuality and anxiety, although less frequent than the psychotic symptoms, also occur as a complication of dopaminergic treatment. Depressive symptoms, although common in Parkinson's disease, are less likely to occur as a side effect of the drug treatment.