Neuropsychiatric Symptom Profile Could Help Parkinson's Disease Patients With Dementia

Neuropsychiatric symptoms are common in Parkinson’s disease patients with dementia, reported Dag Aarsland, MD, PhD, and colleagues in the January Journal of Neurology, Neurosurgery, and Psychiatry. A neuropsychiatric symptom profile could guide treatment options for these patients, according to the researchers.

Dr. Aarsland, of Stavanger University Hospital in Norway, and his team studied data from 537 patients with Parkinson’s disease and mild to moderate dementia who had been in an international multicenter drug trial. All patients were receiv­ing antiparkinsonian agents: 26.6% were using an antidepressant, 27.4% were using an antipsychotic, and 19.5% were using an anxiolytic; 13.1% were taking more than one psychotropic drug.

A total of 89% of patients had at least one symptom on the Neuropsychiatric Inventory (NPI), 77% had two or more symptoms, and 64% had at least one symptom with an NPI score of 4 or higher, considered clinically significant. Depression, apathy, anxiety, and hallucinations were the most common symptoms, with prevalence rates of 58%, 54%, 49%, and 44%, respectively. More severe dementia and advanced Parkinson’s disease were associated with more neuropsychiatric symptoms.

“In addition to being common, the clinical relevance of neuropsychiatric symptoms in Parkinson’s disease patients with dementia is further underlined by the finding that nearly 60% of the caregivers reported at least one NPI symptom to be a cause of moderate or severe distress,” noted Dr. Aarsland and colleagues.

NPI cluster analysis classified participants as having few and mild symptoms (52%); high scores on apathy and low scores on other items (apathy cluster, 24%); high scores on depression, anxiety, and apathy (mood cluster, 11%); high scores on delusions and hallucinations (psychosis cluster, 8%); and high scores on agitation and high total NPI score (agitation cluster, 5%). “The psychosis and agitation clusters had the lowest Mini-Mental State Examination score and the highest Unified Parkinson’s Disease Rating Scale and caregiver distress scores,” the investigators pointed out.

CONTRASTING FINDINGS

Dr. Aarsland’s team noted that their study results differed “markedly” from the findings of the Cache County Study of Memory in Aging, which mainly focused on Alzheimer’s disease and used the NPI. Although 24% of patients in the study by Aarsland et al displayed prominent apathy but had low scores on mood symptoms, no such finding was seen in patients with Alzheimer’s disease. Furthermore, “in the psychosis group, hallucinations were twice as common as delusions in Parkinson’s disease patients with dementia, whereas the reverse is true in Alzheimer’s disease,” stated the researchers, and the “hallucinations were present in 44% of Parkinson’s disease patients with dementia compared with only 13% of those with Alzheimer’s disease.” Dr. Aarsland and colleagues noted that differences between these two studies add further evidence to the possibility that “dementia in patients with Parkinson’s disease is not mainly due to concomitant Alzheimer’s disease.”

LIMITATIONS AND IMPLICATIONS

The investigators acknowledged several limitations to their study. Neuropsychiatric symptoms that required a more subjective analysis than the symptoms reported in the study’s findings might have been overlooked, while other symptoms—such as those that were obsessive-compulsive in nature—were not examined. The use of antidepressants among patients may also have introduced a bias, although antidepressant use did not differ among clusters. The cross-sectional nature of the study (as opposed to a longitudinal approach) and a lack of a control group could be considered limiting factors.

“Nevertheless, our findings do provide an empirical basis for testing the neurochemical hypotheses in future clinical trials,” noted Dr. Aarsland and colleagues. “On the basis of the current study, we propose subgroups of Parkinson’s disease patients with dementia based on the neuropsychiatric symptom profile, with potential treatment implications.”

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