Representations of hallucinations and dissociation in young adult literature: using literature to challenge stigma about psychosis

This paper explores the role that sensitively portrayed literary representations of hallucinations and dissociation may have in counteracting stigma associated with these experiences. In it, we focus on narratives of young people experiencing hallucinatory and dissociative phenomena in two award-winning, young adult novels: How It Feels to Float by Helena Fox and A Monster Calls by Patrick Ness. We identify and discuss three literary devices in these two novels that promote empathy for the characters and their experiences. The narrative accounts in both novels challenge conceptions of hallucinations and dissociation as unknowable and unrelatable experiences with their empathic portrayals of relatable characters that create comprehensible accounts of adolescents grappling with their sense of reality. Importantly, they highlight the potential role that literature can play in stigma reduction by positively shaping young peoples' understandings of unfamiliar mental health experiences.

Childhood adversity and recurrence of psychotic experiences during adolescence: the role of mediation in an analysis of a population-based longitudinal cohort study

BACKGROUND

Psychotic experiences (PEs) are relatively common in childhood and adolescence and are associated with increased risk of functional issues and psychiatric illness in young adulthood, and PEs that recur are associated with increased risk of poorer psychiatric and functional outcomes. Childhood adversity is a well-established risk factor for PEs. The aim of this study was to investigate (1) the relationship between childhood adversity and recurring PEs in adolescence and (2) candidate mediators of that relationship.

METHODS

We used data from Cohort '98 of the Growing Up in Ireland study (n = 6039) at three time points (ages 9, 13 and 17) to investigate the relationship between childhood adversity (parent-reported at age 9), recurring PEs (measured using a subset of the Adolescent Psychotic-like Symptoms Screener at ages 13 and 17). The mediating roles of parent-child relationship, internalising and externalising difficulties, self-concept, physical activity, dietary quality, perceived neighbourhood safety and friendship quantity were investigated using the KHB path decomposition method.

RESULTS

Childhood adversity was associated with an increased risk of recurring PEs with a population attributable fraction of 23%. Internalising difficulties and self-concept explained 13% of the relationship between childhood adversity and PEs suggesting a partial mediation. A significant direct effect remained between childhood adversity and recurring PEs.

CONCLUSIONS

The established relationship between childhood adversity and PEs may be mainly driven by the relationship between childhood adversity and recurring PEs. Internalising difficulties and self-concept together mediate part of the relationship between childhood adversity and recurring PEs.

Prediction of ADHD symptoms from prenatal data in two large population-based cohorts

Introduction

The association between low birth weight and attention problems in childhood has been replicated many times (e.g. Momany, Kamradt, & Nikolas, 2018). However birth weight is unlikely the aetiological start-point of this association, as birth weight is itself the product of many prenatal factors e.g. gestational complications, maternal toxin exposure during pregnancy and basic demographics.

Objectives

We explore (1) which prenatal factors best predict attention problems in two independant population-based cohorts of children (2) which associations, if any, are moderated by sex and (3) we report accuracy statistics of our prenatal prediction algorithm for attention problems.

Methods

Participants were children aged 9 from ABCD study from the United States (N > 9,000) and the Growing Up in Ireland (GUI) study from Ireland (N > 6,000). Selected variables included familial pscyhiatric history, maternal smoking during gestation, prescription and non-prescription drug-use during gestation and a variety of gestational complications. All interactions with sex were also included. We used 5-fold cross-validation and elastic net regression (glmnet) to identify the optimal predictors of attention problems (measured by CBCL and SDQ).

Results

Strongest predictors of attention problems in the U.S. cohort included male sex, number of drugs used during pregnancy, number of family members with a history of mental illness, and number of gestational complications. Sex interacted with several of these risks. Protective factors included being a twin/triplet, being Asian, having higher household income and higher parental education level.

Conclusions

Several risk factors for childhood attention problems were identified across both cohorts, supporting their generalizabilty. Other findings were cohort-specific.

Disclosure

No significant relationships.

The association between transient childhood psychotic experiences and psychosocial outcomes in young adulthood: examining the role of mental disorder and attachment

Introduction

Psychotic experiences (PE) occur most often in childhood, at the same age many mental disorders (MD) develop. There is growing evidence that those who report PE and MD show poorer health outcomes. If this occurs in psychosocial outcomes e.g. self-esteem, stress, mental distress, or social support, is under examined. Attachment anxiety and avoidance are the dimensions of attachment, which is hypothesized to develop in infancy as a mechanism for interpersonal relationships in times of need.

Objectives

To examine the role of transient childhood PE in adult psychosocial outcomes, in those with and without MD. Additionally, to examine if the dimensions of attachment attenuate this model.

Methods

One hundred and three participants attended baseline (age 11 – 13) and 10-year follow-up. PE and MD were collected using the Schedule for Affective Disorders and Schizophrenia for School-aged Children, Present & Lifetime Version. Attachment and outcomes were collected using self-report measures. Analysis compared those with PE, MD and PE and MD, to healthy controls.

Results

PE in childhood was associated with lower self-esteem and lower perceived social support from friends. Lower self-esteem in adulthood was more pronounced in those reporting PE and MD, and was additionally associated with stress in relationships, daily life, and mental distress. Childhood MD without PE was not significantly associated with any psychosocial outcomes. Attachment dimensions significantly attenuated the relationship between PE and self-esteem.

Conclusions

This paper illustrates the significant association of childhood PE on adult outcomes, independent of the effect of co-occurring MD, and demonstrate attachment dimensions role in this model.

Disclosure

No significant relationships.

Student mental health and well-being: Overview and Future Directions

The mental health of third-level students is of major societal concern with the gap between the demand for services and supports offered at crisis level. In Ireland, similar to elsewhere, colleges have responded to this need in vastly differing ways, with student counselling services available to all institutions, and student health departments and sessional psychiatry in some of the larger institutions, with none operating as a single multidisciplinary service. There is an increasing recognition for a more systematised approach, with the establishment of International Networks, Charters and Frameworks. These advocate for a whole institutional approach to student mental health, in addition to the development of an integrated system of supports with effective pathways to appropriate care. This paper, by members of the Youth and Student Special Interest Group of the College of Psychiatrists of Ireland, contextualises student mental health currently and describes future directions for this emerging field. It is a call to action to develop a structure that supports the needs of students with mental health problems across the full range of the spectrum from mild to severe.

Prenatal tobacco exposure and psychiatric outcomes in adolescence: is the effect mediated through birth weight?

OBJECTIVE

This study aims to examine the associations between prenatal exposure to maternal smoking, birth weight and persistent offspring psychiatric symptoms. Additionally, we aim to examine whether the relationship between prenatal maternal smoking and persistent offspring psychiatric symptoms is mediated by offspring birth weight.

METHODS

This study used the Growing Up in Ireland (GUI) longitudinal cohort. The GUI is a nationally representative longitudinal study of children which consisted of three data collection waves, at ages 9, 13, and 17 years. Logistic regression analysis was used to examine associations between prenatal tobacco exposure, and offspring psychiatric symptoms. Linear regression was used to examine associations between prenatal tobacco exposure and offspring birth weight. We conducted a mediation analysis examining potential etiological pathways linking maternal smoking during pregnancy, offspring birth weight, and later offspring psychiatric symptoms. All analyses were adjusted for confounders including household income, maternal level of education, and family psychiatric history. Additionally, examination of birth weight and subsequent psychiatric symptoms also was controlled for prematurity.

RESULTS

We found that the association between prenatal tobacco exposure and later psychiatric symptoms is mediated by birth weight.

CONCLUSIONS

This work provides further evidence that maternal smoking during pregnancy is an important modifiable lifestyle factor that has an impact not just on the physical health of offspring but also their mental wellbeing. Supporting women with structured smoking cessation programs at the earliest stages of pregnancy should be a public health priority.

The association between subjective maternal stress during pregnancy and offspring clinically diagnosed psychiatric disorders

OBJECTIVE

Exposure to prenatal stress is a ubiquitous and non-specific risk factor for adverse outcomes in adulthood. In this study, we examined associations between exposure to subjective maternal stress during pregnancy and subsequent diagnosis of psychiatric disorders in offspring.

METHOD

This study used the Helsinki Longitudinal Temperament Cohort, a prospective birth cohort of individuals born between 1 July 1975 and 30 June 1976 in Helsinki, Finland. The sample for this study comprised 3626 infants whose mothers had completed health and well-being assessments during pregnancy which included a measure of self-reported stress. We ran logistic regressions to assess potential associations between prenatal stress and offspring psychiatric disorder in adulthood, identified through the Finnish Hospital Discharge Register.

RESULTS

Individuals whose mothers reported stress during pregnancy had significantly greater odds of developing a psychiatric disorder (OR = 1.41, 95% CI = 1.10-1.81) particularly a mood disorder (OR = 1.67, 95% CI = 1.10-2.54). These associations remained after adjusting for parental psychiatric history, and other prenatal factors.

CONCLUSIONS

Individuals exposed to prenatal stress had significantly increased risk of developing psychiatric disorders later in life. This finding highlights the importance of supporting the mental health and emotional well-being of women during pregnancy.

Childhood psychotic experiences are associated with poorer global functioning throughout adolescence and into early adulthood

BACKGROUND

Psychotic experiences (PEs) are common in childhood and have been associated with concurrent mental disorder and poorer global functioning. Little is known about the effects of childhood PEs on future functioning. We investigated the effects of childhood PEs on global functioning from childhood into early adulthood.

METHOD

Fifty-six participants from a community sample completed all three waves of the Adolescent Brain Development study (T1x¯ Age: 11.69, T2x¯ Age: 15.80 T3x¯Age: 18.80). At each phase, participants completed a clinical interview assessing for PEs, mental disorder and global function. Repeated measures models, adjusted for mental disorder and gender, were used to compare current (C-GAF) and most severe past (MSP-GAF) functioning in participants who had reported PEs in childhood and controls.

RESULTS

Participants with a history of PEs had significantly poorer C-GAF (P < 0.001) and MSP-GAF scores (P < 0.001). Poorer functioning was evident in childhood (C-GAF: P = 0.001; MSP-GAF: P < 0.001), adolescence (C-GAF: P < 0.001; MSP-GAF: P = 0.004) and early adulthood (C-GAF: P = 0.001; MSP-GAF: P = 0.076).

DISCUSSION

Children who report PEs have persistently poorer functioning through to early adulthood. The longitudinal association between childhood PEs and global functioning highlights the underlying global vulnerability in children reporting PEs, beyond what can be explained by mental disorder.

Identification of a plasma signature of psychotic disorder in children and adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort

The identification of an early biomarker of psychotic disorder is important as early treatment is associated with improved patient outcome. Metabolomic and lipidomic approaches in combination with multivariate statistical analysis were applied to identify plasma alterations in children (age 11) (38 cases vs 67 controls) and adolescents (age 18) (36 cases vs 117 controls) preceeding or coincident with the development of psychotic disorder (PD) at age 18 in the Avon Longitudinal Study of Parents and Children (ALSPAC). Overall, 179 lipids were identified at age 11, with 32 found to be significantly altered between the control and PD groups. Following correction for multiple comparisons, 8 of these lipids remained significant (lysophosphatidlycholines (LPCs) LPC(18:1), LPC(18:2), LPC(20:3); phosphatidlycholines (PCs) PC(32:2; PC(34:2), PC(36:4), PC(0-34-3) and sphingomyelin (SM) SM(d18:1/24:0)), all of which were elevated in the PD group. At age 18, 23 lipids were significantly different between the control and PD groups, although none remained significant following correction for multiple comparisons. In conclusion, the findings indicate that the lipidome is altered in the blood during childhood, long before the development of psychotic disorder. LPCs in particular are elevated in those who develop PD, indicating inflammatory abnormalities and altered phospholipid metabolism. These findings were not found at age 18, suggesting there may be ongoing alterations in the pathophysiological processes from prodrome to onset of PD.

Long-term follow-up of patients with spontaneous clearance of hepatitis C: does viral clearance mean cure?

Up to 40% of patients with hepatitis C virus (HCV) antibodies are negative for HCV RNA at initial evaluation. If there is a risk of viral re-activation, long term follow-up is required with attendant financial, psychological and medical implications. We investigated the risk of re-activation in the Irish anti-D cohort. Information was obtained from the national hepatitis C database which includes data on patients infected by anti-D immunoglobulin in two large outbreaks, 1977-9 and 1991-94. As part of a screening programme, starting in 1994, 64,907 females exposed to anti-D immunoglobulin were evaluated. Three hundred and forty-seven were found to be antibody positive but HCV RNA negative at initial assessment. 93% had subsequent RNA tests. There was no evidence of HCV recurrence in patients whose infection resolved spontaneously. It appears that two initial sequential negative results for HCV RNA are sufficient to confirm spontaneous viral clearance and probable cure of hepatitis C virus infection.

Effectiveness of interferon-free therapy for the treatment of HCV-patients with compensated cirrhosis treated through the Irish early access program

BACKGROUND

We investigated the real-world effectiveness of interferon-free regimens for the treatment of patients with compensated cirrhosis infected with hepatitis C virus (HCV).

METHOD

Using the Irish national HCV treatment registry, the effectiveness and safety of interferon-free regimens for HCV-infected patients treated between April 2015 and August 2016, was determined.

RESULTS

A SVR12 was achieved in 86% of subjects treated with sofosbuvir/ledipasvir ± ribavirin (SOF/LDV±RBV), 93% treated with paritaprevir, ombitasvir and ritonavir combined with dasabuvir ± ribavirin (3D±RBV) and 89% treated with sofosbuvir/daclatasvir ± ribavirin (SOF/DCV±RBV). The discontinuation rate was 5% and the on-treatment mortality rate was 1%.

CONCLUSION

The availability of interferon-free regimens represents a significant breakthrough for the treatment of HCV infection. Treatments options, with high SVR12 rates, are now available for patients with compensated cirrhosis who were unsuitable for treatment with interferon-based regimens. Data obtained from studies conducted in real world practice provide robust information fundamental for input into future economic evaluations for agents used for the treatment of HCV infection.

Enhanced hydrogen adsorption on graphene by manganese and manganese vanadium alloy decoration

In this work, two kinds of novel manganese decorated (G + Mn) and manganese-vanadium co-decorated (G + MnV) graphene composites are synthesized by in situ wet chemical reduction, and their hydrogen storage properties and microstructures are characterized by Sievert-type adsorption apparatus, BET, SEM, TEM/STEM, EDX and EELS. Compared with pristine graphene, Mn decoration marginally increases the hydrogen adsorption capacity of graphene at room temperature and 4 MPa hydrogen pressure from 0.25 wt% to 0.36 wt%. On the other hand, the co-decoration of Mn and V increases the room temperature hydrogen storage capacity of graphene significantly to 1.81 wt% under 4 MPa hydrogen pressure, which is 1.56 wt% higher than the capacity of pristine graphene. The microstructures and valence states of the decorated Mn and Mn-V nanoparticles are investigated by TEM, EDX and EELS analyses, and strong interactions between the decorated nanoparticles and graphene are observed. Based on the results from structural analyses, potential enhancement mechanisms are suggested in terms of the catalytic effects of nanoparticles on graphene hydrogen adsorption. Given the relatively low cost of Mn and V metals compared to noble metals such as Pd, Pt and Au, these results demonstrate a low cost and effective way to significantly enhance the room temperature hydrogen adsorption properties of graphene for potential hydrogen storage applications.

Analysis of anticaries potential of pit and fissures sealants containing amorphous calcium phosphate using synchrotron microtomography

The aim of this study was to analyze the anticaries potential of pit and fissure sealants containing amorphous calcium phosphate (ACP) by synchrotron microtomography. Bovine enamel blocks (4×4 mm; n=50) were selected through surface hardness (Knoop) analysis. Slabs were obtained through cross-sections taken 1 mm from the border of the enamel. Five indentations, spaced 100 μm apart, were made 300 μm from the border. Ten specimens were prepared for each tested material (Ultraseal XT plus TM, Aegis, Embrace, Vitremer and Experimental Sealant). The materials were randomly attached to the sectioned surfaces of the enamel blocks and fixed with sticky wax. The specimens were submitted to pH cycling. After that, the surface hardness (SH1) was determined, and the blocks were submitted to synchrotron microcomputed tomography analysis to calculate the mineral concentration (ΔgHAp cm(-3)) at different areas of the enamel. The comparison between the SH1 and ΔgHAp cm(-3) showed a correlation for all groups (r=0.840; p<0.001). The fluoride groups presented positive values of ΔgHAp cm(-3), indicating a mineral gain that was observed mainly in the outer part of the enamel. The ACP showed mineral loss in the outer enamel compared with fluoride groups, although it inhibited the demineralization in the deeper areas of enamel. The combination of two remineralizing agents (fluoride and ACP) was highly effective in preventing demineralization.

Common versus psychopathology-specific risk factors for psychotic experiences and depression during adolescence

BACKGROUND

An argument often used to support the view that psychotic experiences (PEs) in general population samples are a valid phenotype for studying the aetiology of schizophrenia is that risk factors for schizophrenia show similar patterns of association with PEs. However, PEs often co-occur with depression, and no study has explicitly tested whether risk factors for schizophrenia are shared between PEs and depression, or are psychopathology specific, while jointly modelling both outcomes.

METHOD

We used data from 7030 subjects from a birth cohort study. Depression and PEs at age 18 years were assessed using self-report questionnaires and semi-structured interviews. We compared the extent to which risk factors for schizophrenia across sociodemographic, familial, neurodevelopmental, stress-adversity, emotional-behavioural and substance use domains showed different associations with PEs and depression within bivariate models that allowed for their correlation.

RESULTS

Most of the exposures examined were associated, to a similar degree, with an increased risk of both outcomes. However, whereas female sex and family history of depression showed some discrimination as potential risk factors for depression and PEs, with stronger associations in the former, markers of abnormal neurodevelopment showed stronger associations with PEs.

CONCLUSIONS

The argument that PEs are valid markers for studying the aetiology of schizophrenia, made simply on the basis that they share risk factors in common, is not well supported. PEs seem to be a weak index of genetic and environmental risk for schizophrenia; however, studies disentangling aetiological pathways to PEs from those impacting upon co-morbid psychopathology might provide important insights into the aetiology of psychotic disorders.

Psychotic experiences in a mental health clinic sample: implications for suicidality, multimorbidity and functioning

BACKGROUND

Recent community-based research has suggested that psychotic experiences act as markers of severity of psychopathology. There has, however, been a lack of clinic-based research. We wished to investigate, in a clinical sample of adolescents referred to a state-funded mental health service, the prevalence of (attenuated or frank) psychotic experiences and the relationship with (i) affective, anxiety and behavioural disorders, (ii) multimorbid psychopathology, (iii) global functioning, and (iv) suicidal behaviour.

METHOD

The investigation was a clinical case-clinical control study using semi-structured research diagnostic psychiatric assessments in 108 patients newly referred to state adolescent mental health services.

RESULTS

Psychotic experiences were prevalent in a wide range of (non-psychotic) disorders but were strong markers of risk in particular for multimorbid psychopathology (Z = 3.44, p = 0.001). Young people with psychopathology who reported psychotic experiences demonstrated significantly poorer socio-occupational functioning than young people with psychopathology who did not report psychotic experiences, which was not explained by multimorbidity. Psychotic experiences were strong markers of risk for suicidal behaviour. Stratified analyses showed that there was a greatly increased odds of suicide attempts in patients with a major depressive disorder [odds ratio (OR) 8.89, 95% confidence interval (CI) 1.59-49.83], anxiety disorder (OR 15.4, 95% CI 1.85-127.94) or behavioural disorder (OR 3.13, 95% CI 1.11-8.79) who also had psychotic experiences compared with patients who did not report psychotic experiences.

CONCLUSIONS

Psychotic experiences (attenuated or frank) are an important but under-recognized marker of risk for severe psychopathology, including multimorbidity, poor functioning and suicidal behaviour in young people who present to mental health services.

Resting-state connectivity deficits associated with impaired inhibitory control in non-treatment-seeking adolescents with psychotic symptoms

OBJECTIVE

Psychotic symptoms are common in the population and index risk for a range of severe psychopathological outcomes. We wished to investigate functional connectivity in a community sample of adolescents who reported psychotic symptoms (the extended psychosis phenotype).

METHOD

This study investigated intrinsic functional connectivity (iFC) during resting-state functional magnetic resonance imaging (fMRI; rs-fMRI). Following screening in schools, 11 non-treatment seeking, youth with psychotic symptoms (aged 11-13) and 14 community controls participated in the study. Seed regions of interest comprised brain regions previously shown to exhibit aberrant activation during inhibitory control in adolescents with psychotic symptoms.

RESULTS

Relative to controls, adolescents with psychotic symptoms exhibited reduced iFC between regions supporting inhibitory control. Specifically, they showed weaker iFC between the right inferior frontal gyrus (IFG) and the cingulate, IFG and the striatum, anterior cingulate and claustrum, and precuneus and supramarginal gyrus. Conversely, the psychotic symptoms group exhibited stronger iFC between the superior frontal gyrus and claustrum and IFG and lingual gyrus.

CONCLUSION

The present findings are the first to reveal aberrant functional connectivity in resting-state networks in a community sample of adolescents with psychotic symptoms and suggest that disruption in integration between distributed neural networks (particularly between prefrontal, cingulate and striatal brain regions) may be a key neurobiological feature of the extended psychosis phenotype.

Facial emotion recognition in adolescents with psychotic-like experiences: a school-based sample from the general population

BACKGROUND

Psychotic symptoms, also termed psychotic-like experiences (PLEs) in the absence of psychotic disorder, are common in adolescents and are associated with increased risk of schizophrenia-spectrum illness in adulthood. At the same time, schizophrenia is associated with deficits in social cognition, with deficits particularly documented in facial emotion recognition (FER). However, little is known about the relationship between PLEs and FER abilities, with only one previous prospective study examining the association between these abilities in childhood and reported PLEs in adolescence. The current study was a cross-sectional investigation of the association between PLEs and FER in a sample of Irish adolescents.

METHOD

The Adolescent Psychotic-Like Symptom Screener (APSS), a self-report measure of PLEs, and the Penn Emotion Recognition-40 Test (Penn ER-40), a measure of facial emotion recognition, were completed by 793 children aged 10-13 years.

RESULTS

Children who reported PLEs performed significantly more poorly on FER (β=-0.03, p=0.035). Recognition of sad faces was the major driver of effects, with children performing particularly poorly when identifying this expression (β=-0.08, p=0.032).

CONCLUSIONS

The current findings show that PLEs are associated with poorer FER. Further work is needed to elucidate causal relationships with implications for the design of future interventions for those at risk of developing psychosis.

Prevalence of psychotic symptoms in childhood and adolescence: a systematic review and meta-analysis of population-based studies

BACKGROUND

Psychotic symptoms occur more frequently in the general population than psychotic disorder and index risk for psychopathology. Multiple studies have reported on the prevalence of these symptoms using self-report questionnaires or clinical interviews but there is a lack of consensus about the prevalence of psychotic symptoms among children and adolescents.

METHOD

We conducted a systematic review of all published literature on psychotic symptom prevalence in two age groups, children aged 9-12 years and adolescents aged 13-18 years, searching through electronic databases PubMed, Ovid Medline, PsycINFO and EMBASE up to June 2011, and extracted prevalence rates.

RESULTS

We identified 19 population studies that reported on psychotic symptom prevalence among children and adolescents. The median prevalence of psychotic symptoms was 17% among children aged 9-12 years and 7.5% among adolescents aged 13-18 years.

CONCLUSIONS

Psychotic symptoms are relatively common in young people, especially in childhood. Prevalence is higher in younger (9-12 years) compared to older (13-18 years) children.

Psychotic-like experiences in the general population: characterizing a high-risk group for psychosis

Recent research shows that psychotic symptoms, or psychotic-like experiences (PLEs), are reported not only by psychosis patients but also by healthy members of the general population. Healthy individuals who report these symptoms are considered to represent a non-clinical psychosis phenotype, and have been demonstrated to be at increased risk of schizophrenia-spectrum disorder. Converging research now shows that this non-clinical psychosis phenotype is familial, heritable and covaries with familial schizophrenia-spectrum disorder. A review of the research also shows that the non-clinical phenotype is associated extensively with schizophrenia-related risk factors, including social, environmental, substance use, obstetric, developmental, anatomical, motor, cognitive, linguistic, intellectual and psychopathological risk factors. The criterion and construct validity of the non-clinical psychosis phenotype with schizophrenia demonstrates that it is a valid population in which to study the aetiology of psychosis. Furthermore, it suggests shared genetic variation between the clinical and non-clinical phenotypes. Much remains to be learned about psychosis by broadening the scope of research to include the non-clinical psychosis phenotype.

Cannabis use and childhood trauma interact additively to increase the risk of psychotic symptoms in adolescence

BACKGROUND

Adolescent cannabis use has been shown in many studies to increase the risk of later psychosis. Childhood trauma is associated with both substance misuse and risk for psychosis. In this study our aim was to investigate whether there is a significant interaction between cannabis use and childhood trauma in increasing the risk for experiencing psychotic symptoms during adolescence.

METHOD

Psychiatric interviews using the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS) semi-structured instrument were carried out with 211 adolescents aged between 12 and 15 years and their parents as part of a population-based study. The interview enquired about early traumatic events, cannabis use and psychiatric symptoms in adolescence.

RESULTS

In separate analyses both cannabis use and childhood trauma were significantly associated with risk of experiencing psychotic symptoms. However, the presence of both childhood trauma and early cannabis use significantly increased the risk for psychotic symptoms beyond the risk posed by either risk factor alone, indicating that there was a greater than additive interaction between childhood trauma and cannabis use.

CONCLUSION

Our finding of a greater than additive interaction between childhood trauma and cannabis use may have implications for the identification of individuals at high risk of experiencing psychotic symptoms. For example, measures to actively discourage or intensively treat cannabis use in children and adolescents who have experienced abuse may help to prevent the development of psychosis in this vulnerable group. Our findings require replication in larger samples to confirm this interaction effect.

Lifetimes of heavy-Rydberg ion-pair states formed through Rydberg electron transfer

The lifetimes of K(+)..Cl(-), K(+)..CN(-), and K(+)..SF(6)(-) heavy-Rydberg ion-pair states produced through Rydberg electron transfer reactions are measured directly as a function of binding energy using electric field induced detachment and the ion-pair decay channels discussed. The data are interpreted using a Monte Carlo collision code that models the detailed kinematics of electron transfer reactions. The lifetimes of K(+)..Cl(-) ion-pair states are observed to be very long, >100 micros, and independent of binding energy. The lifetimes of strongly bound (>30 meV) K(+)..CN(-) ion pairs are found to be similarly long but begin to decrease markedly as the binding energy is reduced below this value. This behavior is attributed to conversion of rotational energy in the CN(-) ion into translational energy of the ion pair. No long-lived K(+)..SF(6)(-) ion pairs are observed, their lifetimes decreasing with increasing binding energy. This behavior suggests that ion-pair loss is associated with mutual neutralization as a result of charge transfer.

Temperature dependence of reactions involving electron transfer in K(np)/C2Cl4 collisions

Electron transfer in K(np)-C(2)Cl(4) collisions, which leads to formation of both Cl(-) and C(2)Cl(4)(-) anions, is investigated as a function of target temperature over the range of 300-650 K. Measurements at high n (n approximately 30) show that the likelihood of Cl(-) production increases rapidly with temperature indicating the presence of a dissociation barrier. The data yield an activation energy of approximately 0.1 eV. A broad distribution of product C(2)Cl(4)(-) lifetimes is observed that extends from microseconds to milliseconds, this distribution moving toward shorter lifetimes as the target temperature is increased. The measured lifetimes are consistent with the predictions of quasiequilibrium theory. Studies at low n (n approximately 14) show a substantial fraction of the product K(+)-Cl(-) and K(+)-C(2)Cl(4)(-) ion pairs is electrostatically bound leading to creation of heavy-Rydberg ion-pair states. Variations in target temperature lead to changes in kinetic energy of relative motion of the reactants that can result in marked changes in the fraction of ion pairs that is bound, especially at low Rydberg atom velocities. In the case of bound K(+)-C(2)Cl(4)(-) ion pairs a few percent subsequently dissociate by the conversion of internal energy in the anion into translational energy of the ion pair. Analysis of the data points to a mean energy conversion of approximately 60-90 meV, much less than the available excess energy of reaction, approximately 0.7 eV.

Formation of heavy-Rydberg ion-pair states in collisions of K(np) Rydberg atoms with attaching targets

The formation of heavy-Rydberg ion-pair states through electron transfer in collisions between K(np) Rydberg atoms and molecules that attach low-energy electrons is investigated. The measurements show that low-n collisions with a wide variety of target species (SF(6), c-C(7)F(14), C(6)F(6), and CCl(4)) can lead to formation of bound ion-pair states and that, under appropriate conditions, a small fraction of these can subsequently dissociate as free ions through internal-to-translational energy transfer. Analysis of the data suggests that those ion pairs that do dissociate typically have lifetimes of approximately 1 micros, although some can have lifetimes of 5 micros or longer.

Dipole-bound CH3CN- ions: temperature dependence of ion production rates and lifetimes

The formation of long-lived (tau less, similar10 mus) dipole-bound CH(3)CN(-) ions through electron transfer in K(14p)CH(3)CN collisions is investigated as a function of target temperature. The rate for their formation is observed to decrease steadily with increasing target temperature. The results are consistent with earlier suggestions that only target molecules in the ground vibrational state and low-lying rotational states can form long-lived dipole-bound anions. For CH(3)CN, the data indicate that creation of long-lived ions requires that the target molecules be in states with rotational quantum numbers j less, similar20. The measurements further demonstrate that the lifetime of the longest-lived (tau greater, similar50 mus) ions is limited by blackbody-radiation-induced photodetachment.

Selecting a restoration technique to minimize OCR error

This paper introduces a learning problem related to the task of converting printed documents to ASCII text files. The goal of the learning procedure is to produce a function that maps documents to restoration techniques in such a way that on average the restored documents have minimum optical character recognition error. We derive a general form for the optimal function and use it to motivate the development of a nonparametric method based on nearest neighbors. We also develop a direct method of solution based on empirical error minimization for which we prove a finite sample bound on estimation error that is independent of distribution. We show that this empirical error minimization problem is an extension of the empirical optimization problem for traditional M-class classification with general loss function and prove computational hardness for this problem. We then derive a simple iterative algorithm called generalized multiclass ratchet (GMR) and prove that it produces an optimal function asymptotically (with probability 1). To obtain the GMR algorithm we introduce a new data map that extends Kesler's construction for the multiclass problem and then apply an algorithm called Ratchet to this mapped data, where Ratchet is a modification of the Pocket algorithm . Finally, we apply these methods to a collection of documents and report on the experimental results.

Effect of leg exercises on popliteal venous blood flow during prolonged immobility of seated subjects: implications for prevention of travel-related deep vein thrombosis

BACKGROUND

Venous stasis is an important contributing factor in the development of travel-related deep vein thrombosis. This study examined factors affecting popliteal venous blood flow in order to determine the most effective exercise regimen to prevent venous stasis.

METHODS

Twenty-one healthy subjects were randomly assigned to various activities over a 9-week period. Subjects remained seated throughout the investigation and 3660 duplex ultrasound examinations were performed by a single examiner using a SonoSite 180 Plus handheld ultrasound. Baseline popliteal vein blood flow velocity, cross-sectional area and volume flow in subjects sitting motionless were assessed in the first 3 weeks.The remaining 6 weeks involved subjects performing airline-recommended activities, foot exercises, foot exercises against moderate resistance and foot exercises against increased resistance in order to determine the most beneficial method for enhancing popliteal venous flow. Sitting with feet not touching the floor and the effect of sleeping were also assessed.

RESULTS

The median age of the subjects was 22 years (range: 18-25.5 years), height 171 cm (162.5-180.5 cm) and body mass index 25.3 kg m(-2) (23.2-26.3 kg m(-2)). Blood volume flow in the popliteal vein was reduced by almost 40% with immobility of seated subjects and by almost 2-fold when sitting motionless with feet not touching the floor. Foot exercises against increased resistance positively enhanced volume flow (P < 0.0001).

CONCLUSION

Leg exercise regimens enhanced popliteal venous flow during prolonged immobility of seated subjects, reinforcing the importance of regular leg movement to prevent venous stasis during prolonged sitting, such as in long-distance travel.

Temperature dependence of negative ion lifetimes

The autodetachment lifetimes of SF6-* and C6F6-* ions formed by charge transfer in K(np)/SF6, C6F6 collisions are measured as a function of target temperature over the range of approximately 300-600 K with the aid of time-of-flight techniques and a Penning ion trap. At room temperature only formation of long-lived SF6 -* ions with lifetimes tau >or similar to 1 ms is seen. As the temperature is increased the lifetime of these long-lived ions is reduced, some having lifetimes as short as approximately 0.4 ms. The appearance of a short-lived, tau <or similar to 10 micros, SF6-* signal is also observed. Rydberg electron transfer to room temperature C6F6 leads predominantly to formation of short-lived, tau <or similar to 10 micros, C6F6-* ions, although a small number of longer-lived anions with lifetimes of approximately 50-100 micros is also evident. This signal disappears as the temperature is raised and the lifetime of the short-lived ions decreases dramatically. The measured lifetimes are compared to those predicted using quasiequilibrium theory and updated values of the input parameters, including calculated vibrational frequencies for the anions. For C6F6, the calculated anion lifetimes are in good agreement with those measured experimentally. While similarly good agreement is obtained for SF6 at room temperature, the predicted temperature dependence of the lifetime is very different to that observed. This suggests that the excitation energy is not completely randomized in the anion and the measurements point to formation of at least two quasi-independent groups of anion states that have very different lifetimes. The present results are compared to those of earlier work.

The KSHV and other human herpesviral G protein-coupled receptors

Kaposi sarcoma-associated herpesvirus (KSHV) is a gamma2-herpesvirus discovered in 1994 and is the agent responsible for Kaposi sarcoma (KS), an endothelial cell malignancy responsible for significant morbidity and mortality worldwide. Over time, KSHV has pirated many human genes whose products regulate angiogenesis, inflammation, and the cell cycle. One of these encodes for a mutated G protein-coupled receptor (GPCR) that is a homologue of the human IL-8 receptor. GPCRs are the largest family of signaling molecules and respond to a wide array of ligands. Unlike its normal counterpart, the mutations present in KSHV vGPCR result in constitutive, ligand-independent signaling activity. Signaling by the KSHV vGPCR results in the elaboration of many mitogenic and angiogenic cytokines that are vital to the biology of KS and other KSHV-driven malignancies. Several other herpesviruses also encode GPCRs, the functions of which are under ongoing investigation. In addition, several human diseases are associated with mutated mammalian GPCRs in germline or somatic cells.

Locally advanced resectable larynx (L) or oropharynx (OP) cancer: Updated results of organ preservation trial ECOG 2399

5527

Background: Taxane-based concurrent chemoradiation (CCR) for head and neck cancers has proven feasible and has a favorable toxicity profile compared to concurrent cisplatin and radiation. This phase II multi-institutional trial evaluates taxane-based induction chemotherapy followed by CCR for organ preservation in resectable Stage III/IV L and OP patients. Methods: Eligibility: Resectable stage T2N+, or T3-T4N0–3M0 biopsy-proven squamous Ca, age ≥18, PS 0–2, good organ function, and no prior chemotherapy or radiation. Treatment: induction paclitaxel (P) 175 mg/m2 and carboplatin (C) AUC 6 for 2 cycles q21d followed by concurrent P 30 mg/m2 q7d with 70 Gy if no evidence of progression. Weekly epoetin alpha 40kU was used if Hgb ≤15 (male) or ≤14 (female). The primary endpoint is organ preservation (freedom from salvage surgery with preserved speech and swallowing). Results: 105/111 pts (69 OP, 36 larynx) were eligible. Median FU is 33 months. No grade 5 toxicities occurred. 94% received full dose RT and 91% received ≥5 cycles of concurrent paclitaxel. At one year post-treatment, 13 (12%) patients required salvage surgery at the primary site (7-L, 6-OP), and 6 pts (6%) progressed and died (3-L, 3-OP). 1 pt (1%) died without progression and 85 pts (81%) are alive without progression (25-L, 60-OP). 12 pts (10%) have developed distant mets (6-L, 6-OP). 1-yr and 2-yr PFS for all pts is 77% and 64%. 12/69 OP and 9/36 L pts have died of disease. 1-yr event-free survival (EFS = no salvage surgery, recurrence or death) is 72% (77%-OP, 64%-L), and 2-yr EFS is 57% (68%-OP, 34%-L) (p = 0.02). 1-yr OS is 93%, 2-yr OS is 74% (OP vs. L p = 0.11). Conclusions: This regimen is well tolerated and is feasible in a multi-institutional setting. EFS with this regimen is lower than expected in larynx patients. The benefit of induction chemotherapy in this setting remains unproven but does not preclude CCR delivery. Funded, in part, by Bristol-Myers Squibb.

[Table: see text]