[Psychic disorders]
Parkinson's disease is a neuropsychiatric disease with multiple psychic disorders. They mainly result from a combination between neuropathogical lesions and antiparkinsonian drugs. The most frequent psychic disorders are depression and psychosis. So far, pharmacological treatments of depression has been poorly evaluated. It is suggested that the first-line treatment of depression in Parkinson's disease is the class of the Selective Serotonin Reuptake Inhibitors. The occurrence of worsening in parkinsonism and agitation in rare cases necessitates a meticulous clinical follow-up. The treatment of psychosis is based on the reduction of antiparkinsonian medications, by tapering and stopping, if necessary, the drugs with the highest risk-to-benefit ratio first. When psychosis persists despite a simple levodopa monotherapy, then an antipsychotic drug is added. Clozapine is the only officially approved drug for psychosis in Parkinson's disease. Two double blind studies showed a clear antipsychotic effect without worsening of parkinsonism. Quetiapine, another atypical neuroleptic drug without risk of blood dyscrasia may prove to be as effective than clozapine. Olanzapine and risperidone can aggravate parkinsonism and should be used only as a last resort. Future studies will precise the place of anticholinesterases in the treatment of psychosis associated with dementia.