A systematic meta-review grading the evidence for non-genetic risk factors and putative antecedents of schizophrenia

Risk and protective factors for severe mental disorders in Asia

Among 369 diseases and injuries, the years lived with disability (YLDs) and disability-adjusted life-years (DALYs) rates for severe mental illnesses (SMIs) are within the top 20 %. Research on risk and protective factors for SMIs is critically important, as acting on modifiable factors may reduce their incidence or postpone their onset, while early detection of new cases enables prompt treatment and improves prognosis. However, as most of the studies on these factors are from Western countries, the findings are not generalizable across ethnic groups. This led us to conduct a systematic review of the risk and protective factors for SMIs identified in Asian studies. There were common factors in Asian and Western studies and unique factors in Asian studies. In-depth knowledge of these factors could help reduce disability, and the economic and emotional burden of SMIs. We hope that this review will inform future research and policy-making on mental health in Asian countries.

The relative and interactive impact of multiple risk factors in schizophrenia spectrum disorders: a combined register-based and clinical twin study

BACKGROUND

Research has yielded evidence for genetic and environmental factors influencing the risk of schizophrenia. Numerous environmental factors have been identified; however, the individual effects are small. The additive and interactive effects of multiple risk factors are not well elucidated. Twin pairs discordant for schizophrenia offer a unique opportunity to identify factors that differ between patients and unaffected co-twins, who are perfectly matched for age, sex and genetic background.

METHODS

Register data were combined with clinical data for 216 twins including monozygotic (MZ) and dizygotic (DZ) proband pairs (one or both twins having a schizophrenia spectrum diagnosis) and MZ/DZ healthy control (HC) pairs. Logistic regression models were applied to predict (1) illness vulnerability (being a proband v. HC pair) and (2) illness status (being the patient v. unaffected co-twin). Risk factors included: A polygenic risk score (PRS) for schizophrenia, birth complications, birth weight, Apgar scores, paternal age, maternal smoking, season of birth, parental socioeconomic status, urbanicity, childhood trauma, estimated premorbid intelligence and cannabis.

RESULTS

The PRS [odds ratio (OR) 1.6 (1.1-2.3)], childhood trauma [OR 4.5 (2.3-8.8)], and regular cannabis use [OR 8.3 (2.1-32.7)] independently predicted illness vulnerability as did an interaction between childhood trauma and cannabis use [OR 0.17 (0.03-0.9)]. Only regular cannabis use predicted having a schizophrenia spectrum diagnosis between patients and unaffected co-twins [OR 3.3 (1.1-10.4)].

CONCLUSION

The findings suggest that several risk factors contribute to increasing schizophrenia spectrum vulnerability. Moreover, cannabis, a potentially completely avoidable environmental risk factor, seems to play a substantial role in schizophrenia pathology.

A bibliometric analysis of the cannabis and cannabinoid research literature

Background

Cannabis refers to a plant in the family Cannabaceae, which has been used medically, recreationally, and industrially. The last two decades, in particular, have seen a large increase in the volume of literature on this topic. The present bibliometric analysis aims to capture the characteristics of scholarly journal publications on the topic of cannabis and cannabinoid research.

Methods

Searches were run on the Scopus database on April 02, 2021, as follows “(TITLE (cannabi* OR hashish OR marijuana OR marihuana)) AND ( LIMIT-TO ( DOCTYPE,"ar" ) OR LIMIT-TO ( DOCTYPE,"re" ) )”. Results were exported on the same day to prevent discrepancies between daily database updates. Only “article” and “review” publication types were included; no further search limits were applied. The “article” publication type includes publications featuring original research, whereas “review” includes reviews and conference papers. The following data were collected: number of publications (in total and per year), authors, and journals; open access status; publications per journal; journals publishing the highest volume of literature and their impact factors, language of publication; document type; publication country; author affiliations; funding sponsors; most highly cited publications; and most highly published authors. Trends in this subset of publications were identified and presented. Bibliometric networks were constructed using the software tool VOSviewer.

Results

A total of 29 802 publications (10 214 open access), published by 65 109 authors, were published in 5474 journals from 1829 to 2021. The greatest number of publications was published over the last 20 years. The journal that published the largest number of publications was Drug and Alcohol Dependence (n = 705). The most productive countries included the USA (n = 12 420), the UK (n = 2236), and Canada (n = 2062); many of the most common institutional affiliations and funding sponsors originated from these countries.

Conclusions

The number of publications published on the topic of cannabis follows an upward trend. Over the past 20 years, the volume of cannabis research has grown steeply, which can be attributed to a large amount of funding dedicated to researching this topic. Future research should continue to investigate changes in the publication characteristics of emerging research, as the volume of publications on this topic is expected to rapidly grow.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42238-022-00133-0.

We are not ready to abandon the current schizophrenia construct, but should be prepared to do so

The current schizophrenia construct as delineated in the latest editions of the DSM and the ICD has some strengths, but also many weaknesses. It improved the reliability of the diagnosis, made communication among clinicians, users and families less ambiguous, is useful for education and training, and for reimbursement and insurance purposes. However, many serious weaknesses should be considered. The term "Schizophrenia" does not recognize the heterogeneity of the disorder and might nourish the belief that schizophrenia represents a unitary disease. In addition, there is no agreement on the existence and nature of a "core aspect" of the disorder. Stable dimensions, in particular negative symptoms and cognitive impairment, which are key determinants of functioning, are not de facto regarded as core aspects. Finally, the construct is associated to the notion of a poor outcome, to a high level of stigma and has acquired a derogatory connotation. We are not ready but should be prepared to abandon the current schizophrenia construct. Clinicians and researchers should be encouraged to complement the ICD/DSM diagnosis with an in-depth characterization of the individual clinical picture, along with other variables, such as family history, comorbidities, vulnerability factors and personal trajectory. The "Primary Psychoses" construct, together with improved cross-sectional and longitudinal phenotypes from representative population and patient cohorts, and the availability of artificial intelligence methods, could lead to a new and more precise taxonomy of psychotic disorders, and increase the probability of identifying meaningful biomarkers to improve prevention, diagnosis, prognosis, and treatment for people suffering from psychotic disorders.

A population-based follow-up study shows high psychosis risk in women with PCOS

Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting up to 18% of women. Besides metabolic and fertility aspects, attention has lately been directed towards the detrimental effect of PCOS on psychological health. The objective of the study was to investigate whether women with PCOS are at higher risk for psychotic disorders. The study population derives from the Northern Finland Birth Cohort 1966 (N = 5889 women). The women with PCOS were identified by two simple questions on oligo-amenorrhea and hirsutism at age 31. Women reporting both symptoms were considered PCOS (N = 124) and asymptomatic women as controls (N = 2145). The diagnosis of psychosis was traced using multiple national registers up to the year 2016. Symptoms of psychopathology were identified using validated questionnaires at age 31. Women with PCOS showed an increased risk for any psychosis by age 50 (HR [95% CI] 2.99, [1.52-5.82]). Also, the risk for psychosis after age 31 was increased (HR 2.68 [1.21-5.92]). The results did not change after adjusting for parental history of psychosis, nor were they explained by body mass index or hyperandrogenism at adulthood. The scales of psychopathology differed between women with PCOS and non-PCOS controls showing more psychopathologies among the affected women. PCOS cases were found to be at a three-fold risk for psychosis, and they had increased psychopathological symptoms. PCOS should be taken into consideration when treating women in psychiatric care. More studies are required to further assess the relationship between PCOS and psychotic diseases.

Comparative Efficacy and Tolerability of Antipsychotics for Juvenile Psychotic Disorders: A Systematic Review and Network Meta-Analysis

BACKGROUND

Psychotic disorders produce important morbidity and disability in children and adolescents. There have been few relevant treatment trials, encouraging assessment of research aimed at testing efficacy and safety of antipsychotics for juveniles. We aimed to compare the short- and long-term efficacy and safety of antipsychotics to treat psychotic disorders among children and adolescents.

METHODS

Four major bibliographic databases (PubMed, MEDLINE, PsycINFO, and EMBASE) were searched for clinical trials of antipsychotics in children or adolescents, from database inception to May 2021. We searched for clinical trials comparing antipsychotics with control conditions for juvenile psychosis based on blinded review by 2 independent investigators (C.S.Y. and M.L.). We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses and applied the Cochrane risk-of-bias tool to appraise study quality. One reviewer (A.B.) performed data abstraction which was confirmed by 2 independent, blinded reviewers (C.S.Y. and M.L.). Primary outcomes were scores rating psychosis symptoms and dichotomized retention in treatment protocols versus dropouts because of adverse events. Effect sizes were pooled using frequentist random-effects network meta-analysis modeling to generate summary rate ratios (RRs) and Cohen d standardized mean differences.

RESULTS

Systematic searching generated 1330 unique records. Of these, short-term (n = 15, for 6 [3-12] weeks) and long-term (n = 10, for 12 [6-60] months) treatment trials involved 2208 (39.2% females; median age, 15.3 years), and 1366 subjects (35.0% females; median age, 15.6 years), respectively. Short-term reduction of psychosis scores ranked clozapine (d = -1.35; 95% confidence interval [CI], -1.97 to -0.73]), molindone (-1.22; 95% CI, -1.68 to -0.75), olanzapine (-1.12; 95% CI, -1.44 to -0.81), and risperidone (-0.93; 95% CI, -1.22 to -0.63) as the most effective agents. In longer-term treatment, only lurasidone was effective. Clozapine (RR, 12.8) and haloperidol (RR, 5.15) led to more all-cause and adverse event-related dropouts. There were few trials/drug (1 each for aripiprazole, asenapine, lurasidone, molindone, paliperidone, and ziprasidone, short term; aripiprazole, clozapine, haloperidol, lurasidone, and molindone, long-term). Heterogeneity and inconsistency were high, especially in long-term trials, without evidence of publication bias.

CONCLUSIONS

Some antipsychotics were effective and tolerated short term, but longer-term evidence was very limited. The overall paucity of trials and of adequate controls indicates that more well-designed randomized controlled trials are required for adequate assessment of antipsychotic drug treatment for juveniles.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021232937.

Development of the Korea-Polyenvironmental Risk Score for Psychosis

OBJECTIVE

Comprehensive understanding of polyenvironmental risk factors for the development of psychosis is important. Based on a review of related evidence, we developed the Korea Polyenvironmental Risk Score (K-PERS) for psychosis. We investigated whether the K-PERS can differentiate patients with schizophrenia spectrum disorders (SSDs) from healthy controls (HCs).

METHODS

We reviewed existing tools for measuring polyenvironmental risk factors for psychosis, including the Maudsley Environmental Risk Score (ERS), polyenviromic risk score (PERS), and Psychosis Polyrisk Score (PPS). Using odds ratios and relative risks for Western studies and the "population proportion" (PP) of risk factors for Korean data, we developed the K-PERS, and compared the scores thereon between patients with SSDs and HCs. In addition, correlation was performed between the K-PERS and Positive and Negative Syndrome Scale (PANSS).

RESULTS

We first constructed the "K-PERS-I," comprising five factors based on the PPS, and then the "K-PERS-II" comprising six factors based on the ERS. The instruments accurately predicted participants' status (case vs. control). In addition, the K-PERS-I and -II scores exhibited significant negative correlations with the negative symptom factor score of the PANSS.

CONCLUSION

The K-PERS is the first comprehensive tool developed based on PP data obtained from Korean studies that measures polyenvironmental risk factors for psychosis. Using pilot data, the K-PERS predicted patient status (SSD vs. HC). Further research is warranted to examine the relationship of K-PERS scores with clinical outcomes of psychosis and schizophrenia.

Traumatic Events, Social Adversity and Discrimination as Risk Factors for Psychosis - An Umbrella Review

Exposure to childhood trauma is a well-known risk factor for severe mental disorders including schizophrenia and other non-affective psychoses. Beyond childhood trauma, there is increasing evidence that bullying, social exclusion, and discrimination during adolescence and adulthood may increase the risk of developing a psychotic disorder, and that such forms of traumatization may also underlie the elevated psychosis risk among migrants or persons with a visible minority status. In this umbrella review, we systematically assess meta-analyses regarding trauma and social adversity. A systematic literature review yielded 11 meta-analyses that met inclusion criteria and could be summarized quantitatively with a random effect model. Furthermore, six meta-analyses were evaluated qualitatively. Heterogeneity and publication bias were apparent in several meta-analyses. We observed that most significant social risk factors for psychosis were vulnerability for racist discrimination [OR = 3.90 (3.25-4.70)], migration [OR = 2.22 (1.75-2.80)], and childhood adversities [OR = 2.81 (2.03-3.83)]. Furthermore, social factors increasing the risk for psychosis were variation/impairment of parental communication, aversive adult life events, bullying, and factors associated with social isolation and discrimination. In spite of these environmental risk factors, there is a lack of evidence regarding treatment of trauma and psychosis, although some psychotherapeutic and art therapy approaches appear to be promising. Beyond individual interventions, stigmatization, racism, and other forms of discrimination need to be targeted to increase solidarity and communal support.

Resting state alpha oscillatory activity is a valid and reliable marker of schizotypy

Schizophrenia is among the most debilitating neuropsychiatric disorders. However, clear neurophysiological markers that would identify at-risk individuals represent still an unknown. The aim of this study was to investigate possible alterations in the resting alpha oscillatory activity in normal population high on schizotypy trait, a physiological condition known to be severely altered in patients with schizophrenia. Direct comparison of resting-state EEG oscillatory activity between Low and High Schizotypy Group (LSG and HSG) has revealed a clear right hemisphere alteration in alpha activity of the HSG. Specifically, HSG shows a significant slowing down of right hemisphere posterior alpha frequency and an altered distribution of its amplitude, with a tendency towards a reduction in the right hemisphere in comparison to LSG. Furthermore, altered and reduced connectivity in the right fronto-parietal network within the alpha range was found in the HSG. Crucially, a trained pattern classifier based on these indices of alpha activity was able to successfully differentiate HSG from LSG on tested participants further confirming the specific importance of right hemispheric alpha activity and intrahemispheric functional connectivity. By combining alpha activity and connectivity measures with a machine learning predictive model optimized in a nested stratified cross-validation loop, current research offers a promising clinical tool able to identify individuals at-risk of developing psychosis (i.e., high schizotypy individuals).

Schizophrenia: Complement Cleaning or Killing

Schizophrenia is a psychiatric disorder with a typical onset occurring during adolescence or young adulthood. The heterogeneity of the disorder complicates our understanding of the pathophysiology. Reduced cortical synaptic densities are commonly observed in schizophrenia and suggest a role for excessive synaptic elimination. A major pathway hypothesised to eliminate synapses during postnatal development is the complement system. This review provides an overview of genetic and functional evidence found for the individual players of the classical complement pathway. In addition, the consequences of the absence of complement proteins, in the form of complement protein deficiencies in humans, are taken into consideration. The collective data provide strong evidence for excessive pruning by the classical complement pathway, contributing to cognitive impairment in schizophrenia. In future studies, it will be important to assess the magnitude of the contribution of complement overactivity to the occurrence and prevalence of phenotypic features in schizophrenia. In addition, more insight is required for the exact mechanisms by which the complement system causes excessive pruning, such as the suggested involvement of microglial engulfment and degradation of synapses. Ultimately, this knowledge is a prerequisite for the development of therapeutic interventions for selective groups of schizophrenia patients.

Real-world digital implementation of the Psychosis Polyrisk Score (PPS): A pilot feasibility study

BACKGROUND

The Psychosis Polyrisk Score (PPS) is a potential biomarker integrating non-purely genetic risk/protective factors for psychosis that may improve identification of individuals at risk and prediction of their outcomes at the individual subject level. Biomarkers that are easy to administer are direly needed in early psychosis to facilitate clinical implementation. This study digitally implements the PPS and pilots its feasibility of use in the real world.

METHODS

The PPS was implemented digitally and prospectively piloted across individuals referred for a CHR-P assessment (n = 16) and healthy controls (n = 66). Distribution of PPS scores was further simulated in the general population.

RESULTS

98.8% of individuals referred for a CHR-P assessment and healthy controls completed the PPS assessment with only one drop-out. 96.3% of participants completed the assessment in under 15 min. Individuals referred for a CHR-P assessment had high PPS scores (mean = 6.2, SD = 7.23) than healthy controls (mean = -1.79, SD = 6.78, p < 0.001). In simulated general population data, scores were normally distributed ranging from -15 (lowest risk, RR = 0.03) to 39.5 (highest risk, RR = 8912.51).

DISCUSSION

The PPS is a promising biomarker which has been implemented digitally. The PPS can be easily administered to both healthy controls and individuals at potential risk for psychosis on a range of devices. It is feasible to use the PPS in real world settings to assess individuals with emerging mental disorders. The next phase of research should be to include the PPS in large-scale international cohort studies to evaluate its ability to refine the prognostication of outcomes.

Risk factors for postpartum depression: An evidence-based systematic review of systematic reviews and meta-analyses

PURPOSE

Postpartum depression (PPD) is the most common psychiatric condition after childbirth which not only effects the mother's health, but also might have impact on child's development and parenting behaviors. Because the etiology of PPD has not been fully cleared, the efforts towards identification of risk factors are crucial for both the children and mother's health.

METHOD

PubMed, EMBASE and PsycINFO databases were searched since inception until July 2019 to collect data about the risk factors of PPD and only systematic review and meta-analysis can be included.

RESULT

To identify the real risk factors, protective factors and controversial factors, nineteen parts of the interpretation were adopted. The risk factors are mainly concentrated in the following aspects: violence and abuse, immigration status, gestational diabetes, cesarean section, depressive history, vitamin D deficiency, obese and overweight, postpartum sleep disruption and poor postpartum sleep, lack of social support, traditional dietary pattern (Japanese, Indian, United Kingdom, and Brazilian dietary pattern), multiple births, preterm and low-birth-weight infants, postpartum anemia, negative birth experience. The controversial factors are serum level of cortisol, thyroid peroxidase autoantibodies status, acculturation, traditional confinement practices. Skin-to-skin care, higher concentrations of DHA in mothers' milk, greater seafood consumption, healthy dietary patterns, multivitamin supplementation, fish and PUFA intake, calcium, Vitamin D, zinc and possibly selenium are protective factors.

CONCLUSION

Thirteen risk factors were identified, but five factors still controversial due to the insufficient of the evidence. What's more, skin-to-skin care and some nutrition related factors are protective factors against PPD.

Psychotic Experiences Are Associated With Paternal Age But Not With Delayed Fatherhood in a Large, Multinational, Community Sample

Advanced paternal age has been consistently associated with an increased risk of schizophrenia. It is less known if such an association also exists with subclinical/attenuated forms of psychosis. Additionally, it has been suggested that it is not paternal age per se, but rather delayed fatherhood, as a marker of a genetic liability of psychosis, that is the cause of the association. The aim of the current study was to examine whether paternal age and/or delayed fatherhood (paternity age) predict self-reported positive, negative, and/or depressive dimensions of psychosis in a large sample from the general population. The sample (N = 1465) was composed of control subjects from the 6 countries participating in the European Union Gene-Environment Interaction study. The CAPE, a self-report questionnaire, was used to measure dimensions of subclinical psychosis. Paternal age at the time of respondents' birth and age of paternity were assessed by self-report. We assessed the influence of the variables of interest (paternal age or paternity age) on CAPE scores after adjusting for potential confounders (age, gender, and ethnicity). Paternal age was positively associated with the positive dimension of the CAPE. By contrast, paternity age was not associated with any of the psychosis dimensions assessed by the CAPE. Thus, our results do not support the idea that delayed fatherhood explains the association between age of paternity and psychosis risk. Furthermore, our results provide arguments for the hypothesis of an etiologic continuum of psychosis.

Academic achievement and schizophrenia: a systematic meta-analysis

BACKGROUND

Cognitive impairments in childhood are associated with increased risk of schizophrenia in later life, but the extent to which poor academic achievement is associated with the disorder is unclear.

METHODS

Major databases were searched for articles published in English up to 31 December 2019. We conducted random-effects meta-analyses to: (1) compare general academic and mathematics achievement in youth who later developed schizophrenia and those who did not; (2) to examine the association between education level achieved and adult-onset schizophrenia; and, (3) compare general academic achievement in youth at-risk for schizophrenia and typically developing peers. Meta-regression models examined the effects of type of academic assessment, educational system, age at assessment, measurement of educational level attained, school leaving age, and study quality on academic achievement and education level among individuals with schizophrenia.

RESULTS

Meta-analyses, comprising data of over four million individuals, found that: (1) by age 16 years, those who later developed schizophrenia had poorer general academic (Cohen's d = -0.29, p ⩽ 0.0001) and mathematics achievement (d = -0.23, p = 0.01) than those who did not; (2) individuals with schizophrenia were less likely to enter higher education (odds ratio = 0.49, p ⩽ 0.0001); and, (3) youth reporting psychotic-like experiences and youth with a family history of schizophrenia had lower general academic achievement (d = -0.54, p ⩽ 0.0001; d = -0.39, p ⩽ 0.0001, respectively). Meta-regression analyses determined no effect modifiers.

DISCUSSION

Despite significant heterogeneity across studies, various routinely collected indices of academic achievement can identify premorbid cognitive dysfunction among individuals who are vulnerable for schizophrenia, potentially aiding the early identification of risk in the population.

Sleep-related memory consolidation in the psychosis spectrum phenotype

Sleep and memory processing impairments range from mild to severe in the psychosis spectrum. Relationships between memory processing and sleep characteristics have been described for schizophrenia, including unaffected first-degree relatives, but they are less clear across other high-risk groups within the psychosis spectrum. In this study, we investigated high-risk individuals with accumulated risk-factors for psychosis and subthreshold symptoms. Out of 1898 screened individuals, 44 age- and sex-matched participants were sub-grouped into those with substantial environmental risk factors for psychosis and subthreshold psychotic symptoms (high-risk group) and those without these phenotypes (low-risk controls). Four groups (high/low risk, morning/evening training) were trained and tested in the laboratory for sustained attention, motor skill memory (finger-tapping task) and declarative memory (word-pair learning task) immediately after training, again after a night of EEG-recorded sleep at home or a period of daytime wakefulness, and again after 24 h from training. No differences in sustained attention or in memory consolidation of declarative and motor skill memory were found between groups for any time period tested. However, a group difference was found for rapid-eye movement (REM) sleep in relation to motor skill memory: the longer the total sleep time, particularly longer REM sleep, the greater the performance gain, which occurred only in high-risk individuals. In conclusion, our results suggest a gain in motor skill performance with sufficient sleep opportunity for longer REM sleep in high-risk individuals with subthreshold psychotic symptoms. Declarative memory did not benefit from sleep consolidation above or beyond that of the control group.

Database combinations to retrieve systematic reviews in overviews of reviews: a methodological study

Background

When conducting an Overviews of Reviews on health-related topics, it is unclear which combination of bibliographic databases authors should use for searching for SRs. Our goal was to determine which databases included the most systematic reviews and identify an optimal database combination for searching systematic reviews.

Methods

A set of 86 Overviews of Reviews with 1219 included systematic reviews was extracted from a previous study. Inclusion of the systematic reviews was assessed in MEDLINE, CINAHL, Embase, Epistemonikos, PsycINFO, and TRIP. The mean inclusion rate (% of included systematic reviews) and corresponding 95% confidence interval were calculated for each database individually, as well as for combinations of MEDLINE with each other database and reference checking.

Results

Inclusion of systematic reviews was higher in MEDLINE than in any other single database (mean inclusion rate 89.7%; 95% confidence interval [89.0–90.3%]). Combined with reference checking, this value increased to 93.7% [93.2–94.2%]. The best combination of two databases plus reference checking consisted of MEDLINE and Epistemonikos (99.2% [99.0–99.3%]). Stratification by Health Technology Assessment reports (97.7% [96.5–98.9%]) vs. Cochrane Overviews (100.0%) vs. non-Cochrane Overviews (99.3% [99.1–99.4%]) showed that inclusion was only slightly lower for Health Technology Assessment reports. However, MEDLINE, Epistemonikos, and reference checking remained the best combination. Among the 10/1219 systematic reviews not identified by this combination, five were published as websites rather than journals, two were included in CINAHL and Embase, and one was included in the database ERIC.

Conclusions

MEDLINE and Epistemonikos, complemented by reference checking of included studies, is the best database combination to identify systematic reviews on health-related topics.

Comorbidity Profiles of Psychotic Patients in Emergency Psychiatry

Objectives: Individuals with psychotic symptoms presenting to emergency psychiatry often have comorbid symptoms, such as substance misuse, depression, and anxiety. Many will also have symptoms linked to previous traumatic experiences such as impulsivity, often found in comorbid personality disorders. Although various studies have looked at specific comorbid symptoms, little is known regarding how these symptoms co-exist in individuals with psychotic symptoms and their link with social functioning. The primary objective of the present study was to identify comorbidity profiles among individuals seeking emergency room services for psychotic symptoms. The secondary objective was to investigate the relationship between comorbid symptoms and social functioning deficits in this same population. Methods: Data from 546 individuals seeking psychiatric help for psychotic symptoms was collected within the Signature Project (large data bank) in a psychiatric emergency. Participants answered brief measures of symptoms of alcohol/substance misuse (AUDIT, DAST), depression (PHQ-9), anxiety (STAI-6), childhood trauma (CEVQ), impulsivity (UPPS) and social functioning deficits (WHODAS). For this study, symptom measures and social functioning at baseline were used. Results: Cluster analyses conducted using three different methods revealed a consensus of five classes of comorbid presentations. Class 1 (n = 90) grouped people who had a high score for childhood trauma, with fairly high scores for anxiety and depression. Class 2 (n = 176) included people with mostly psychotic symptoms with little comorbid presentation across other measures. Class 3 (n = 81) grouped people with the highest anxiety and depression scores as well as high drug use and impulsivity. Individuals in Class 4 (n = 87) had the highest scores on alcohol and substance abuse, as well as high impulsivity. Class 5 (n = 112) grouped people with very low anxiety and depression scores but average trauma, alcohol, and substance misuse scores. Linear regressions revealed an association between social functioning, and depression, anxiety, and childhood trauma. Conclusions: Comorbid presentations of individuals with psychosis are frequent and diverse. Depression and anxiety, in particular, worsen social functioning deficits in people with psychotic symptoms. Given their impact on functioning, psychiatric treatments should address these comorbidities during hospitalization, as well as when followed in the community.

School success in childhood and subsequent prodromal symptoms and psychoses in the Northern Finland Birth Cohort 1986

BACKGROUND

Low IQ is a risk factor for psychosis, but the effect of high IQ is more controversial. The aim was to explore the association of childhood school success with prodromal symptoms in adolescence and psychoses in adulthood.

METHODS

In the general population-based Northern Finland Birth Cohort 1986 (n = 8 229), we studied the relationship between teacher-assessed learning deficits, special talents and general school success at age 8 years and both prodromal symptoms (PROD-screen) at age 15-16 years and the occurrence of psychoses by age 30 years.

RESULTS

More prodromal symptoms were experienced by those talented in oral presentation [boys: adjusted odds ratio (OR) 1.49; 95% confidence interval 1.14-1.96; girls: 1.23; 1.00-1.52] or drawing (boys: 1.44; 1.10-1.87). Conversely, being talented in athletics decreased the probability of psychotic-like symptoms (boys: OR 0.72; 0.58-0.90). School success below average predicted less prodromal symptoms with boys (OR 0.68; 0.48-0.97), whereas above-average success predicted more prodromal symptoms with girls (OR 1.22; 1.03-1.44). The occurrence of psychoses was not affected. Learning deficits did not associate with prodromal symptoms or psychoses.

CONCLUSIONS

Learning deficits in childhood did not increase the risk of prodromal symptoms in adolescence or later psychosis in this large birth cohort. Learning deficits are not always associated with increased risk of psychosis, which might be due to, e.g. special support given in schools. The higher prevalence of prodromal symptoms in talented children may reflect a different kind of relationship of school success with prodromal symptoms compared to full psychoses.

Premorbid Adjustment and IQ in Patients With First-Episode Psychosis: A Multisite Case-Control Study of Their Relationship With Cannabis Use

Psychotic patients with a lifetime history of cannabis use generally show better cognitive functioning than other psychotic patients. Some authors suggest that cannabis-using patients may have been less cognitively impaired and less socially withdrawn in their premorbid life. Using a dataset comprising 948 patients with first-episode psychosis (FEP) and 1313 population controls across 6 countries, we examined the extent to which IQ and both early academic (Academic Factor [AF]) and social adjustment (Social Factor [SF]) are related to the lifetime frequency of cannabis use in both patients and controls. We expected a higher IQ and a better premorbid social adjustment in psychotic patients who had ever used cannabis compared to patients without any history of use. We did not expect such differences in controls. In both patients and controls, IQ was 3 points higher among occasional-users than in never-users (mean difference [Mdiff] = 2.9, 95% CI = [1.2, 4.7]). Both cases and control daily-users had lower AF compared to occasional (Mdiff = -0.3, 95% CI = [-0.5; -0.2]) and never-users (Mdiff = -0.4, 95% CI = [-0.6; -0.2]). Finally, patient occasional (Mdiff = 0.3, 95% CI = [0.1; 0.5]) and daily-users (Mdiff = 0.4, 95% CI = [0.2; 0.6]) had better SF than their never-using counterparts. This difference was not present in controls (Fgroup*frequency(2, 2205) = 4.995, P = .007). Our findings suggest that the better premorbid social functioning of FEP with a history of cannabis use may have contributed to their likelihood to begin using cannabis, exposing them to its reported risk-increasing effects for Psychotic Disorders.

The interplay between childhood trauma, cognitive biases, and cannabis use on the risk of psychosis in nonclinical young adults in Poland

Background.

Childhood traumatic events are risk factors for psychotic-like experiences (PLEs). However, the mechanisms explaining how trauma may contribute to the development of PLEs are not fully understood. In our study, we investigated whether cannabis use and cognitive biases mediate the relationship between early trauma and PLEs.

Methods.

A total sample of 6,772 young adults (age 26.6 ± 4.7, 2,181 male and 3,433 female) was recruited from the general population to participate in an online survey. We excluded 1,158 individuals due to a self-reported lifetime diagnosis of any mental disorder. The online survey included selected items from the following questionnaires: Traumatic Experience Checklist (TEC, 3 items), Childhood Experience of Care and Abuse Questionnaire (CECA.Q, 3 items), Cannabis Problems Questionnaire (CPQ, 10 items), Davos Assessment of Cognitive Biases Scale (DACOBS-18, 9 items), and Prodromal Questionnaire-16 (PQ-16). Mediation analyses were performed with respect to different categories of traumatic experiences (emotional, physical and sexual abuse as well as emotional neglect).

Results.

Our results showed significant associations of any time of childhood trauma with higher scores of cannabis use (CPQ), cognitive biases (DACOBS), and PLEs (PQ-16) (p < 0.001). We found a direct effect of childhood trauma on PLEs as well as significant indirect effect mediated through cannabis use and cognitive biases. All models tested for the effects of specific childhood adversities revealed similar results. The percentage of variance in PQ-16 scores explained by serial mediation models varied between 32.8 and 34.2% depending on childhood trauma category.

Conclusion.

Cannabis use and cognitive biases play an important mediating role in the relationship between childhood traumatic events and the development of PLEs in a nonclinical young adult population.

Auditory sensory gating in young adolescents with early-onset psychosis: a comparison with attention deficit/hyperactivity disorder

Numerous studies have demonstrated impaired sensory gating in schizophrenia and this impairment has been proposed as a candidate biomarker for the disorder. The typical age of onset for schizophrenia is early adulthood, however a sizable group of patients present with psychotic symptoms before the age of 18, commonly referred to as early-onset psychosis (EOP). How an earlier onset influences sensory gating is currently unknown. Impaired sensory gating may not be specific to psychosis, but rather a shared disturbance of neurodevelopmental disorders, such as attention deficit/hyperactivity disorder (ADHD). Therefore, the current study investigated P50 suppression in young adolescents (12-17 years old) with either EOP (N = 55) or ADHD (N = 28) and age and gender matched healthy controls (HC) (N = 71). In addition to P50 suppression, N100 and P200 suppression data were also analyzed. No significant group differences in either raw mean P50 amplitude or mean P50 gating ratios were observed between EOP, ADHD, and HC. Additionally, we observed no P50 suppression deficit in those EOP patients diagnosed with schizophrenia (N = 39). Similarly, we observed no differences in N100 or P200 between the three groups. Healthy levels of P50 suppression were found in both patient groups. The results are in line with some previous studies showing healthy levels of P50 suppression in the early phases of schizophrenia. Our findings do not support P50 sensory gating as a valid biomarker for EOP or ADHD.

Cannabis use and nonuse in patients with first-episode psychosis: A systematic review and meta-analysis of studies comparing neurocognitive functioning

BACKGROUND

The implications of cannabis use in the onset of early psychosis and the severity of psychotic symptoms have resulted in a proliferation of studies on this issue. However, few have examined the effects of cannabis use on the cognitive symptoms of psychosis (i.e., neurocognitive functioning) in patients with first-episode psychosis (FEP). This systematic review and meta-analysis aim to assess the neurocognitive functioning of cannabis users (CU) and nonusers (NU) with FEP.

METHODS

Of the 110 studies identified through the systematic review of 6 databases, 7 met the inclusion criteria, resulting in 14 independent samples and 78 effect sizes. The total sample included 304 CU with FEP and 369 NU with FEP. The moderator variables were age at first use, duration of use, percentage of males, and age.

RESULTS

Effect sizes were not significantly different from zero in any neurocognitive domain when users and NU were compared. Part of the variability in effect sizes was explained by the inclusion of the following moderator variables: (1) frequency of cannabis use (β = 0.013, F = 7.56, p = 0.017); (2) first-generation antipsychotics (β = 0.019, F = 34.46, p ≤ 0.001); and (3) country where the study was carried out (β = 0.266, t = 2.06, p = 0.043).

CONCLUSIONS

This meta-analysis indicates that cannabis use is not generally associated with neurocognitive functioning in patients with FEP. However, it highlights the deleterious effect of low doses of cannabis in some patients. It also stresses the importance of the type of antipsychotic prescription and cannabis dose as moderator variables in the neurocognitive functioning of CU with FEP.

What Causes the Onset of Psychosis in Individuals at Clinical High Risk? A Meta-analysis of Risk and Protective Factors

Twenty percent of individuals at clinical high risk for psychosis (CHR-P) develop the disorder within 2 years. Extensive research has explored the factors that differentiate those who develop psychosis and those who do not, but the results are conflicting. The current systematic review and meta-analysis comprehensively addresses the consistency and magnitude of evidence for non-purely genetic risk and protective factors associated with the risk of developing psychosis in CHR-P individuals. Random effects meta-analyses, standardized mean difference (SMD) and odds ratio (OR) were used, in combination with an established stratification of evidence that assesses the association of each factor and the onset of psychotic disorders (from class I, convincing evidence to class IV weak evidence), while controlling for several types of biases. A total of 128 original controlled studies relating to 26 factors were retrieved. No factors showed class I-convincing evidence. Two further factors were associated with class II-highly suggestive evidence: attenuated positive psychotic symptoms (SMD = 0.348, 95% CI: 0.280, 0.415) and global functioning (SMD = -0.291, 95% CI: -0.370, -0.211). There was class III-suggestive evidence for negative psychotic symptoms (SMD = 0.393, 95% CI: 0.317, 0.469). There was either class IV-weak or no evidence for all other factors. Our findings suggest that despite the large number of putative risk factors investigated in the literature, only attenuated positive psychotic symptoms, global functioning, and negative psychotic symptoms show suggestive evidence or greater for association with transition to psychosis. The current findings may inform the refinement of clinical prediction models and precision medicine in this field.

Nutritional assessment of omega-3 fatty acids intake in schizophrenia patients group

Introduction: Schizophrenia is a chronic mental disease which significantly affects functioning and quality of life of patients. Lifestyle, including irregular eating habits, is a factor possibly intensifying symptoms of the disease and unwanted effects of pharmacotherapy. Due to positive effect on metabolic parameters demonstrated in numerous studies and participation in structure and functioning of central nervous system, omega-3 essential unsaturated fatty acids (EFAs) are the suggested form of schizophrenia cotheraphy.

Aim: The purpose of this paper was to evaluate EFAs (especially omega-3 family) consumption by individuals with schizophrenia and comparing contents of these acids in the diets of female and male patients.

Method: A study was conducted with the participation of 32 patients, recruited in the Psychiatric Outpatient Department of the Independent Public Clinical Hospital No. 1 in Lublin, with diagnosed schizophrenia. Data concerning the intake of EFAs was acquired in the course of 24-hour diet recall.

Results: Average intake of omega-3 EFAs in the examined population was 2.40 ± 2.85 g, of which only 201.6 ± 501.5 mg was constituted by EPA and DHA acids. The intake of omega-3 EFAs did not differ between men and women groups (p>0.05). Food rations of the 91% responders were characterised with the intake of EPA and DHA acids below the adequate intake level (AI).

Conclusions: Patients suffering from schizophrenia consume insufficient amounts of EPA and DHA acids. Evidence suggests that optimum intake of omega-3 EFAs could bring significant benefits for this group of patients. People suffering from schizophrenia should be attended with the care of a dietician, who will choose optimum strategy for supplying sufficient amount of nutrients in the diet.

Impact of Polygenic Risk for Schizophrenia on Cortical Structure in UK Biobank

BACKGROUND

Schizophrenia is a neurodevelopmental disorder with many genetic variants of individually small effect contributing to phenotypic variation. Lower cortical thickness (CT), surface area, and cortical volume have been demonstrated in people with schizophrenia. Furthermore, a range of obstetric complications (e.g., lower birth weight) are consistently associated with an increased risk for schizophrenia. We investigated whether a high polygenic risk score for schizophrenia (PGRS-SCZ) is associated with CT, surface area, and cortical volume in UK Biobank, a population-based sample, and tested for interactions with birth weight.

METHODS

Data were available for 2864 participants (n_male/n_female = 1382/1482; mean age = 62.35 years, SD = 7.40). Linear mixed models were used to test for associations among PGRS-SCZ and cortical volume, surface area, and CT and between PGRS-SCZ and birth weight. Interaction effects of these variables on cortical structure were also tested.

RESULTS

We found a significant negative association between PGRS-SCZ and global CT; a higher PGRS-SCZ was associated with lower CT across the whole brain. We also report a significant negative association between PGRS-SCZ and insular lobe CT. PGRS-SCZ was not associated with birth weight and no PGRS-SCZ × birth weight interactions were found.

CONCLUSIONS

These results suggest that individual differences in CT are partly influenced by genetic variants and are most likely not due to factors downstream of disease onset. This approach may help to elucidate the genetic pathophysiology of schizophrenia. Further investigation in case-control and high-risk samples could help identify any localized effects of PGRS-SCZ, and other potential schizophrenia risk factors, on CT as symptoms develop.

An Early Developmental Marker of Deficit versus Nondeficit Schizophrenia

People with schizophrenia and primary negative symptoms (deficit schizophrenia) differ from those without such symptoms (nondeficit schizophrenia) on risk factors, course of illness, other signs and symptoms, treatment response, and biological correlates. These differences suggest that the 2 groups may also have developmental differences. A previous study found that people with schizophrenia have a wider palate than comparison subjects. We tested the hypothesis that those with deficit and nondeficit schizophrenia would differ on palate width. A dentist made blinded measurements of palate shape in deficit (N = 21) and nondeficit (N = 25) patients and control subjects (N = 127), matched for age and gender. The deficit group had significantly wider palates than either nondeficit or control subjects (respective means [standard deviation] 37.5 [3.9], 33.7 [3.1], and 34.0 [2.9]; P < .001 for both deficit/nondeficit and deficit/control comparisons, respective effect sizes 1.08 and 1.01). The nondeficit/control difference in width was not significant (P = .83), and there were no significant group differences in length or depth. The power to detect a nondeficit/control difference in width equal in size to that of the deficit/control difference in width (3.5 mm) was 0.99 and 0.92 for a 2.0-mm difference. This difference in palate width may reflect a divergence in development between deficit and nondeficit patients that occurs by the early second trimester and is consistent with the hypothesis that deficit schizophrenia is a separate disease within the syndrome of schizophrenia.

Cerebellar Gray Matter Volume Is Associated With Cognitive Function and Psychopathology in Adolescence

BACKGROUND

Accumulating evidence supports cerebellar involvement in mental disorders, such as schizophrenia, bipolar disorder, depression, anxiety disorders, and attention-deficit/hyperactivity disorder. However, little is known about the cerebellum in developmental stages of these disorders. In particular, whether cerebellar morphology is associated with early expression of specific symptom domains remains unclear.

METHODS

We used machine learning to test whether cerebellar morphometric features could robustly predict general cognitive function and psychiatric symptoms in a large and well-characterized developmental community sample centered on adolescence (Philadelphia Neurodevelopmental Cohort, n = 1401, age 8-23 years).

RESULTS

Cerebellar morphology was associated with both general cognitive function and general psychopathology (mean correlations between predicted and observed values: r = .20 and r = .13; p < .001). Analyses of specific symptom domains revealed significant associations with rates of norm-violating behavior (r = .17; p < .001) as well as psychosis (r = .12; p < .001) and anxiety (r = .09; p = .012) symptoms. In contrast, we observed no associations with attention deficits or depressive, manic, or obsessive-compulsive symptoms. Crucially, across 52 brain-wide anatomical features, cerebellar features emerged as the most important for prediction of general psychopathology, psychotic symptoms, and norm-violating behavior. Moreover, the association between cerebellar volume and psychotic symptoms and, to a lesser extent, norm-violating behavior remained significant when adjusting for several potentially confounding factors.

CONCLUSIONS

The robust associations with psychiatric symptoms in the age range when these typically emerge highlight the cerebellum as a key brain structure in the development of severe mental disorders.

Childhood adversities in people at ultra-high risk (UHR) for psychosis: a systematic review and meta-analysis

Childhood adversities have been reported to be more common among individuals at ultra-high risk (UHR) for psychosis. This paper systematically reviewed and meta-analysed (i) the severity and prevalence of childhood adversities (childhood trauma exposure, bullying victimisation and parental separation or loss) among the UHR, and (ii) the association between adversities and transition to psychosis (TTP). PsycINFO, PubMed and Embase databases were searched for studies reporting childhood adversities among UHR individuals. Only published articles were included. Risk of bias was assessed using Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guideline (von Elm et al., 2007) and the tool developed by Hoy et al. (2012). Seventeen case-control, cross-sectional and longitudinal studies were included. UHR individuals experienced significantly more severe trauma than controls, regardless of trauma subtype. UHR were 5.5, 2.5 and 3.1 times as likely to report emotional abuse, physical abuse and bullying victimisation, respectively. There was no association with parental separation. However, childhood trauma was not significantly associated with TTP (follow-up periods: 6 months to 15 years), suggesting that trauma alone may not be a sufficient risk factor. Sexual abuse was associated with TTP but this may have been driven by a single large study. Potential confounders and low rates of TTP among UHR are limitations of this review. This is the first meta-analysis that quantitatively summarises the associations between childhood adversities and TTP among UHR, and between specific abuse subtypes and TTP. Specific recommendations have been made to increase the quality of future research. PROSPERO registration no. CRD42017054884.

Psychosis Polyrisk Score (PPS) for the Detection of Individuals At-Risk and the Prediction of Their Outcomes

Primary prevention in individuals at Clinical High Risk for psychosis (CHR-P) can ameliorate the course of psychotic disorders. Further advancements of knowledge have been slowed by the standstill of the field, which is mostly attributed to its epidemiological weakness. The latter, in turn, underlies the limited identification power of at-risk individuals and the relatively modest ability of CHR-P interviews to rule-in a state of risk for psychosis. In the first part, this perspective review discusses these limitations and traces a new approach to overcome them. Theoretical concepts to support a Psychosis Polyrisk Score (PPS) integrating genetic and non-genetic risk and protective factors for psychosis are presented. The PPS hinges on recent findings indicating that risk enrichment in CHR-P samples is accounted for by the accumulation of non-genetic factors such as: parental and sociodemographic risk factors, perinatal risk factors, later risk factors, and antecedents. In the second part of this perspective review we present a prototype of a PPS encompassing core predictors beyond genetics. The PPS prototype may be piloted in the next generation of CHR-P research and combined with genetic information to refine the detection of individuals at-risk of psychosis and the prediction of their outcomes, and ultimately advance clinical research in this field.

Maternal stress, prenatal medical illnesses and obstetric complications: Risk factors for schizophrenia spectrum disorder, bipolar disorder and major depressive disorder

Maternal stress and medical illnesses during early life are well-documented environmental indicators of an increased risk of schizophrenia. Few studies, conversely, have confirmed an association with major affective disorders. The present study examined the impact of maternal stress, medical illnesses and obstetric complications on the development of severe mental disorder in 240 patients with a diagnosis of schizophrenia spectrum disorder, bipolar disorder, or major depressive disorder and matched with 85 controls. Mothers of participants were asked about stressful events during pregnancy using the Social Readjustment Scale; information on prenatal/perinatal illnesses were acquired from medical records. Schizophrenia spectrum disorder was positively associated with maternal stress (OR = 2.16), infections (OR = 7.67), inadequate weight gain (OR = 9.52) during pregnancy, and peripartum asphyxia (OR = 4.00). An increased risk of bipolar disorder was associated with head circumference < 32 cm at birth (OR = 5.40) and inversely with inadequate weight gain (OR = 0.29). Major depressive disorder diagnosis was inversely related to inadequate weight gain (OR = 0.22). These results support a role for maternal stress, medical illnesses and obstetric complications as risk factors for subsequent severe mental illness in adulthood. Further research is needed, especially with regard to affective disorders.

Childhood adversities are different in Schizophrenic Spectrum Disorders, Bipolar Disorder and Major Depressive Disorder

BACKGROUND

Research has shown that a history of childhood adversities is common in patients with psychiatric disorders but few studies have investigated links between specific types of adversity and specific psychiatric disorders.

METHODS

We investigated the frequency of early childhood adversities in a sample consisting of 91 patients with diagnosis of schizophrenic spectrum disorders (SSD), 74 patients with bipolar disorder (BD), 83 patients with major depressive disorder (MDD) and 85 healthy controls and sought to identify adverse early childhood life events that predict the development of major psychiatric disorders. The Childhood Experiences of Care and Abuse questionnaire was used to collect data on traumatic experiences occurring before the age of 17 years and comprehensive demographic data were also collected. The data were analyzed with chi-squared tests, t-tests, post-hoc and logistic regression.

RESULTS

Maternal absence/loss and economic difficulties in the early life were more prevalent in the BD group than other groups. Escape from home, cannabis abuse, psychological abuse, physical abuse and loneliness were more frequent in the SSD group than in other groups. Paternal absence, neglect of core needs, serious familial tension and absence of adult and peer confidants were all less common in the HC group than in the other groups. The regression model confirmed that different types of adversities play a crucial role in the development of the three investigated disorders.

CONCLUSIONS

Our results support that SSD, BD and MDD are associated to different childhood adversities. This suggests that psychosocial interventions that reduce the incidence of these early life adversities might reduce the incidence of severe and disabling psychiatric disorders.

Obstetric Phenotypes in the Heterogeneity of Schizophrenia

Schizophrenia is a complex mental disorder with genetic and environmental components. Obstetric complications (OCs) are one of the most common environmental risk factors described. However, despite being different in timing and outcome, OCs are usually described as a homogeneous entity. In the present study, we evaluate the presence of different patterns of OCs evaluated with the Lewis-Murray Scale in chronic schizophrenia patients (n = 101) and their association with a crude marker of the intrauterine environment such as weight at birth.OCs related with abnormal fetal growth (p < 0.001) and OCs during gestation (p = 0.003) were associated with lower birth weight. However, difficulties in delivery, complications in pregnancy, and OCs all together (as a set) were not associated with weight at birth.Our results infer that OCs cannot be taken as a homogeneous group. Different patterns of OCs result in different birth weights, which is associated with specific metabolic, cognitive, and brain structure outcomes.

Search for protective factors for psychosis - a population-based sample with special interest in unaffected individuals with parental psychosis

AIM

To find factors that are associated with not having psychotic illness in a prospective general population sample, with a special interest in individuals with parental psychosis.

METHODS

Data from the Northern Finland Birth Cohort 1966 (n = 10 458) and several registers were used to detect individuals with and without parental psychosis. Altogether, 594 persons had parent(s) with psychosis and 48 of them also had psychosis subsequently. Variables related to pregnancy and birth, family and childhood, health and habits in adolescence, school performance and physical activity were studied to identify determinants of unaffected status among individuals with and without parental psychosis.

RESULTS

In the parental psychosis group, the unaffected persons had more likely a mother who was non-depressed during pregnancy, and who worked outside the home or studied than among those who developed psychosis.

CONCLUSIONS

Protective factors for psychosis were surprisingly few in this sample. These factors were related to the mother's non-depressed mood and the mother's work outside the home or studies. This could relate to better health and functioning of a mother. This work highlights the need for more research on protective factors for psychosis in order to identify methods for prevention of psychosis.

Risk factors and peripheral biomarkers for schizophrenia spectrum disorders: an umbrella review of meta-analyses

OBJECTIVE

This study aimed to systematically appraise the meta-analyses of observational studies on risk factors and peripheral biomarkers for schizophrenia spectrum disorders.

METHODS

We conducted an umbrella review to capture all meta-analyses and Mendelian randomization studies that examined associations between non-genetic risk factors and schizophrenia spectrum disorders. For each eligible meta-analysis, we estimated the summary effect size estimate, its 95% confidence and prediction intervals and the I² metric. Additionally, evidence for small-study effects and excess significance bias was assessed.

RESULTS

Overall, we found 41 eligible papers including 98 associations. Sixty-two associations had a nominally significant (P-value <0.05) effect. Seventy-two of the associations exhibited large or very large between-study heterogeneity, while 13 associations had evidence for small-study effects. Excess significance bias was found in 18 associations. Only five factors (childhood adversities, cannabis use, history of obstetric complications, stressful events during adulthood, and serum folate level) showed robust evidence.

CONCLUSION

Despite identifying 98 associations, there is only robust evidence to suggest that cannabis use, exposure to stressful events during childhood and adulthood, history of obstetric complications, and low serum folate level confer a higher risk for developing schizophrenia spectrum disorders. The evidence on peripheral biomarkers for schizophrenia spectrum disorders remains limited.

What causes psychosis? An umbrella review of risk and protective factors

Psychosis is a heterogeneous psychiatric condition for which a multitude of risk and protective factors have been suggested. This umbrella review aimed to classify the strength of evidence for the associations between each factor and psychotic disorders whilst controlling for several biases. The Web of Knowledge database was searched to identify systematic reviews and meta-analyses of observational studies which examined associations between socio-demographic, parental, perinatal, later factors or antecedents and psychotic disorders, and which included a comparison group of healthy controls, published from 1965 to January 31, 2017. The literature search and data extraction followed PRISMA and MOOSE guidelines. The association between each factor and ICD or DSM diagnoses of non-organic psychotic disorders was graded into convincing, highly suggestive, suggestive, weak, or non-significant according to a standardized classification based on: number of psychotic cases, random-effects p value, largest study 95% confidence interval, heterogeneity between studies, 95% prediction interval, small study effect, and excess significance bias. In order to assess evidence for temporality of association, we also conducted sensitivity analyses restricted to data from prospective studies. Fifty-five meta-analyses or systematic reviews were included in the umbrella review, corresponding to 683 individual studies and 170 putative risk or protective factors for psychotic disorders. Only the ultra-high-risk state for psychosis (odds ratio, OR=9.32, 95% CI: 4.91-17.72) and Black-Caribbean ethnicity in England (OR=4.87, 95% CI: 3.96-6.00) showed convincing evidence of association. Six factors were highly suggestive (ethnic minority in low ethnic density area, second generation immigrants, trait anhedonia, premorbid IQ, minor physical anomalies, and olfactory identification ability), and nine were suggestive (urbanicity, ethnic minority in high ethnic density area, first generation immigrants, North-African immigrants in Europe, winter/spring season of birth in Northern hemisphere, childhood social withdrawal, childhood trauma, Toxoplasma gondii IgG, and non-right handedness). When only prospective studies were considered, the evidence was convincing for ultra-high-risk state and suggestive for urbanicity only. In summary, this umbrella review found several factors to be associated with psychotic disorders with different levels of evidence. These risk or protective factors represent a starting point for further etiopathological research and for the improvement of the prediction of psychosis.

Evidence of a Causal Relationship Between Smoking Tobacco and Schizophrenia Spectrum Disorders

There has been emerging evidence of an association between tobacco smoking and schizophrenia spectrum disorders (SSD). Two meta-analyses have reported that people who smoke tobacco have an ~2-fold increased risk of incident schizophrenia or psychosis, even after adjusting for confounding factors. This study aimed to critically appraise the research which has examined the association between tobacco smoking and SSD against the Bradford Hill criteria for causality, to determine the strength of the evidence for a causal relationship. Eight longitudinal studies (seven cohort studies and one case control study) were identified which examined tobacco smoking as an exposure and psychosis as an outcome. All seven cohort studies were assessed as being of high quality using the Newcastle-Ottawa Scale. Six of the eight studies found a statistically significant positive association between tobacco smoking and onset of SSD. These studies reported a consistent association with a moderate to large effect size and a dose response relationship. The studies adjusted for multiple potential confounders including age, sex, socioeconomic status, shared genetic risk, prodromal symptoms, and comorbid cannabis and other substance use. The studies did not adjust for exposure to childhood trauma or prenatal tobacco. There was substantial though inconclusive evidence supporting a causal relationship between tobacco smoking and increased risk of SSD. If a causal relationship does exist, nicotine is most likely responsible for this association. This raises serious public health concerns about the increasing use of e-cigarettes and other products, particularly by adolescents whose nicotine use may increase their risk of SSD. Research is urgently needed to examine the association between e-cigarette use and incident psychosis, particularly in adolescents and young adults.

Modelling gene-environment interaction in first episodes of psychosis

INTRODUCTION

Recent research demonstrates the heterogeneous etiology of psychotic disorders, where gen-environment (GxE) interaction plays a key role. Large genetic studies have linked many genetic variants with schizophrenia, but each variant is only associated with a small effect and the GxE interaction contribution has not been evaluated.

METHODS

The PEPs Project was designed to carefully collect a large amount of genetic and environmental exposure data of 335 FEP patients and 253 matched healthy controls.780single-nucleotide polymorphisms (from 159 candidate genes)and 16 environmental variables previously reported as the main psychosis non-genetic risk factors were analyzed together using entropy-based measures of information gain.

RESULTS

Our analyses identified an interaction between nine SNPs and the exposition to the environmental risk factors of psychosis, showing a clear enrichment of genes linked to serotonin neurotransmission and neurodevelopmental processes.

CONCLUSIONS

This study has allowed the identification of several GxE-environment interactions involved in the risk of presenting a FEP. Our results highlight the importance of serotonin neurotransmission interacting with certain environmental stimuli. The serotoninergic system may be playing a key role in the regulatory network of stress and other systems implicated in the emergence and development of psychotic disorders.

Advanced paternal age is associated with earlier schizophrenia onset in offspring. Results from the national multicentric FACE-SZ cohort

The association between advanced paternal age (APA) and increased risk of schizophrenia (SZ) is well established. The objectives of the present study were to further determine if SZ participants with APA (APA+), versus those without (APA-), had: (i) different illness characteristics; (ii) different responses to antipsychotic medication; and (iii) different cognitive characteristics. Participants were a non-selected representative multicentric sample of stabilized community-dwelling people diagnosed with SZ included in the FACE-SZ cohort. 389 participants (73% males, mean aged 32.7 years, mean illness duration 10.8 years) formed the study sample, with each comprehensively evaluated, clinically and neuropsychologically, over 2 days. 118 participants (30.3%) were defined as APA+ according to their father's age at birth (≥35 years). APA+ was associated with a wide range of cognitive dysfunctions in univariate analyses. In multivariate analyses, the only significant difference was the age at onset, with a mean 1.6 year earlier in APA+, compared to APA- (20.7 vs. 22.3 years; p=0.02). This difference is independent of sociodemographic characteristics and I.Q. No association with clinical symptomatology and treatment response was found. The present study supports the neomutation hypothesis and confirms APA as a relevant clinical variable to discriminate potential schizophrenia subtypes. Potential underlying pathophysiological mechanisms are discussed.

A comparison of the cumulative incidence and early risk factors for psychotic disorder in young adults in the Northern Finland Birth Cohorts 1966 and 1986

AIMS

Few studies have compared time trends for the incidence of psychosis. To date, the results have been inconsistent, showing a decline, an increase or no significant change. As far as we know, no studies explored changes in prevalence of early risk factors. The aim of this study was to investigate differences in early risk factors and cumulative incidences of psychosis by type of psychosis in two comparable birth cohorts.

METHODS

The Northern Finland Birth cohorts (NFBCs) 1966 (N = 12 058) and 1986 (N = 9432) are prospective general population-based cohorts with the children followed since mother's mid-pregnancy. The data for psychoses, i.e. schizophrenia (narrow, spectrum), bipolar disorder with psychotic features, major depressive episode with psychotic features, brief psychosis and other psychoses (ICD 8-10) were collected from nationwide registers including both inpatients and outpatients. The data on early risk factors including sex and place of birth of the offspring, parental age and psychosis, maternal education at birth were prospectively collected from the population registers. The follow-up reached until the age of 27 years.

RESULTS

An increase in the cumulative incidence of all psychoses was seen (1.01% in NFBC 1966 v. 1.90% in NFBC 1986; p < 0.001), which was due to an increase in diagnosed affective and other psychoses. Earlier onset of cases and relatively more psychoses in women were observed in the NFBC 1986. Changes in prevalence of potential early risk factors were identified, but only parental psychosis was a significant predictor in both cohorts (hazard ratios ≥3.0; 95% CI 1.86-4.88). The difference in psychosis incidence was not dependent on changes in prevalence of studied early risk factors.

CONCLUSIONS

Surprisingly, increase in the cumulative incidence of psychosis and also changes in the types of psychoses were found between two birth cohorts 20 years apart. The observed differences could be due to real changes in incidence or they can be attributable to changes in diagnostic practices, or to early psychosis detection and treatment.

Effects of environmental risks and polygenic loading for schizophrenia on cortical thickness

There are established differences in cortical thickness (CT) in schizophrenia (SCZ) and bipolar (BD) patients when compared to healthy controls (HC). However, it is unknown to what extent environmental or genetic risk factors impact on CT in these populations. We have investigated the effect of Environmental Risk Scores (ERS) and Polygenic Risk Scores for SCZ (PGRS-SCZ) on CT. Structural MRI scans were acquired at 3T for patients with SCZ or BD (n=57) and controls (n=41). Cortical reconstructions were generated in FreeSurfer (v5.3). The ERS was created by determining exposure to cannabis use, childhood adverse events, migration, urbanicity and obstetric complications. The PGRS-SCZ were generated, for a subset of the sample (Patients=43, HC=32), based on the latest PGC GWAS findings. ANCOVAs were used to test the hypotheses that ERS and PGRS-SCZ relate to CT globally, and in frontal and temporal lobes. An increase in ERS was negatively associated with CT within temporal lobe for patients. A higher PGRS-SCZ was also related to global cortical thinning for patients. ERS effects remained significant when including PGRS-SCZ as a fixed effect. No relationship which survived FDR correction was found for ERS and PGRS-SCZ in controls. Environmental risk for SCZ was related to localised cortical thinning in patients with SCZ and BD, while increased PGRS-SCZ was associated with global cortical thinning. Genetic and environmental risk factors for SCZ appear therefore to have differential effects. This provides a mechanistic means by which different risk factors may contribute to the development of SCZ and BD.

Environmental risk factors for autism: an evidence-based review of systematic reviews and meta-analyses

BACKGROUND

According to recent evidence, up to 40-50% of variance in autism spectrum disorder (ASD) liability might be determined by environmental factors. In the present paper, we conducted a review of systematic reviews and meta-analyses of environmental risk factors for ASD. We assessed each review for quality of evidence and provided a brief overview of putative mechanisms of environmental risk factors for ASD.

FINDINGS

Current evidence suggests that several environmental factors including vaccination, maternal smoking, thimerosal exposure, and most likely assisted reproductive technologies are unrelated to risk of ASD. On the contrary, advanced parental age is associated with higher risk of ASD. Birth complications that are associated with trauma or ischemia and hypoxia have also shown strong links to ASD, whereas other pregnancy-related factors such as maternal obesity, maternal diabetes, and caesarian section have shown a less strong (but significant) association with risk of ASD. The reviews on nutritional elements have been inconclusive about the detrimental effects of deficiency in folic acid and omega 3, but vitamin D seems to be deficient in patients with ASD. The studies on toxic elements have been largely limited by their design, but there is enough evidence for the association between some heavy metals (most important inorganic mercury and lead) and ASD that warrants further investigation. Mechanisms of the association between environmental factors and ASD are debated but might include non-causative association (including confounding), gene-related effect, oxidative stress, inflammation, hypoxia/ischemia, endocrine disruption, neurotransmitter alterations, and interference with signaling pathways.

CONCLUSIONS

Compared to genetic studies of ASD, studies of environmental risk factors are in their infancy and have significant methodological limitations. Future studies of ASD risk factors would benefit from a developmental psychopathology approach, prospective design, precise exposure measurement, reliable timing of exposure in relation to critical developmental periods and should take into account the dynamic interplay between gene and environment by using genetically informed designs.

The "polyenviromic risk score": Aggregating environmental risk factors predicts conversion to psychosis in familial high-risk subjects

BACKGROUND

Young relatives of individuals with schizophrenia (i.e. youth at familial high-risk, FHR) are at increased risk of developing psychotic disorders, and show higher rates of psychiatric symptoms, cognitive and neurobiological abnormalities than non-relatives. It is not known whether overall exposure to environmental risk factors increases risk of conversion to psychosis in FHR subjects.

METHODS

Subjects consisted of a pilot longitudinal sample of 83 young FHR subjects. As a proof of principle, we examined whether an aggregate score of exposure to environmental risk factors, which we term a 'polyenviromic risk score' (PERS), could predict conversion to psychosis. The PERS combines known environmental risk factors including cannabis use, urbanicity, season of birth, paternal age, obstetric and perinatal complications, and various types of childhood adversity, each weighted by its odds ratio for association with psychosis in the literature.

RESULTS

A higher PERS was significantly associated with conversion to psychosis in young, familial high-risk subjects (OR=1.97, p=0.009). A model combining the PERS and clinical predictors had a sensitivity of 27% and specificity of 96%.

CONCLUSION

An aggregate index of environmental risk may help predict conversion to psychosis in FHR subjects.

Metabolic syndrome or glucose challenge in first episode of psychosis?

Patients with schizophrenia exhibit a reduced life expectancy. Although unhealthy lifestyle or suicide risk plays a role, the main causes are diverse medical conditions such as cardiovascular diseases, type 2 diabetes mellitus and metabolic syndrome. Albeit pharmacological secondary side effects might also trigger previous conditions, studies in naïve patients reflect diverse anomalies at the onset. Patients with a first episode of psychosis, display a wide scope of metabolic abnormalities, ranging from normality till pathological values depending on the parameters studied. We attempted to evaluate the metabolic syndrome and glycemic homeostasis in a subset of antipsychotic-naïve patients with a first episode of non-affective psychosis. Patients (n = 84) showed a similar prevalence of metabolic syndrome compared with a matched control sample (n = 98) (6% vs 4%, P = 0.562), while glucose homeostasis values differed significantly (14% vs. 5%, P = 0.034). Our results suggest that metabolic syndrome is not a useful clinical condition to be evaluated in patients before pharmacological treatment. Abnormal glycemic homeostasis at the onset of the disease requires specific diagnostic tools and preventive measures in order to avoid future cardiovascular events. New strategies must be implemented in order to evaluate the cardiovascular risk and subsequent morbidity in patients at the onset of the disease.

25 years of research on global asphyxia in the immature rat brain

Hypoxic-ischemic encephalopathy remains a common cause of brain damage in neonates. Preterm infants have additional complications, as prematurity by itself increases the risk of encephalopathy. Currently, therapy for this subset of asphyxiated infants is limited to supportive care. There is an urgent need for therapies in preterm infants - and for representative animal models for preclinical drug development. In 1991, a novel rodent model of global asphyxia in the preterm infant was developed in Sweden. This method was based on the induction of asphyxia during the birth processes itself by submerging pups, still in the uterine horns, in a water bath followed by C-section. This insult occurs at a time-point when the rodent brain maturity resembles the brain of a 22-32 week old human fetus. This model has developed over the past 25 years as an established model of perinatal global asphyxia in the early preterm brain. Here we summarize the knowledge gained on the short- and long-term neuropathological and behavioral effects of asphyxia on the immature central nervous system.

Neurological soft signs in Tunisian patients with first-episode psychosis and relation with cannabis use

BACKGROUND

Neurological soft signs (NSS) are minor non-localizing neurological abnormalities that are conceptualized as neurodevelopmental markers that mediate the biological risk for psychosis. We aimed to explore the relationship between NSS and cannabis use, an environmental risk factor of psychosis.

METHODS

This was a cross-sectional study in consecutively admitted patients hospitalized for first-episode psychosis. NSS were assessed by the NSS scale (23 items exploring motor coordination, motor integrative function, sensory integration, involuntary movements or posture, quality of lateralization). Presence of NSS was defined as a NSS scale total score ≥9.5. Cannabis use was ascertained with the cannabis subsection in the Composite International Diagnostic Interview.

RESULTS

Among 61 first-episode psychosis patients (mean age = 28.9 ± 9.4 years; male = 86.9%, antipsychotic-naïve = 75.4%), the prevalence of current cannabis use was 14.8% (heavy use = 8.2%, occasional use = 6.6%). NSS were present in 83.6% of the sample (cannabis users = 66.7% versus cannabis non-users = 85.5%, p = 0.16). The mean total NSS score was 15.3 ± 6.7, with a significant lower total NSS score in cannabis users (11.2 ± 5.6 versus 16.0 ± 6.7, p = 0.048). Differences were strongest for the "motor coordination" (p = 0.06) and "involuntary movements" (p = 0.07) sub-scores.

CONCLUSIONS

This study demonstrated a negative association between cannabis use and NSS, especially regarding motor discoordination. This finding supports the hypothesis that a strong environmental risk factor, such as cannabis, may contribute to the onset of psychosis even in the presence of lower biological and genetic vulnerability, as reflected indirectly by lower NSS scores. Nevertheless, additional studies are needed that explore this interaction further in larger samples and considering additional neurobiological and environmental risk factors.

Do adverse perinatal events predict mortality in schizophrenia during midlife?

BACKGROUND

We examined mortality in schizophrenia spectrum disorder (SSD) and non-schizophrenic psychosis (NSSD) compared to individuals without psychosis, and whether perinatal factors predict mortality.

METHODS

Within Northern Finland Birth Cohort 1966 (n=10 933; 203 with SSD, 178 with NSSD), mortality was followed until end of 2011 by national register. Wantedness of pregnancy, mother's antenatal depression, smoking and age, parity, paternal socio-economic status (SES) and family type at birth were examined as predictors of mortality.

RESULTS

Mortality was higher in SSD (hazard ratio (HR) 3.60; 95% confidence interval (CI) 2.38-5.45) and NSSD (4.05; 2.65-6.17) compared to persons without psychoses after adjustment for gender. HR for natural death was 2.01 (0.82-4.91) in SSD and 4.63 (2.43-8.80) in NSSD after adjustment for gender. Corresponding figures for unnatural deaths were 4.71 (2.94-7.54) and 2.94 (1.56-5.55), respectively. Among non-psychotic persons, mother's depression, smoking and low SES predicted mortality after adjustment for gender and parental psychoses (and SES), whereas among psychosis those whose father was a farmer had lower risk of mortality compared to those with high SES.

CONCLUSIONS

Individuals with SSD had a higher risk of unnatural death and individuals with NSSD of natural and unnatural deaths. Perinatal factors seem to be more important predictors of mortality in individuals without psychoses than with psychoses. According to population-based long follow-up data, it is important to pay attention to somatic morbidity behind natural causes of death in psychoses and to prevent suicides in order to prevent excess mortality.

Deconstructing Vulnerability for Psychosis: Meta-Analysis of Environmental Risk Factors for Psychosis in Subjects at Ultra High-Risk

Background

Subjects at ultra high-risk (UHR) for psychosis have an enhanced vulnerability to develop the disorder but the risk factors accounting for this accrued risk are undetermined.

Method

Systematic review of associations between genetic or environmental risk factors for psychosis that are widely established in the literature and UHR state, based on comparisons to controls.

Results

Forty-four studies encompassing 170 independent datasets and 54 risk factors were included. There were no studies on association between genetic or epigenetic risk factors and the UHR state that met the inclusion criteria. UHR subjects were more likely to show obstetric complications, tobacco use, physical inactivity, childhood trauma/emotional abuse/physical neglect, high perceived stress, childhood and adolescent low functioning, affective comorbidities, male gender, single status, unemployment and low educational level as compared to controls.

Conclusions

The increased vulnerability of UHR subjects can be related to environmental risk factors like childhood trauma, adverse life events and affective dysfunction. The role of genetic and epigenetic risk factors awaits clarification.

Cannabidiol, among Other Cannabinoid Drugs, Modulates Prepulse Inhibition of Startle in the SHR Animal Model: Implications for Schizophrenia Pharmacotherapy

Schizophrenia is a severe psychiatric disorder that involves positive, negative and cognitive symptoms. Prepulse inhibition of startle reflex (PPI) is a paradigm that assesses the sensorimotor gating functioning and is impaired in schizophrenia patients as well as in animal models of this disorder. Recent data point to the participation of the endocannabinoid system in the pathophysiology and pharmacotherapy of schizophrenia. Here, we focus on the effects of cannabinoid drugs on the PPI deficit of animal models of schizophrenia, with greater focus on the SHR (Spontaneously Hypertensive Rats) strain, and on the future prospects resulting from these findings.