Stanley Zammit

London School of Hygiene and Tropical Medicine, London, ENG, United Kingdom

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Publications (97)785.37 Total impact

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    ABSTRACT: To examine associations between specific parasomnias and psychotic experiences in childhood. Birth cohort study. Information on the presence of frequent nightmares in children was obtained prospectively from mothers during multiple assessments conducted when children were aged between 2.5 and 9 y. Children were interviewed at age 12 y about nightmares, night terrors, sleepwalking, and psychotic experiences (delusions, hallucinations, and thought interference) occurring in the previous 6 mo. Assessments were completed in participants' homes or a University clinic within the UK. There were 6,796 children (3,462 girls, 50.9%) who completed the psychotic experiences interview. Children who were reported by their mothers as experiencing frequent nightmares between 2.5 and 9 y of age were more likely to report psychotic experiences at age 12 y, regardless of sex, family adversity, emotional or behavioral problems, IQ and potential neurological problems (odds ratio (OR) = 1.16, [95% confidence intervals (CI) = 1.00, 1.35], P = 0.049). Children reporting any of the parasomnias at age 12 y also had higher rates of concurrent psychotic experiences than those without such sleeping problems, when adjusting for all confounders (OR = 3.62 [95% CI = 2.57, 5.11], P < 0.001). Difficulty getting to sleep and night waking were not found to be associated with psychotic experiences at age 12 y when controlling for confounders. Nightmares and night terrors, but not other sleeping problems, in childhood were associated with psychotic experiences at age 12 years. These findings tentatively suggest that arousal and rapid eye movement forms of sleep disorder might be early indicators of susceptibility to psychotic experiences. Fisher HL; Lereya ST; Thompson A; Lewis G; Zammit S; Wolke D. Childhood parasomnias and psychotic experiences at age 12 years in a United Kingdom birth cohort. SLEEP 2014;37(3):475-482.
    Sleep 01/2014; 37(3):475-82. · 5.10 Impact Factor
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    ABSTRACT: The Mood and Feelings Questionnaire (MFQ) is widely used for the assessment of depression in adolescents. The main aim of this study was to examine the concurrent and predictive validity of a composite of four MFQ items related to suicidal ideation using an interview measure of suicidal ideation. A prospective 3-wave high-risk study of offspring of parents with recurrent depression was used including 294 families where children were initially aged 9–17 years. Measures included four parent and child rated MFQ items assessing suicide-related ideation (referred to here as the “MFQ-SI”) and a clinically-defined interview measure of suicidal ideation. A parent-child combined MFQ-SI subscale performed well as a screening tool against the interview measure of suicidal ideation (baseline AUC (95% CI):0.92 (0.85–1.00)). Longitudinally, this measure showed reasonable predictive validity against future suicidal ideation (AUC (95% CI):0.73 (0.58–0.88)). Lastly, there was evidence that a child-rated MFQ-SI scale performed better than a parent-rated one in detecting concurrent suicidal ideation. Longitudinally, both parent and child scales showed reasonable predictive validity against future suicidal ideation. In summary, a brief screen using four MFQ items related to suicidal ideation performs well in identifying concurrent and future suicidal ideation in high-risk adolescents.
    Psychiatry Research. 01/2014;
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    ABSTRACT: Victims of bullying are at risk for psychotic experiences in early adolescence. It is unclear if this elevated risk extends into late adolescence. The aim of this study was to test whether bullying perpetration and victimization in elementary school predict psychotic experiences in late adolescence. Method The current study is based on the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective community-based study. A total of 4720 subjects with bullying perpetration and victimization were repeatedly assessed between the ages of 8 and 11 years by child and mother reports. Suspected or definite psychotic experiences were assessed with the Psychosis-Like Symptoms semi-structured interview at age 18 years. Controlling for child's gender, intelligence quotient at age 8 years, childhood behavioural and emotional problems, and also depression symptoms and psychotic experiences in early adolescence, victims [child report at 10 years: odds ratio (OR) 2.4, 95% confidence interval (CI) 1.6���3.4; mother report: OR 1.6, 95% CI 1.1���2.3], bully/victims (child report at 10 years: OR 3.1, 95% CI 1.7���5.8; mother: OR 2.9, 95% CI 1.7���5.0) and bullies (child report at 10 years: OR 4.9, 95% CI 1.3���17.7; mother: OR 1.2, 95% CI 0.46���3.1, n.s.) had a higher prevalence of psychotic experiences at age 18 years. Path analysis revealed that the association between peer victimization in childhood and psychotic experiences at age 18 years was only partially mediated by psychotic or depression symptoms in early adolescence. Involvement in bullying, whether as victim, bully/victim or bully, may increase the risk of developing psychotic experiences in adolescence. Health professionals should ask routinely during consultations with children about their bullying of and by peers.
    Psychological Medicine 12/2013; · 5.59 Impact Factor
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    ABSTRACT: Psychotic experiences are not uncommon in general population samples, but no studies have examined to what extent confirmed risk variants for schizophrenia are associated with such experiences. A total of 3483 children in a birth cohort study participated in semistructured interviews for psychotic experiences at ages 12 and 18. We examined whether (1) a composite measure of risk for schizophrenia conferred by common alleles (polygenic score) was associated with psychotic experiences, (2) variants with genome-wide evidence for association with schizophrenia were associated with psychotic experiences, and (3) we could identify genetic variants for psychotic experiences using a genome-wide association (GWA) approach. We found no evidence that a schizophrenia polygenic score, or variants showing genome-wide evidence of association with schizophrenia, were associated with adolescent psychotic experiences within the general population. In fact, individuals who had a higher number of risk alleles for genome-wide hits for schizophrenia showed a decreased risk of psychotic experiences. In the GWA study, no variants showed GWA for psychotic experiences, and there was no evidence that the strongest hits (P < 5 × 10(-5)) were enriched for variants associated with schizophrenia in large consortia. Although polygenic scores are weak tools for prediction of schizophrenia, they show strong evidence of association with this disorder. Our findings, however, lend little support to the hypothesis that psychotic experiences in population-based samples of adolescents share a comparable genetic architecture to schizophrenia, or that utilizing a broader and more common phenotype of psychotic experiences will be an efficient approach to increase understanding of the genetic etiology of schizophrenia.
    Schizophrenia Bulletin 10/2013; · 8.80 Impact Factor
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    ABSTRACT: Children with 22q11.2 deletion syndrome (22q11.2DS) have been reported to have high rates of cognitive and psychiatric problems. To establish the nature and prevalence of psychiatric disorder and neurocognitive impairment in children with 22q11.2DS and test whether risk of psychopathology is mediated by the children's intellectual impairment. Neurocognition and psychopathology were assessed in 80 children with 22q11.2DS (mean age 10.2 years, s.d. = 2.1) and 39 sibling controls (mean age 10.9 years, s.d. = 2.0). More than half (54%) of children with 22q11.2DS met diagnostic criteria for one or more DSM-IV-TR psychiatric disorder. These children had lower IQ (mean 76.8, s.d. = 13.0) than controls (mean 108.6, s.d. = 15.2) (P<0.001) and showed a range of neurocognitive impairments. Increased risk of psychopathology was not mediated by intellectual impairment. 22q11.2DS is not related to a specific psychiatric phenotype in children. Moreover, the deletion has largely independent effects on IQ and risk of psychopathology, indicating that psychopathology in 22q11.2DS is not a non-specific consequence of generalised cognitive impairment.
    The British journal of psychiatry: the journal of mental science 10/2013; · 6.62 Impact Factor
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    ABSTRACT: The risk of childhood behavioural and psychiatric diseases could be substantially reduced if modifiable risk factors for these disorders were identified. The critical period for many of these exposures is likely to be in utero as this is the time when brain development is most rapid. However, due to confounding and other limitations of traditional epidemiological studies, identification of causal risk factors has proved challenging and on the whole research in this area has not been fruitful. In this review, we highlight several alternative approaches including; comparisons across settings, the use of negative controls and natural experiments, which includes migration studies, studies of individuals conceived using in vitro fertilisation and not least Mendelian randomisation. We have illustrated these approaches using examples of behavioural and psychiatric disorders. By having these approaches outlined together in one review, researchers can consider which of these methods would be most suitable for their study question. We have particularly focussed on Mendelian randomisation, as this is a relatively novel concept, in doing so, we have illustrated the concept and discused the implementation and the limitations of this approach.
    Journal of Child Psychology and Psychiatry 10/2013; 54(10):1095-108. · 5.42 Impact Factor
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    ABSTRACT: Psychotic symptoms are common in adolescents in the general population but it is unknown whether they are associated with poor social functioning. To investigate whether adolescent psychotic symptoms are associated with poor social functioning measured by peer relationships. Data from the Avon Longitudinal Study of Parents and Children cohort was used. Logistic regression was used to explore the relationship between psychotic symptoms at 12.9years detected using a semi-structured interview and poor social functioning at 13.2years using parent-reported peer problems from the Strengths and Difficulties Questionnaire. There was strong evidence (p<0.001) of an unadjusted association between psychotic symptoms and poor social functioning (OR 1.41, 95% CI 1.24-1.61). The association was attenuated after adjusting for earlier social functioning, socio-demographic variables, bullying status and IQ (OR 1.28, 95% CI 1.09-1.50). The majority of the crude association was explained by additional adjustment for emotional problems including depression at age 12, emotional symptoms, hyperactivity and conduct problems at age 11 (OR 1.07, 95% CI 0.89-1.29). Adolescents with psychotic symptoms may be no more likely to have poor social functioning than other adolescents, once other emotional problems have been taken into account. The discussion addressed two explanations. First, emotional problems may be on the causal pathway from psychotic symptoms to poor social functioning. Alternatively, emotional symptoms may act as a confounder, suggesting that medical intervention may be inappropriate. It is the impact of psychotic symptoms on the individual that should dictate whether any intervention is required.
    Schizophrenia Research 09/2013; · 4.59 Impact Factor
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    ABSTRACT: Most psychiatric disorders are moderately to highly heritable. The degree to which genetic variation is unique to individual disorders or shared across disorders is unclear. To examine shared genetic etiology, we use genome-wide genotype data from the Psychiatric Genomics Consortium (PGC) for cases and controls in schizophrenia, bipolar disorder, major depressive disorder, autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD). We apply univariate and bivariate methods for the estimation of genetic variation within and covariation between disorders. SNPs explained 17–29% of the variance in liability. The genetic correlation calculated using common SNPs was high between schizophrenia and bipolar disorder (0.68 ± 0.04 s.e.), moderate between schizophrenia and major depressive disorder (0.43 ± 0.06 s.e.), bipolar disorder and major depressive disorder (0.47 ± 0.06 s.e.), and ADHD and major depressive disorder (0.32 ± 0.07 s.e.), low between schizophrenia and ASD (0.16 ± 0.06 s.e.) and non-significant for other pairs of disorders as well as between psychiatric disorders and the negative control of Crohn’s disease. This empirical evidence of shared genetic etiology for psychiatric disorders can inform nosology and encourages the investigation of common pathophysiologies for related disorders.
    Nature Genetics 08/2013; AOP. · 35.21 Impact Factor
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    ABSTRACT: Depression and anxiety co-occur with substance use and abuse at a high rate. Ascertaining whether substance use plays a causal role in depression and anxiety is difficult or impossible with conventional observational epidemiology. Mendelian randomisation uses genetic variants as a proxy for environmental exposures, such as substance use, which can address problems of reverse causation and residual confounding, providing stronger evidence about causality. Genetic variants can be used instead of directly measuring exposure levels, in order to gain an unbiased estimate of the effect of various exposures on depression and anxiety. The suitability of the genetic variant as a proxy can be ascertained by confirming that there is no relationship between variant and outcome in those who do not use the substance. At present, there are suitable instruments for tobacco use, so we use that as a case study. Proof-of-principle Mendelian randomisation studies using these variants have found evidence for a causal effect of smoking on body mass index. Two studies have investigated tobacco and depression using this method, but neither found strong evidence that smoking causes depression or anxiety; evidence is more consistent with a self-medication hypothesis. Mendelian randomisation represents a technique that can aid understanding of exposures that may or may not be causally related to depression and anxiety. As more suitable instruments emerge (including the use of allelic risk scores rather than individual single nucleotide polymorphisms), the effect of other substances can be investigated. Linkage disequilibrium, pleiotropy, and population stratification, which can distort Mendelian randomisation studies, are also discussed.
    Depression and Anxiety 07/2013; · 4.61 Impact Factor
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    ABSTRACT: BACKGROUND: Low early life vitamin D status is associated with an increased risk of schizophrenia and psychotic experiences. Here we examine if maternal pregnancy vitamin D concentrations are associated with offspring psychotic experiences as young adults. METHODS: A community sample of 2047 participants was investigated. Maternal prenatal 25 hydroxyvitamin D (25(OH)D) concentrations were assessed with tandem mass spectroscopy. Psychotic experiences were assessed at age 18years using a semi-structured clinical interview. RESULTS: 177 cohort members reported suspected or definite psychotic experiences, There was no evidence of an association between maternal 25(OH)D concentrations as quartiles (p=0.85 hypothesis test of general association versus no association across the quartiles) or as a continuous variable (p=0.89) versus experience of suspected and definite psychotic experiences at 18years. Within the cohort, only 29 subjects met criteria for a psychotic disorder at age 18. Based on this sample, there was no significant association between maternal 25(OH)D and psychotic disorder at 18years. DISCUSSION: Maternal vitamin D levels were not associated with risk of psychotic experiences nor psychotic disorders in this birth cohort.
    Schizophrenia Research 06/2013; · 4.59 Impact Factor
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    ABSTRACT: OBJECTIVE The authors examined the development of psychotic experiences and psychotic disorders in a large population-based sample of young adults and explored their relationship to psychotic phenomena earlier in childhood. METHOD The authors conducted a longitudinal birth cohort study of individuals assessed with the semistructured Psychosis-Like Symptom Interviews at ages 12 and 18 years. RESULTS Of the 4,724 individuals interviewed at age 18, 433 (9.2%) had either suspected (N=203 [4.3%]) or definite (N=230 [4.9%]) psychotic experiences. Of these, 79 (1.7%) met criteria for a psychotic disorder, and of those, only 50% sought professional help. All psychotic outcomes were more likely in young women and in those from socioeconomically disadvantaged backgrounds. Of the participants who had psychotic experiences at age 12, 78.7% had remitted by age 18. The risk of psychotic disorders at age 18 was greater in those with suspected (odds ratio=5.6, 95% CI=2.6-12.1) and especially in those with definite (odds ratio=12.7, 95% CI=6.2-26.1) psychotic experiences at age 12, and also among those with psychotic experiences at age 12 attributed to sleep or fever or with nonpsychotic experiences such as depersonalization. The positive predictive values for increasing frequency of experiences at age 12 predicting psychotic disorders at age 18 ranged from 5.5% to 22.8%. CONCLUSIONS Despite evidence for a continuum of psychotic experiences from as early as age 12, positive predictive values for predicting psychotic disorders were too low to offer real potential for targeted interventions. Psychotic disorders in young adults are relatively uncommon, but they constitute an important unmet need for care given that half of the individuals in this study who met criteria for a psychiatric disorder had not sought help for these problems despite high levels of associated distress and impairment.
    American Journal of Psychiatry 05/2013; · 14.72 Impact Factor
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    ABSTRACT: OBJECTIVE Psychotic experiences in children are associated with an elevated risk of developing psychosis. The authors investigated whether the pattern of cognitive deficits present in psychosis also exists in children with psychotic experiences within the general population. METHOD The authors examined the longitudinal relationships between key cognitive domains, selected a priori based on their association with schizophrenia, and onset of psychotic experiences in children from the Avon Longitudinal Study of Parents and Children and whether these associations were independent of one another. RESULTS Lower performance in the domains of processing speed at age 8 years (odds ratio=1.24, 95% CI=1.12-1.36) and attention at age 11 (odds ratio=1.14, 95% CI=1.04-1.25) and decline of processing speed between the ages of 8 and 11 (odds ratio=1.29, 95% CI=1.15-1.45) were associated with higher risk of psychotic experiences at age 12. When adjusting for the other cognitive domains, processing speed at age 8 (odds ratio=1.20, 95% CI=1.09-1.33) was the measure most strongly associated with psychotic experiences. CONCLUSIONS Defective processing speed is a particularly strong predictor of psychotic experiences in children. Furthermore, the pattern of associations between cognition and psychotic experiences in children within the general population is similar to the one between cognition and schizophrenia. These findings have potentially important implications for understanding the pathogenesis of psychotic disorders and the specific deficits that seem to place children at higher risk of psychopathology.
    American Journal of Psychiatry 05/2013; 170(5):550-7. · 14.72 Impact Factor
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    ABSTRACT: BACKGROUND: Characteristics related to the areas where people live have been associated with suicide risk, although these might reflect aggregation into these communities of individuals with mental health or social problems. No studies have examined whether area characteristics during childhood are associated with subsequent suicide, or whether risk associated with individual characteristics varies according to childhood neighbourhood context. Method We conducted a longitudinal study of 204 323 individuals born in Sweden in 1972 and 1977 with childhood data linked to suicide (n = 314; 0.15%) up to age 26-31 years. Multilevel modelling was used to examine: (i) whether school-, municipality- or county-level characteristics during childhood are associated with later suicide, independently of individual effects, and (ii) whether associations between individual characteristics and suicide vary according to school context (reflecting both peer group and neighbourhood effects). RESULTS: Associations between suicide and most contextual measures, except for school-level gender composition, were explained by individual characteristics. There was some evidence of cross-level effects of individual- and school-level markers of ethnicity and deprivation on suicide risk, with qualitative interaction patterns. For example, having foreign-born parents increased the risk for individuals raised in areas where they were in a relative minority, but protected against suicide in areas where larger proportions of the population had foreign-born parents. CONCLUSIONS: Characteristics that define individuals as being different from most people in their local environment as they grow up may increase suicide risk. If robustly replicated, these findings have potentially important implications for understanding the aetiology of suicide and informing social policy.
    Psychological Medicine 04/2013; · 5.59 Impact Factor
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    ABSTRACT: The aim of this study was to use prospective data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine the differences in literacy skills in children who later completed the psychotic like symptoms (PLIKS) interview at 12years of age. We further examined the association between literacy skills over time in relation to the likelihood of reporting psychotic experiences (PEs). This study examined data from n=6790 children from the ALSPAC cohort who participated in the PLIKS semi-structured interview. Literacy skills such as spelling, basic real and non-real word reading, and reading skills and comprehension were assessed by an ALSPAC spelling task, Wechsler Objective Reading Dimension, and the revised Neale Analysis of Reading Ability (NARA II) respectively. Relative to the group unaffected by PEs, we found a lower performance in all measurements of child literacy skills in those with suspected or definite PEs. The majority of these differences persisted after adjusting for a range of covariates. In addition, both a consistently low pattern of performance and a decline were associated with suspected or definite PEs. Implications for preventative intervention models focussed on children at risk of developing psychotic disorders are discussed within the context of speech and language development.
    Schizophrenia Research 02/2013; · 4.59 Impact Factor
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    ABSTRACT: Although Attention Deficit Hyperactivity Disorder (ADHD) is recognised to be a familial and heritable disorder, little is known about the broader family characteristics of having a parent with ADHD problems. The main aim of this study was to investigate the relationship between parent ADHD problems, child clinical presentation and family functioning in a sample of children with ADHD. The sample consisted of 570 children with ADHD. Child psychopathology was assessed using a semi-structured diagnostic interview. Questionnaires were used to assess ADHD in the parents (childhood and current symptoms), family environment and mother/father-child relationship. Parental ADHD problems were associated with a range of adverse clinical outcomes in children with no difference in effects for mothers with ADHD problems compared to fathers with ADHD problems. Levels of maternal hostility were higher in families where mothers had ADHD problems, but reduced where fathers had ADHD problems. Parental ADHD problems index higher risk for more severe clinical presentation of ADHD in children and higher levels of family conflict (where there are maternal but not paternal ADHD problems). This study highlights that children with more severe behavioural symptoms are more likely to have a parent with persistent ADHD which has important implications when considering treatment and intervention strategies.
    European Child & Adolescent Psychiatry 02/2013; · 3.70 Impact Factor
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    Suzanne H Gage, Stanley Zammit, Matthew Hickman
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    ABSTRACT: Schizophrenia is a debilitating but poorly understood condition with very few known modifiable risk factors. Cannabis use can acutely induce psychotic experiences, but its causal relationship to schizophrenia is less well understood. Longitudinal cohort studies suggest that the association between cannabis and psychotic outcomes is not due to chance or reverse causation. However, the association could be due to bias or residual confounding. Methods that can test alternative explanations in greater depth are required. This is especially important as ecological studies have found little association between the increase in cannabis use over recent decades and incidence of psychotic disorders; public health models suggest that cannabis use may need to be treated and prevented in many thousands of users in order to prevent one case of schizophrenia. We believe that, while such uncertainty exists, there is a scientific duty to continue to investigate the role of cannabis in the aetiology of schizophrenia and that the policy case for considering cannabis exposure as a critical target for preventing schizophrenia is yet to be made. However, due to other evidence of the harms of cannabis use, this should not affect the public health message that cannabis can be harmful and that cannabis dependence should be prevented.
    F1000 Medicine Reports 01/2013; 5:2.
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    ABSTRACT: In clinical populations paranoid delusions are associated with making global, stable and external attributions for negative events. Paranoia is common in community samples but it is not known whether it is associated with a similar cognitive style. This study investigates the association between cognitive style and paranoia in a large community sample of young adults. 2694 young adults (mean age 17.8, SD 4.6) from the ALSPAC cohort provided data on psychotic experiences and cognitive style. Psychotic experiences were assessed using a semi-structured interview and cognitive style was assessed using the Cognitive Styles Questionnaire-Short Form (CSQ-SF) on the same occasion. Logistic regression was used to investigate associations between paranoia and CSQ-SF scores, both total and domain-related (global, stable, self, external). The role of concurrent self-reported depressive symptoms in the association was explored. Paranoia was associated with Total CSQ-SF scores (adjusted OR 1.69 95% CI 1.29, 2.22), as well as global (OR 1.56 95% CI 1.17, 2.08), stable (OR 1.56 95% CI 1.17, 2.08) and self (OR 1.37 95% CI 1.05, 1.79) domains, only Total score and global domain associations remained after additional adjustment for self-reported depression. There was no association between paranoia and external cognitive style (OR 1.10 95% CI 0.83, 1.47). Paranoid ideation in a community sample is associated with a global rather than an external cognitive style. An external cognitive style may be a characteristic of more severe paranoid beliefs. Further work is required to determine the role of depression in the association between cognitive style and paranoia.
    PLoS ONE 01/2013; 8(11):e80055. · 3.73 Impact Factor
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    The Lancet 01/2013; 381(9875):1371-1379. · 39.06 Impact Factor
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    ABSTRACT: Objective Schizophrenia is associated with atopy and increased inflammatory markers. We report a population-based longitudinal study of the associations between childhood atopic disorders, subsequent serum inflammatory markers, interleukin 6 (IL-6) and C-reactive protein (CRP), and the risk of psychotic experiences (PEs). Method PEs were assessed at age 13 years (n = 6785). Presence of clinician-diagnosed atopic disorders (asthma and eczema) was determined from parent-completed questionnaires at age 10 years (n = 7814). Serum IL-6 and CRP were measured at age 9 years (n = 5076). Logistic regression examined the association between (1) atopy and PEs, (2) inflammatory markers and PEs, and (3) mediating effects of inflammatory markers on the atopy–PEs association. Linear regression examined the association between atopy and inflammatory markers. Age, gender, social class, ethnicity and body mass index were included as potential confounders. Results At age 10 years, about 14% of the sample was reported to have asthma, 12% eczema, and 7% both asthma and eczema. Compared with children with no atopy, risk of PEs at age 13 years was increased for all of these groups; adjusted odds ratios (95% CI) were, respectively, 1.39 (1.10–1.77), 1.33 (1.04–1.69), and 1.44 (1.06–1.94). Atopy was associated with increased serum IL-6 and CRP; however, this did not mediate association between atopy and PEs. Inflammatory markers were not associated with later PEs. Conclusion Childhood atopic disorders increase the risk of psychotic experiences in adolescence. Follow-up of these individuals will be useful to determine the effect of atopy and inflammation on different trajectories of early-life PEs.
    Schizophrenia Research 01/2013; · 4.59 Impact Factor
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    The Lancet 01/2013; 381(9875):1371-1379. · 39.06 Impact Factor

Publication Stats

3k Citations
785.37 Total Impact Points


  • 2013
    • London School of Hygiene and Tropical Medicine
      • Centre for Global Mental Health
      London, ENG, United Kingdom
    • Deakin University
      • School of Psychology
      Geelong, Victoria, Australia
  • 2012
    • Karolinska Institutet
      • Institutionen för folkhälsovetenskap
      Solna, Stockholm, Sweden
  • 2005–2012
    • University of Bristol
      • • School of Social and Community Medicine
      • • MRC Centre for Causal Analyses in Translational Epidemiology
      Bristol, ENG, United Kingdom
  • 2002–2012
    • Cardiff University
      • Department of Psychological Medicine and Neurology
      Cardiff, WLS, United Kingdom
  • 2009
    • The University of Warwick
      • Warwick Medical School (WMS)
      Warwick, ENG, United Kingdom
  • 2008
    • King's College London
      • Institute of Psychiatry
      London, ENG, United Kingdom
    • University of Washington Seattle
      Seattle, Washington, United States
  • 2000–2008
    • University of Wales
      • College of Medicine
      Cardiff, Wales, United Kingdom