Examining the Psychosis Continuum

DeRosse, Pamela; Karlsgodt, Katherine H.

doi:10.1007/s40473-015-0040-7

Cited by 104 publications

(81 citation statements)

References 110 publications

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“…This approach has been used in previous studies on AD psychosis 15,16,39 and is consistent with a continuum model of psychosis. 40,41 Patients were coded as non-psychotic (AD) if psychotic symptoms were not present either at the baseline or at any of the follow-up examinations during the observation period.…”

Section: Subjectsmentioning

confidence: 99%

Psychosis of Alzheimer's disease: Neuropsychological and neuroimaging longitudinal study

D'Antonio

Vita

Zazzaro

et al. 2019

Int J Geriat Psychiatry

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Objectives Psychosis of Alzheimer's disease (AD) may represent a distinct disease phenotype; however, neuropsychological profile and neural basis linked to this phenotype have not yet been clarified. In this study, we aimed at detecting whether impairment in specific cognitive domains predicts the onset of psychosis in AD patients and what grey matter alterations, their location, and the rate of atrophy are associated with psychosis of AD. Methods Longitudinal neuropsychological data from AD patients with and without psychosis were analysed to determine whether the neuropsychological profile can predict the onset of psychosis. A voxel‐based morphometry (VBM) on longitudinal T1‐weighted images was used to explore differences in grey matter volume and in the rate of atrophy between groups. Results Noncognitive domain predicted the psychosis onset. However, AD patients with psychosis exhibited greater atrophy in the right anterior‐inferior temporal lobe, including the fusiform gyrus (cluster‐p‐family‐wise error [pfwe] < 0.05; peak‐p uncorrected [pUNC] < 0.001) as well as greater rate of atrophy in the right insula than nonpsychotic patients (cluster‐pFWE = 0.075; peak‐pUNC < 0.001). The anterior‐inferior temporal lobe is part of the ventral visual stream, and the insula plays a key role in the salience network. Conclusions This finding suggests that damage in these areas underpins an impairment in the visual processing of the objects and an impairment in the attribution of salience to the misperceived stimuli, which in turn leads to the onset of psychosis. These findings tie in well with the neuropsychological model of psychosis, according to which the simultaneous presence of two factors, namely misperception and misattribution, underlies psychosis in dementia.

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Section: Subjectsmentioning

confidence: 99%

Psychosis of Alzheimer's disease: Neuropsychological and neuroimaging longitudinal study

D'Antonio

Vita

Zazzaro

et al. 2019

Int J Geriat Psychiatry

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“…Next, from each participant, windows with the highest variance in FNC ('local extrema') were chosen to initialize clustering. K-means clustering was first performed on the local extrema with varying numbers of clusters k (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20): The ratio of within-to between-cluster distances was plotted for each k. The turning point in the graph where the amount of additionally explained variance becomes marginal, and therefore reflecting the optimal number of clusters ('elbow criterion'), was five, which is typical for this type of analysis. 51 These five cluster centroids were then used as starting points to cluster all windowed FNC matrices in such a way that each windowed FNC matrix was assigned to the one cluster with which it was most highly correlated.…”

Section: Group Independent Component Analysismentioning

confidence: 99%

“…Substantial evidence now indicates that psychotic symptoms (PS) occur on a continuum ranging from sub-threshold PS to full-blown psychotic disorders such as schizophrenia. [1][2][3] Clinically, PS include abnormalities of perception, emotion, and cognition that vary in severity, frequency, and level of conviction across the psychosis spectrum. 4,5 Traditionally, individuals on the severe end of this continuum have been studied.…”

Section: Introductionmentioning

confidence: 99%

“…[8][9][10][11][12] Symptoms of many psychiatric illnesses typically appear during adolescence, a sensitive period of brain development, [13][14][15] and frequency of PS peaks in late childhood and adolescence. 2,16 Therefore, brain imaging studies of youth experiencing PS are likely to be informative regarding neural substrates of developmental vulnerability to psychosis. Publicly available data from the Philadelphia Neurodevelopmental Cohort (PNC) utilized in the current study offer an unprecedented opportunity to study neural substrates of PS from late-childhood through adolescence and early adulthood, overlapping with critical periods for the onset of many neuropsychiatric disorders.…”

Section: Introductionmentioning

confidence: 99%

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Transient patterns of functional dysconnectivity in youth with psychosis spectrum symptoms

Mennigen¹,

Jolles²,

Ce³

et al. 2018

Preprint

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Psychosis spectrum disorders are conceptualized as neurodevelopmental disorders accompanied by disruption of large-scale functional brain networks. Both static and dynamic dysconnectivity have been described in patients with schizophrenia and, more recently, in helpseeking individuals at clinical high-risk for psychosis. Less is known, however, about developmental aspects of dynamic functional network connectivity (FNC) associated with psychotic symptoms (PS) in the general population. Here, we investigate resting state fMRI data using established dynamic FNC methods in the Philadelphia Neurodevelopmental Cohort (ages 8-22), including 129 participants experiencing PS and 452 participants without PS (non-PS).Applying a sliding window approach and k-means clustering, 5 dynamic states with distinct whole-brain connectivity patterns were identified. PS-associated dysconnectivity was most prominent in states characterized by synchronization or antagonism of the default mode network (DMN) and cognitive control (CC) domains. Hyperconnectivity between DMN, salience, and CC domains in PS youth only occurred in a state characterized by synchronization of the DMN and CC domains, a state that also becomes less frequent with age. However, dysconnectivity of the sensorimotor and visual systems in PS youth was revealed in other transient states completing the picture of whole-brain dysconnectivity patterns associated with PS.Overall, state-dependent dysconnectivity was observed in PS youth, providing the first evidence that disruptions of dynamic functional connectivity are present across a broader psychosis continuum.

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“…The psychosis continuum comprises the full spectrum of psychotic experiences, from healthy individuals who experience a range of psychotic-like experiences, to prodromal individuals with subclinical symptoms, and to those with florid psychosis at the very end of the spectrum 26,27 . In this study, we zoom in to the non-clinical population, as there is conflicting evidence whether PEs are also reduced on the healthy end of the continuum 28,29 .…”

Section: Introductionmentioning

confidence: 99%

Sensory learning and inference is impaired in the non-clinical continuum of psychosis: a replication study

Dzafic

Randeniya

Harris

et al. 2018

Preprint

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Our perceptions result from the brain’s ability to make inferences, or predictive models, of sensory information. Recently, it has been proposed that psychotic traits may be linked to impaired predictive processes. Here, we examine the brain dynamics underlying sensory learning and inference in stable and volatile environments, in a population of healthy individuals (N=75) with a range of psychotic-like experiences. We measured prediction error responses to sound sequences with electroencephalography, gauged sensory inference explicitly by behaviourally recording sensory ‘regularity’ learning errors, and used dynamic causal modelling to tap into the underlying neural circuitry. We discuss the findings that were robust to replication across the two experiments (N=31 and N=44 for the discovery and the validation datasets, respectively). First, we found that during stable conditions, participants demonstrated a stronger predictive model, reflected in a larger prediction error response to unexpected sounds, and decreased regularity learning errors. Moreover, individuals with attenuated prediction errors in stable conditions were found to make greater incorrect predictions about sensory information. Critically, we show that greater errors in sensory learning and inference are related to increased psychotic-like experiences. These findings link neurophysiology to behaviour during sensory learning and prediction formation, as well as providing further evidence for the idea of a continuum of psychosis in the healthy, non-clinical population.Significance StatementWhilst perceiving the world, we make inferences by learning the regularities present in the sensory environment. It has been argued that psychosis may emerge due to a failure to learn sensory regularities, resulting in an impaired representation of the world. Recently it has been proposed that psychosis exists on a continuum; however, there is conflicting evidence on whether sensory learning deficits align on the non-clinical end of the psychosis continuum. We found that sensory learning is associated with brain prediction errors, and critically, it is impaired in healthy people who report more psychotic-like experiences. We replicated these findings in an independent sample, demonstrating strengthened credibility to support that the continuum of psychosis extends into the non-clinical population.

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Examining the Psychosis Continuum

Cited by 104 publications

References 110 publications

Psychosis of Alzheimer's disease: Neuropsychological and neuroimaging longitudinal study

Psychosis of Alzheimer's disease: Neuropsychological and neuroimaging longitudinal study

Transient patterns of functional dysconnectivity in youth with psychosis spectrum symptoms

Sensory learning and inference is impaired in the non-clinical continuum of psychosis: a replication study

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