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1.
Mol Psychiatry ; 29(5): 1361-1381, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38302562

RESUMO

BACKGROUND: Preventing or delaying the onset of psychosis requires identification of those at risk for developing psychosis. For predictive purposes, the prodrome - a constellation of symptoms which may occur before the onset of psychosis - has been increasingly recognized as having utility. However, it is unclear what proportion of patients experience a prodrome or how this varies based on the multiple definitions used. METHODS: We conducted a systematic review and meta-analysis of studies of patients with psychosis with the objective of determining the proportion of patients who experienced a prodrome prior to psychosis onset. Inclusion criteria included a consistent prodrome definition and reporting the proportion of patients who experienced a prodrome. We excluded studies of only patients with a prodrome or solely substance-induced psychosis, qualitative studies without prevalence data, conference abstracts, and case reports/case series. We searched Ovid MEDLINE, Embase (Ovid), APA PsycInfo (Ovid), Web of Science Core Collection (Clarivate), Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, APA PsycBooks (Ovid), ProQuest Dissertation & Thesis, on March 3, 2021. Studies were assessed for quality using the Critical Appraisal Checklist for Prevalence Studies. Narrative synthesis and proportion meta-analysis were used to estimate prodrome prevalence. I2 and predictive interval were used to assess heterogeneity. Subgroup analyses were used to probe sources of heterogeneity. (PROSPERO ID: CRD42021239797). RESULTS: Seventy-one articles were included, representing 13,774 patients. Studies varied significantly in terms of methodology and prodrome definition used. The random effects proportion meta-analysis estimate for prodrome prevalence was 78.3% (95% CI = 72.8-83.2); heterogeneity was high (I2 97.98% [95% CI = 97.71-98.22]); and the prediction interval was wide (95% PI = 0.411-0.936). There were no meaningful differences in prevalence between grouped prodrome definitions, and subgroup analyses failed to reveal a consistent source of heterogeneity. CONCLUSIONS: This is the first meta-analysis on the prevalence of a prodrome prior to the onset of first episode psychosis. The majority of patients (78.3%) were found to have experienced a prodrome prior to psychosis onset. However, findings are highly heterogenous across study and no definitive source of heterogeneity was found despite extensive subgroup analyses. As most studies were retrospective in nature, recall bias likely affects these results. While the large majority of patients with psychosis experience a prodrome in some form, it is unclear if the remainder of patients experience no prodrome, or if ascertainment methods employed in the studies were not sensitive to their experiences. Given widespread investment in indicated prevention of psychosis through prospective identification and intervention during the prodrome, a resolution of this question as well as a consensus definition of the prodrome is much needed in order to effectively direct and organize services, and may be accomplished through novel, densely sampled and phenotyped prospective cohort studies that aim for representative sampling across multiple settings.


Assuntos
Sintomas Prodrômicos , Transtornos Psicóticos , Humanos , Prevalência , Transtornos Psicóticos/epidemiologia
2.
Brain ; 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38637303

RESUMO

The prediction error account of delusions has had success. However, its explanation of delusions with different contents has been lacking. Persecutory delusions and paranoia are the common unfounded beliefs that others have harmful intentions towards us. Other delusions include believing that one's thoughts or actions are under external control, or that events in the world have specific personal meaning. We compare learning on two different cognitive tasks, probabilistic reversal learning (PRL) and Kamin blocking, that have relationships to paranoid and non-paranoid delusion-like beliefs, respectively. We find that Clinical High-Risk status alone does not result in different behavioral results on the PRL task but that an individual's level of paranoia is associated with excessive switching behavior. During the Kamin blocking task, paranoid individuals learned inappropriately about the blocked cue. However, they also had decreased learning about the control cue, suggesting more general learning impairments. Non-paranoid delusion-like belief conviction (but not paranoia) was associated with aberrant learning about the blocked cue but intact learning about the control cue, suggesting specific impairments in learning related to cue combination. We fit task-specific computational models separately to behavioral data to explore how latent parameters vary within individuals between tasks, and how they can explain symptom-specific effects. We find that paranoia is associated with low learning rates on the PRL task as well as the blocking task. Non-paranoid delusion-like belief conviction was instead related to parameters controlling the degree and direction of similarity between cue updating during simultaneous cue presentation. These results suggest that paranoia and other delusion-like beliefs involve dissociable deficits in learning and belief updating, which - given the transdiagnostic status of paranoia - may have differential utility in predicting psychosis.

3.
Mol Psychiatry ; 28(6): 2189-2196, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37280282

RESUMO

Computational psychiatry is a field aimed at developing formal models of information processing in the human brain, and how alterations in this processing can lead to clinical phenomena. There has been significant progress in the development of tasks and how to model them, presenting an opportunity to incorporate computational psychiatry methodologies into large- scale research projects or into clinical practice. In this viewpoint, we explore some of the barriers to incorporation of computational psychiatry tasks and models into wider mainstream research directions. These barriers include the time required for participants to complete tasks, test-retest reliability, limited ecological validity, as well as practical concerns, such as lack of computational expertise and the expense and large sample sizes traditionally required to validate tasks and models. We then discuss solutions, such as the redesigning of tasks with a view toward feasibility, and the integration of tasks into more ecologically valid and standardized game platforms that can be more easily disseminated. Finally, we provide an example of how one task, the conditioned hallucinations task, might be translated into such a game. It is our hope that interest in the creation of more accessible and feasible computational tasks will help computational methods make more positive impacts on research as well as, eventually, clinical practice.


Assuntos
Encéfalo , Psiquiatria , Humanos , Reprodutibilidade dos Testes , Cognição , Psiquiatria/métodos , Alucinações
4.
Mol Psychiatry ; 28(3): 1182-1189, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36434057

RESUMO

Progressive grey matter loss has been demonstrated among clinical high-risk (CHR) individuals who convert to psychosis, but it is unknown whether these changes occur prior to psychosis onset. Identifying illness-related neurobiological mechanisms that occur prior to conversion is essential for targeted early intervention. Among participants in the third wave of the North American Prodrome Longitudinal Study (NAPLS3), this report investigated if steeper cortical thinning was observable prior to psychosis onset among CHR individuals who ultimately converted (CHR-C) and assessed the shortest possible time interval in which rates of cortical thinning differ between CHR-C, CHR non-converters (CHR-NC), and health controls (HC). 338 CHR-NC, 42 CHR-C, and 62 HC participants (age 19.3±4.2, 44.8% female, 52.5% racial/ethnic minority) completed up to 5 MRI scans across 8 months. Accelerated thinning among CHR-C compared to CHR-NC and HC was observed in multiple prefrontal, temporal, and parietal cortical regions. CHR-NC also exhibited accelerated cortical thinning compared to HC in several of these areas. Greater percent decrease in cortical thickness was observed among CHR-C compared to other groups across 2.9±1.8 months, on average, in several cortical areas. ROC analyses discriminating CHR-C from CHR-NC by percent thickness change in a left hemisphere region of interest, scanner, age, age2, and sex had an AUC of 0.74, with model predictive power driven primarily by percent thickness change. Findings indicate that accelerated cortical thinning precedes psychosis onset and differentiates CHR-C from CHR-NC and HC across short time intervals. Mechanisms underlying cortical thinning may provide novel treatment targets prior to psychosis onset.


Assuntos
Afinamento Cortical Cerebral , Transtornos Psicóticos , Humanos , Feminino , Adolescente , Masculino , Estudos Longitudinais , Etnicidade , Grupos Minoritários , Sintomas Prodrômicos
5.
Acta Psychiatr Scand ; 147(6): 623-633, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36905387

RESUMO

INTRODUCTION: Paranoia is a common and impairing psychosis symptom, which exists along a severity continuum that extends into the general population. Individuals at clinical high-risk for psychosis (CHR) frequently experience paranoia and this may elevate their risk for developing full psychosis. Nonetheless, limited work has examined the efficient measurement of paranoia in CHR individuals. The present study aimed to validate an often-used self-report measure, the revised green paranoid thoughts scale (RGPTS), in this critical population. METHOD: Participants were CHR individuals (n = 103), mixed clinical controls (n = 80), and healthy controls (n = 71) who completed self-report and interview measures. Confirmatory factor analysis (CFA), psychometric indices, group differences, and relations to external measures were used to evaluate the reliability and validity of the RGPTS. RESULTS: CFA replicated a two-factor structure for the RGPTS and the associated reference and persecution scales were reliable. CHR individuals scored significantly higher on both reference and persecution, relative to both healthy (ds = 1.03, 0.86) and clinical controls (ds = 0.64, 0.73). In CHR participants, correlations between reference and persecution and external measures were smaller than expected, though showed evidence of discriminant validity (e.g., interviewer-rated paranoia, r = 0.24). When examined in the full sample, correlation magnitude was larger and follow-up analyses indicated that reference related most specifically to paranoia (ß = 0.32), whereas persecution uniquely related to poor social functioning (ß = -0.29). CONCLUSION: These results demonstrate the reliability and validity of the RGPTS, though its scales related more weakly to severity in CHR individuals. The RGPTS may be useful in future work aiming to develop symptom-specific models of emerging paranoia in CHR individuals.


Assuntos
Transtornos Psicóticos , Humanos , Reprodutibilidade dos Testes , Transtornos Psicóticos/diagnóstico , Transtornos Paranoides/diagnóstico , Autorrelato , Relações Interpessoais
6.
Hum Brain Mapp ; 42(7): 2159-2180, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33539625

RESUMO

"Resting-state" functional magnetic resonance imaging (rs-fMRI) is widely used to study brain connectivity. So far, researchers have been restricted to measures of functional connectivity that are computationally efficient but undirected, or to effective connectivity estimates that are directed but limited to small networks. Here, we show that a method recently developed for task-fMRI-regression dynamic causal modeling (rDCM)-extends to rs-fMRI and offers both directional estimates and scalability to whole-brain networks. First, simulations demonstrate that rDCM faithfully recovers parameter values over a wide range of signal-to-noise ratios and repetition times. Second, we test construct validity of rDCM in relation to an established model of effective connectivity, spectral DCM. Using rs-fMRI data from nearly 200 healthy participants, rDCM produces biologically plausible results consistent with estimates by spectral DCM. Importantly, rDCM is computationally highly efficient, reconstructing whole-brain networks (>200 areas) within minutes on standard hardware. This opens promising new avenues for connectomics.


Assuntos
Encéfalo/fisiologia , Conectoma/métodos , Imageamento por Ressonância Magnética/métodos , Rede Nervosa/fisiologia , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Conectoma/normas , Humanos , Imageamento por Ressonância Magnética/normas , Pessoa de Meia-Idade , Modelos Teóricos , Rede Nervosa/diagnóstico por imagem , Análise de Regressão , Adulto Jovem
8.
Behav Brain Sci ; 41: e83, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-31064450

RESUMO

Individual-specific predispositions may precede the cultural evolution of shamanism and may be linked to it via principles of predictive coding. We have used these principles to identify commonalities between clinical and shaman-like non-clinical voice-hearers. The author may find this approach helpful in relating the experiences of shamans to those of their clients.


Assuntos
Transtornos Psicóticos , Xamanismo , Evolução Cultural , Humanos
9.
Psychopathology ; 48(6): 376-85, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26361209

RESUMO

BACKGROUND: Ketamine, the NMDA glutamate receptor antagonist drug, is increasingly employed as an experimental model of psychosis in healthy volunteers. At subanesthetic doses, it safely and reversibly causes delusion-like ideas, amotivation and perceptual disruptions reminiscent of the aberrant salience experiences that characterize first-episode psychosis. However, auditory verbal hallucinations, a hallmark symptom of schizophrenia, have not been reported consistently in healthy volunteers even at high doses of ketamine. SAMPLING AND METHODS: Here we present data from a set of healthy participants who received moderately dosed, placebo-controlled ketamine infusions in the reduced stimulation environment of the magnetic resonance imaging (MRI) scanner. We highlight the phenomenological experiences of 3 participants who experienced particularly vivid hallucinations. RESULTS: Participants in this series reported auditory verbal and musical hallucinations at a ketamine dose that does not induce auditory hallucination outside of the scanner. CONCLUSIONS: We interpret the observation of ketamine-induced auditory verbal hallucinations in the context of the reduced perceptual environment of the MRI scanner and offer an explanation grounded in predictive coding models of perception and psychosis - the brain fills in expected perceptual inputs, and it does so more in situations of altered perceptual input. The altered perceptual input of the MRI scanner creates a mismatch between top-down perceptual expectations and the heightened bottom-up signals induced by ketamine. Such circumstances induce aberrant percepts, including musical and auditory verbal hallucinations. We suggest that these circumstances might represent a useful experimental model of auditory verbal hallucinations and highlight the impact of ambient sensory stimuli on psychopathology.


Assuntos
Lobo Frontal/efeitos dos fármacos , Lobo Frontal/fisiopatologia , Alucinações/induzido quimicamente , Ketamina/efeitos adversos , Transtornos Psicóticos/tratamento farmacológico , Adulto , Delusões/induzido quimicamente , Relação Dose-Resposta a Droga , Feminino , Alucinações/diagnóstico , Humanos , Ketamina/administração & dosagem , Imageamento por Ressonância Magnética , Masculino , Percepção , Transtornos Psicóticos/patologia , Adulto Jovem
10.
Schizophr Res ; 269: 64-70, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38733801

RESUMO

BACKGROUND AND HYPOTHESIS: Hearing voices is a common and often distressing experience for people with psychosis, and many individuals experience medication-resistant auditory verbal hallucinations (AVH). Psychosocial interventions are often employed to address distress over hearing voices. However, although links have been made between adverse social experiences and psychosis broadly, no work has yet delineated the relationship between day-to-day social stress and hallucination severity. We aimed to define that relationship in both clinical and non-clinical voice-hearers. STUDY DESIGN: A sample of 278 participants with a history of hearing voices was selected from the Yale Control Over Perceptual Experiences (COPE) Project. They were administered self-report measures of recent stress and recent auditory experiences within a cross-sectional design. Regression models were used to evaluate whether self-reported aspects of recent stress-and social stress in particular-were related to recent frequency of and distress over hearing voices. Related demographics and clinical characteristics were included as covariates. STUDY RESULTS: A significant relationship was observed between recent social stress and both recent frequency of and distress over hearing voices. While other aspects of recent stress were also related to recent distress over voices, social stressors uniquely predicted distress over voice-hearing, beyond the influence of other stressors. Depressive symptom severity was also related to distress over voices. CONCLUSIONS: Results suggest that daily social stress may be an important consideration and a potential treatment target for individuals experiencing clinical distress over auditory hallucinations.


Assuntos
Alucinações , Estresse Psicológico , Humanos , Alucinações/fisiopatologia , Alucinações/etiologia , Feminino , Masculino , Adulto , Estudos Transversais , Pessoa de Meia-Idade , Transtornos Psicóticos/fisiopatologia , Adulto Jovem , Autorrelato , Escalas de Graduação Psiquiátrica , Índice de Gravidade de Doença
11.
Schizophr Bull ; 50(2): 349-362, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-37830405

RESUMO

BACKGROUND: There is increasing evidence that people with hallucinations overweight perceptual beliefs relative to incoming sensory evidence. Past work demonstrating prior overweighting has used simple, nonlinguistic stimuli. However, auditory hallucinations in psychosis are often complex and linguistic. There may be an interaction between the type of auditory information being processed and its perceived quality in engendering hallucinations. STUDY DESIGN: We administered a linguistic version of the conditioned hallucinations (CH) task to an online sample of 88 general population participants. Metrics related to hallucination-proneness, hallucination severity, stimulus thresholds, and stimulus detection rates were collected. Data were used to fit parameters of a Hierarchical Gaussian Filter (HGF) model of perceptual inference to determine how latent perceptual states influenced task behavior. STUDY RESULTS: Replicating past results, higher CH rates were observed both in those with recent hallucinatory experiences as well as participants with high hallucination-proneness; CH rates were positively correlated with increased prior weighting; and increased prior weighting was related to hallucination severity. Unlike past results, participants with recent hallucinatory experiences as well as those with higher hallucination-proneness had higher stimulus thresholds, lower sensitivity to stimuli presented at the highest threshold, and had lower response confidence, consistent with lower precision of sensory evidence. CONCLUSIONS: We replicate the finding that increased CH rates and recent hallucinations correlate with increased prior weighting using a linguistic version of the CH task. Results support a role for reduced sensory precision in the interplay between prior weighting and hallucination-proneness.


Assuntos
Alucinações , Transtornos Psicóticos , Humanos , Alucinações/diagnóstico
12.
Sci Rep ; 14(1): 5607, 2024 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453946

RESUMO

There are many different kinds of 'phantom' percepts but it is unknown whether they are united by common mechanisms. For example, synaesthesia (e.g., numbers evoking colour) and hallucinations appear conceptually and phenomenologically similar: both result in a percept that does not have an environmental correlate. Here, people with synaesthesia (n = 66) performed a conditioned hallucinations paradigm known to be sensitive to hallucination susceptibility, and we asked whether synaesthetes would show the same behavioural profile as hallucinators in this task. Repeated pairing of checkerboards with tones, and gratings with colours encourages the participant to draw on prior knowledge when asked to report on the presence of the difficult-to-detect target stimulus. Synaesthetes show increased modelled expectancies for the stimulus association across the board, resulting in a higher number of detections at all stimulus intensities. This is in contrast to the pattern observed in hallucinators, who weigh their prior beliefs more strongly than controls, giving rise to more conditioned hallucinations. Results indicate that fundamentally different perceptual processes may be at the core of these seemingly similar experiences.


Assuntos
Transtornos da Percepção , Humanos , Sinestesia , Percepção de Cores , Alucinações , Cafeína
13.
bioRxiv ; 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38895308

RESUMO

BACKGROUND: While the amygdala receives early tau deposition in Alzheimer's disease (AD) and is involved in social and emotional processing, the relationship between amygdalar tau and early neuropsychiatric symptoms in AD is unknown. We sought to determine whether focal tau binding in the amygdala and abnormal amygdalar connectivity were detectable in a preclinical AD cohort and identify relationships between these and self-reported mood symptoms. METHODS: We examined n=598 individuals (n=347 amyloid-positive (58% female), n=251 amyloid-negative (62% female); subset into tau PET and fMRI cohorts) from the A4 Study. In our tau PET cohort, we used amygdalar segmentations to examine representative nuclei from three functional divisions of the amygdala. We analyzed between-group differences in division-specific tau binding in the amygdala in preclinical AD. We conducted seed-based functional connectivity analyses from each division in the fMRI cohort. Finally, we conducted exploratory post-hoc correlation analyses between neuroimaging biomarkers of interest and anxiety and depression scores. RESULTS: Amyloid-positive individuals demonstrated increased tau binding in medial and lateral amygdala (F(4,442)=14.61, p=0.00045; F(4,442)=5.83, p=0.024, respectively). Across amygdalar divisions, amyloid-positive individuals had relatively increased regional connectivity from amygdala to other temporal regions, insula, and orbitofrontal cortex. There was an interaction by amyloid group between tau binding in the medial and lateral amygdala and anxiety. Medial amygdala to retrosplenial connectivity negatively correlated with anxiety symptoms (rs=-0.103, p=0.015). CONCLUSIONS: Our findings suggest that preclinical tau deposition in the amygdala may result in meaningful changes in functional connectivity which may predispose patients to mood symptoms.

14.
ArXiv ; 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38699166

RESUMO

The mechanisms of psychotic symptoms like hallucinations and delusions are often investigated in fully-formed illness, well after symptoms emerge. These investigations have yielded key insights, but are not well-positioned to reveal the dynamic forces underlying symptom formation itself. Understanding symptom development over time would allow us to identify steps in the pathophysiological process leading to psychosis, shifting the focus of psychiatric intervention from symptom alleviation to prevention. We propose a model for understanding the emergence of psychotic symptoms within the context of an adaptive, developing neural system. We will make the case for a pathophysiological process that begins with cortical hyperexcitability and bottom-up noise transmission, which engenders inappropriate belief formation via aberrant prediction error signaling. We will argue that this bottom-up noise drives learning about the (im)precision of new incoming sensory information because of diminished signal-to-noise ratio, causing an adaptive relative over-reliance on prior beliefs. This over-reliance on priors predisposes to hallucinations and covaries with hallucination severity. An over-reliance on priors may also lead to increased conviction in the beliefs generated by bottom-up noise and drive movement toward conversion to psychosis. We will identify predictions of our model at each stage, examine evidence to support or refute those predictions, and propose experiments that could falsify or help select between alternative elements of the overall model. Nesting computational abnormalities within longitudinal development allows us to account for hidden dynamics among the mechanisms driving symptom formation and to view established symptomatology as a point of equilibrium among competing biological forces.

15.
J Neurosci ; 32(18): 6263-74, 2012 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-22553032

RESUMO

The brain's ability to bind incoming auditory and visual stimuli depends critically on the temporal structure of this information. Specifically, there exists a temporal window of audiovisual integration within which stimuli are highly likely to be perceived as part of the same environmental event. Several studies have described the temporal bounds of this window, but few have investigated its malleability. Recently, our laboratory has demonstrated that a perceptual training paradigm is capable of eliciting a 40% narrowing in the width of this window that is stable for at least 1 week after cessation of training. In the current study, we sought to reveal the neural substrates of these changes. Eleven human subjects completed an audiovisual simultaneity judgment training paradigm, immediately before and after which they performed the same task during an event-related 3T fMRI session. The posterior superior temporal sulcus (pSTS) and areas of auditory and visual cortex exhibited robust BOLD decreases following training, and resting state and effective connectivity analyses revealed significant increases in coupling among these cortices after training. These results provide the first evidence of the neural correlates underlying changes in multisensory temporal binding likely representing the substrate for a multisensory temporal binding window.


Assuntos
Percepção Auditiva/fisiologia , Encéfalo/fisiologia , Sinais (Psicologia) , Aprendizagem/fisiologia , Rede Nervosa/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adulto , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino
16.
Exp Brain Res ; 225(4): 479-89, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23307155

RESUMO

The importance of multisensory integration for human behavior and perception is well documented, as is the impact that temporal synchrony has on driving such integration. Thus, the more temporally coincident two sensory inputs from different modalities are, the more likely they will be perceptually bound. This temporal integration process is captured by the construct of the temporal binding window-the range of temporal offsets within which an individual is able to perceptually bind inputs across sensory modalities. Recent work has shown that this window is malleable and can be narrowed via a multisensory perceptual feedback training process. In the current study, we seek to extend this by examining the malleability of the multisensory temporal binding window through changes in unisensory experience. Specifically, we measured the ability of visual perceptual feedback training to induce changes in the multisensory temporal binding window. Visual perceptual training with feedback successfully improved temporal visual processing, and more importantly, this visual training increased the temporal precision across modalities, which manifested as a narrowing of the multisensory temporal binding window. These results are the first to establish the ability of unisensory temporal training to modulate multisensory temporal processes, findings that can provide mechanistic insights into multisensory integration and which may have a host of practical applications.


Assuntos
Percepção Auditiva/fisiologia , Retroalimentação Fisiológica/fisiologia , Aprendizagem/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica , Adulto , Feminino , Humanos , Julgamento/fisiologia , Masculino , Estimulação Luminosa
17.
Artigo em Inglês | MEDLINE | ID: mdl-37075881

RESUMO

There is conflicting evidence on the efficacy of exercise as intervention for psychosis. This article aims to analyze the effect of exercise on psychotic symptoms. A database search was conducted in PubMed, Web of Science, Scopus, ScienceDirect, EBSCO and Cochrane CENTRAL, based on a protocol (PROSPERO: CRD42022326944). Papers available by March 2023 assessing exercise interventions in psychotic patients were included. A significant improvement was found in Positive and Negative Syndrome Scale (PANSS) positive symptoms (MD = -0.75 [-1.35, -0.15], p = 0.01), with large effect sizes for PANSS-negative and general symptoms (-2.14 [-3.36, -0.92]) and (-2.53 [-3.15, -1.91]), respectively. Heterogeneity was high among studies, 49 and 73% for PANSS-positive and negative symptoms, and low, 0%, for general symptoms. It was hypothesized that functioning of specific brain areas, such as the temporal lobe and hippocampus, may underlie the improvement seen with exercise. Based on neuroimaging/neurophysiology studies, we propose a neurobiological model accounting for the association between exercise and psychotic symptom improvement.


Assuntos
Transtornos Psicóticos , Humanos , Transtornos Psicóticos/terapia , Terapia por Exercício
18.
Schizophr Bull ; 49(12 Suppl 2): S3-S12, 2023 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-36840538

RESUMO

There are communities in which hearing voices frequently is common and expected, and in which participants are not expected to have a need for care. This paper compares the ideas and practices of these communities. We observe that these communities utilize cultural models to identify and to explain voice-like events-and that there are some common features to these models across communities. All communities teach participants to "discern," or identify accurately, the legitimate voice of the spirit or being who speaks. We also observe that there are roughly two methods taught to participants to enable them to experience spirits (or other invisible beings): trained attention to inner experience, and repeated speech to the invisible other. We also observe that all of these communities model a learning process in which the ability to hear spirit (or invisible others) becomes more skilled with practice, and in which what they hear becomes clearer over time. Practice-including the practice of discernment-is presumed to change experience. We also note that despite these shared cultural ideas and practices, there is considerable individual variation in experience-some of which may reflect psychotic process, and some perhaps not. We suggest that voice-like events in this context may be shaped by cognitive expectation and trained practice as well as an experiential pathway. We also suggest that researchers could explore these common features both as a way to help those struggling with psychosis, and to consider the possibility that expectations and practice may affect the voice-hearing experience.


Assuntos
Transtornos Psicóticos , Voz , Humanos , Transtornos Psicóticos/psicologia , Alucinações/psicologia , Aprendizagem
19.
Sci Rep ; 13(1): 3196, 2023 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-36823292

RESUMO

Pain perception can be studied as an inferential process in which prior information influences the perception of nociceptive input. To date, there are no suitable psychophysical paradigms to measure this at an individual level. We developed a quantitative sensory testing paradigm allowing for quantification of the influence of prior expectations versus current nociceptive input during perception. Using a Pavlovian-learning task, we investigated the influence of prior expectations on the belief about the varying strength of association between a painful electrical cutaneous stimulus and a visual cue in healthy subjects (N = 70). The belief in cue-pain associations was examined with computational modelling using a Hierarchical Gaussian Filter (HGF). Prior weighting estimates in the HGF model were compared with the established measures of conditioned pain modulation (CPM) and temporal summation of pain (TSP) assessed by cuff algometry. Subsequent HGF-modelling and estimation of the influence of prior beliefs on perception showed that 70% of subjects had a higher reliance on nociceptive input during perception of acute pain stimuli, whereas 30% showed a stronger weighting of prior expectations over sensory evidence. There was no association between prior weighting estimates and CPM or TSP. The data demonstrates relevant individual differences in prior weighting and suggests an importance of top-down cognitive processes on pain perception. Our new psychophysical testing paradigm provides a method to identify individuals with traits suggesting greater reliance on prior expectations in pain perception, which may be a risk factor for developing chronic pain and may be differentially responsive to learning-based interventions.


Assuntos
Dor Crônica , Limiar da Dor , Humanos , Medição da Dor , Teorema de Bayes , Percepção da Dor
20.
Schizophr Bull ; 49(3): 746-755, 2023 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-36939086

RESUMO

BACKGROUND AND HYPOTHESIS: Deficits in performing and interpreting communicative nonverbal behaviors, such as gesture, have been linked to varied psychopathology and dysfunction. Some evidence suggests that individuals at risk for psychosis have deficits in gesture interpretation and performance; however, individuals with internalizing disorders (eg, depression) may have similar deficits. No previous studies have examined whether gesture deficits in performance and interpretation are specific to those at risk for psychosis. Additionally, the underlying mechanisms (eg, cognition) and consequences (eg, functioning) of these deficits are poorly understood. STUDY DESIGN: This study examined self-reported gesture interpretation (SRGI) and performance (SRGP) in those at clinical high risk for psychosis (CHR; N = 88), those with internalizing disorders (INT; N = 51), and healthy controls (HC; N = 53). Participants completed questionnaires, clinical interviews, and neurocognitive tasks. STUDY RESULTS: Results indicated that the CHR group was characterized by significantly lower SRGI scores than the HC or INT groups (d = 0.41); there were no differences among groups in SRGP. Within CHR participants, greater deficits in SRGP were associated with lower verbal learning and memory (r = -.33), but not general intelligence or processing speed. Furthermore, gesture deficits were associated with higher cross-sectional risk for conversion to a full psychotic disorder in the CHR group. CONCLUSIONS: Overall, these findings suggest that specific subdomains of gesture may reflect unique vulnerability for psychosis, self-report may be a viable assessment tool in understanding these phenomena, and gesture dysfunction may signal risk for transition to psychosis.


Assuntos
Gestos , Transtornos Psicóticos , Humanos , Autorrelato , Estudos Transversais , Testes Neuropsicológicos , Transtornos Psicóticos/complicações , Sintomas Prodrômicos
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