17 research outputs found

    Psychotic-like Experiences in Childhood and Adolescence: A Cognitive Neuropsychiatric Approach

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    Psychotic-like experiences (PLEs) include experiences such as hallucinations and delusional thinking that can occur in the absence of a clinical disorder. PLEs peak in middle childhood but appear to spontaneously remit in most children. Nevertheless, their presence, and particularly their persistence, are associated with an increased risk of developing later psychosis and poor psychiatric and social outcomes. However, the mechanisms by which they are generated during childhood are unclear. Existing models of psychosis cite early life experience and childhood neurodevelopment as important but often examine these retrospectively. Furthermore, they suggest mechanisms for how psychotic experiences are generated that are assumed to apply across the lifespan. This assumption has remained untested, however. Consequently, in this thesis, I investigated neurocognitive mechanisms of PLEs in 9-10 year-old-children using data from the Adolescent Brain Cognitive Development (ABCD) study. In Study 1, I examined whether the established mechanistic risk factors in adult psychosis – affective symptoms, traumatic experiences, cognitive function, structural brain changes – are associated with PLEs using network analysis, finding only that depression-related symptoms were associated with PLEs. In Study 2, I tested whether fMRI activation in striatal reward pathways was associated with PLEs in children, as this is an established finding in adults. This study found no strong evidence for alteration to striatal reward pathways with a high likelihood that it was absent, rather than undetectable. Given the prognostic and aetiological important of persistence of PLEs, in Study 3, I tested affective, trauma-related, cognitive and striatal reward activation predictors of 1-year PLE persistence. Only depressive symptoms were substantial predictors. Depressive symptoms emerged as the strongest predictor of PLEs at this developmental stage, both cross-sectionally and longitudinally. The findings indicate that PLEs in childhood are not a ‘mini psychosis syndrome’ and developmental-stage specific models of psychotic experiences in children are required

    Reward Processing in Children With Psychotic-Like Experiences.

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    Alterations to striatal reward pathways have been identified in individuals with psychosis. They are hypothesized to be a key mechanism that generate psychotic symptoms through the production of aberrant attribution of motivational salience and are proposed to result from accumulated childhood adversity and genetic risk, making the striatal system hyper-responsive to stress. However, few studies have examined whether children with psychotic-like experiences (PLEs) also exhibit these alterations, limiting our understanding of how differences in reward processing relate to hallucinations and delusional ideation in childhood. Consequently, we examined whether PLEs and PLE-related distress were associated with reward-related activation in the nucleus accumbens (NAcc). The sample consisted of children (N = 6718) from the Adolescent Brain Cognitive Development (ABCD) study aged 9-10 years who had participated in the Monetary Incentive Delay (MID) task in functional MRI. We used robust mixed-effects linear regression models to investigate the relationship between PLEs and NAcc activation during the reward anticipation and reward outcome stages of the MID task. Analyses were adjusted for gender, household income, ethnicity, depressive symptoms, movement in the scanner, pubertal development, scanner ID, subject and family ID. There was no reliable association between PLEs and alterations to anticipation- or outcome-related striatal reward processing. We discuss the implications for developmental models of psychosis and suggest a developmental delay model of how PLEs may arise at this stage of development

    Exposure to potentially morally injurious events in U.K. health and social care workers during COVID-19: Associations with PTSD and complex PTSD

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    OBJECTIVE: Health and social care workers (HSCWs) have been shown to be at risk of exposure to potentially morally injurious events (PMIEs) and mental health problems during the COVID-19 pandemic. This study aimed to examine associations between exposure to PMIEs and meeting threshold criteria for probable posttraumatic stress disorder (PTSD) and probable complex PTSD (CPTSD) in U.K. HSCWs immediately after the peak of the first COVID-19 wave. METHOD: Frontline HSCWs from across the United Kingdom working in diverse roles in hospitals, nursing or care homes, and other community settings were recruited to the Frontline-COVID study via social media. Participants (n = 1,056) completed a cross-sectional online survey (May 27, 2020-July 23, 2020) which assessed exposure to PMIEs (nine-item Moral Injury Events Scale), and meeting symptom thresholds for probable PTSD and probable CPTSD (International Trauma Questionnaire). RESULTS: PMIEs related to witnessing others' wrongful actions and betrayal events were more commonly endorsed than perceived self-transgressions. The rate of probable International Classification of Diseases, 11th Revision (ICD-11) PTSD was 8.3%, and of probable ICD-11 CPTSD was 14.2%. Betrayal-related PMIEs were a significant predictor of probable PTSD or probable CPTSD, together with having been redeployed during the pandemic. The only variable that differentially predicted probable CPTSD as compared with probable PTSD was not having had reliable access to personal protective equipment; none of the PMIE types were differential predictors for screening positive for probable PTSD versus probable CPTSD. CONCLUSIONS: Exposure to PIMEs could be important for PTSD and CPTSD development. Interventions for moral injury in HSCWs should be investigated. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

    Psychosis Endophenotypes:A Gene-Set-Specific Polygenic Risk Score Analysis

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    BACKGROUND AND HYPOTHESIS: Endophenotypes can help to bridge the gap between psychosis and its genetic predispositions, but their underlying mechanisms remain largely unknown. This study aims to identify biological mechanisms that are relevant to the endophenotypes for psychosis, by partitioning polygenic risk scores into specific gene sets and testing their associations with endophenotypes. STUDY DESIGN: We computed polygenic risk scores for schizophrenia and bipolar disorder restricted to brain-related gene sets retrieved from public databases and previous publications. Three hundred and seventy-eight gene-set-specific polygenic risk scores were generated for 4506 participants. Seven endophenotypes were also measured in the sample. Linear mixed-effects models were fitted to test associations between each endophenotype and each gene-set-specific polygenic risk score. STUDY RESULTS: After correction for multiple testing, we found that a reduced P300 amplitude was associated with a higher schizophrenia polygenic risk score of the forebrain regionalization gene set (mean difference per SD increase in the polygenic risk score: -1.15 ”V; 95% CI: -1.70 to -0.59 ”V; P = 6 × 10-5). The schizophrenia polygenic risk score of forebrain regionalization also explained more variance of the P300 amplitude (R2 = 0.032) than other polygenic risk scores, including the genome-wide polygenic risk scores. CONCLUSIONS: Our finding on reduced P300 amplitudes suggests that certain genetic variants alter early brain development thereby increasing schizophrenia risk years later. Gene-set-specific polygenic risk scores are a useful tool to elucidate biological mechanisms of psychosis and endophenotypes, offering leads for experimental validation in cellular and animal models

    Psychosis Endophenotypes: A Gene-Set-Specific Polygenic Risk Score Analysis

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    BACKGROUND AND HYPOTHESIS: Endophenotypes can help to bridge the gap between psychosis and its genetic predispositions, but their underlying mechanisms remain largely unknown. This study aims to identify biological mechanisms that are relevant to the endophenotypes for psychosis, by partitioning polygenic risk scores into specific gene sets and testing their associations with endophenotypes. STUDY DESIGN: We computed polygenic risk scores for schizophrenia and bipolar disorder restricted to brain-related gene sets retrieved from public databases and previous publications. Three hundred and seventy-eight gene-set-specific polygenic risk scores were generated for 4506 participants. Seven endophenotypes were also measured in the sample. Linear mixed-effects models were fitted to test associations between each endophenotype and each gene-set-specific polygenic risk score. STUDY RESULTS: After correction for multiple testing, we found that a reduced P300 amplitude was associated with a higher schizophrenia polygenic risk score of the forebrain regionalization gene set (mean difference per SD increase in the polygenic risk score: -1.15 ”V; 95% CI: -1.70 to -0.59 ”V; P = 6 × 10-5). The schizophrenia polygenic risk score of forebrain regionalization also explained more variance of the P300 amplitude (R2 = 0.032) than other polygenic risk scores, including the genome-wide polygenic risk scores. CONCLUSIONS: Our finding on reduced P300 amplitudes suggests that certain genetic variants alter early brain development thereby increasing schizophrenia risk years later. Gene-set-specific polygenic risk scores are a useful tool to elucidate biological mechanisms of psychosis and endophenotypes, offering leads for experimental validation in cellular and animal models

    Genetic copy number variants, cognition and psychosis: a meta-analysis and a family study

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    The burden of large and rare copy number genetic variants (CNVs) as well as certain specific CNVs increase the risk of developing schizophrenia. Several cognitive measures are purported schizophrenia endophenotypes and may represent an intermediate point between genetics and the illness. This paper investigates the influence of CNVs on cognition. We conducted a systematic review and meta-analysis of the literature exploring the effect of CNV burden on general intelligence. We included ten primary studies with a total of 18,847 participants and found no evidence of association. In a new psychosis family study, we investigated the effects of CNVs on specific cognitive abilities. We examined the burden of large and rare CNVs (>200 kb, <1% MAF) as well as known schizophrenia-associated CNVs in patients with psychotic disorders, their unaffected relatives and controls (N = 3428) from the Psychosis Endophenotypes International Consortium (PEIC). The carriers of specific schizophrenia-associated CNVs showed poorer performance than non-carriers in immediate (P = 0.0036) and delayed (P = 0.0115) verbal recall. We found suggestive evidence that carriers of schizophrenia-associated CNVs had poorer block design performance (P = 0.0307). We do not find any association between CNV burden and cognition. Our findings show that the known high-risk CNVs are not only associated with schizophrenia and other neurodevelopmental disorders, but are also a contributing factor to impairment in cognitive domains such as memory and perceptual reasoning, and act as intermediate biomarkers of disease risk.This work was supported by the Medical Research Council (G0901310) and the Wellcome Trust (grants 085475/B/08/Z, 085475/Z/08/Z). This study was supported by the NIHR Biomedical Research Centre at University College London Hospitals NHS Foundation Trust and University College London and by the NIHR Biomedical Research Centre for Mental Health at the South London and Maudsley NHS Foundation Trust at King’s College London. Further support to EB: Mental Health Research UK’s John Grace QC award, BMA Margaret Temple grants 2016 and 2006, MRC—Korean Health Industry Development Institute Partnering Award (MC_PC_16014), MRC New Investigator Award and a MRC Centenary Award (G0901310), National Institute of Health Research UK post-doctoral fellowship, the Psychiatry Research Trust, the Schizophrenia Research Fund, the Brain and Behaviour Research foundation’s NARSAD Young Investigator Awards 2005, 2008, Wellcome Trust Research Training Fellowship, the NIHR Biomedical Research Centre at UCLH, and the NIHR Biomedical Research Centre for Mental Health at the South London and Maudsley NHS Foundation Trust and Institute of Psychiatry King’s College London. Further support to co-authors: The Brain and Behaviour Research foundation’s (NARSAD’s) Young Investigator Award (Grant 22604, awarded to CI). The BMA Margaret Temple grant 2016 to JT. A 2014 European Research Council Marie Curie award to A DĂ­ez-Revuelta. HI has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 747429. A Medical Research Council doctoral studentship to JH-S, IA-Z and AB. A Mental Health Research UK studentship to RM. VB is supported by a Wellcome Trust Seed Award in Science (200589/Z/16/Z). FWO Senior Clinical Fellowship to RvW. The infrastructure for the GROUP consortium is funded through the Geestkracht programme of the Dutch Health Research Council (ZON-MW, grant number 10-000-1001), and matching funds from participating pharmaceutical companies (Lundbeck, AstraZeneca, Eli Lilly, Janssen Cilag) and universities and mental health care organisations (Amsterdam: Academic Psychiatric Centre of the Academic Medical Centre and the mental health institutions: GGZ Ingeest, Arkin, Dijk en Duin, GGZ Rivierduinen, Erasmus Medical Centre, GGZ Noord Holland Noord. Groningen: University Medical Centre Groningen and the mental health institutions: Lentis, GGZ Friesland, GGZ Drenthe, Dimence, Mediant, GGNet Warnsveld, Yulius Dordrecht and Parnassia psycho-medical centre The Hague. Maastricht: Maastricht University Medical Centre and the mental health institutions: GGZ Eindhoven en De Kempen, GGZ Breburg, GGZ Oost-Brabant, Vincent van Gogh voor Geestelijke Gezondheid, Mondriaan, Virenze riagg, Zuyderland GGZ, MET ggz, Universitair Centrum Sint-Jozef Kortenberg, CAPRI University of Antwerp, PC Ziekeren Sint-Truiden, PZ Sancta Maria Sint-Truiden, GGZ Overpelt, OPZ Rekem. Utrecht: University Medical Centre Utrecht and the mental health institutions Altrecht, GGZ Centraal and Delta). The Santander cohort was supported by Instituto de Salud Carlos III (PI020499, PI050427, PI060507), SENY FundaciĂł (CI 2005-0308007), Fundacion RamĂłn Areces and Fundacion MarquĂ©s de Valdecilla (API07/011, API10/13). We thank Valdecilla Biobank for providing the biological PAFIP samples and associated data included in this study and for its help in the technical execution of this work; we also thank IDIVAL Neuroimaging Unit for its help in the acquisition and processing of imaging PAFIP data

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    Persistence of psychotic-like experiences

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