Psychosis in parkinsonism: an unorthodox approach

Abstract

Psychosis in Parkinson’s disease (PD) is currently considered as the occurrence of hallucinations and delusions. The historical meaning of the term psychosis was, however, broader, encompassing a disorganization of both consciousness and personality, including behavior abnormalities, such as impulsive overactivity and catatonia, in complete definitions by the International Classification of Diseases-10 (ICD-10) and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Our review is aimed at reminding that complex psychotic symptoms, including impulsive overactivity and somatoform disorders (the last being a recent controversial entity in PD), were carefully described in postencephalitic parkinsonism (PEP), many decades before dopaminergic treatment era, and are now described in other parkinsonisms than PD. Eminent neuropsychiatrists of the past century speculated that studying psychosis in PEP might highlight its mechanisms in other conditions. Yet, functional assessments were unavailable at the time. Therefore, the second part of our article reviews the studies of neural correlates of psychosis in parkinsonisms, by taking into account both theories on the narrative functions of the default mode network (DMN) and hypotheses on DMN modulation.

EEG Resting-State Networks in Dementia with Lewy Bodies Associated with Clinical Symptoms

“…Interestingly, there is substantial evidence that the mPFC is one of the key regions involved in the pathogenesis of major depressive disorder [75-77]. More specifically, MRI and neurochemical studies revealed that DLB patients with depression had significant reductions in the cortical volume and serotonin level, suggesting reduced activities in areas of self-referential and visual perception networks [78, 79].…”

“…Recent neuroimaging studies found enhanced activity of the default mode network and VAN with visual hallucination in Parkinson disease, which is a related α-synucleinopathy [77, 87-89]. The recently updated diagnostic criteria of DLB adopted the term “cingulate island sign,” to refer to a relative preservation of posterior or midcingulate metabolism on PET imaging, as supportive biomarker of the disease.…”

Disturbances of visual perception in non-demented patients with Parkinson’s disease

“…Psi cho zi niai simp to mai pa si reið kia apie 60 % pa cien tø, ser gan èiø PL, ir yra dar daþ nes ni pa cien tams, ku rie ser ga Le wy kû ne liø de men ci ja [3]. Re gos su vo ki mo su tri ki mai (iliu zi jos ar ha liu ci na ci jos) reikð min gai daþ niau pa si reiðkia ser gant al fa si nuk lei no pa ti jo mis nei ki tø neu ro de ge nera ci niø li gø me tu [4,5], to dël yra svar bus Le wy kû ne liø par kin so niz mo po þy mis, di fe ren ci juo jant PL ir Le wy kûne liø de men ci jà nuo ki tø par kin so niz mo rû ðiø [6].…”

Management of Psychosis in Parkinson’s Disease: Emphasizing Clinical Subtypes and Pathophysiological Mechanisms of the Condition

“…The history of psychosis in PD goes back to the early 19th century, where the presence of mental disturbances among PD patients was described as being rare and was accounted for as either a consequence of a chronic disease evolution or regarded as coincidental [ 5 ]. After an outbreak of encephalitis lethargica between 1915 and 1926, a condition of unknown origin with acute onset and often chronic persistence of various neurological symptoms, including headache, lethargy, catatonia, parkinsonism, and tremor, a potential link between an altered mental state and parkinsonism was proposed and the first idea of complex psychotic symptoms in postencephalitic parkinsonism (PEP) cases was described [ 6 , 7 ]. In more recent years however, the etiologic relationship between the encephalitis outbreak and the alleged PEP has been discussed as controversial due to a lack of consistency in clinical features and in the onset of symptoms and the possibility of other causes of parkinsonism has been postulated [ 7 , 8 ].…”

“…After an outbreak of encephalitis lethargica between 1915 and 1926, a condition of unknown origin with acute onset and often chronic persistence of various neurological symptoms, including headache, lethargy, catatonia, parkinsonism, and tremor, a potential link between an altered mental state and parkinsonism was proposed and the first idea of complex psychotic symptoms in postencephalitic parkinsonism (PEP) cases was described [ 6 , 7 ]. In more recent years however, the etiologic relationship between the encephalitis outbreak and the alleged PEP has been discussed as controversial due to a lack of consistency in clinical features and in the onset of symptoms and the possibility of other causes of parkinsonism has been postulated [ 7 , 8 ]. Moreover, in subsequent years, confusional states were reported under treatment with L-Dopa and later under dopamine agonist therapy in PD patients, giving rise to this new core feature in PD.…”