Risk of Psychosis among those with Parkinson’s disease with and without Minor Hallucinations
Ruth Schneider1, Peggy Auinger1, Taylor Myers1, Kelly Mills2, Roseanne Dobkin3, Gregory Pontone2, Catherine Kulick4, Melissa Nirenberg5
1University of Rochester, 2Johns Hopkins University, 3Rutgers University, 4The Hospital of the University of Pennsylvania, Department of Neurology, 5Icahn School of Medicine at Mount Sinai
Objective:
To determine the risk of incident psychosis over a one-year period in a large Parkinson’s disease (PD) cohort, comparing those with versus without minor hallucinations.
Background:
Minor hallucinations, which include illusions, passage phenomena, and feeling of presence, are common in PD and may represent a prodromal form of psychosis. Fox Insight is a large, community-based online PD cohort in which participants complete quarterly standardized questionnaires and may elect to complete additional questionnaires.
Design/Methods:
Fox Insight participants completed a novel patient-reported questionnaire assessing for minor hallucinations, major hallucinations, and delusions over the prior month. We excluded from our analyses those with baseline psychosis, defined as report of major hallucinations or delusions on our questionnaire or on the Non-Motor Symptoms Questionnaire (NMS Quest), or antipsychotic use. Based on the responses to our questionnaire, participants were classified as either PD-minor hallucinations or PD-no minor hallucinations. We determined the incidence of psychosis at one year, defined as a new positive response to the NMS Quest hallucinations and delusions question or new report of antipsychotic use.
Results:
A total of 35,509 with PD were invited to participate; over an 18-month period, 5,950 (17%) completed the questionnaire. We identified 1,052 with PD-minor hallucinations (18%; mean age 68.9±8.2 years, 53% male, mean years since diagnosis 6.2±4.9, PD medication use 95%) and 2,708 with PD-no minor hallucinations (46%; mean age 68.6±8.5 years, 52% male, mean years since diagnosis 5.9±4.8, PD medication use 94%). Median duration of follow-up was 1.0 (interquartile range 0.4-1.4) years. At one year, the incidence rate for psychosis per 100 person-years was 20.1 (95% CI: 17.2-23.0) for PD-minor hallucinations versus 5.1 (95% CI: 4.2-6.0) for PD-no minor hallucinations, with a relative risk of 3.9.
Conclusions:
In PD, minor hallucinations are associated with nearly 4 times the risk of incident psychosis over one year.