Publications by authors named "Siew-eng Chua"

Introduction: Pharmacogenomic testing in psychiatry is an emerging area with potential clinical application of guiding medication choice and dosing. Interest has been fanned by commercial pharmacogenomic providers who have commonly marketed combinatorial panels that are direct-to-consumer. However, this has not been adopted widely due to a combination of barriers that include a varying evidence base, clinician and patient familiarity and acceptance, uncertainty about cost-effectiveness, and regulatory requirements.

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Rationale: Rodents exposed to valproic acid (VPA) in prenatal life exhibit post-natal characteristics analogous to autism spectrum disorder (ASD). Many previous studies used relatively high doses of VPA during early pregnancy, potentially confounding interpretation because the offspring are the 'survivors' of a toxic insult. Low dose or late gestation exposure has not been widely studied.

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Oxytocin has been suggested as a promising new treatment for neurodevelopmental disorders. However, important gaps remain in our understanding of its mode of action, in particular, to what extent oxytocin modulates social and non-social behaviours and whether its effects are generalizable across both sexes. Here we investigated the effects of a range of oxytocin doses on social and non-social behaviours in C57BL/6N mice of both sexes.

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Background: Visual hallucinations are an important non-motor complication of Parkinson's disease (PD) and carry a negative prognosis. Their biological basis is uncertain, but may relate to the activity of resting state networks in brain. We therefore aimed to investigate functional activity of brain in patients with visual hallucinations (PDVH) in resting state compared to patients without hallucinations (PDnonVH) and a healthy control group (HC).

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Visual hallucinations carry poor prognosis in Parkinson's disease. Here we tested the hypothesis that the hippocampus and visuospatial memory impairment play a central role in the pathology of PD with visual hallucinations. Multimodal magnetic resonance imaging of the brain was carried out in 12 people with PD and visual hallucinations; 15 PD individuals without hallucinations; and 14 healthy controls.

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Background/aims: The Remission in Schizophrenia Working Group has defined remission as 'a low-mild symptom intensity level, maintained for a minimum of 6 months, where such symptoms do not affect an individual's behaviour' [Andreasen et al.: Am J Psychiatry 2005;162:441-449]. Since brain morphology relates to symptomatology, treatment and illness progression, MRI may assist in predicting remission.

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Background: Visual hallucinations (VH) are one of the most striking nonmotor symptoms in Parkinson's disease (PD), and predict dementia and mortality. Aberrant default mode network (DMN) is associated with other psychoses. Here, we tested the hypothesis that DMN dysfunction contributes to VH in PD.

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Background: Maternal immune activation (MIA) during prenatal life is a risk factor for neurodevelopmental disorders including schizophrenia and autism. Such conditions are associated with alterations in fronto-subcortical circuits, but their molecular basis is far from clear.

Methodology/principal Findings: Using two-dimensional differential in-gel electrophoresis (2D-DIGE) and mass spectrometry, with targeted western blot analyses for confirmation, we investigated the impact of MIA on the prefrontal and striatal proteome from an established MIA mouse model generated in C57B6 mice, by administering the viral analogue PolyI:C or saline vehicle (control) intravenously on gestation day (GD) 9.

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The use of second-generation antipsychotics (SGAs) for the treatment of schizophrenia has surged worldwide. Amisulpride, aripiprazole, olanzapine, quetiapine, risperidone, sertindole and ziprasidone have now been commonly prescribed. Their effects on QT interval differ but evidence remains sparse and mostly inconclusive.

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Background: Despite extensive investigation of the neural systems for face perception and emotion recognition in adults and young children in the past, the precise temporal activation of brain sources specific to the processing of emotional facial expressions in older children and adolescents is not well known. This preliminary study aims to trace the spatiotemporal dynamics of facial emotion processing during adolescence and provide a basis for future developmental studies and comparisons with patient populations that have social-emotional deficits such as autism.

Methods: We presented pictures showing happy, angry, fearful, or neutral facial expressions to healthy adolescents (aged 10-16 years) and recorded 128-channel event-related potentials (ERPs) while they performed an emotion discrimination task.

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