Variability and magnitude of brain glutamate levels in schizophrenia: a meta and mega-analysis.

Glutamatergic dysfunction is implicated in schizophrenia pathoaetiology, but this may vary in extent between patients. It is unclear whether inter-individual variability in glutamate is greater in schizophrenia than the general population. We conducted meta-analyses to assess (1) variability of glutamate measures in patients relative to controls (log coefficient of variation ratio: CVR); (2) standardised mean differences (SMD) using Hedges g; (3) modal distribution of individual-level glutamate data (Hartigan's unimodality dip test).

Association of Age, Antipsychotic Medication, and Symptom Severity in Schizophrenia With Proton Magnetic Resonance Spectroscopy Brain Glutamate Level: A Mega-analysis of Individual Participant-Level Data.

Importance: Proton magnetic resonance spectroscopy (1H-MRS) studies indicate that altered brain glutamatergic function may be associated with the pathophysiology of schizophrenia and the response to antipsychotic treatment. However, the association of altered glutamatergic function with clinical and demographic factors is unclear.

Objective: To assess the associations of age, symptom severity, level of functioning, and antipsychotic treatment with brain glutamatergic metabolites.

Low prevalence of substance use in people with 22q11.2 deletion syndrome.

Background: 22q11.2 deletion syndrome (22q11DS), one of the most common recurrent copy number variant disorders, is associated with dopaminergic abnormalities and increased risk for psychotic disorders.

Aims: Given the elevated prevalence of substance use and dopaminergic abnormalities in non-deleted patients with psychosis, we investigated the prevalence of substance use in 22q11DS, compared with that in non-deleted patients with psychosis and matched healthy controls.

Dopamine in high-risk populations: A comparison of subjects with 22q11.2 deletion syndrome and subjects at ultra high-risk for psychosis.

Striatal dopamine (DA) dysfunction has been consistently reported in psychotic disorders. Differences and similarities in the pathogenesis between populations at clinical and genetic risk for developing psychosis are yet to be established. Here we explored markers of dopamine (DA) function in subjects meeting clinically ultra-high risk criteria for psychosis (UHR) and in subjects with 22q11.

The effect of the muscarinic M receptor antagonist biperiden on cognition in medication free subjects with psychosis.

The acetylcholine muscarinic M receptor has been implicated in both psychosis and cognition. Post-mortem research has shown reduced muscarinic M receptor density in 25% of chronic patients with schizophrenia. It is unknown whether reduced M receptor density is related to cognitive symptoms of psychosis.

PRODH rs450046 and proline x COMT Val¹⁵⁸ Met interaction effects on intelligence and startle in adults with 22q11 deletion syndrome.

Rationale: 22q11 deletion syndrome (22q11DS) is associated with an increased risk for psychotic disorders, suggesting a relationship between genotypes and the pathophysiology of psychotic disorders. Two genes in the deleted region, catechol-O-methyl-transferase (COMT) and proline dehydrogenase (oxidase) 1 (PRODH), contain polymorphisms associated with neuropsychiatric phenotypes.

Objectives: Here, we explored the association between polymorphisms and full-scale intelligence (FSIQ), startle reactivity (SR) and prepulse inhibition (PPI) in adults with 22q11DS.

Pharmacological Interventions for the MATRICS Cognitive Domains in Schizophrenia: What's the Evidence?

Schizophrenia is a disabling, chronic psychiatric disorder with a prevalence rate of 0.5-1% in the general population. Symptoms include positive (e.

Startle reactivity and prepulse inhibition of the acoustic startle response are modulated by catechol-O-methyl-transferase Val(158) Met polymorphism in adults with 22q11 deletion syndrome.

22q11 deletion syndrome (22q11DS) is a genetic disorder caused by a microdeletion on chromosome 22, which includes the gene coding for catechol-O-methyl-transferase (COMT). High dopamine (DA) levels due to COMT haplo-insufficiency may be associated with the increased risk of developing schizophrenia in adults with 22q11DS. Reduced prepulse inhibition (PPI) of the acoustic startle response has been associated with schizophrenia and with disrupted DAergic transmission in the prefrontal cortex (PFC).

Striatal dopamine D2/3 receptor binding following dopamine depletion in subjects at Ultra High Risk for psychosis.

Altered striatal dopaminergic neurotransmission is thought to be fundamental to schizophrenia. Increased presynaptic dopaminergic activity ([18F]-DOPA PET) may predate the onset of psychotic symptoms and correlates to clinical symptoms in subjects at Ultra High Risk (UHR) for developing psychosis. Postsynaptic dopaminergic neurotransmission has not been investigated yet in UHR patients.

White matter integrity in Asperger syndrome: a preliminary diffusion tensor magnetic resonance imaging study in adults.

Background: Autistic Spectrum Disorder (ASD), including Asperger syndrome and autism, is a highly genetic neurodevelopmental disorder. There is a consensus that ASD has a biological basis, and it has been proposed that it is a "connectivity" disorder. Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) allows measurement of the microstructural integrity of white matter (a proxy measure of "connectivity").

White matter microstructure in 22q11 deletion syndrome: a pilot diffusion tensor imaging and voxel-based morphometry study of children and adolescents.

Young people with 22q11 Deletion Syndrome (22q11DS) are at substantial risk for developing psychosis and have significant differences in white matter (WM) volume. However, there are few in vivo studies of both WM microstructural integrity (as measured using Diffusion Tensor (DT)-MRI) and WM volume in the same individual. We used DT-MRI and structural MRI (sMRI) with voxel based morphometry (VBM) to compare, respectively, the fractional anisotropy (FA) and WM volume of 11 children and adolescents with 22q11DS and 12 controls.

Psychosis and autism: magnetic resonance imaging study of brain anatomy.

Background: Autism-spectrum disorder is increasingly recognised, with recent studies estimating that 1% of children in South London are affected. However, the biology of comorbid mental health problems in people with autism-spectrum disorder is poorly understood.

Aims: To investigate the brain anatomy of people with autism-spectrum disorder with and without psychosis.