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Biomedical subjects

Gregor E Berger

Publications and source records attributed to Gregor E Berger.

10 recordsLinked to original sources
PubMed2007

Antibodies to infectious agents in individuals at ultra-high risk for psychosis.

BACKGROUND: While there is evidence that some cases of schizophrenia may be associated with microbial infections, the role of microbial agents has not been investigated in people with emerging psychosis. METHODS: Participants were 105 help seeking ultra-high risk individuals. Psychiatric measures included the Brief Psychiatric Rating Scale and the Scale for the Assessment of Negative Symptoms. Serum IgG antibodies against human herpesviruses and Toxoplasma gondii were determined using immunoassay methods. Multiple linear regression with adjustment for age and sex was applied to test associations between serum antibodies and psychiatric measures. RESULTS: Higher levels of serum IgG antibodies against Toxoplasma gondii in Toxoplasma-positive individuals were significantly associated with more severe positive psychotic symptoms. No significant association was observed between antibody levels and psychiatric measures in individuals positive for human herpesviruses. CONCLUSIONS: In some individuals infection with Toxoplasma gondii may be an environmental factor contributing to the manifestation of positive psychotic symptoms.

Adolescent↗
PubMed2006

Olfactory sensitivity through the course of psychosis: Relationships to olfactory identification, symptomatology and the schizophrenia odour.

There is some evidence for an unusual body odour in schizophrenia that has been linked to a hexenoic acid derivative (trans-3-methyl-2-hexenoic acid; MHA). Poor body odour has been linked to increased negative symptoms and reduced olfactory identification ability. However, the relationship between these findings and MHA, including olfactory sensitivity for MHA, has not been examined. Olfactory sensitivity thresholds were assessed for MHA and n-butyl-alcohol (NBA), in normal controls (CTL; n=24), patients with chronic schizophrenia (CHR; n=32) and a first-episode psychosis cohort (FE; n=31). In addition, forced choice detection of the pheromonal steroids 5-alpha-androst-16-en-3-one, androsterone-sulphate and estrone-3-sulphate was performed along with a measure of olfactory identification. CHR patients had significantly reduced sensitivity to MHA, but not NBA, compared to FE and CTL subjects. While sensitivity to pheromones was not different between the groups, CHR patients who could not detect them also showed poorer sensitivity to MHA. Further, the CHR group showed a significant association between reduced MHA sensitivity and greater levels of disorganised and negative symptoms. No relationships between identification and sensitivity for any substance were found. Our findings are the first to report reduced sensitivity for MHA in chronic schizophrenia patients, in the absence of similar impairment for more traditionally used substances. This may be linked to olfactory habituation effects, abnormal chemical processing or a genetic predisposition.

1-Butanol↗
PubMed2006

Omega-3 fatty acids supplementation in children with autism: a double-blind randomized, placebo-controlled pilot study.

BACKGROUND: There is increasing evidence that fatty acid deficiencies or imbalances may contribute to childhood neurodevelopmental disorders. METHODS: We conducted a randomized, double-blind, placebo-controlled 6-week pilot trial investigating the effects of 1.5 g/d of omega-3 fatty acids (.84 g/d eicosapentaenoic acid, .7 g/d docosahexaenoic acid) supplementation in 13 children (aged 5 to 17 years) with autistic disorders accompanied by severe tantrums, aggression, or self-injurious behavior. The outcome measure was the Aberrant Behavior Checklist (ABC) at 6 weeks. RESULTS: We observed an advantage of omega-3 fatty acids compared with placebo for hyperactivity and stereotypy, each with a large effect size. Repeated-measures ANOVA indicated a trend toward superiority of omega-3 fatty acids over placebo for hyperactivity. No clinically relevant adverse effects were elicited in either group. CONCLUSIONS: The results of this study provide preliminary evidence that omega-3 fatty acids may be an effective treatment for children with autism.

Adolescent↗
PubMed2006

Prediction of functional outcome 18 months after a first psychotic episode: a proton magnetic resonance spectroscopy study.

CONTEXT: Recent magnetic resonance imaging studies have attempted to relate volumetric brain measurements in early schizophrenia to clinical and functional outcome some years later. These studies have generally been negative, perhaps because gray and white matter volumes inaccurately assess the underlying dysfunction that might be predictive of outcome. OBJECTIVE: To investigate the predictive value of frontal and temporal spectroscopy measures for outcome in patients with first-episode psychoses. DESIGN: Left prefrontal cortex and left mediotemporal lobe voxels were assessed using proton magnetic resonance spectroscopy to provide the ratio of N-acetylaspartate (NAA) and choline-containing compounds to creatine and phosphocreatine (Cr) (NAA/Cr ratio). These data were used to predict outcome at 18 months after admission, as assessed by a systematic medical record audit. SETTING: Early psychosis clinic. PARTICIPANTS: Forty-six patients with first-episode psychosis. MAIN OUTCOME MEASURES: We used regression models that included age at imaging and duration of untreated psychosis to predict outcome scores on the Global Assessment of Functioning Scale, Clinical Global Impression scales, and Social and Occupational Functional Assessment Scale, as well as the number of admissions during the treatment period. We then further considered the contributions of premorbid function and baseline level of negative symptoms. RESULTS: The only spectroscopic predictor of outcome was the NAA/Cr ratio in the prefrontal cortex. Low scores on this variable were related to poorer outcome on all measures. In addition, the frontal NAA/Cr ratio explained 17% to 30% of the variance in outcome. CONCLUSIONS: Prefrontal neuronal dysfunction is an inconsistent feature of early psychosis; rather, it is an early marker of poor prognosis across the first years of illness. The extent to which this can be used to guide treatment and whether it predicts outcome some years after first presentation are questions for further research.

Adult↗
PubMed2006

Bioactive lipids in schizophrenia.

Bioactive lipids, in particular arachidonic acid (AA), are vital for monoaminergic neurotransmission, brain development and synaptic plasticity. Phospholipases A2 (PLA2) are key-enzymes in AA metabolism and are activated during monoaminergic neurotransmission. Reduced membrane AA levels, and an altered activity of PLA2 have been found in peripheral membranes of drug-naïve patients with schizophrenia with some conflicting results in more chronic patient populations. Furthermore, in vivo brain phosphorus-31 magnetic resonance spectroscopy suggests reduced lipid membrane precursors (phosphomonoesters) and increased membrane breakdown products (phosphodiesters) in drug-naïve or early treated first-episode schizophrenia patients compared to age-matched controls or chronic populations and these changes were correlated with peripheral red blood cell membrane AA levels. We postulate that processes modulating membrane lipid metabolism are associated with psychotic illnesses and might partially explain the mechanism of action of antipsychotic agents, as well as experimental agents such as purified ethyl-eicosapentaenoic acid (E-EPA). Recent supplementation trials suggest that E-EPA is a modestly effective augmentation treatment resulting in reduced doses of antipsychotic medication in acutely ill patients with schizophrenia (but not in residual-type schizophrenia). This review investigates the role of bioactive lipids in schizophrenia and its treatment, as well as its potential use in prevention.

Antipsychotic Agents↗
PubMed2005

Pituitary volume predicts future transition to psychosis in individuals at ultra-high risk of developing psychosis.

BACKGROUND: We examined pituitary volume before the onset of psychosis in subjects who were at ultra-high risk (UHR) for developing psychosis. METHODS: Pituitary volume was measured on 1.5-mm, coronal, 1.5-T magnetic resonance images in 94 UHR subjects recruited from admissions to the Personal Assessment and Crisis Evaluation Clinic in Melbourne, Australia and in 49 healthy control subjects. The UHR subjects were scanned at baseline and were followed clinically for a minimum of 1 year to detect transition to psychosis. RESULTS: Within the UHR group, a larger baseline pituitary volume was a significant predictor of future transition to psychosis. The UHR subjects who later went on to develop psychosis (UHR-P, n = 31) had a significantly larger (+12%; p = .001) baseline pituitary volume compared with UHR subjects who did not go on to develop psychosis (UHR-NP, n = 63). The survival analysis conducted by Cox regression showed that the risk of developing psychosis during the follow-up increased by 20% for every 10% increase in baseline pituitary volume (p = .002). Baseline pituitary volume of the UHR-NP subjects was smaller not only compared with UHR-P (as described above) but also compared with control subjects (-6%; p = .032). CONCLUSIONS: The phase before the onset of psychosis is associated with a larger pituitary volume, suggesting activation of the HPA axis.

Adolescent↗
PubMed2004

Insight in relation to psychosocial adjustment in schizophrenia.

Insight impairment occurs commonly in patients with schizophrenia, and it can be expected that patients with impaired insight may subsequently have poorer psychosocial adjustment. The aim of the present study was to measure the relationship between insight and psychosocial adjustment in 38 inpatients with a diagnosis of DSM-IV schizophrenia. Insight was assessed using the Scale to Assess Unawareness of Mental Disorder. A comprehensive set of measures was used to assess psychosocial adjustment. No relationship was found between measures of psychosocial adjustment and insight. However, a self-rated measure of psychosocial adjustment was partially related to insight. Our results suggest that patients' insight levels may not be reliable predictors of the patients' level of psychosocial adjustment, and that these findings may need to be considered in continuous care of psychotic patients, in particular when outpatient care needs to be planned.

Adaptation, Psychological↗
PubMed2003

Incipient neurovulnerability and neuroprotection in early psychosis.

The objective of this study was to review the implications of altered regulatory mechanisms of progenitor cell generation and death for neurodevelopment and adult brain functioning in early intervention in schizophrenia and related disorders. MEDLINE databases were searched from 1966 to 2002 using the following key words: stem cells, progenitor cells, glia, neurogenesis, apoptosis, and combined with brain and schizophrenia. Necropsy evidence suggests alterations in synaptic connectivity and a reduction in glial cell numbers with no substantial signs of neuronal cell loss or necrotic neurodegeneration (gliosis). Neuroimaging data propose dynamic structural changes with some evidence of volume loss of the hippocampus during the transition to psychosis. Central and peripheral tissues of patients with schizophrenia give indirect evidence of reduced neurotrophic and anti-apoptotic factors relevant for generation, and atrophic degeneration of cells of glial and, in some brain areas, even neuronal origin. In vivo brain magnetic resonance spectroscopy data in schizophrenia support the loss of neuropil (reduction in n-acetylaspartate) and increased membrane turnover (decrease in phosphomonoesters [PMEs], increase in phosphodiesterases [PDEs]) at the onset of illness, which potentially corresponds with increased apoptotic activity of progenitor cells. In conclusion, dysfunctional regulation of generation and degeneration of progenitor cells of glial and, in some brain areas, neuronal origin may potentially explain early and late neurodevelopmental abnormalities in early psychosis. A reduced genesis or an increased death of glial cells in the grey matter may provide the cellular substrate for synaptic and dendritic changes resulting in local atrophy and disconnectivity. Neuroprotective strategies counteracting the loss or supporting the generation of progenitor cells may therefore be a potent therapeutic avenue to explore.

Animals↗
PubMed2002

Implications of lipid biology for the pathogenesis of schizophrenia.

OBJECTIVE: Preclinical and clinical data suggest that lipid biology is integral to brain development and neurodegeneration. Both aspects are proposed as being important in the pathogenesis of schizophrenia. The purpose of this paper is to examine the implications of lipid biology, in particular the role of essential fatty acids (EFA), for schizophrenia. METHODS: Medline databases were searched from 1966 to 2001 followed by the cross-checking of references. RESULTS: Most studies investigating lipids in schizophrenia described reduced EFA, altered glycerophospholipids and an increased activity of a calcium-independent phospholipase A2 in blood cells and in post-mortem brain tissue. Additionally, in vivo brain phosphorus-31 Magnetic Resonance Spectroscopy (31P-MRS) demonstrated lower phosphomonoesters (implying reduced membrane precursors) in first- and multi-episode patients. In contrast, phosphodiesters were elevated mainly in first-episode patients (implying increased membrane breakdown products), whereas inconclusive results were found in chronic patients. EFA supplementation trials in chronic patient populations with residual symptoms have demonstrated conflicting results. More consistent results were observed in the early and symptomatic stages of illness, especially if EFA with a high proportion of eicosapentaenoic acid was used. CONCLUSION: Peripheral blood cell, brain necropsy and 31P-MRS analysis reveal a disturbed lipid biology, suggesting generalized membrane alterations in schizophrenia. 31P-MRS data suggest increased membrane turnover at illness onset and persisting membrane abnormalities in established schizophrenia. Cellular processes regulating membrane lipid metabolism are potential new targets for antipsychotic drugs and might explain the mechanism of action of treatments such as eicosapentaenoic acid.

Fatty Acids, Essential↗