Patients with neuropsychiatric disorders such as Alzheimer's disease (AD), schizophrenia (Sz), and brain injury (BI) often show memory deficits and lack of awareness of those deficits. This study ...aimed to investigate the role of memory in awareness of memory deficits and illness in multiple patient groups. Comparison of awareness profiles between groups can reveal common or distinct patterns of awareness and predictors, which may inform theories about the structure of awareness. Using the same standardized measures, AD (N = 27) Sz (N = 31), and BI (N = 26) patients were compared on memory functioning, awareness of illness, and awareness of memory deficits-measured by discrepancy of pretest estimate and actual test scores. All groups were poor at pretest estimation of memory functioning, particularly the AD and BI groups. In AD, patients with the lowest memory functioning rated their performance highest. The BI group and to a lesser extent the AD group showed improved estimations of performance following the memory test. Those with the poorest memory showed the greatest improvement in ratings accuracy post test. The relationship between memory and awareness of memory was stronger than the association between memory and awareness of illness. There was a double dissociation between awareness of memory and awareness of illness across patient groups. The study shows that awareness of memory is linked to memory functioning, while memory is only modestly related to awareness of illness. Dissociations in the role of memory in different domains of awareness and "online" awareness of performance provide information to refine cognitive models of awareness. However, the results should be interpreted with caution given the heterogeneous nature of the sample.
Abstract
Background
Neuroanatomical studies have provided some evidence for a neurobiological continuity between psychotic symptoms in patients with schizophrenia and subclinical psychotic-like ...experiences as identified via self-report questionnaires (or schizotypy) in otherwise healthy individuals. Despite a number of structural brain imaging studies published in subjects with schizotypy, these have often been limited by relatively small sample sizes. This study represents the first meta-analysis of structural MRI scans in schizotypy assessed with standardized methods at 17 centres worldwide.
Methods
The total sample included in the case-control meta-analysis involved 496 subjects with high schizotypy and 588 comparison subjects with low schizotypy as identified with validated self-report schizotypy questionnaires (i.e., the Community Assessment of Psychic Experiences, the Oxford-Liverpool Inventory of Feelings and Experiences, or the Schizotypal Personality Questionnaire). Left and right lateral ventricle, thalamus, caudate, putamen, pallidum, accumbens, hippocampus and amygdala volumes, as well as intracranial volumes (ICV), were obtained with FreeSurfer from high-resolution T1-weighted structural brain scans locally by each site. Analyses of individual subject data were also performed by the site that contributed the sample, using code created within the ENIGMA collaboration. Group differences for each ROI within each sample were examined using univariate linear regression analysis in R predicting the left, right and mean subcortical volumes with group (low or high schizotypy) controlling for age, sex, site and ICV. For each sample, Cohen’s d effect sizes for each ROI were computed based on the group contrast t-statistics. Random-effects meta-analyses of Cohen’s d effect sizes for each ROI were performed using R’s metafor package.
Results
For the case-control meta-analysis, mean (range) age across samples was 29.2 (19.2–44.9) years for subjects with high schizotypy and 28.5 (19.4–42.5) years for subjects with low schizotypy. High and low schizotypy samples were on average 48.6% (25–100) and 49.0% (8–100) male. Compared to low schizotypy, people with high schizotypy had smaller left nucleus accumbens volumes (Cohen’s d = -0.13, p = 0.04). No other significant meta-analytical effects were identified.
Discussion
Worldwide cooperative analyses of brain imaging data support a profile of subcortical abnormalities involving the ventral striatum in healthy individuals with subclinical psychotic-like experiences. Though the effect size is small, the result is consistent with findings in schizophrenia patients and suggesting that these effects are not secondary to potential influences of disease chronicity or antipsychotic medication. The lack of significant effects in other reported regions in schizophrenia research may indicate that further subcortical abnormalities may not be present or detectable in schizotypy samples and could reflect mechanisms of resilience in this population.
Abstract
Background
Cortical neuroanatomical abnormalities have been reported along a continuum between individuals with chronic schizophrenia, first-episode psychosis, clinical high risk for ...psychosis, and healthy individuals self-reporting subclinical psychotic-like experiences (or schizotypy). Recently, the Schizophrenia Working Group within the ENIGMA (Enhancing Neuro Imaging Genetics through Meta Analysis) consortium provided meta-analytic evidence for robust cortical thickness abnormalities in schizophrenia, while also indicating that these abnormalities are influenced by illness severity and treatment with antipsychotic medications. In this context, schizotypy research allows the investigation of cortical neuroanatomy associated with the expression of subclinical psychotic-like symptoms without the potential influence of a psychotic illness, its severity, or the use of antipsychotics. This study presents the first large-scale imaging meta-analysis of cortical thickness in schizotypy using standardized methods from 23 datasets worldwide.
Methods
Cortical thickness and surface area were assessed in MRI scans of 2,695 healthy individuals (mean range age of 29.1 17–55.8, 46.3% male) who had also completed validated self-report schizotypy questionnaires. Each site processed their local T1-weighted MRI scans using FreeSurfer and, following the protocol outlined in the ENIGMA Schizophrenia Working Group study, extracted cortical thickness for 70 Desikan-Killiany (DK) atlas regions (34 regions per hemisphere + left and right hemisphere mean thickness). At each site, partial correlation analyses were performed between regional cortical thickness by ROI and total schizotypy scores in R, predicting the left, right and mean cortical thickness, adjusting for sex, age and site. Random-effects meta-analyses of partial correlation effect sizes for each of the DK atlas regions were performed using R’s metafor package. False discovery rate (pFDR < .05) was used to control for multiple comparisons.
Results
We found significant positive associations between subclinical psychotic-like experiences and mean cortical thickness of the medial orbitofrontal cortex (r = .077; pFDR = .006) and the frontal pole (r = .073; pFDR = .006). When assessed separately by hemisphere, meta-analysis revealed a significant positive association between subclinical psychotic-like experiences and cortical thickness of the left medial orbitofrontal cortex (r = .066; pFDR = .044), and at trend-level with the right medial orbitofrontal cortex (r = .062; pFDR = .053) and the left frontal pole (r = .062; pFDR = .053). No significant associations were observed for surface area.
Discussion
Worldwide cooperative analyses of large-scale brain imaging data support a profile of cortical thickness abnormalities involving prefrontal cortical regions positively related to schizotypy in healthy individuals. These findings are not secondary to potential influences of disease chronicity or antipsychotic medication on the neuroanatomical correlates of psychotic-like experiences. The directionality of the observed meta-analytical effects in schizotypy is opposite to those previously reported in patients with schizophrenia (i.e., thinner cortex). The present findings of increased thickness may indicate early microstructural deficits (e.g. in myelination) that contribute to vulnerability for psychosis. Alternatively, these may reflect mechanisms of resilience associated with the expression of subclinical manifestations of psychotic symptoms in otherwise healthy individuals.
Background Auditory verbal hallucinations in schizophrenia have been linked to defective monitoring of one's own verbal thoughts. Previous studies have shown that patients with auditory verbal ...hallucinations show attenuated activation of brain regions involved with auditory processing during the monitoring of inner speech. However, there are no functional magnetic resonance imaging studies explicitly comparing the perception of external speech with internal speech in the same patients with schizophrenia. The present study investigated the functional neuroanatomy of inner and external speech in both patients with schizophrenia and healthy control subjects. Methods Fifteen patients with schizophrenia and 12 healthy control subjects were studied using functional magnetic resonance imaging while listening to sentences or imagining sentences. Results Significant interactions between group (control subjects vs. patients) and task (listening vs. inner speech) were seen for the left superior temporal gyrus, as well as regions within the cingulate gyrus. Conclusions Attenuated deactivation of the left superior temporal gyrus in schizophrenia patients during the processing of inner speech may reflect deficits in the forward models subserving self-monitoring.
Background: Community treatment orders (CTOs) are increasingly being used, despite a weak evidence base, and problems continue regarding Second Opinion Appointed Doctor (SOAD) certification of ...medication.
Aims: The aim of the current study was to describe current CTO usage regarding patient characteristics, prescribed medication and CTO conditions.
Method: A 1-year prospective cohort study with consecutive sampling was conducted for all patients whose CTO was registered in a large mental health trust. Only the first CTO for each patient was included. Measures included sociodemographic variables, psychiatric diagnosis, CTO date of initiation and conditions, psychotropic medication and date of SOAD certification for medication. This study was conducted in the first year of CTO legislation in England and Wales.
Results: A total of195 patients were sampled (mean age 40.6 years, 65% male, 52% black ethnic origin). There was significant geographical variability in rates of CTO use (χ
2 = 11.3, p = 0.012). A total of 53% had their place of residence specified as a condition and 29% were required to allow access into their homes. Of those with schizophrenia, 64% were prescribed an antipsychotic long-acting injection (LAI). Of the total group, 7% received high-dose antipsychotics, 10% were prescribed two antipsychotics and only 15% received SOAD certification in time.
Conclusions: There was geographical and ethnic variation in CTO use but higher rates of hospital detention in minority ethnic groups may be contributory. Most patients were prescribed antipsychotic LAIs and CTO conditions may not follow the least restrictive principle.
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