Results from a study published in Parkinsonism and Related Disorders show that factors associated with early onset of psychosis in Parkinson disease include presence of rapid eye movement sleep behavior disorder (RBD), excessive daytime sleepiness, frontal lobe dysfunction, and postural instability with gait difficulty (PIGD).
Psychosis is one of the most debilitating non-motor symptoms associated with Parkinson disease, and it often manifests as visual hallucinations and minor hallucinatory phenomena. Lifetime prevalence of visual hallucinations in Parkinson disease may run as high as 50%; however, psychosis does not occur in all patients, and there is considerable variation in the onset of the disorder.
To determine factors that are associated with the onset of psychosis in patients with Parkinson disease, Abhishek Lenka, MBBS, PhD, and colleagues conducted a prospective case-control study, recruiting 51 consecutive patients with Parkinson disease and psychosis. The median latency of onset of psychotic symptoms from the onset of motor symptoms was 5.5 years.
After doing a median split, the cohort of patients was divided into those with early onset psychosis (EOP) and late onset psychosis (LOP). Compared with patients with LOP, patients with EOP had poor scores on frontal assessment battery (13.8 vs. 15.3; P =0.007) and were more likely to have RBD (80% vs 46.2%; P =0.02), PIGD phenotype (72% vs 26.9%; P=0.002), and excessive daytime sleepiness (Epworth Sleepiness Scale: 8.04 vs 3.9).
In contrast, patients with LOP were older (63.4 years vs 56.5; P =0.04) and had higher levodopa equivalent dose/day (819.1 vs 608.5; P =0.04).
The researchers concluded that these differences may be directly related to the natural course of psychosis in Parkinson disease and that these factors should be considered in future longitudinal studies aimed at understanding the pathogenesis of psychosis in Parkinson disease.
Lenka A, George L, Arumugham SS, et al. Predictors of onset of psychosis in patients with Parkinson’s disease: Who gets it early? [published online September 14, 2017]. Parkinsonism Relat Disord. doi:10.1016/j.parkreldis.2017.09.015