Adults aged 65 years and older who develop psychotic manifestations are significantly more likely than those without such manifestations to develop prodromal Parkinson’s disease, data from 925 individuals suggest.
“The presence of perceptual abnormalities and/or delusional ideation among community-dwelling elderly individuals is more widespread than considered in the past,” wrote Ioanna Pachi, MD, of National and Kapodistrian University of Athens Medical School and colleagues. However, those psychoses and their potential impact on prodromal Parkinson’s disease (PD) have not been well studied in community-dwelling populations, they noted in the study, published in Parkinsonism and Related Disorders.
In the study, Dr. Pachi and colleagues reviewed data from 914 participants in the Hellenic Longitudinal Investigation of Aging and Diet study (HELIAD), a cross-sectional, population-based cohort study of older adults in Greece. The average age of the participants was 76 years, and 41% were men. Participants had no delusional features at baseline; delusional features were assessed using the Neuropsychiatric Inventory scale and the Columbia University Scale for Psychopathology in Alzheimer’s disease. The researchers calculated the probability of prodromal PD (pPD) for each participant based on the 2019 International Parkinson and Movement Disorders Society research criteria for prodromal PD.
Over a 3-year follow-up period, 20 participants developed psychotic manifestations and were 1.3 times more likely to have pPD, compared with those without psychoses (P = .006). Those with new-onset psychotic features were categorized together as the NPSY group, regardless of symptom severity or frequency; those with no symptoms at either baseline or during follow-up were categorized as unaffected (UPSY). Most of the NPSY participants showed isolated delusional features, although some expressed hallucinations. Most symptoms were mild.
New-onset psychosis was associated with a fivefold increased risk of both subthreshold parkinsonism and depression (adjusted odds ratios, 4.5 and 5.0, respectively) and with a threefold increased risk of constipation (aOR 2.6). Other factors, including nonsmoking, global cognitive deficit, and anxiety were not significantly associated with new-onset psychotic symptoms after adjusting for confounding factors.
Although the mechanism behind the association remains unclear,
The study findings were limited by several factors, including the administration of neuropsychiatric questionnaires by nonpsychiatrists, and lack of detailed psychiatric history, including complete information on medication use, the researchers noted. The small size of the NPSY group also prevented evaluation of the potential associations between pPD and different modalities of hallucinations, they said.
However, the results were strengthened by the overall large and population-based sample size, and the comprehensive evaluation of psychotic features, they wrote. More follow-up evaluations in the HELIAD cohort are planned to further explore the underlying mechanism of the association between late-life psychosis and pPD.
“Provided that these results are confirmed in other community cohorts of elderly subjects, psychotic features may be added to the list of manifestations of pPD,” they concluded.
The study was supported in part by grants from the Alzheimer’s Association, ARISTEIA, and the ESPA-EU program Excellence Grant. It was cofunded by the European Social Fund and Greek National resources, the Ministry for Health and Social Solidarity, Greece, and the Greek State Scholarships Foundation. Dr. Pachi had no disclosures.