Publications by authors named "Tyrone Cannon"

Background: Attention Deficit Hyperactivity Disorder (ADHD) affects a significant proportion of the population and is associated with numerous adverse outcomes including lower educational attainment, occupational challenges, increased substance use, and various mental health issues including psychosis. This study examined the demographic, clinical, cognitive, social cognitive, and functional differences between youth at clinical high-risk (CHR) for psychosis with and without comorbid ADHD.

Method: Data were drawn from the North American Prodrome Longitudinal Studies (NAPLS2 and NAPLS3), which included 764 and 710 CHR individuals, respectively.

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Mismatch negativity (MMN) event-related potential (ERP) component reduction, indexing N-methyl-D-aspartate receptor (NMDAR)-dependent auditory echoic memory and short-term plasticity, is a well-established biomarker of schizophrenia that is sensitive to psychosis risk among individuals at clinical high-risk (CHR-P). Based on the NMDAR-hypofunction model of schizophrenia, NMDAR-dependent plasticity is predicted to contribute to aberrant neurodevelopmental processes involved in the pathogenesis of schizophrenia during late adolescence or young adulthood, including gray matter loss. Moreover, stress and inflammation disrupt plasticity.

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Experimental cognitive tests are designed to measure particular cognitive domains, although evidence supporting test validity is often limited. The Consortium for Neuropsychiatric Phenomics test battery administered 23 experimental and traditional neuropsychological tests to a large sample of community volunteers ( = 1,059) and patients with psychiatric diagnoses ( = 137), providing a unique opportunity to examine convergent validity with factor analysis. Traditional tests included subtests from the Wechsler and Delis-Kaplan batteries, while experimental tests included the Attention Networks Test, Balloon Analogue Risk Task, Delay Discounting Task, Remember-Know, Reversal Learning Task, Scene Recognition, Spatial and Verbal Capacity and Manipulation Tasks, Stop-Signal Task, and Task Switching.

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Background And Hypothesis: Studying individuals at Clinical High Risk (CHR) for psychosis provides an opportunity to examine protective factors that predict resilient outcomes. Here, we present a model for the study of protective factors in CHR participants at the very highest risk for psychotic conversion based on the Psychosis Risk Calculator.

Study Design: CHR participants (N = 572) from NAPLS3 were assessed on the Risk Calculator.

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Article Synopsis
  • This study looked at how living in diverse neighborhoods affects young people at risk for schizophrenia compared to those who are not.
  • Researchers found that living in neighborhoods with lots of different racial and ethnic groups can lead to fewer symptoms of mental health issues for some young people.
  • They also discovered that experiences like being bullied and discrimination can play a role in how these feelings are affected by neighborhood diversity.
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Introduction: Research has established that adverse childhood experiences (ACEs) confer risk for psychiatric diagnoses, and that protective factors moderate this association. Investigation into the effect of protective factors in the relationship between ACEs and internalizing disorders (e.g.

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Background: Although the clinical high risk for psychosis (CHR-P) criteria are widely used to ascertain individuals at heightened risk for imminent onset of psychosis, it remains controversial whether CHR-P status defines a diagnostic construct in its own right. In a previous study, CHR-P nonconverters were observed to follow 3 distinct trajectories in symptoms and functioning: remission, partial remission, and maintenance of symptoms and functional impairments at subthreshold levels of intensity.

Methods: Here, we utilized the NAPLS3 (North American Prodrome Longitudinal Study phase 3) sample (N = 806) to determine whether 1) the same trajectory groups can be detected when assessing symptoms at 2-month intervals over an 8-month period and 2) the resulting trajectory groups differ from each other and from healthy control participants and converting CHR-P cases in terms of risk factors, comorbidities, and functional outcomes.

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Schizophrenia spectrum disorders (SSDs) are characterized by substantial clinical and genetic heterogeneity. Multiple recurrent copy number variants (CNVs) increase risk for SSDs; however, how known risk CNVs and broader genome-wide CNVs influence clinical variability is unclear. The current study examined associations between borderline intellectual functioning or childhood-onset psychosis, known risk CNVs, and burden of deletions affecting genes in 18 previously validated neurodevelopmental gene-sets in 618 SSD individuals.

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Introduction: Schizophrenia is a mental health condition that severely impacts well-being. Cognitive impairment is among its core features, often presenting well before the onset of overt psychosis, underscoring a critical need to study it in the psychosis proneness (clinical high risk; CHR) stage, to maximize the benefits of interventions and to improve clinical outcomes. However, given the heterogeneity of cognitive impairment in this population, a one-size-fits-all approach to therapeutic interventions would likely be insufficient.

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Article Synopsis
  • Schizophrenia and bipolar disorder are heritable psychiatric conditions; this study aims to explore how genetic factors, specifically polygenic risk scores (PRS), influence psychosis among twins.* -
  • Using data from the Schizophrenia and Bipolar Twin Study and the Swedish Twin Registry, researchers analyzed twin pairs to see if those with higher PRS had increased likelihood of psychosis.* -
  • The final analysis included over 300 twin pairs, assessing psychosis through clinical interviews, with the goal of determining the heritability of psychosis and understanding genetic overlap between the two disorders.*
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Background: 22q11.2 deletion syndrome (22qDel) is a copy number variant that is associated with psychosis and other neurodevelopmental disorders. Adolescents who are at clinical high risk for psychosis (CHR) are identified based on the presence of subthreshold psychosis symptoms.

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Article Synopsis
  • Monozygotic (MZ) twins, typically considered genetically identical, actually can have differing DNA variants due to early post-zygotic events, which may relate to differences in disease manifestation.
  • In a study involving whole genome sequencing of 17 pairs of MZ twins discordant for psychotic disorders, researchers found rare genetic variants unique to affected individuals, including specific genes linked to schizophrenia and bipolar disorder.
  • The research identified significant genetic variations, such as deleterious missense variants and rare genic copy number variants (CNVs), suggesting a potential link to the disorders, and emphasizes the need for further investigation in this area.
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Background: Neurocognitive impairment is a well-known phenomenon in schizophrenia that begins prior to psychosis onset. Connectome-wide association studies have inconsistently linked cognitive performance to resting-state functional magnetic resonance imaging. We hypothesized that a carefully selected cognitive instrument and refined population would allow identification of reliable brain-behavior associations with connectome-wide association studies.

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Sex differences have been observed in individuals with schizophrenia and for those at clinical high risk (CHR) for psychosis. However, specific differences in CHR individuals who transition to psychosis remain inconsistent and understudied. This study aimed to investigate sex differences in 156 CHR individuals who made the transition to psychosis.

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The prodromal phase of schizophrenia provides an optimal opportunity to mitigate the profound functional disability that is often associated with fully expressed psychosis. Considerable evidence supports the importance of neurocognition in the development of interpersonal (social) and academic (role) skills. Further findings from adolescents and young adults at clinical high risk for developing psychosis (CHRP) suggest that treatment for functioning might be most effective when targeting early and specific neurocognitive deficits.

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Background And Hypothesis: Individuals with schizophrenia (SCZ) suffer from comorbidities that substantially reduce their life expectancy. Socioeconomic inequalities could contribute to many of the negative health outcomes associated with SCZ.

Study Design: We investigated genome-wide datasets related to SCZ (52 017 cases and 75 889 controls) from the Psychiatric Genomics Consortium, household income (HI; N = 361 687) from UK Biobank, and 2202 medical endpoints assessed in up to 342 499 FinnGen participants.

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Aims: The study aims are to present the Italian adaptation of the Abbreviated Clinical Structured Interview for DSM-5 Attenuated Psychosis Syndrome (Mini-SIPS) and illustrate its implementation in a clinical setting.

Methods: The Mini-SIPS was developed from the original extended version as a tool designed to identify, within the clinical high risk (CHR) framework, the DSM-5 Attenuated Psychosis Syndrome (APS) and to be implemented in clinical settings. The Mini-SIPS was translated in Italian by a Yale-certified SIPS trainer, then back-translated in English by a trained psychologist, then approved by the Mini-SIPS authors.

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Background And Hypothesis: The Structured Interview for Psychosis-Risk Syndromes (SIPS) and other assessments of psychosis risk define clinical high risk for psychosis (CHR) by the presence of attenuated psychotic symptoms. Despite extensive research on attenuated psychotic symptoms, substantial questions remain about their internal psychometric structure and relationships to comorbid non-psychotic symptoms.

Study Design: Hierarchical and bifactor models were developed for the SIPS in a large CHR sample (NAPLS-3, N = 787) and confirmed through preregistered replication in an independent sample (NAPLS-2, N = 1043).

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This study investigates the factors contributing to COVID vaccine hesitancy. Vaccine hesitancy has commonly been attributed to susceptibility to misinformation and linked to particular socio-demographic factors and personality traits. We present a new perspective, emphasizing the interplay between individual cognitive styles and perceptions of public health institutions.

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Background And Hypothesis: Social and academic adjustment deteriorate in the years preceding a psychotic disorder diagnosis. Analyses of premorbid adjustment have recently been extended into the clinical high risk for psychosis (CHR) syndrome to identify risk factors and developmental pathways toward psychotic disorders. Work so far has been at the between-person level, which has constrained analyses of premorbid adjustment, clinical covariates, and conversion to psychosis.

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Aim: There is limited research on the effects of sociodemographic and socioeconomic factors on treatment outcomes in youth at clinical high risk for psychosis (CHRp). This study examined sociodemographic factors that may affect functional outcomes within this population. Specifically, we investigated the influence of race/ethnicity (dichotomized as non-Hispanic whites [NHW] vs.

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Introduction: Negative symptoms impact the quality of life of individuals with psychosis and current treatment options for negative symptoms have limited effectiveness. Previous studies have demonstrated that complement and coagulation pathway protein levels are related to later psychotic experiences, psychotic disorder, and functioning. However, the prognostic relationship between complement and coagulation proteins and negative symptoms is poorly characterised.

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The Hierarchical Taxonomy of Psychopathology (HiTOP) consortium's transdiagnostic dimensional model of psychopathology has considerable support; however, this model has been underresearched in individuals at clinical high risk for psychosis (CHR-P), a population that may advance the model. CHR-P individuals not only have attenuated psychotic symptoms that vary in severity, but also have many comorbid diagnoses and varied clinical outcomes, including disorders with uncertain relations to HiTOP (e.g.

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