Centre for Youth Mental Health - Research Publications
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ItemNo Preview AvailableImpaired olfactory ability associated with larger left hippocampus and rectus volumes at earliest stages of schizophrenia: A sign of neuroinflammation?(ELSEVIER IRELAND LTD, 2020-07-01)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.
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ItemNo Preview AvailableCharacterization and Prediction of Clinical Pathways of Vulnerability to Psychosis through Graph Signal Processing( 2020)There is a growing recognition that psychiatric symptoms have the potential to causally interact with one another. Particularly in the earliest stages of psychopathology dynamic interactions between symptoms could contribute heterogeneous and cross-diagnostic clinical evolutions. Current clinical approaches attempt to merge clinical manifestations that co-occur across subjects and could therefore significantly hinder our understanding of clinical pathways connecting individual symptoms. Network approaches have the potential to shed light on the complex dynamics of early psychopathology. In the present manuscript we attempt to address 2 main limitations that have in our opinion hindered the application of network approaches in the clinical setting. The first limitation is that network analyses have mostly been applied to cross-sectional data, yielding results that often lack the intuitive interpretability of simpler categorical or dimensional approaches. Here we propose an approach based on multi-layer network analysis that offers an intuitive low-dimensional characterization of longitudinal pathways involved in the evolution of psychopathology, while conserving high-dimensional information on the role of specific symptoms. The second limitation is that network analyses typically characterize symptom connectivity at the level of a population, whereas clinical practice deals with symptom severity at the level of the individual. Here we propose an approach based on graph signal processing that exploits knowledge of network interactions between symptoms to predict longitudinal clinical evolution at the level of the individual. We test our approaches in two independent samples of individuals with genetic and clinical vulnerability for developing psychosis.
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ItemThe MAC-P program: A pilot study of a mindfulness and compassion program for youth with psychotic experiences(WILEY, 2020-12-19)BACKGROUND: The purpose of this pilot study was to determine the feasibility, acceptability and the potential clinical utility of a novel mindfulness and compassion program (MAC-P) designed for youth with a range of psychotic experiences. METHOD: A non-randomised, non-controlled prospective follow-up study was conducted. Eighteen participants who either met criteria for the 'at risk mental state' or were experiencing a psychotic episode or had a recent diagnosis of schizophrenia attended the 8-week program. Participants completed clinical assessments pre-treatment, post-treatment and at 6-week follow-up which measured a range of symptoms (psychosis, anxiety, depression and stress) and psychosocial outcomes. RESULTS: Attendance and retention data indicated that MAC-P is a feasible and acceptable program. There was a large significant increase in self-compassion. Mindfulness demonstrated a positive change over time. There was a large significant effect on one subscale-acting with awareness. There were significant reductions in distress associated with psychotic experiences as well as anxiety, depression, stress and self-criticism. Significant improvements in functioning and insecure attachment styles were also found. Regression results demonstrated that self-compassion was associated with a number of these findings. CONCLUSION: The MAC-P for youth shows potential as a clinically effective intervention provided as an addition to treatment as usual for youth with psychotic experiences. A larger controlled study is needed to validate the effectiveness of this intervention.
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ItemOmega-3 fatty acids and neurocognitive ability in young people at ultra-high risk for psychosis(WILEY, 2020-09-06)BACKGROUND: Neurocognitive impairments are core early features of psychosis and are observed in those at ultra-high risk (UHR) for psychosis. The aim of the present study was to explore whether neurocognition is associated with polyunsaturated fatty acids (PUFAs), as has been observed in other clinical populations. METHOD: Erythrocyte levels of total omega-3-and omega-6 PUFAs the omega-3/omega-6 ratio, were measured in 265 UHR individuals. Six domains of neurocognition as well a Composite Score, were assessed using the Brief Assessment of Cognition in Schizophrenia. Pearson's correlations were used to assess the relationship between PUFAs and neurocognition. All analyses were controlled for tobacco smoking. RESULTS: Verbal Fluency correlated positively with eicosapentaenoic acid (P = .024) and alpha-linolenic acid (P = .01), and negatively with docosahexanoic acid (P = .007) and Working Memory positively correlated with omega-3/omega-6 ratio (P = .007). CONCLUSIONS: The current results provide support for a relationship between Verbal Fluency and omega-3 PUFAs in UHR. Further investigation is required to elucidate whether these biomarkers are useful as risk markers or in understanding the biological underpinning of neurocognitive impairment in this population.
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ItemPrediction of clinical outcomes beyond psychosis in theultra-highrisk for psychosis population(WILEY, 2020-06-17)AIM: Several prediction models have been introduced to identify young people at greatest risk of transitioning to psychosis. To date, none has examined the possibility of developing a clinical prediction model of outcomes other than transition. The aims of this study were to examine the association between baseline clinical predictors and outcomes including, but not limited to, transition to psychosis in young people at risk for psychosis, and to develop a prediction model for these outcomes. METHODS: Several evidence-based variables previously associated with transition to psychosis and some important clinical comorbidities experienced by ultra-high risk (UHR) individuals were identified in 202 UHR individuals. Secondary analysis of the Neurapro clinical trial were conducted to investigate the associations between these variables and favourable (remission and recovery) or unfavourable (transition to psychosis, no remission, any recurrence and relapse) clinical outcomes. Logistic regression, best subset selection, Akaike Information Criterion and receiver operating characteristic curves were used to seek the best prediction model for clinical outcomes from all combinations of possible predictors. RESULTS: When considered individually, only higher general psychopathology levels (P = .023) was associated with the unfavourable outcomes. Prediction models suggest that general psychopathology and functioning are predictive of unfavourable outcomes. CONCLUSION: The predictive performance of the resulting models was modest and further research is needed. Nonetheless, when designing early intervention centres aiming to support individuals in the early phases of a mental disorder, the proper assessment of general psychopathology and functioning should be considered in order to inform interventions and length of care provided.
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ItemS166. EFFECTIVE CONNECTIVITY OF FRONTOSTRIATAL SYSTEMS IN FIRST-EPISODE PSYCHOSIS(Oxford University Press (OUP), 2020-05-18)Abstract Background Neuroimaging studies have found dysconnectivity of frontostriatal circuits across a broad spectrum of psychotic symptoms. However, it is unknown whether dysconnectivity within frontostriatal circuits originates from disrupted bottom-up or top-down control signaling within these systems. Here, we used dynamic causal modelling (DCM) to examine the effective connectivity of frontostriatal systems in first-episode psychosis (FEP). Methods A total of 55 FEP patients (26 males; mean [SD] age = 19.24 [2.89]) and 24 healthy controls (15 males; mean [SD] age = 21.83 [1.93]) underwent a resting-state functional magnetic resonance imaging protocol. Biologically plausible connections between eight left hemisphere regions encompassing the dorsal and ventral frontostriatal systems were modelled using spectral DCM. The regions comprise dorsolateral prefrontal cortex, ventromedial prefrontal cortex, anterior hippocampus, amygdala, dorsal caudate, nucleus accumbens, thalamus, and the midbrain. Effective connectivity between groups were assessed using a parametric Bayesian model. Associations between effective connectivity parameters and positive symptoms, measured by the Brief Psychiatric Rating Scale positive subscale, was assessed in the patient group in a separate Bayesian general linear model. Results DCM shows evidence for differences in effective connectivity between patients and healthy controls, namely in the bottom-down connections distributed in the frontostriatal system encompassing the hippocampus, amygdala, striatum, and midbrain. Compared to healthy controls, patients also demonstrated increased disinhibition of the midbrain. In patients, positive symptoms are associated with increased top-down connections to the midbrain. Outgoing connection from the midbrain to the nucleus accumbens is also increased in association with positive symptoms. Discussion Aberrant top-down connectivity in the frontostriatal system in patients is consistent with top-down dysregulation of dopamine function in FEP, as dopaminergic activity in the midbrain is proposed to be under the control of higher brain areas. In patients, increased self-inhibition of the midbrain, as well as symptom associations in both ingoing and outgoing connections of this region, are congruous with hyperactivity of the midbrain as proposed by the dopamine dysregulation hypothesis. Here, we demonstrate that mathematical models of brain imaging signals can be used to identify the key disruptions driving brain circuit dysfunction, identifying new targets for treatment.
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ItemT34. THE IMPACT OF ANTIDEPRESSANT USE ON THE TRANSITION TO PSYCHOSIS RATE IN THE NEURAPRO TRIAL(Oxford University Press (OUP), 2020-05-18)Abstract Background Over the last two decades, several randomised controlled trials (RCTs) have indicated that preventive psychosocial, pharmacologic (Van der Gaag et al. 2013), and nutritional interventions (Amminger et al. 2010) are likely to be beneficial in people at ultra-high risk (UHR) of psychosis, in terms of delaying or preventing a transition to psychosis. Antidepressant medication is commonly prescribed in young people at UHR for psychosis; however, the evidence regarding its efficacy for psychosis prevention is limited (Fusar-Poli et al. 2007; Cornblatt et al. 2007; Fusar-Poli et al. 2015). The main aim of the present study is to investigate the impact of concomitant AD medication on the transition to psychosis rate in young people at ultra-high risk of psychosis who participated in the NEURAPRO trial (McGorry et al. 2017). Methods In this secondary analysis, data from 304 participants of a multicenter, double-blind, placebo-controlled, randomized clinical trial (NEURAPRO) of omega-3 polyunsaturated fatty acids (omega-3 PUFAs) were included. During the trial, concomitant antidepressant medication was permitted for treatment of moderate to severe major depressive disorder (a score of ≥ 21 on the Montgomery-Asberg Depression Rating Scale, MADRS) in all participants. Results Of 304 participants, 189 (62.2%) were treated with ADs. 98 (64.1%) of those were in the omega-3 group and 91 (60.3%) in the placebo group. The transition rate to psychosis was higher in individuals who received AD treatment (13.2%; 25 of 189) as in individuals without ADs (6.1%; 7 of 115). The Kaplan-Meier survival curve estimated a group difference of X2 = 3.237, P = .072 (log rank test). Discussion Antidepressants are widely used in early psychosis. This analysis does not support the view that antidepressants may have reduced the transition to psychosis rate in this cohort. The findings are limited by the fact that antidepressants were prescribed based on clinical discretion. A randomised controlled trial is needed to determine whether antidepressants have a role in prevention of transition to psychosis.
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ItemM22. IGG ANTIBODIES TO TOXOPLASMA GONDII ARE ASSOCIATED WITH INCREASED LONG-TERM RISK FOR PSYCHOSIS IN INDIVIDUALS AT ULTRA-HIGH RISK FOR PSYCHOSIS(Oxford University Press (OUP), 2020-05-18)Abstract Background The prevalence of antibodies to Toxoplasma gondii, a ubiquitous parasitic protozoan causing the infectious disease toxoplasmosis, is increased in patients with psychotic disorders compared to the general population. We have previously shown that antibody titers for T.gondii correlate with the severity of positive symptoms in young people at ultra-high risk (UHR) for psychosis, suggesting that infection with T. gondii may be relevant to the manifestation of psychosis. However, it is unclear if T. gondii antibodies represent a risk factor for psychosis onset or non-psychotic outcome in UHR individuals. The aim of the present study was to examine whether seropositivity for T.gondii is associated with transition to psychosis and other outcomes in young people at UHR for psychosis. Methods The study sample consisted of 96 individuals at UHR for psychosis who were referred to the Personal Assistance and Crisis Evaluation (PACE) clinic in Melbourne, Australia, between 2001 and 2004, consented to optional blood tests for infectious agents and were followed up for up to 10 years after baseline (median (interquartile range) duration of follow-up: 7.15 (3.14 – 7.72) years). Serum IgG antibodies to six viral and parasitic pathogens (Toxoplasma gondii, Herpes Simplex Virus Type 1 and 2, Cytomegalovirus, Epstein Barr Virus, Varicella-Zoster Virus) were measured at baseline. Outcome measures included transition to psychosis, general psychiatric symptomatology and positive psychotic symptoms (BPRS), negative symptoms (SANS), depressive symptoms (HAM-D), anxiety symptoms (HAM-A) and functioning (SOFAS and GAF). Cox proportional hazards regression and linear regression models were used to examine the associations of seropositivity and antibody titers at baseline and transition to psychosis and other outcomes at follow-up. Results A total of 17 individuals (17.7%) were seropositive for Toxoplasma gondii at baseline. The rate of transition to psychosis was higher among seropositive (35.7%) compared to seronegative participants (14.6%), although this was not statistically significant (p=0.101). Antibody titers (IgG) for Toxoplasma gondii were significantly higher at baseline in participants who later transitioned to psychosis (1.34 ± 1.36 vs. 0.79 ± 0.73, p=0.027). Seropositivity for T.gondii IgG at baseline significantly predicted transition to psychosis within the follow-up duration (hazard ratio [HR]=3.61, 95%CI 1.08 – 12.00, p=0.036). Toxoplasma IgG at baseline were significantly associated with higher BPRS scores at follow-up in participants who were seropositive at baseline (Beta=6.38, 95%CI 0.43 – 12.34, p=0.038). No significant associations were found between antibodies to other pathogens and outcome, or between antibodies to Toxoplasma gondii and any other outcomes. Discussion Our findings suggest that the presence of IgG class antibodies for Toxoplasma gondii is associated with a higher risk for psychosis transition in individuals at UHR for psychosis, but not with risk for other long-term outcomes. These observations provide support for the hypothesis that infection with Toxoplasma gondii may be an environmental risk factor for psychosis and suggest that IgG antibodies for Toxoplasma gondii in individuals at UHR for psychosis have prognostic relevance.