Centre for Youth Mental Health - Research Publications

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    Intelligence trajectories in individuals at ultra-high risk for psychosis: An 8-year longitudinal analysis
    Cheng, N ; Lin, A ; Bowden, S ; Gao, C ; Yung, AR ; Nelson, B ; Thompson, A ; Yuen, HP ; Brewer, WJ ; Cagliarini, D ; Bruxner, A ; Simmons, M ; Broussard, C ; Pantelis, C ; McGorry, PD ; Allott, K ; Wood, SJ (ELSEVIER, 2022-10)
    Cognitive impairment is a well-documented predictor of transition to a full-threshold psychotic disorder amongst individuals at ultra-high risk (UHR) for psychosis. However, less is known about whether change in cognitive functioning differs between those who do and do not transition. Studies to date have not examined trajectories in intelligence constructs (e.g., acquired knowledge and fluid intelligence), which have demonstrated marked impairments in individuals with schizophrenia. This study aimed to examine intelligence trajectories using longitudinal data spanning an average of eight years, where some participants completed assessments over three time-points. Participants (N = 139) at UHR for psychosis completed the Wechsler Abbreviated Scale of Intelligence (WASI) at each follow-up. Linear mixed-effects models mapped changes in WASI Full-Scale IQ (FSIQ) and T-scores on Vocabulary, Similarities, Block Design, and Matrix Reasoning subtests. The sample showed stable and improving trajectories for FSIQ and all subtests. There were no significant differences in trajectories between those who did and did not transition to psychosis and between individuals with good and poor functional outcomes. However, although not significant, the trajectories of the acquired knowledge subtests diverged between transitioned and non-transitioned individuals (β = -0.12, 95 % CI [-0.29, 0.05] for Vocabulary and β = -0.14, 95 % CI [-0.33, 0.05] for Similarities). Overall, there was no evidence for long-term deterioration in intelligence trajectories in this UHR sample. Future studies with a larger sample of transitioned participants may be needed to explore potential differences in intelligence trajectories between UHR transition groups and other non-psychosis outcomes.
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    Twelve-Month Cognitive Trajectories in Individuals at Ultra-High Risk for Psychosis: A Latent Class Analysis
    Allott, K ; Schmidt, SJ ; Yuen, HP ; Wood, SJ ; Nelson, B ; Markulev, C ; Lavoie, S ; Brewer, WJ ; Schäfer, MR ; Mossaheb, N ; Schlögelhofer, M ; Smesny, S ; Hickie, IB ; Berger, GE ; Chen, EYH ; De Haan, L ; Nieman, DH ; Nordentoft, M ; Riecher-Rössler, A ; Verma, S ; Thompson, A ; Yung, AR ; Amminger, P ; McGorry, PD ; Hartmann, J (Oxford University Press (OUP), 2022-01-01)
    Abstract Understanding longitudinal cognitive performance in individuals at ultra-high risk for psychosis (UHR) is important for informing theoretical models and treatment. A vital step in this endeavor is to determine whether there are UHR subgroups that have similar patterns of cognitive change over time. The aims were to: i) identify latent class trajectories of cognitive performance over 12-months in UHR individuals, ii) identify baseline demographic and clinical predictors of the resulting classes, and iii) determine whether trajectory classes were associated with transition to psychosis or functional outcomes. Cognition was assessed using the Brief Assessment of Cognition in Schizophrenia (BACS) at baseline, 6- and 12-months (N = 288). Using Growth Mixture Modeling, a single unimpaired improving trajectory class was observed for motor function, speed of processing, verbal fluency, and BACS composite. A two-class solution was observed for executive function and working memory, showing one unimpaired and a second impaired class. A three-class solution was found for verbal learning and memory: unimpaired, mildly impaired, and initially extremely impaired, but improved (“caught up”) to the level of the mildly impaired. IQ, omega-3 index, and premorbid adjustment were associated with class membership, whereas clinical variables (symptoms, substance use), including transition to psychosis, were not. Working memory and verbal learning and memory trajectory class membership was associated with functioning outcomes. These findings suggest there is no short-term progressive cognitive decline in help-seeking UHR individuals, including those who transition to psychosis. Screening of cognitive performance may be useful for identifying UHR individuals who may benefit from targeted cognitive interventions.
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    Impaired olfactory ability associated with larger left hippocampus and rectus volumes at earliest stages of schizophrenia: A sign of neuroinflammation?
    Masaoka, Y ; Velakoulis, D ; Brewer, WJ ; Cropley, VL ; Bartholomeusz, CF ; Yung, AR ; Nelson, B ; Dwyer, D ; Wannan, CMJ ; Izumizaki, M ; McGorry, PD ; Wood, SJ ; Pantelis, C (ELSEVIER IRELAND LTD, 2020-07)
    Impaired olfactory identification has been reported as a first sign of schizophrenia during the earliest stages of illness, including before illness onset. The aim of this study was to examine the relationship between volumes of these regions (amygdala, hippocampus, gyrus rectus and orbitofrontal cortex) and olfactory ability in three groups of participants: healthy control participants (Ctls), patients with first-episode schizophrenia (FE-Scz) and chronic schizophrenia patients (Scz). Exploratory analyses were performed in a sample of individuals at ultra-high risk (UHR) for psychosis in a co-submission paper (Masaoka et al., 2020). The relationship to brain structural measures was not apparent prior to psychosis onset, but was only evident following illness onset, with a different pattern of relationships apparent across illness stages (FE-Scz vs Scz). Path analysis found that lower olfactory ability was related to larger volumes of the left hippocampus and gyrus rectus in the FE-Scz group. We speculate that larger hippocampus and rectus in early schizophrenia are indicative of swelling, potentially caused by an active neurochemical or immunological process, such as inflammation or neurotoxicity, which is associated with impaired olfactory ability. The volumetric decreases in the chronic stage of Scz may be due to degeneration resulting from an active immune process and its resolution.