The majority of patients with dementia associated with Parkinson’s disease also suffer from a range of psychiatric and neurological symptoms, including anxiety, agitation and hallucinations, according to researchers at Stavanger University Hospital in Norway.

Researchers assessed the neuropsychiatric symptoms of 537 patients with Parkinson’s disease-related dementia who had an average age of 73. All subjects suffered from Parkinson’s disease for at least 10 years and had been demented for about 2 years. At least one neuropsychiatric symptom was present in 89% of the patients, and 77% had two or more symptoms.

Patients with the most severe dementia and in the advanced stages of Parkinson’s disease had the most symptoms. Depression, apathy, anxiety and hallucinations were the most common symptoms seen in the subjects. The study was published in the Journal of Neurology, Neurosurgery, and Psychiatry.