Multivariate neuroanatomical classification of cognitive subtypes in schizophrenia: A support vector machine learning approach

AbstractHeterogeneity in the structural brain abnormalities associated with schizophrenia has made identification of reliable neuroanatomical markers of the disease difficult. The use of more homogenous clinical phenotypes may improve the accuracy of predicting psychotic disorder/s on the basis of observable brain disturbances. Here we investigate the utility of cognitive subtypes of schizophrenia – ‘cognitive deficit’ and ‘cognitively spared’ – in determining whether multivariate patterns of volumetric brain differences can accurately discriminate these clinical subtypes from healthy controls, and from each other. We applied support vector machine classification to grey- and white-matter volume data from 126 schizophrenia patients previously allocated to the cognitive spared subtype, 74 cognitive deficit schizophrenia patients, and 134 healthy controls. Using this method, cognitive subtypes were distinguished from healthy controls with up to 72% accuracy. Cross-validation analyses between subtypes achieved an accuracy of 71%, suggesting that some common neuroanatomical patterns distinguish both subtypes from healthy controls. Notably, cognitive subtypes were best distinguished from one another when the sample was stratified by sex prior to classification analysis: cognitive subtype classification accuracy was relatively low (<60%) without stratification, and increased to 83% for females with sex stratification. Distinct neuroanatomical patterns predicted cognitive subtype status in each sex: sex-specific multivariate patterns did not predict cognitive subtype status in the other sex above chance, and weight map analyses demonstrated negative correlations between the spatial patterns of weights underlying classification for each sex. These results suggest that in typical mixed-sex samples of schizophrenia patients, the volumetric brain differences between cognitive subtypes are relatively minor in contrast to the large common disease-associated changes. Volumetric differences that distinguish between cognitive subtypes on a case-by-case basis appear to occur in a sex-specific manner that is consistent with previous evidence of disrupted relationships between brain structure and cognition in male, but not female, schizophrenia patients. Consideration of sex-specific differences in brain organization is thus likely to assist future attempts to distinguish subgroups of schizophrenia patients on the basis of neuroanatomical features

Self-harm and suicidal ideation among young people is more often recorded by child protection than health services in an Australian population cohort

OBJECTIVE: We investigated patterns of service contact for self-harm and suicidal ideation recorded by a range of human service agencies - including health, police and child protection - with specific focus on overlap and sequences of contacts, age of first contact and demographic and intergenerational characteristics associated with different service responses to self-harm.METHODS: Participants were 91,597 adolescents for whom multi-agency linked data were available in a longitudinal study of a population cohort in New South Wales, Australia. Self-harm and suicide-related incidents from birth to 18 years of age were derived from emergency department, inpatient hospital admission, mental health ambulatory, child protection and police administrative records. Descriptive statistics and binomial logistic regression were used to examine patterns of service contacts.RESULTS: Child protection services recorded the largest proportion of youth with reported self-harm and suicidal ideation, in which the age of first contact for self-harm was younger relative to other incidents of self-harm recorded by other agencies. Nearly 40% of youth with a health service contact for self-harm also had contact with child protection and/or police services for self-harm. Girls were more likely to access health services for self-harm than boys, but not child protection or police services.CONCLUSION: Suicide prevention is not solely the responsibility of health services; police and child protection services also respond to a significant proportion of self-harm and suicide-related incidents. High rates of overlap among different services responding to self-harm suggest the need for cross-agency strategies to prevent suicide in young people.</p

A randomised controlled trial of cognitive behaviour therapy versus non-directive reflective listening for young people at ultra high risk of developing psychosis:The detection and evaluation of psychological therapy (DEPTh) trial

Background: Intervention trials for young people at ultra high risk (UHR) for psychosis have shown cognitive behaviour therapy (CBT) to have promising effects on treating psychotic symptoms but have not focused on functional outcomes. We hypothesized that compared to an active control, CBT would: (i) reduce the likelihood of, and/or delay, transition to psychosis; (ii) reduce symptom severity while improving social functioning and quality of life, whether or not transition occurred. Method: This was a single-blind randomised controlled trial for young people at UHR for psychosis comparing CBT to an active control condition, Non Directive Reflective Listening (NDRL), both in addition to standard care, with a 6 month treatment phase and 12 months of follow-up. Statistical analysis is based on intention-to-treat and used random effect models to estimate treatment effects common to all time-points. Results: Fifty-seven young people (mean age = 16.5 years) were randomised to CBT (n = 30) or NDRL (n = 27). Rate of transition to psychosis was 5%; the 3 transitions occurred in the CBT condition (baseline, 2 months, 5 months respectively). The NDRL condition resulted in a significantly greater reduction in distress associated with psychotic symptoms compared to CBT (treatment effect = 36.71, standard error = 16.84, p = 0.029). There were no significant treatment effects on frequency and intensity of psychotic symptoms, global, social or role functioning. Conclusion: Our sample was higher functioning, younger and experiencing lower levels of psychotic like experiences than other trials. The significantly better treatment effect of NDRL on distress associated with psychotic symptoms supports the recommendations for a stepped-care model of service delivery. This treatment approach would accommodate the younger UHR population and facilitate timely intervention

Stress debriefing and patterns of recovery following a natural disaster

Stress debriefing has been used extensively following traumatic events; however, there is little evidence of its effectiveness. This paper reports the effects of stress debriefing on the rate of recovery of 195 helpers (e.g., emergency service personnel and disaster workers) following an earthquake in Newcastle, Australia (62 debriefed helpers and 133 who were not debriefed). Post-trauma stress reactions (Impact of Event Scale) and general psychological morbidity (General Health Questionnaire: GHQ-12) were assessed on four occasions over the first 2 years postearthquake. There was no evidence of an improved rate of recovery among those helpers who were debriefed, even when level of exposure and helping-related stress were taken into account. More rigorous investigation of the effectiveness of stress debriefing and its role in posttrauma recovery is urgently required

Health-related quality of life, functioning and social experiences in people with psychotic disorders

To inform development of a model for health-related quality of life (HRQoL) in people with psychotic disorders, we aimed to assess correlations between utilities and dimension scores for the Assessment of Quality of Life (AQoL)-4D with functioning and social experiences; ascertain if patient housing and clinical status affected correlations; and determine aspects of functioning that jointly predict HRQoL. We analyzed data for 1642 people with an ICD-10 psychotic disorder from the 2010 Australian National Survey of Psychosis. Global functioning was measured with the Personal and Social Performance scale, independent functioning with the Multidimensional Scale of Independent Functioning and social functioning through level of social dysfunction. Social experiences comprised perceived loneliness and experienced stigma. We assessed Spearman’s rank correlation coefficients and undertook linear regression analyses. Moderate associations were found between AQoL-4D utilities and all variables, except experienced stigma. Perceived loneliness had the strongest association. The AQoL-4D social relationships dimension was most strongly associated with social variables; its independent living dimension with global and independent functioning. Correlations between utilities and all variables, except for social dysfunction, were modified by housing. Course of disorder impacted correlations with utilities and independent functioning. Global functioning and social dysfunction were found to jointly predict HRQoL. In conclusion, as the AQoL-4D can differentiate between functioning and social experiences individually and when categorized by housing and clinical status in people with psychosis, predictive models of HRQoL in this population are feasible, and only need include select aspects of functioning and social experiences, particularly perception of loneliness

Gamma-ray bursts and X-ray melting of material to form chondrules and planets

Chondrules are millimeter sized objects of spherical to irregular shape that constitute the major component of chondritic meteorites that originate in the region between Mars and Jupiter and which fall to Earth. They appear to have solidified rapidly from molten or partially molten drops. The heat source that melted the chondrules remains uncertain. The intense radiation from a gamma-ray burst (GRB) is capable of melting material at distances up to 300 light years. These conditions were created in the laboratory for the first time when millimeter sized pellets were placed in a vacuum chamber in the white synchrotron beam at the European Synchrotron Radiation Facility. The pellets were rapidly heated in the X-ray and gamma-ray furnace to above 1400C melted and cooled. This process heats from the inside unlike normal furnaces. The melted spherical samples were examined with a range of techniques and found to have microstructural properties similar to the chondrules that come from meteorites. This experiment demonstrates that GRBs can melt precursor material to form chondrules that may subsequently influence the formation of planets. This work extends the field of laboratory astrophysics to include high power synchrotron sources.Comment: 4 pages, 4 figures. Full resolution figures available from A&

Place preference induced by nucleus accumbens amphetamine is impaired by local blockade of Group II metabotropic glutamate receptors in rats

BACKGROUND: The nucleus accumbens (NAc) plays a critical role in amphetamine-produced conditioned place preference (CPP). In previous studies, NAc basal and amphetamine-produced DA transmission was altered by Group II mGluR agents. We tested whether NAc amphetamine CPP depends on Group II mGluR transmission. RESULTS: NAc injections (0.5 μl/side) of the Group II mGluR antagonist (2 S)- a-ethylglutamic acid (EGLU: 0.01–0.8 μg but not 0.001 μg) impaired CPP. The drug did not block the acute locomotor effect of amphetamine. CONCLUSION: Results suggest that Group II mGluRs may be necessary for the establishment of NAc amphetamine-produced CPP. These receptors may also mediate other forms of reward-related learning dependent on this structure

Invigoration of convection by an overrunning diabatically modified cloud-top layer

This paper investigates the factors that invigorated an outbreak of warm-sector convection which was instrumental in transporting high momentum downwards to give damaging surface winds. We have re-examined a wintertime extratropical cyclone from the Fronts and Atlantic Storm-Track EXperiment for which an earlier study had shown the warm-sector convection to be in the form of a series of arc-shaped rainbands. Using a 5 km grid version of the WRF (Weather Research and Forecasting) model, we show that this convection was enhanced as a result of the properties of an airstream at the base of the dry intrusion that overran the shallow moist zone (SMZ) of the warm sector. This airstream, which we refer to as the Diabatically Modified Cloud-Top Layer (DMCTL), is shown to have originated several hours earlier in part of an ana-cold frontal cloud layer where a region of previously ascending air began systematically to descend. Air from the DMCTL descended from heights of 2–3 km to heights of 1–2 km over a roughly 5 h period during which sustained evaporation occurred and its potential temperature dropped by up to 5 °C. This substantially enhanced the convective instability where this airstream overran the SMZ, leading to vigorous boundary-layer convection. The same region of evaporative cooling is also shown to have generated positive potential vorticity (PV) in the upper parts of the DMCTL, with values reaching about 3 PV units where it overran the SMZ. This layer of high PV, although we have not quantified its impact, may have increased the convective instability further by inducing differential advection below it. The cyclone in the present study later underwent frontal fracture and developed a cloud head but the processes diagnosed in this study were underway before the transition occurred

Total smoking bans in psychiatric inpatient services: a survey of perceived benefits, barriers and support among staff

Background: The introduction of total smoking bans represents an important step in addressing the smoking and physical health of people with mental illness. Despite evidence indicating the importance of staff support in the successful implementation of smoking bans, limited research has examined levels of staff support prior to the implementation of a ban in psychiatric settings, or factors that are associated with such support. This study aimed to examine the views of psychiatric inpatient hospital staff regarding the perceived benefits of and barriers to implementation of a successful total smoking ban in mental health services. Secondly, to examine the level of support among clinical and non-clinical staff for a total smoking ban. Thirdly, to examine the association between the benefits and barriers perceived by clinicians and their support for a total smoking ban in their unit. Methods: Cross-sectional survey of both clinical and non-clinical staff in a large inpatient psychiatric hospital immediately prior to the implementation of a total smoking ban. Results: Of the 300 staff, 183 (61%) responded. Seventy-three (41%) of total respondents were clinical staff, and 110 (92%) were non-clinical staff. More than two-thirds of staff agreed that a smoking ban would improve their work environment and conditions, help staff to stop smoking and improve patients' physical health. The most prevalent clinician perceived barriers to a successful total smoking ban related to fear of patient aggression (89%) and patient non-compliance (72%). Two thirds (67%) of all staff indicated support for a total smoking ban in mental health facilities generally, and a majority (54%) of clinical staff expressed support for a ban within their unit. Clinical staff who believed a smoking ban would help patients to stop smoking were more likely to support a smoking ban in their unit. Conclusions: There is a clear need to more effectively communicate to staff the evidence that consistently applied smoking bans do not increase patient aggression. There is also a need to communicate the benefits of smoking bans in aiding the delivery of smoking cessation care, and the benefits of both smoking bans and such care in aiding patients to stop smoking