The perception of self-produced sensory stimuli in patients with auditory hallucinations and passivity experiences: evidence for a breakdown in self-monitoring

BACKGROUND: To test the hypothesis that certain psychotic symptomatology is due to a defect in self-monitoring, we investigated the ability of groups of psychiatric patients to differentiate perceptually between self-produced and externally produced tactile stimuli. METHODS: Responses to tactile stimulation were assessed in three groups of subjects: schizophrenic patients; patients with bipolar affective disorder or depression; and normal control subjects. Within the psychiatric groups subjects were divided on the basis of the presence or absence of auditory hallucinations and/or passivity experiences. The subjects were asked to rate the perception of a tactile sensation on the palm of their left hand. The tactile stimulation was either self-produced by movement of the subject's right hand or externally produced by the experimenter. RESULTS: Normal control subjects and those psychiatric patients with neither auditory hallucinations nor passivity phenomena experienced self-produced stimuli as less intense, tickly and pleasant than identical, externally produced tactile stimuli. In contrast, psychiatric patients with these symptoms did not show a decrease in their perceptual ratings for tactile stimuli produced by themselves as compared with those produced by the experimenter. This failure to show a difference in perception between self-produced and externally produced stimuli appears to relate to the presence of auditory hallucinations and/or passivity experiences rather than to the diagnosis of schizophrenia. CONCLUSIONS: We propose that auditory hallucinations and passivity experiences are associated with an abnormality in the self-monitoring mechanism that normally allows us to distinguish self-produced from externally produced sensations

Complications of pregnancy and delivery in relation to psychosis in adult life: data from the British perinatal mortality survey sample

Original article can be found at: http://www.pubmedcentral.nih.gov/tocrender.fcgi?iid=137629 Copyright BMJ PublishingTo evaluate whether events occurring at or around the time of birth contribute to the onset of psychotic illness in adult life.Peer reviewe

Cortical Surface Area Differentiates Familial High Risk Individuals Who Go on to Develop Schizophrenia

BACKGROUND: Schizophrenia is associated with structural brain abnormalities that may be present before disease onset. It remains unclear whether these represent general vulnerability indicators or are associated with the clinical state itself. METHODS: To investigate this, structural brain scans were acquired at two time points (mean scan interval 1.87 years) in a cohort of individuals at high familial risk of schizophrenia (n 5 142) and control subjects (n 5 36). Cortical reconstructions were generated using FreeSurfer. The high-risk cohort was subdivided into individuals that remained well during the study, individuals that had transient psychotic symptoms, and individuals that subsequently became ill. Baseline measures and longitudinal change in global estimates of thickness and surface area and lobar values were compared, focusing on overall differences between high-risk individuals and control subjects and then on group differences within the high-risk cohort. RESULTS: Longitudinally, control subjects showed a significantly greater reduction in cortical surface area compared with the high-risk group. Within the high-risk group, differences in surface area at baseline predicted clinical course, with individuals that subsequently became ill having significantly larger surface area than individuals that remained well during the study. For thickness, longitudinal reductions were most prominent in the frontal, cingulate, and occipital lobes in all high-risk individuals compared with control subjects. CONCLUSIONS: Our results suggest that larger surface areas at baseline may be associated with mechanisms that go above and beyond a general familial disposition. A relative preservation over time of surface area, coupled with a thinning of the cortex compared with control subjects, may serve as vulnerability markers of schizophrenia

Causal categories: relativistically interacting processes

A symmetric monoidal category naturally arises as the mathematical structure that organizes physical systems, processes, and composition thereof, both sequentially and in parallel. This structure admits a purely graphical calculus. This paper is concerned with the encoding of a fixed causal structure within a symmetric monoidal category: causal dependencies will correspond to topological connectedness in the graphical language. We show that correlations, either classical or quantum, force terminality of the tensor unit. We also show that well-definedness of the concept of a global state forces the monoidal product to be only partially defined, which in turn results in a relativistic covariance theorem. Except for these assumptions, at no stage do we assume anything more than purely compositional symmetric-monoidal categorical structure. We cast these two structural results in terms of a mathematical entity, which we call a `causal category'. We provide methods of constructing causal categories, and we study the consequences of these methods for the general framework of categorical quantum mechanics.Comment: 43 pages, lots of figure

Photon-induced proton knockout from 208Pb

No abstract available

Childhood antecedents of schizophrenia and affective illness: social adjustment at ages 7 and 11

Original article can be found at: http://www.bmj.com/ Copyright BMJ PublishingTo investigate the social adjustment in childhood of people who as adults have psychiatric disorders. Design - Subjects in a prospectively followed up cohort (the national child development study) who had been admitted as adults to psychiatric hospitals were compared with the rest of the cohort on ratings of social behaviour made by teachers at the ages of 7 and 11 years.Peer reviewe

Suicide and undetermined death in south east Scotland. A case-control study using the psychological autopsy method

Controls were receiving more care of whatever kind. Treatment of mental disorder comorbid with physical illness and a history of deliberate self-harm may be especially important. Factors that separate those with mental disorder at high risk from those at lesser risk relate to care levels provided, which may be a function of engagement by and with health services. The role of mental health professionals is beneficial in suicide prevention. The focusing of that role towards engaging alienated or 'difficult' patients should be addressed