Psychiatry - 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)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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ItemCortical Brain Abnormalities in 4474 Individuals With Schizophrenia and 5098 Control Subjects via the Enhancing Neuro Imaging Genetics Through Meta Analysis (ENIGMA) Consortium(ELSEVIER SCIENCE INC, 2018-11-01)BACKGROUND: The profile of cortical neuroanatomical abnormalities in schizophrenia is not fully understood, despite hundreds of published structural brain imaging studies. This study presents the first meta-analysis of cortical thickness and surface area abnormalities in schizophrenia conducted by the ENIGMA (Enhancing Neuro Imaging Genetics through Meta Analysis) Schizophrenia Working Group. METHODS: The study included data from 4474 individuals with schizophrenia (mean age, 32.3 years; range, 11-78 years; 66% male) and 5098 healthy volunteers (mean age, 32.8 years; range, 10-87 years; 53% male) assessed with standardized methods at 39 centers worldwide. RESULTS: Compared with healthy volunteers, individuals with schizophrenia have widespread thinner cortex (left/right hemisphere: Cohen's d = -0.530/-0.516) and smaller surface area (left/right hemisphere: Cohen's d = -0.251/-0.254), with the largest effect sizes for both in frontal and temporal lobe regions. Regional group differences in cortical thickness remained significant when statistically controlling for global cortical thickness, suggesting regional specificity. In contrast, effects for cortical surface area appear global. Case-control, negative, cortical thickness effect sizes were two to three times larger in individuals receiving antipsychotic medication relative to unmedicated individuals. Negative correlations between age and bilateral temporal pole thickness were stronger in individuals with schizophrenia than in healthy volunteers. Regional cortical thickness showed significant negative correlations with normalized medication dose, symptom severity, and duration of illness and positive correlations with age at onset. CONCLUSIONS: The findings indicate that the ENIGMA meta-analysis approach can achieve robust findings in clinical neuroscience studies; also, medication effects should be taken into account in future genetic association studies of cortical thickness in schizophrenia.
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ItemCommon mechanisms of executive attention underlie executive function and effortful control in children(WILEY, 2020-05)Executive Function (EF) and Effortful Control (EC) have traditionally been viewed as distinct constructs related to cognition and temperament during development. More recently, EF and EC have been implicated in top-down self-regulation - the goal-directed control of cognition, emotion, and behavior. We propose that executive attention, a limited-capacity attentional resource subserving goal-directed cognition and behavior, is the common cognitive mechanism underlying the self-regulatory capacities captured by EF and EC. We addressed three related questions: (a) Do behavioral ratings of EF and EC represent the same self-regulation construct? (b) Is this self-regulation construct explained by a common executive attention factor as measured by performance on cognitive tasks? and (c) Does the executive attention factor explain additional variance in attention deficit hyperactivity disorder (ADHD) problems to behavioral ratings of self-regulation? Measures of performance on complex span, general intelligence, and response inhibition tasks were obtained from 136 preadolescent children (M = 11 years, 10 months, SD = 8 months), along with self- and parent-reported EC, and parent-reported EF, and ADHD problems. Results from structural equation modeling demonstrated that behavioral ratings of EF and EC measured the same self-regulation construct. Cognitive tasks measured a common executive attention factor that significantly explained 30% of the variance in behavioral ratings of self-regulation. Executive attention failed to significantly explain additional variance in ADHD problems beyond that explained by behavioral ratings of self-regulation. These findings raise questions about the utility of task-based cognitive measures in research and clinical assessment of self-regulation and psychopathology in developmental samples.
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ItemPopulation-based identity-by-descent mapping combined with exome sequencing to detect rare risk variants for schizophrenia(WILEY, 2019-04)Genome-wide association studies (GWASs) are highly effective at identifying common risk variants for schizophrenia. Rare risk variants are also important contributors to schizophrenia etiology but, with the exception of large copy number variants, are difficult to detect with GWAS. Exome and genome sequencing, which have accelerated the study of rare variants, are expensive so alternative methods are needed to aid detection of rare variants. Here we re-analyze an Irish schizophrenia GWAS dataset (n = 3,473) by performing identity-by-descent (IBD) mapping followed by exome sequencing of individuals identified as sharing risk haplotypes to search for rare risk variants in coding regions. We identified 45 rare haplotypes (>1 cM) that were significantly more common in cases than controls. By exome sequencing 105 haplotype carriers, we investigated these haplotypes for functional coding variants that could be tested for association in independent GWAS samples. We identified one rare missense variant in PCNT but did not find statistical support for an association with schizophrenia in a replication analysis. However, IBD mapping can prioritize both individual samples and genomic regions for follow-up analysis but genome rather than exome sequencing may be more effective at detecting risk variants on rare haplotypes.
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ItemAripiprazole compared with placebo for auditory verbal hallucinations in youth with borderline personality disorder: Protocol for the VERBATIM randomized controlled trial(WILEY, 2019-12)AIM: Up to half of patients with borderline personality disorder report auditory verbal hallucinations that are phenomenologically indistinguishable from those in schizophrenia, occur early in the course of the disorder, and are enduring, distressing and disabling. In clinical practice, this symptom is widely assumed to be unresponsive to treatment with antipsychotic medication and early intervention is rarely offered. The Verbal Experiences Response in Borderline personality disorder to Aripiprazole TrIal Medication (VERBATIM) study aims to be the first controlled trial to investigate the effectiveness of conventional pharmacotherapy for this symptom in this patient group. METHOD: VERBATIM is a 12-week, triple-blind, single-centre, parallel groups randomised controlled trial, with a 27-week follow-up period. Participants between the ages of 15 and 25 years receive either aripiprazole or placebo daily, commencing at 2 mg and increasing to 10 mg by day 15. Further dose escalations (up to 30 mg) may occur, as clinically indicated. This trial was prospectively registered with the Australian and New Zealand Clinical Trials Registry ACTRN12616001192471 on 30/08/2016. RESULTS: The primary outcome is severity of auditory verbal hallucinations assessed using the Psychotic Symptom Rating Scale. Secondary outcomes include the severity of general psychopathology, borderline personality pathology, social and occupational functioning and change in brain resting state connectivity. The primary endpoint is week 12 and secondary endpoint is week 39. CONCLUSION: The results will inform treatment decisions for individuals with borderline personality disorder who present with auditory verbal hallucinations.
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ItemCan youth at high risk of illness progression be identified by measures of rumination and sleep-wake disturbance(WILEY, 2019-10)AIM: Clinical staging models offer a useful framework for understanding illness trajectories, where individuals are located on a continuum of illness progression from stage 0 (at-risk but asymptomatic) to stage 4 (end-stage disease). Importantly, clinical staging allows investigation of risk factors for illness progression with the potential to target trans-diagnostic mechanisms at an early stage, especially in help-seeking youth who often present with sub-threshold syndromes. While depressive symptoms, rumination and sleep-wake disturbances may worsen syndrome outcomes, the role of these related phenomena has yet to be examined as risk factors for trans-diagnostic illness progression in at-risk youth. METHODS: This study is a prospective follow-up of 248 individuals aged 12 to 25 years presenting to headspace services with sub-threshold syndromes (stage 1) classified under the clinical staging model to determine transition to threshold syndromes (stage 2). Factor analysis of depression, rumination and sleep-wake patterns was used to identify key dimensions and any associations between factors and transition to stage 2 at follow-up. RESULTS: At 1 year, 9% of cases met criteria for stage 2 (n = 22). One of three identified factors, namely the factor reflecting the commonalities shared between rumination and sleep-wake disturbance, significantly differentiated cases that transitioned to stage 2 vs those that did not demonstrate transition. Items loading onto this factor, labelled Anergia, included depression severity and aspects of rumination and sleep-wake disturbance that were characterized as introceptive. CONCLUSIONS: Common dimensions between rumination and sleep-wake disturbance present a detectable trans-diagnostic marker of illness progression in youth, and may represent a target for early intervention.
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ItemStaged treatment and acceptability guidelines in early psychosis study (STAGES): A randomized placebo controlled trial of intensive psychosocial treatment plus or minus antipsychotic medication for first-episode psychosis with low-risk of self-harm or aggression. Study protocol and baseline characteristics of participants(WILEY, 2019-08)AIM: It is now necessary to investigate whether recovery in psychosis is possible without the use of antipsychotic medication. This study will determine (1) whether a first-episode psychosis (FEP) group receiving intensive psychosocial interventions alone can achieve symptomatic remission and functional recovery; (2) whether prolonging the duration of untreated psychosis (DUP) in a sub-group according to randomisation will be associated with a poorer outcome and thereby establish whether the relationship between DUP and outcome is causative; and (3) whether neurobiological changes observed in FEP are associated with the psychotic disorder or antipsychotic medication. Baseline characteristics of participants will be presented. METHODS: This study is a triple-blind randomized placebo-controlled non-inferiority trial. The primary outcome is the level of functioning measured by the Social and Occupational Functioning Assessment Scale at 6 months. This study is being conducted at the Early Psychosis Prevention and Intervention Centre, Melbourne and includes young people aged 15 to 24 years with a DSM-IV psychotic disorder, a DUP less than 6 months and not high risk for suicide or harm to others. Strict discontinuation criteria are being applied. Participants are also undergoing three 3-Tesla-MRI scans. RESULTS: Ninety participants have been recruited and baseline characteristics are presented. CONCLUSIONS: Staged treatment and acceptability guidelines in early psychosis will determine whether antipsychotic medications are indicated in all young people with a FEP and whether antipsychotic medication can be safely delayed. Furthermore, the relative contribution of psychotic illness and antipsychotic medication in terms of structural brain changes will also be elucidated. The findings will inform clinical practice guidelines.
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ItemPredictors and consequences of health anxiety symptoms: a novel twin modeling study(WILEY, 2018-03)OBJECTIVE: The question of how to best conceptualize health anxiety (HA) from a diagnostic and etiological perspective remains debated. The aim was to examine the relationship between HA and the symptoms of anxiety and obsessive-compulsive-related disorders in a normative twin population. METHOD: Four hundred and ninety-six monozygotic adult twin pairs from the Australian Twin Registry participated in the study (age, 34.4 ± 7.72 years; 59% females). Validated scales were used to assess each domain. We applied a twin regression methodology-ICE FALCON-to determine whether there was evidence consistent with 'causal' relationships between HA and other symptoms by fitting and comparing model estimates. RESULTS: Estimates were consistent with higher levels of obsessing ('unwanted thoughts') (P = 0.008), social anxiety (P = 0.03), and body dysmorphic symptoms (P = 0.008) causing higher levels of HA symptoms, and with higher levels of HA symptoms causing higher levels of physical/somatic anxiety symptoms (P = 0.001). CONCLUSION: Obsessional thoughts, body dysmorphic concerns, and social anxiety symptoms may have a causal influence on HA. To report physical/somatic anxiety appears to be a consequence of the underlying presence of HA-related fears. Should our results be confirmed by longitudinal studies, the evaluation and treatment of HA may benefit from the consideration of these identified risk factors.
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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.