Search

Background and Hypothesis: Childhood adversity is often described as a potential cause of incident psychotic experiences, but the underlying mechanisms are not well understood. We aimed to examine the mediating role of cognitive and psychopathological factors in the relation between childhood adversity and incident psychotic experiences in early adulthood., Study Design: We analyzed data from the Avon Longitudinal Study of Parents and Children, a large population-based cohort study. Childhood adversity was measured prospectively from birth to age 11 years, mediators (anxiety, depression, external locus of control [LoC], negative symptoms) were assessed at approximately 16 years of age, and incident psychotic experiences were assessed at ages 18 and 24 years. Mediation was examined via the counterfactual g-computation formula., Study Results: In total, 7% of participants had incident suspected or definite psychotic experiences in early adulthood. Childhood adversity was related to more incident psychotic experiences (ORadjusted = 1.34, 95% CI = 1.21; 1.49), and this association was partially mediated via all mediators examined (proportion mediated: 19.9%). In separate analyses for each mediator, anxiety, depression, external LoC, and negative symptoms were all found to mediate the link between adversity and incident psychotic experiences. Accounting for potential confounders did not modify our results., Conclusions: Our study shows that cognitive biases as well as mood symptomatology may be on the causal pathway between early-life adversity and the development of psychotic experiences. Future studies should determine which mediating factors are most easily modifiable and most likely to reduce the risk of developing psychotic experiences., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.)

Postpartum psychosis is a psychiatric emergency that is currently not represented in diagnostic systems, to the detriment of people with lived experience. Engaging with stakeholders offers an important avenue to improve clinical practice and make research more impactful, by providing perspectives based on first-hand, expert experience. There is a paucity of reports on stakeholders' engagement in psychiatry. Activities have thus far been limited to Western countries and there are few reports on postpartum psychosis. We report the results of public involvement activities (in the form of discussion groups) with key stakeholders in India, Malawi and the UK. These discussions centred around the clinical picture of postpartum psychosis and the terminologies used to describe these episodes. Seven major areas were highlighted: how postpartum psychosis is handled within services, common symptoms and characteristics, impact of episode, barriers to care, non-medical approaches, terminology and research areas of interest. According to the discussions, postpartum psychosis presents similarly across countries, although there are differences in access to services, approaches to mental health and terminologies used within and across countries. With this understanding comes the foundation for cross-cultural assessment, service improvement and a stakeholder-informed research agenda., (© 2023. The Author(s).)

Background: Traumatic experiences are associated with a higher risk of psychotic illnesses, but little is known about potentially modifiable mechanisms underlying this relationship. This study aims to examine whether post-traumatic stress disorder (PTSD) symptoms mediate the relationship between trauma and psychotic experiences (PEs)., Methods: We used data from the Avon Longitudinal Study of Parents and Children to examine whether: PTSD symptoms mediate the relationships between (a) childhood trauma and adolescent PEs (study of adolescent PEs; n = 2952), and (b) childhood/adolescent trauma and PEs in early adulthood (study of adult PEs; n = 2492). We examined associations between variables using logistic regression, and mediation using the parametric g-computation formula., Results: Exposure to trauma was associated with increased odds of PEs (adolescent PEs: OR adjusted 1.48, 95% CI 1.23-1.78; adult PEs: OR adjusted 1.57, 95% CI 1.25-1.98) and PTSD symptoms (adolescent PTSD: OR adjusted 1.59, 95% CI 1.31-1.93; adult PTSD: OR adjusted 1.50, 95% CI 1.36-1.65). The association between PTSD symptoms and PE was stronger in adolescence (OR adjusted 4.63, 95% CI 2.34-9.17) than in adulthood (OR adjusted 1.62, 95% CI 0.80-3.25). There was some evidence that PTSD symptoms mediated the relationship between childhood trauma and adolescent PEs (proportion mediated 14%), though evidence of mediation was weaker for adult PEs (proportion mediated 8%)., Conclusions: These findings are consistent with the hypothesis that PTSD symptoms partly mediate the association between trauma exposure and PEs. Targeting PTSD symptoms might help prevent the onset of psychotic outcomes.

Background: Psychotic experiences emerge from abnormalities in perception and belief formation and occur more commonly in those experiencing childhood trauma. However, which precise aspects of belief formation are atypical in psychosis is not well understood. We used a computational modeling approach to characterize belief updating in young adults in the general population, examine their relationship with psychotic outcomes and trauma, and determine the extent to which they mediate the trauma-psychosis relationship., Methods: We used data from 3360 individuals from the Avon Longitudinal Study of Parents and Children birth cohort who completed assessments for psychotic outcomes, depression, anxiety, and two belief updating tasks at age 24 and had data available on traumatic events assessed from birth to late adolescence. Unadjusted and adjusted regression and counterfactual mediation methods were used for the analyses., Results: Basic behavioral measures of belief updating (draws-to-decision and disconfirmatory updating) were not associated with psychotic experiences. However, computational modeling revealed an association between increased decision noise with both psychotic experiences and trauma exposure, although <3% of the trauma-psychotic experience association was mediated by decision noise. Belief updating measures were also associated with intelligence and sociodemographic characteristics, confounding most of the associations with psychotic experiences. There was little evidence that belief updating parameters were differentially associated with delusions compared with hallucinations or that they were differentially associated with psychotic outcomes compared with depression or anxiety., Conclusions: These findings challenge the hypothesis that atypical belief updating mechanisms (as indexed by the computational models and behavioral measures we used) underlie the development of psychotic phenomena., (Copyright © 2022 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.)

Childhood trauma is associated with an increased risk of psychosis, but the mechanisms that mediate this relationship are unknown. Exposure to trauma has been hypothesised to lead to cognitive biases that might have causal effects on psychotic symptoms. The literature on whether childhood trauma is associated with psychosis-related cognitive biases has not been comprehensively reviewed. A systematic review and meta-analysis or narrative synthesis of studies examining the association between childhood trauma and the following biases: external locus of control (LOC), external attribution, probabilistic reasoning, source monitoring, top-down processing, and bias against disconfirmatory evidence. Studies were assessed for quality, and sources of heterogeneity were explored. We included 25 studies from 3,465 studies identified. Individuals exposed to childhood trauma reported a more external LOC (14 studies: SMD Median = 0.40, Interquartile range 0.07 to 0.52), consistent with a narrative synthesis of 11 other studies of LOC. There was substantial heterogeneity in the meta-analysis (I2 = 93%) not explained by study characteristics examined. Narrative syntheses for other biases showed weaker, or no evidence of association with trauma. The quality of included studies was generally low. Our review provides some evidence of an association between childhood trauma and a more external LOC, but not with the other biases examined. The low quality and paucity of studies for most of the cognitive biases examined highlights the need for more rigorous studies to determine which biases occur after trauma, and whether they mediate an effect of childhood trauma on psychosis., Competing Interests: The authors have declared that no competing interests exist.

Background: Long chain polyunsaturated fatty acid (PUFA) levels have been implicated in the pathology of psychotic disorders. We investigated the relationship between childhood PUFA levels and later psychotic experiences (PE's) in a large birth cohort., Methods: Plasma levels of Ω-3 and Ω-6 fatty acids (FA's) were assayed at ages 7 and 16 years. PE's were assessed at ages 12 and 18 years using a semi-structured interview. Primary outcome was any PE's at 18 years; sensitivity analyses examined incident PE's between ages 12 and 18 years, persistent PE's (at 12 and 18) and psychotic disorder at 18 years. Genetic instruments for Ω-3 and Ω-6 were derived and used in a multivariable Mendelian Randomization analysis., Results: Higher levels of Ω-6 FA's AA, OA and AdA at age 7 years were weakly associated with a reduced risk for PE's at 18 years, however, effect sizes were small and attenuated after adjusting for confounders (strongest evidence for OA; adjusted OR, 0.842; 95% CI, 0.711, 0.998; p, 0.048). Total Ω-6 levels at age 16 years were associated with an increased odds of psychotic disorder at age 18 years. However, there was no association between Ω-6/Ω-3 ratio and psychosis outcomes, nor with genetic instruments of total Ω-3 or Ω-6 levels., Conclusions: There is no strong evidence that total plasma Ω-3 FA levels or Ω-6/Ω-3 ratios in childhood and mid-adolescence are associated with increased risk for PE's or psychotic disorder, but very marginal evidence that alterations in the Ω-6 pathway at developmental time points might influence risk 2 ., Competing Interests: Declaration of competing interest The authors report no conflicts of interest., (Crown Copyright © 2020. Published by Elsevier B.V. All rights reserved.)

Objective: The authors investigated the incidence, course, and outcome of psychotic experiences from childhood through early adulthood in the general population and examined prediction of psychotic disorder., Methods: This was a population-based cohort study using the semistructured Psychosis-Like Symptoms Interview at ages 12, 18, and 24 (N=7,900 with any data). Incidence rates were estimated using flexible parametric modeling, and positive predictive values (PPVs), sensitivity, specificity, and area under the curve were estimated for prediction., Results: The incidence rate of psychotic experiences increased between ages 13 and 24, peaking during late adolescence. Of 3,866 participants interviewed at age 24, 313 (8.1%, 95% CI=7.2, 9.0) had a definite psychotic experience since age 12. A total of 109 individuals (2.8%) met criteria for a psychotic disorder up to age 24, of whom 70% had sought professional help. Prediction of current psychotic disorder at age 24 (N=47, 1.2%), by both self-report and interviewer-rated measures of psychotic experiences at age 18 (PPVs, 2.9% and 10.0%, respectively), was improved by incorporating information on frequency and distress (PPVs, 13.3% and 20.0%, respectively), although sensitivities were low. The PPV of an at-risk mental state at age 18 predicting incident disorder at ages 18-24 was 21.1% (95% CI=6.1, 45.6) (sensitivity, 14.3%, 95% CI=4.0, 32.7)., Conclusions: The study results show a peak in incidence of psychotic experiences during late adolescence as well as an unmet need for care in young people with psychotic disorders. Because of the low sensitivity, targeting individuals in non-help-seeking samples based only on more severe symptom cutoff thresholds will likely have little impact on population levels of first-episode psychosis.

Importance: Cross-sectional and longitudinal studies have consistently reported associations between childhood trauma and psychotic experiences and disorders. However, few studies have examined whether the age of exposure or specific trauma types are differently associated with the risk of developing psychotic experiences., Objective: To examine whether exposure to trauma, assessed at multiple age periods between 0 and 17 years of age, is associated with an increased risk of psychotic experiences by age 18 years and whether this association varies according to trauma type as well as age and frequency of exposure., Design, Setting, and Participants: This study used data from the Avon Longitudinal Study of Parents and Children, a large population-based birth cohort in the United Kingdom that recruited women who resided in the Avon Health Authority area and had an expected delivery date between April 1, 1991, and December 31, 1992. Data on psychotic experiences were included in the study, along with trauma variables derived from assessments completed by the parents or self-reported by the participants. The variables represent exposure to any trauma type between ages 0 and 17 years; any trauma type within a distinct age period: early childhood (0-4.9 years), middle childhood (5-10.9 years), or adolescence (11-17 years); specific trauma types between ages 0 and 17 years; and specific trauma types within early childhood, middle childhood, or adolescence. Data were analyzed from January 9, 2017, to November 30, 2017., Main Outcomes and Measures: Suspected or definite psychotic experiences were assessed using the psychosis-like symptoms semistructured interview at age 12 years and then at age 18 years., Results: The sample of 4433 participants included 2504 (56.5%) females, with a mean (SD) age of 17.8 (0.38) years. Exposure to any trauma up to age 17 years was associated with increased odds of psychotic experiences at age 18 years (adjusted odds ratio, 2.91; 95% CI, 2.15-3.93). All trauma types from age 0 to 17 years were associated with an increased odds of psychotic experiences. The population-attributable fraction for childhood and adolescent trauma on psychotic experiences at age 18 years was 45% (95% CI, 25%-60%). Effect sizes for most trauma types were greater for exposure that was more proximal to the outcome, although CIs overlapped with those for more distal trauma. Evidence supported dose-response associations for exposure to multiple trauma types and at multiple age periods. In an analysis aimed at minimizing reverse causality, adolescent trauma was also associated with past-year incident psychotic experiences at age 18 years., Conclusions and Relevance: These findings are consistent with the thesis that trauma could have a causal association with psychotic experiences; if so, identification of modifiable mediators is required to inform prevention strategies.

Background: Postpartum Psychosis is a severe mental health condition following childbirth, with a psychosis and associated mood disturbance. Research to date has primarily focused on mothers' experiences, and on identifying risk factors, aetiology, and intervention efficacy. Within both research and clinical communities, there has been little acknowledgement of partners' experiences of Postpartum Psychosis, nor the important support role that partners can provide. The aim of this study was to consider the lived experiences of partners of women who have had Postpartum Psychosis, and the impact that it has had on their lives and relationships., Methods: Participants (N = 8) were partners recruited through the charity Action on Postpartum Psychosis. Partners completed an in-depth, semi-structured interview regarding their experiences of Postpartum Psychosis. Interpretative Phenomenological Analysis was used to analyse the interview transcripts., Results: Seven superordinate themes emerged from the interview data: loss; powerlessness; united vs. individual coping; hypothesising and hindsight; barriers to accessing care and unmet needs; managing multiple roles; and positive changes from Postpartum Psychosis., Conclusions: These findings provide a rich illustration of the experiences of partners, including some previously unidentified findings relating to partner hypervigilance to signs of relapse and positive changes in their attitudes and relationships. Areas where support could be provided for partners are also highlighted.

Importance: There is concern about potentially causal effects of tobacco use on psychosis, but epidemiological studies have been less robust in attempts to minimize effects of confounding than studies of cannabis use have been., Objectives: To examine the association of patterns of cigarette and cannabis use with preceding and subsequent psychotic experiences, and to compare effects of confounding across these patterns., Design, Setting, and Participants: This cohort study used data from the Avon Longitudinal Study of Parents and Children, which initially consisted of 14 062 children. Data were collected periodically from September 6, 1990, with collection ongoing, and analyzed from August 8, 2016, through June 14, 2017. Cigarette and cannabis use data were summarized using longitudinal latent class analysis to identify longitudinal classes of substance use. Associations between classes and psychotic experiences at age 18 years were assessed., Exposures: Depending on the analysis model, exposures were longitudinal classes of substance use or psychotic experiences at age 12 years., Main Outcomes and Measures: Logistic regression was used to examine the associations between substance use longitudinal classes and subsequent onset of psychotic experiences., Results: Longitudinal classes were derived using 5300 participants (56.1% female) who had at least 3 measures of cigarette and cannabis use from ages 14 to 19 years. Prior to adjusting for a range of potential confounders, there was strong evdience that early-onset cigarette-only use (4.3%), early-onset cannabis use (3.2%), and late-onset cannabis use (11.9%) (but not later-onset cigarette-only use [14.8%]) latent classes were associated with increased psychotic experiences compared with nonusers (65.9%) (omnibus P < .001). After adjusting for confounders, the association for early-onset cigarette-only use attenuated substantially (unadjusted odds ratio [OR], 3.03; 95% CI, 1.13-8.14; adjusted OR, 1.78; 95% CI, 0.54-5.88), whereas those for early-onset cannabis use (adjusted OR, 3.70; 95% CI, 1.66-8.25) and late-onset cannabis use (adjusted OR, 2.97; 95% CI, 1.63-5.40) remained consistent., Conclusions and Relevance: In this study, our findings indicate that while individuals who use cannabis or cigarettes during adolescence have an increased risk of subsequent psychotic experiences, epidemiological evidence is substantively more robust for cannabis use than it is for tobacco use.

Background: A clearer understanding of the basis for the association between cannabis use and psychotic experiences (PEs) is required. Our aim was to examine the extent to which associations between cannabis and cigarette use and PEs are due to confounding., Method: A cohort study of 1756 adolescents with data on cannabis use, cigarette use and PEs., Results: Cannabis use and cigarette use at age 16 were both associated, to a similar degree, with PEs at age 18 [odds ratio (OR) 1.48, 95% confidence interval (CI) 1.18-1.86 for cannabis and OR 1.61, 95% CI 1.31-1.98 for cigarettes]. Adjustment for cigarette smoking frequency (OR 1.27, 95% CI 0.91-1.76) or other illicit drug use (OR 1.25, 95% CI 0.91-1.73) substantially attenuated the relationship between cannabis and PEs. The attenuation was to a lesser degree when cannabis use was adjusted for in the cigarette PE association (OR 1.42, 95% CI 1.05-1.92). However, almost all of the participants used cannabis with tobacco, including those who classed themselves as non-cigarette smokers., Conclusions: Teasing out the effects of cannabis from tobacco is highly complex and may not have been dealt with adequately in studies to date, including this one. Complementary methods are required to robustly examine the independent effects of cannabis, tobacco and other illicit drugs on PEs.

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.

Background: Psychotic experiences are prevalent in community samples and are highly correlated with depressive symptoms. This study aimed to investigate the longitudinal associations between psychotic experiences and depressive symptoms between adolescence and young adulthood., Method: Prospective cohort study with a 6 year follow-up in a community sample of 7632 adolescents and young adults. Depressive symptoms were assessed with the Short Moods and Feelings Questionnaire and psychotic experiences with a semi-structured clinical interview at 12 and 18 years. Longitudinal and cross-sectional associations were investigated with regression and structural equation models., Results: Depressive symptoms and psychotic experiences were associated at each time-point (12 years r = 0.486 [95% CI 0.457, 0.515]; 18 years r = 0.286 [95% CI 0.233, 0.339]) and there were longitudinal within-phenotype associations (depressive symptoms r = 0.252 [95% CI 0.205, 0.299]; psychotic experiences r = 0.662 [95% CI 0.595, 0.729]). There was an across-phenotype association between psychotic experiences at 12 and depressive symptoms at 18 r = 0.139 [95% CI 0.086, 0.192; p<0.001], but no association between depressive symptoms at 12 and psychotic experiences at 18 r = -0.022 [95% CI -0.032, 0.077; p = 0.891]., Conclusions: Longitudinal across-phenotype associations were substantially weaker than cross-sectional associations or within-phenotype longitudinal associations. Whilst psychotic experiences at 12 years were associated with a small increase in depression at 18 years, depression at 12 years was not associated with psychotic experiences at 18 years once across-phenotype cross-sectional and within-phenotype longitudinal associations were accounted for. This suggests that the biological mechanisms underlying depression at this age do not increase subsequent risk of psychotic experiences once they resolve.

Background: International studies indicate that the median prevalence of psychotic experiences in children is 7%. It has been proposed that environmental stress during pregnancy may affect the neurodevelopment of the foetus and lead to a vulnerability in the child to later stressors and psychopathology., Aim: In this study we explore the relationship between environmental stress during pregnancy and psychotic experiences in children in the general population at 12 years., Methods: We analysed a birth cohort of 5038 children from the Avon Longitudinal Study of Parents and Children. Environmental stress was measured as life event exposure. Data on life events were collected on women during their pregnancy, whilst psychotic experiences in the offspring were assessed at age 12., Results: There was a weak association between maternal exposure to life events and psychotic experiences at twelve years (crude OR 1.10 95% CI 1.02-1.18) per quartile of life event score. This association was not reduced after adjustment for socio-economic status, family history of schizophrenia, maternal education or birth weight but after adjustment for maternal anxiety and depression and smoking in early pregnancy there was no longer any evidence for an association (OR 1.01 95% CI 0.93-1.10)., Conclusion: This study provides some evidence to suggest that stressful life events may affect child psychotic experiences through effects on maternal psychopathology, and possibly physiology, during pregnancy., (Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Episodes of postpartum psychosis have been associated with first pregnancies in women with bipolar I disorder. It is unclear, however, if the effect extends to episodes at other times in relation to childbirth and to women with other mood disorders such as major depression and bipolar II disorder. This primiparity effect, which is also seen in other pregnancy related conditions such as pre-eclampsia, is a potentially important clue to the aetiology of childbirth related mood episodes., Methods: Participants were interviewed and case notes reviewed. Best-estimate diagnoses were made according to DSM-IV criteria. Data on the occurrence of episodes in pregnancy and the postpartum were available on 3345 full term deliveries from 1667 participants, 934 with bipolar I disorder (BD-I), 278 with bipolar II disorder (BD-II) and 455 with recurrent major depression (RMD)., Results: Onsets of psychosis/mania within 6 weeks of childbirth were overrepresented in primiparae (p=0.007) with BD-I. Although primiparity was not associated with perinatal bipolar depression, there was an association with the onset of depression within 6 weeks in women with RMD (p=0.035). Whilst women experiencing a postpartum episode were less likely to go on to have further children, this did not account for the association with primiparity., Limitations: Data were collected retrospectively. Information on pharmacological treatment was not available., Conclusions: Primiparity is associated not only with postpartum psychosis/mania in BD-I, but also with postpartum depression in RMD. Psychosocial factors and biological differences between first and subsequent pregnancies may play a role and are candidates for examination in further studies.

Background: Psychotic symptoms are common in adolescents in the general population but it is unknown whether they are associated with poor social functioning., Aims: To investigate whether adolescent psychotic symptoms are associated with poor social functioning measured by peer relationships., Method: 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., Results: 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)., Conclusion: 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., (© 2013.)

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.

Background: Psychotic-like experiences (PLEs) during adolescence are not uncommon and potentially represent a clinical and public health concern. A greater understanding of their aetiology and patterns of change over time is needed. We aimed to describe trajectories of PLEs during adolescence, and examine their association with characteristics earlier during development., Method: This was a cohort study of 7387 adolescents from the ALSPAC birth cohort who completed self-reported questionnaires about PLEs at 4 time points over a five-year period (ages 11.5-16.5years). Association between childhood characteristics and latent class membership was examined., Results: The proportion of children reporting PLEs declined with age. Individuals within decreasing (1.7%), intermittent (16.8%), and persistent (0.9%) PLEs trajectories were more likely to come from adverse backgrounds and have disturbed childhood development compared to the low PLE (80.6%) class. Persistent-class individuals scored highest on most measures though no measure clearly distinguished between persistent, intermittent and decreasing groups., Conclusions: A number of early life characteristics and markers of childhood emotional and behavioural development are associated with trajectories of PLEs during adolescence. Despite the increase in cost and time required to collect data at repeated intervals, studies of trajectories are likely to have greater potential for predicting transition into clinical disorder at an earlier stage., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: A putative interaction between cannabis and variation at rs4680 within the catechol-methyl-transferase (COMT) gene on psychosis has been reported, but not adequately replicated., Aims: To examine whether the relative risk of developing psychosis following use of cannabis is dependent upon variation within COMT., Method: A longitudinal study of 2630 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort who completed questionnaire-based assessments for cannabis use at age 14 and incident psychotic experiences at age 16. Six SNPs within COMT were genotyped., Results: There was no evidence of an interaction under multiplicative models between cannabis use and COMT on the risk of developing psychotic experiences in our primary analyses. In sensitivity analyses we observed highly variable evidence of interaction, whereby psychotomimetic effects of cannabis were greater in methionine homozygotes under some scenarios, but in valine homozygotes under others., Conclusions: Cannabis increases risk of psychosis irrespective of underlying COMT genotypes. These findings argue against the widely held belief that the relative risk of developing psychosis following use of cannabis is dependent upon variation within COMT. The public health message about the potential increase in risk of psychotic disorders following cannabis use should not be tempered by reports that this harm is subgroup specific in the absence of robust evidence of replication.

INTRODUCTION. Specific attributional styles have been demonstrated in individuals with psychotic disorders and are implicated in the development of psychotic symptoms. We aimed to examine the association between locus of control (LOC) assessed in childhood and psychotic symptoms reported in early adolescence. METHODS. We used a prospective longitudinal design using data from a large birth cohort (the Avon Longitudinal Study of Parents and Children, ALPSAC). 6455 subjects completed a semistructured clinical interview assessing 12 individual psychotic symptoms at a mean age of 12.9 years. A measure of LOC was previously collected in the cohort at the age of 8. RESULTS. Children who reported an externalised LOC at age 8 were at increased risk of reporting both broadly defined (OR 1.77, 95% CI 1.49 to 2.08) and narrowly defined (OR 2.06, 95% CI 1.58 to 2.67) psychotic symptoms at age 13 years. These associations were only slightly attenuated after adjustment for potential confounders. The associations were similar for broadly defined specific paranoid symptoms but weaker for narrowly defined specific paranoid symptoms. CONCLUSIONS. An externalised LOC appears to be associated with later reporting of psychotic symptoms in early adolescence. Further investigation of the role of attributional styles, such as LOC, in increasing the risk for psychotic disorders, is warranted.

Introduction: Nonclinical psychotic symptoms (for example, low intensity or low frequency psychotic symptoms such as ideas of reference or single word auditory hallucinations) are common in adolescents and may be associated with an increased risk of developing a psychotic disorder in adulthood. Those at high risk of developing a psychotic disorder appear to perform poorly on facial emotion recognition tasks but the relationship between facial emotion recognition and nonclinical "psychosis like symptoms" (PLIKS) in children is unclear. We aimed to examine the association between childhood facial emotion recognition and PLIKS in adolescents., Methods: Longitudinal study using a large birth cohort. 6455 subjects completed a semistructured clinical assessment for psychotic symptoms (the PLIKSi) at the mean age of 12.9 (SD=0.23). Facial emotion recognition (using the DANVA) was previously assessed at the age of 8 in the cohort., Results: There was no increase in odds of reporting any PLIKS either in relation to the total score on the measure of facial emotion recognition or for the individual emotion scores of fear, sadness, anger, and happiness. Similar results were also found when examining more intense and/or more frequently experienced psychotic symptoms., Conclusions: Deficits in facial emotion recognition in 8-year-olds do not appear to predict later reporting of nonclinical psychotic symptoms in early adolescence. The results do not support the proposal that recognition of emotion is a trait phenomenon in those individuals at increased risk for psychosis. However, further research is warranted in older children/adolescents when more subtle emotion recognition deficits can be investigated.

Background: Previous studies have suggested that impaired fetal and childhood growth are associated with an increased risk of schizophrenia, but the association of pre-adult growth with non-clinical psychotic symptoms (psychosis-like symptoms) in children is not known., Aims: To explore the associations of body size at birth and age 7.5 years with childhood psychosis-like symptoms., Method: Prospective cohort of children followed up from birth to age 12: the ALSPAC cohort., Results: Data on 6000 singleton infants born after 37 weeks of gestation. A one standard deviation increase in birth weight was associated with an 18% reduction in the risk of definite psychosis-like symptoms after adjusting for age and gestation (Odds ratio (OR) = 0.82, 95% CI = 0.73-0.92, P = 0.001). This association was partly confounded by maternal anthropometry, smoking during pregnancy, socioeconomic status and IQ. A similar association was seen for birth length and psychosis-like symptoms, which disappeared after controlling for birth weight. There was little evidence for an association of 7-year height or adiposity with psychosis-like symptoms., Conclusions: Measures of impaired fetal, but not childhood, growth are associated with an increased risk of psychosis-like symptoms in 12-year-olds.