[Emotional and cognitive disorders in Parkinson disease]

The majority of patients with Parkinson's disease develop psychiatric symptoms. 40% of the patients suffer from symptoms of depression, severely affecting daily functioning, motor symptoms, cognition, and quality of life for both the patients and their spouses. Antidepressants may alleviate the depressive symptoms, but treatment is complicated by complex pharmacodynamic interactions. Hallucinations, with or without delusions, occur in 15-20% of patients, and are usually caused by dopaminergic treatment. Patients suffering from dementia and depression are, however at particular risk of developing psychosis. Treatment consists of lowering the dose of dopaminergic agents, but many patients require symptomatic treatment with atypical antipsychotic drugs. Most Parkinsonian patients develop impairment of memory and executive functions, and more than 25% of patients develop dementia. Dementia increases with the age at onset and the duration of Parkinson's disease. Subcortical dementia is the most commonly observed syndrome, but symptoms of cortical dementia are also observed. No treatment is available, although cholinergic agents may prove useful.