The psychosis spectrum in Parkinson disease

Abstract

In 2007, the clinical and research profile of illusions, hallucinations, delusions and related symptoms in Parkinson disease (PD) was raised with the publication of a consensus definition of PD psychosis. Symptoms that were previously deemed benign and clinically insignificant were incorporated into a continuum of severity, leading to the rapid expansion of literature focusing on clinical aspects, mechanisms and treatment. Here, we review this literature and the evolving view of PD psychosis. Key topics include the prospective risk of dementia in individuals with PD psychosis, and the causal and modifying effects of PD medication. We discuss recent developments, including recognition of an increase in the prevalence of psychosis with disease duration, addition of new visual symptoms to the psychosis continuum, and identification of frontal executive, visual perceptual and memory dysfunction at different disease stages. In addition, we highlight novel risk factors — for example, autonomic dysfunction — that have emerged from prospective studies, structural MRI evidence of frontal, parietal, occipital and hippocampal involvement, and approval of pimavanserin for the treatment of PD psychosis. The accumulating evidence raises novel questions and directions for future research to explore the clinical management and biomarker potential of PD psychosis.

Hallucinations, somatic‐functional disorders of PD‐DLB as expressions of thalamic dysfunction

“…The occurrence of hallucinations invariably portends an unfavorable prognostic outcome, as they predict the onset of cognitive decline. However, in some patients hallucinations may appear, mostly those with DLB, during the early stages of the disease before or at the onset of treatment .…”

“…The occurrence of hallucinations invariably portends an unfavorable prognostic outcome, as they predict the onset of cognitive decline. However, in some patients hallucinations may appear, mostly those with DLB, during the early stages of the disease before or at the onset of treatment . Early visual hallucinations may consist of simple distortions of perceived images that are often characterized by the perception of anthropomorphic traits (eidolon‐idol) of visual elements .…”

“…Finally, delusions are the hallmarks of the psychotic narratives that precede or associate with onset of motor symptoms or concomitantly appear with dementia …”

A proposal for a semantic change in the current diagnostic criteria of Parkinson’s disease Psychosis

“…According to a recent comprehensive review is more appropriate to consider that there is a spectrum of psychotic symptoms in the course of PD progression [5]. Early in the disease, symptoms experienced include passage hallucinations (where a person, animal or indefi nite object is seen briefl y passing in the peripheral visual fi eld), illusions (for example, seeing the branch of a tree as a cat), and presence hallucinations (a feeling that someone is nearby).…”

“…Insightthat is, recognition that the experiences are hallucinations -is preserved at this stage, but becomes lost as PD progresses, with the onset of false beliefs (delusions) and hallucinations in other sensory modalities (multimodality hallucinations). Cognitive decline and loss of insight parallel symptom progression [5].…”