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Large biobank samples provide an opportunity to integrate broad phenotyping, familial records, and molecular genetics data to study complex traits and diseases. We introduce Pearson-Aitken Family Genetic Risk Scores (PA-FGRS), a method for estimating disease liability from patterns of diagnoses in extended, age-censored genealogical records. We then apply the method to study a paradigmatic complex disorder, major depressive disorder (MDD), using the iPSYCH2015 case-cohort study of 30,949 MDD cases, 39,655 random population controls, and more than 2 million relatives. We show that combining PA-FGRS liabilities estimated from family records with molecular genotypes of probands improves three lines of inquiry. Incorporating PA-FGRS liabilities improves classification of MDD over and above polygenic scores, identifies robust genetic contributions to clinical heterogeneity in MDD associated with comorbidity, recurrence, and severity and can improve the power of genome-wide association studies. Our method is flexible and easy to use, and our study approaches are generalizable to other datasets and other complex traits and diseases. Our method, the Pearson-Aitken Family Genetic Risk Score, estimates genetic liability in a proband from patterns of disease outcomes in their relatives. The method is flexible, and the resulting scores can be used for genetic classification, describing genetic etiology, and improving power for gene mapping. [ABSTRACT FROM AUTHOR]

Background: Some studies have reported that sunburns and cutaneous melanoma (CM) risk is increasing, but a clear causal link has yet to be established. Methods: This current study conducted a two-sample Mendelian randomization (MR) approach to clarify the association and causality between sunburn history and CM using large-scale genome-wide association study data. Results: The inverse-variance weighted method result showed that sunburn might be associated with the risk of CM increasing (p = 2.21 × 10-23, OR = 1.034, 95% CI= 1.027-1.041), causally. The MR-Egger regression, weighted median method, simple mode method, and weighted mode method results showed similar results. Conclusion: This study offers evidence of sunburn history and increased risk of CM, and it shows that there might be common genetic basics regarding sunburns and CM susceptibility in Caucasian, European, or British ethnic groups. [ABSTRACT FROM AUTHOR]

Introduction: Alcohol use disorder (AUD) is among the strongest correlates of suicide death, but it is unclear whether AUD status is differentially associated with risk of suicide by particular methods. Methods: The authors used competing risks models to evaluate the association between AUD status and risk of suicide by poisoning, suffocation, drowning, firearm, instruments, jumping, or other means in a large Swedish cohort born 1932–1995 (total N = 6,581,827; 48.8% female). Data were derived from Swedish national registers, including the Cause of Death Register and a range of medical registers. Results: After adjusting for sociodemographic factors and familial liability to suicidal behavior, AUD was positively associated with risk of suicide for each method evaluated (cumulative incidence differences: 0.006–1.040 for females, 0.046–0.680 for males), except the association with firearm suicide in females. AUD was most strongly associated with risk of suicide by poisoning. Sex differences in the effects of AUD and family liability were observed for some, but not all, methods. Furthermore, high familial liability for suicidal behavior exacerbated AUD's impact on risk for suicide by poisoning (both sexes) and suffocation and jumping (males only), while the inverse interaction was observed for firearm suicide (males only). Conclusions: AUD increases risk of suicide by all methods examined and is particularly potent with respect to risk of suicide by poisoning. Differences in risk related to sex and familial liability to suicidal behavior underscore AUD's nuanced role in suicide risk. Future research should investigate targeted means restriction effectiveness among persons with AUD. [ABSTRACT FROM AUTHOR]

There is some evidence that offspring of patients with schizophrenia have higher somatic morbidity, which is thought to be partially due to genetic links between somatic disorders and schizophrenia. This study explored differences in somatic diseases and conditions of adoptees with high genetic risk (HR) or low genetic risk (LR) for schizophrenia spectrum disorders. The study is part of the Finnish Adoptive Family Study of Schizophrenia. The adoptive research design used made it possible to examine how the somatic health of adoptees raised in similar adoptive families, is affected by their genetic susceptibility to schizophrenia. The study sample consisted of 373 adoptees, of whom 190 had HR and 183 had LR for schizophrenia spectrum disorders. Data on somatic morbidity were gathered from the hospital records and from the national registers of the Care Register of Health Care and the Social Insurance Institution. The only statistically significant difference found was in genitourinary diseases, the likelihood being twofold higher in HR adoptees compared to LR adoptees (16.8% vs. 8.2%; adj. OR = 2.13, 95% CI 1.06–4.25, p =.033). Adoptees who were female and aged over 40 had a higher prevalence of genitourinary illnesses than non-adoptees. The significant prevalence of genitourinary diseases in adoptees at risk for schizophrenia spectrum disorders suggests that some specific somatic diseases and schizophrenia may have a shared hereditary etiology. More research is required for specific somatic diseases in study populations that can differentiate between the effects of genetic and environmental factors. [ABSTRACT FROM AUTHOR]

• About 38 % of women continued antidepressant treatment in the perinatal period. • Treatment trajectories are not affected by genetic liability or demographics. • Continued antidepressant use is influenced by the severity of the disease. Pregnant women on antidepressants must balance potential fetal harm with the relapse risk. While various clinical and sociodemographic factors are known to influence treatment decisions, the impact of genetic factors remains unexplored. We conducted a cohort study among 2,316 women with diagnosed affective disorders who had redeemed antidepressant prescriptions six months before pregnancy, identified from the Danish Integrated Psychiatric Research study. We calculated polygenic risk scores (PGSs) for major depression (MDD), bipolar disorder (BD), and schizophrenia (SCZ) using individual-level genetic data and summary statistics from genome-wide association studies. We retrieved data on sociodemographic and clinical features from national registers. Applying group-based trajectory modeling, we identified four treatment trajectories across pregnancy and postpartum: Continuers (38.2 %), early discontinuers (22.7 %), late discontinuers (23.8 %), and interrupters (15.3 %). All three PGSs were not associated with treatment trajectories; for instance, the relative risk ratio for continuers versus early discontinuers was 0.93 (95 % CI: 0.81–1.06), 0.98 (0.84–1.13), 1.09 (0.95–1.27) for per 1-SD increase in PGS for MDD, BD, and SCZ, respectively. Sociodemographic factors were generally not associated with treatment trajectories, except for the association between primiparity and continuing antidepressant use. Women who received ≥2 classes or a higher dose of antidepressants had a higher probability of being late discontinuers, interrupters, and continuers. The likelihood of continuing antidepressants or restarting antidepressants postpartum increased with the previous antidepressant treatment duration. Our findings indicate that continued antidepressant use during pregnancy is influenced by the severity of the disease rather than genetic predisposition as measured by PGSs. [ABSTRACT FROM AUTHOR]

BackgroundTelomere has been recognized as a biomarker of accelerating aging, and telomere length (TL) shortening is closely related to diverse chronic illnesses. Human serum metabolites have demonstrated close correlations with TL maintenance or shortening in observational studies. Nevertheless, little is known about the underlying pathological mechanisms, and Mendelian randomization (MR) analysis of serum metabolites may provide a more comprehensive understanding of the potential biological process.MethodsWe employed a two-sample MR analysis method to assess the causal links between 486 serum metabolites and TL. We applied the inverse-variance weighted (IVW) approach as our primary analysis, and to assure the stability and robustness of our results, additional analysis methods including the weighted median, MR-Egger, and weighted mode were conducted. MR-Egger intercept test was utilized to detect the pleiotropy. Cochran’s Q test was implemented to quantify the extent of heterogeneity. Furthermore, the pathway analysis was conducted to identify potential metabolic pathways.ResultsWe identified 11 known blood metabolites associated with TL. Among these metabolites, four were lipid (taurocholate, dodecanedioate, 5,8-tetradecadienoate, and 15-methylpalmitate), one amino acid (levulinate (4-oxovaleate)), one carbohydrate (lactate), one nucleotide (pseudouridine), one energy (phosphate), and three xenobiotics (2-hydroxyacetaminophen sulfate, paraxanthine, and ergothioneine). The known protective metabolites included levulinate (4-oxovaleate), dodecanedioate, 5,8-tetradecadienoate, lactate, phosphate, paraxanthine, and ergothioneine. Multiple metabolic pathways have been identified as being implicated in the maintenance of telomere length.ConclusionOur MR analysis provided suggestive evidence supporting the causal relationships between 11 identified blood metabolites and TL, necessitating further exploration to clarify the mechanisms by which these serum metabolites and metabolic pathways may affect the progression of telomeres.

Offspring of depressed mothers have elevated risk of developing depression because they are exposed to greater stress. While generally assumed that youth's increased exposure to stress is due to the environmental effects of living with a depressed parent, youth's genes may influence stress exposure through gene-environment correlations (rGEs). To understand the relationship between risk for depression and stress, we examined the effects of polygenic risk for depression on youth stress exposure. We examined the relations of a polygenic risk score (PRS) for depression (DEP-PRS), as well as PRSs for 5 other disorders, with youth stress exposure. Data were from a longitudinal study of a community sample of youth and their parents (n = 377) focusing on data collected at youth's aged 12 and 15 assessments. Elevated youth DEP-PRS was robustly associated with increased dependent stress, particularly interpersonal events. Exploratory analyses indicated that findings were driven by major stress and were not moderated by maternal nor paternal history of depression, and of the 5 additional PRSs tested, only elevated genetic liability for bipolar I was associated with increased dependent stress—particularly non-interpersonal events. Like other PRS studies, we focused on those of European ancestry thus, generalizability of findings is limited. Polygenic risk contributes to youth experiencing stressful life events which are dependent on their behavior. This rGE appears to be specific to genetic risk for mood disorders. • Youth elevated polygenic risk for depression is robustly associated with elevated youth stress exposure, supporting a stress generation model. • Of the 5 additional PRSs tested, only bipolar I disorder was associated with elevated youth stress exposure. • Findings suggest that there are gene-environment correlations that are specific to mood disorders--depression and bipolar 1. [ABSTRACT FROM AUTHOR]

We used event-related potentials (ERPs) to examine encoding and retrieval during episodic memory in people with schizophrenia (SZ) and biological relatives of SZ (SZr). To isolate contextual from item-specific aspects of memory, we employed the Relational and Item-Specific Encoding (RISE) task. Twenty two healthy controls (HCs), 22 SZ, and 19 SZr, encoded visual depictions of objects when displayed alone (item-specific) or in pairs (relational encoding), and were later tested on recognition of specific objects and whether pairs of objects had appeared together. An early posterior component (P2) during encoding predicted later recognition and was diminished in SZ. A late negative potential (LNP) over left frontal brain regions during recognition was larger for relationally encoded objects than new and item-specific encoded objects in HCs. This pattern was absent for SZ and SZr. Smaller P2 and LNP components were associated with greater self-reported cognitive-perceptual abnormalities. Early posterior brain responses likely relevant to perceptual functions supporting memory formation were diminished in schizophrenia. Late frontal electrophysiological responses associated with relational aspects of memory appear diminished in SZ and SZr, potentially reflecting the influence of genetic liability for schizophrenia on brain functions supporting episodic memory. [ABSTRACT FROM AUTHOR]

There is accruing evidence of spontaneous dyskinesia in individuals with schizophrenia that is independent of medication exposure. Dyskinetic motor behavior is also present in individuals who are at high risk of schizophrenia and appears to have prognostic value for the development of psychosis. Nonetheless, it remains unclear whether dyskinesia is present in first-degree relatives of individuals with schizophrenia and thus associated with genetic liability for schizophrenia (i.e., an endophenotype), or whether the motor abnormality is a biomarker specific to the disease state spectrum. There is also limited information about links between dyskinesia and clinically relevant phenomena such as symptoms and cognition. Because dyskinesia marking genetic liability is likely to be subtle, we used sensitive instrument-based measurement of handwriting fluency to quantify dyskinesia in medicated individuals with schizophrenia or schizoaffective disorder, unaffected first-degree biological relatives of individuals with schizophrenia and schizoaffective disorder, and control participants. Results indicated that medicated individuals with schizophrenia or schizoaffective disorder exhibited more dyskinesia than both relatives and controls, with no difference between relatives and controls. Dyskinesia in individuals with schizophrenia or schizoaffective disorder was unrelated to current antipsychotic medication dosage, but associated with worse working memory function and greater positive formal thought disorder. These results provide evidence that dyskinesia is not associated with unexpressed genetic liability for schizophrenia.

Background and Hypothesis Facial Emotion Recognition is a key domain of social cognition associated with psychotic disorders as a candidate intermediate phenotype. In this study, we set out to investigate global and specific facial emotion recognition deficits in first-episode psychosis, and whether polygenic liability to psychotic disorders is associated with facial emotion recognition. Study Design 828 First Episode Psychosis (FEP) patients and 1308 population-based controls completed assessments of the Degraded Facial Affect Recognition Task (DFAR) and a subsample of 524 FEP and 899 controls provided blood or saliva samples from which we extracted DNA, performed genotyping and computed polygenic risk scores for schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MD). Study Results A worse ability to globally recognize facial emotion expressions was found in patients compared with controls [ B = −1.5 (0.6), 95% CI −2.7 to −0.3], with evidence for stronger effects on negative emotions (fear [ B = −3.3 (1.1), 95% CI −5.3 to −1.2] and anger [ B = −2.3 (1.1), 95% CI −4.6 to −0.1]) than on happiness [ B = 0.3 (0.7), 95% CI −1 to 1.7]. Pooling all participants, and controlling for confounds including case/control status, facial anger recognition was associated significantly with Schizophrenia Polygenic Risk Score (SZ PRS) [ B = −3.5 (1.7), 95% CI −6.9 to −0.2]. Conclusions Psychosis is associated with impaired recognition of fear and anger, and higher SZ PRS is associated with worse facial anger recognition. Our findings provide evidence that facial emotion recognition of anger might play a role as an intermediate phenotype for psychosis. [ABSTRACT FROM AUTHOR]

Poor verbal learning and memory function is well-documented among individuals with schizophrenia and those at clinical high-risk for psychosis. This study aimed to identify these impairments among children aged 9–12 years with different schizophrenia risk profiles (family history or antecedents of schizophrenia, each of higher[H] or lower[L] risk load) relative to typically developing peers. These three groups were recruited via community-screening, and differentiated for analysis into: typically developing children (TD = 45); children who had 1 first- or ≥2 second-degree affected relatives (FHxH = 16) or one second-degree relative (FHxL = 15); and children presenting multiple replicated antecedents of schizophrenia whose clinical symptoms persisted at 2- and/or 4-year follow-up (ASzH = 16) or remitted during follow-up (ASzL = 16). Verbal learning/memory measures assessed at baseline (age 9–12 years) included: (i) total recall; (ii) trial 1 recall; (iii) learning score; (iv) intrusions; (v) total words lost; and (vi) serial position patterns. Analyses of variance indicated that FHxH and ASzH youth demonstrated impaired total recall compared to TD and ASzL children and lost significantly more words between trials than TD and FHxL children. Learning score was impaired among both FHxH and FHxL relative to TD and ASzL children. Thus, among putatively at-risk children, total words recalled and lost distinguished those with higher risk load (by family history or persistent antecedent symptomology), whereas learning score indexed familial vulnerability. Follow-up of the sample is needed to determine the capacity of verbal learning deficits to predict later illness and provide a potential avenue for early remediation to improve clinical or functional outcomes.

Abstract In this case of idiopathic environmental intolerance, a little known disease characterized by many symptoms of irritation due to exposure to several toxic compounds, genetic analysis could be helpful in case of differential diagnosis issue.

Background: Some studies have reported that sunburns and cutaneous melanoma (CM) risk is increasing, but a clear causal link has yet to be established., Methods: This current study conducted a two-sample Mendelian randomization (MR) approach to clarify the association and causality between sunburn history and CM using large-scale genome-wide association study data., Results: The inverse-variance weighted method result showed that sunburn might be associated with the risk of CM increasing (p = 2.21 × 10 -23 , OR = 1.034, 95% CI= 1.027-1.041), causally. The MR-Egger regression, weighted median method, simple mode method, and weighted mode method results showed similar results., Conclusion: This study offers evidence of sunburn history and increased risk of CM, and it shows that there might be common genetic basics regarding sunburns and CM susceptibility in Caucasian, European, or British ethnic groups., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lu, Wang, Ma and Li.)

Background: Telomere has been recognized as a biomarker of accelerating aging, and telomere length (TL) shortening is closely related to diverse chronic illnesses. Human serum metabolites have demonstrated close correlations with TL maintenance or shortening in observational studies. Nevertheless, little is known about the underlying pathological mechanisms, and Mendelian randomization (MR) analysis of serum metabolites may provide a more comprehensive understanding of the potential biological process., Methods: We employed a two-sample MR analysis method to assess the causal links between 486 serum metabolites and TL. We applied the inverse-variance weighted (IVW) approach as our primary analysis, and to assure the stability and robustness of our results, additional analysis methods including the weighted median, MR-Egger, and weighted mode were conducted. MR-Egger intercept test was utilized to detect the pleiotropy. Cochran's Q test was implemented to quantify the extent of heterogeneity. Furthermore, the pathway analysis was conducted to identify potential metabolic pathways., Results: We identified 11 known blood metabolites associated with TL. Among these metabolites, four were lipid (taurocholate, dodecanedioate, 5,8-tetradecadienoate, and 15-methylpalmitate), one amino acid (levulinate (4-oxovaleate)), one carbohydrate (lactate), one nucleotide (pseudouridine), one energy (phosphate), and three xenobiotics (2-hydroxyacetaminophen sulfate, paraxanthine, and ergothioneine). The known protective metabolites included levulinate (4-oxovaleate), dodecanedioate, 5,8-tetradecadienoate, lactate, phosphate, paraxanthine, and ergothioneine. Multiple metabolic pathways have been identified as being implicated in the maintenance of telomere length., Conclusion: Our MR analysis provided suggestive evidence supporting the causal relationships between 11 identified blood metabolites and TL, necessitating further exploration to clarify the mechanisms by which these serum metabolites and metabolic pathways may affect the progression of telomeres., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu and Pan.)

We studied healthy, first-degree relatives of patients with schizophrenia to test the hypothesis that deficits in cognitive skill learning are associated with genetic liability to schizophrenia. Using the Weather Prediction Task (WPT), 23 healthy controls and 10 adult first-degree Relatives Of Schizophrenia (ROS) patients were examined to determine the extent to which cognitive skill learning was automated using a dual-task paradigm to detect subtle impairments in skill learning. Automatization of a skill is the ability to execute a task without the demand for executive control and effortful behavior and is a skill in which schizophrenia patients possess a deficit. ROS patients did not differ from healthy controls in accuracy or reaction time on the WPT either during early or late training on the single-task trials. In contrast, the healthy control and ROS groups were differentially affected during the dual-task trials. Our results demonstrate that the ROS group did not automate the task as well as controls and continued to rely on controlled processing even after extensive practice. This suggests that adult ROS patients may engage in compensatory strategies to achieve normal levels of performance and support the hypothesis that impaired cognitive skill learning is associated with genetic risk for schizophrenia.

Objectives: Whilst reduced signalling and gene expression related to gamma‐aminobutyric acid (GABA) play a role in the presumed pathophysiology of schizophrenia, its origin is unclear. Studying asymptomatic individuals with high genetic liability to schizophrenia (AIs) would provide insights. Therefore, this study aimed to investigate the role of genetic liability in GABAergic dysfunction of schizophrenia by exploring in vivo GABA‐A/benzodiazepine receptor (GABAR) availability in AIs. Methods: A total of 10 AIs with multiple relatives diagnosed as schizophrenia and 11 healthy controls underwent [11C]flumazenil positron emission tomography and neurocognitive function tests. Results: There was no significant difference in [11C]flumazenil availability based on the groups. GABAR availability in caudate nuclei had positive correlations with genetic liability of AIs. GABAR availability in caudate nuclei and verbal memory measures of AIs revealed positive correlations. Only the correlation between right caudate and short‐term verbal memory survived multiple‐comparison correction (p = 0.030). Conclusions: This study, for the first time, reports correlations between the genetic liability of schizophrenia and GABAR availability. Correlations between [11C]flumazenil binding in caudate of individuals with high genetic liability to schizophrenia suggests that the GABAergic dysfunction may arise from shared genetic factors and also that it may be responsible for cognitive impairment of AIs. [ABSTRACT FROM AUTHOR]

Impaired vigilance is a core cognitive deficit in schizophrenia and may serve as an endophenotype (i.e., mark genetic liability). We used a continuous performance task with perceptually degraded stimuli in schizophrenia patients (N = 48), bipolar disorder patients (N = 26), first-degree biological relatives of schizophrenia patients (N = 55) and bipolar disorder patients (N = 28), as well as healthy controls (N = 68) to clarify whether previously reported vigilance deficits and abnormal neural functions were indicative of genetic liability for schizophrenia as opposed to a generalized liability for severe psychopathology. We also examined variation in the Catechol-O-methyltransferase gene to evaluate whether brain responses were related to genetic variation associated with higher-order cognition. Relatives of schizophrenia patients had an increased rate of misidentification of nontarget stimuli as targets when they were perceptually similar, suggestive of difficulties with contour perception. Larger early visual responses (i.e., N1) were associated with better task performance in patients with schizophrenia consistent with enhanced N1 responses reflecting beneficial neural compensation. Additionally, reduced N2 augmentation to target stimuli was specific to schizophrenia. Both patients with schizophrenia and first-degree relatives displayed reduced late cognitive responses (P3b) that predicted worse performance. First-degree relatives of bipolar patients exhibited performance deficits, and displayed aberrant neural responses that were milder than individuals with liability for schizophrenia and dependent on sex. Variation in the Catechol-O-methyltransferase gene was differentially associated with P3b in schizophrenia and bipolar groups. Poor vigilance in schizophrenia is specifically predicted by a failure to enhance early visual responses, weak augmentation of mid-latency brain responses to targets, and limited engagement of late cognitive responses that may be tied to genetic variation associated with prefrontal dopaminergic availability. Experimental results illustrate specific neural functions that distinguish schizophrenia from bipolar disorder and provides evidence for a putative endophenotype that differentiates genetic liability for schizophrenia from severe mental illness more broadly.

• Major depression and asthma often co-occur, suggesting shared genetic liability. • Limited evidence exists on this topic. • In this cohort study, genetic liability to major depression was related to asthma. • There is no evidence of a sex-specific difference in the association. • Major depression and childhood asthma may share a common genetic contribution. Major depression and asthma frequently co-occur, suggesting shared genetic vulnerability between these two disorders. We aimed to determine whether a higher genetic liability to major depression was associated with increased childhood asthma risk, and if so, whether such an association differed by sex of the child. We conducted a population-based cohort study comprising 16,687 singletons born between 1991 and 2005 in Denmark. We calculated the polygenic risk score (PRS) for major depression as a measure of genetic liability based on the summary statistics from the Major Depressive Disorder Psychiatric Genomics Consortium collaboration. The outcome was incident asthma from age 5 to 15 years, identified from the Danish National Patient Registry and the Danish National Prescription Registry. Stratified Cox regression was used to analyze the data. Greater genetic liability to major depression was associated with an increased asthma risk with a hazard ratio (HR) of 1.06 (95% CI: 1.01–1.10) per standard deviation increase in PRS. Children in the highest major depression PRS quartile had a HR for asthma of 1.20 (95% CI: 1.06–1.36), compared with children in the lowest quartile. However, major depression PRS explained only 0.03% of asthma variance (Pseudo-R2). The HRs of asthma by major depression PRS did not differ between boys and girls. Our results suggest a shared genetic contribution to major depression and childhood asthma, and there is no evidence of a sex-specific difference in the association. [ABSTRACT FROM AUTHOR]

This paper challenges the common assumption that some phenotypic traits are quantitative while others are qualitative. The distinction between these two kinds of traits is widely influential in biological and biomedical research as well as in scientific education and communication. This is probably due to both historical and epistemological reasons. However, the quantitative/qualitative distinction involves a variety of simplifications on the genetic causes of phenotypic variability and on the development of complex traits. Here, I examine three cases from the life sciences that show inconsistencies in the distinction: Mendelian traits (dwarfism and pigmentation in plant and animal models), Mendelian diseases (phenylketonuria), and polygenic mental disorders (schizophrenia). I show that these traits can be framed both quantitatively and qualitatively depending, for instance, on the methods through which they are investigated and on specific epistemic purposes (e.g., clinical diagnosis versus causal explanation). This suggests that the received view of quantitative and qualitative traits has a limited heuristic power—limited to some local contexts or to the specific methodologies adopted. Throughout the paper, I provide directions for framing phenotypes beyond the quantitative/qualitative distinction. I conclude by pointing at the necessity of developing a principled characterisation of what phenotypic traits, in general, are. [ABSTRACT FROM AUTHOR]

In this case of idiopathic environmental intolerance, a little known disease characterized by many symptoms of irritation due to exposure to several toxic compounds, genetic analysis could be helpful in case of differential diagnosis issue. [ABSTRACT FROM AUTHOR]

• This is the hitherto most comprehensive characterization of comorbidity patterns, genetic and environmental risk factors for conduct disorder and disruptive behaviour. • Conduct disorder was comorbid with several child and adult-onset mental disorders. • This clinical overlap corresponded with associations between polygenic risk scores for a range of mental disorders and conduct disorder. • These findings suggest that conduct disorder is a less specific precursor to antisocial personality disorder than previously hypothesized. • Exposure to bullying was strongly associated with an increased risk of conduct disorder. Conduct disorder (CD), a common mental disorder in children and adolescents, is characterized by antisocial behavior. Despite similarities with antisocial personality disorder (ASPD) and possible diagnostic continuity, CD has been shown to precede a range of adult-onset mental disorders. Additionally, little is known about the putative shared genetic liability between CD and adult-onset mental disorders and the underlying gene-environment interplay. Here, we interrogated comorbidity between CD and other mental disorders from the Norwegian Mother, Father and Child Cohort Study (n = 114 500) and investigated how polygenic risk scores (PRS) for mental health traits were associated with CD/CD traits in childhood and adolescence. Gene-environment interplay patterns for CD was explored with data on bullying and parental education. We found CD to be comorbid with several child and adult-onset mental disorders. This phenotypic overlap corresponded with associations between PRS for mental disorders and CD. Additionally, our findings support an additive gene-environment model. Previously conceptualized as a precursor of ASPD, we found that CD was associated with polygenic risk for several child- and adult-onset mental disorders. High comorbidity of CD with other psychiatric disorders reflected on the genetic level should inform research studies, diagnostic assessments and clinical follow-up of this heterogenous group. [Display omitted] [ABSTRACT FROM AUTHOR]

The age of large-scale genome-wide association studies (GWAS) has provided us with an unprecedented opportunity to evaluate the genetic liability of complex disease using polygenic risk scores (PRS). In this study, we have analysed 162 PRS (p

Objective: The interplay between genetic and environmental factors on risk for psychotic illness remains poorly understood. The aim of this study was to estimate independent and combined effects of familial liability for schizophrenia and exposure to obstetric complications on risk for developing psychotic illness, covarying with exposure to other environmental stressors. Methods: This whole-population birth cohort study used record linkage across Western Australian statewide data collections (midwives, psychiatric, hospital admissions, child protection, mortality) to identify liveborn offspring (n = 1046) born 1980–1995 to mothers with schizophrenia, comparing them to offspring of mothers with no recorded psychiatric history (n = 298,370). Results: Both maternal schizophrenia and pregnancy complications were each significantly associated with psychotic illness in offspring, with no interaction. Non-obstetric environmental stressors significantly associated with psychotic illness in offspring included the following: being Indigenous; having a mother who was not in a partnered relationship; episodes of disrupted parenting due to hospitalisation of mother, father or child; abuse in childhood; and living in areas of greatest socioeconomic disadvantage and with elevated rates of violent crime. Adjustment for these other environmental stressors reduced the hazard ratio for maternal schizophrenia substantially (from hazard ratio: 5.7, confidence interval: 4.5–7.2 to hazard ratio: 3.5, confidence interval: 2.8–4.4), but not the estimate for pregnancy complications (hazard ratio: 1.1, confidence interval: 1.0–1.2). The population attributable fraction for maternal schizophrenia was 1.4 and for pregnancy complications was 2.1. Conclusion: Our finding of a substantial decrease in risk of psychotic illness associated with familial liability for psychosis following adjustment for other environmental stressors highlights potentially modifiable risk factors on the trajectory to psychotic illness and suggests that interventions that reduce or manage exposure to these risks may be protective, despite a genetic liability. [ABSTRACT FROM AUTHOR]

Introduction: To investigate the impact of a polygenic risk score for schizophrenia (PRS-SZ) and urbanicity on the risk of treatment-resistant schizophrenia (TRS) in people diagnosed with schizophrenia and to evaluate the association between PRS-SZ and TRS across levels of urbanicity.Methods: Cohort study of people born after 1981 with a first registered diagnosis of schizophrenia between 1996 and 2012 using Danish population registry data. Through linkage to genome-wide data, we calculated PRS-SZ based on a Psychiatric Genomics Consortium meta-analysis. We assessed urbanicity at birth (capital, provincial and rural areas). TRS was defined using prescription and hospital data. Performing Cox regression analysis, we calculated hazard rate ratios (HRs) and 95% confidence intervals (CI).Results: Among 4475 people with schizophrenia, we identified 593 (13.3%) with TRS during 17,558 person years of follow-up. The adjusted HR for TRS associated with one standard deviation (SD) increase in the PRS-SZ was 1.11 (95% CI: 1.00-1.24). The adjusted HRs for TRS across levels of urbanicity were 1.20 (95% CI: 0.98-1.47) for provincial areas and 1.19 (95% CI 0.96-1.47) for rural areas compared with the capital area. Within strata of urbanicity, the adjusted HR for TRS was 1.39 (95% CI: 1.14-1.70) in the capital area with 1 SD increase in the PRS-SZ, 0.99 (95% CI 0.84-1.17) in provincial areas, and 1.03 (95% CI: 0.86-1.25) in rural areas.Conclusion: The effect of genetic liability (i.e. PRS) on risk of TRS varied across urbanicity levels and was highest for people with schizophrenia born in the capital areas. [ABSTRACT FROM AUTHOR]

Purpose: Whilst childhood trauma (CT) is a known risk factor across the spectrum of psychosis expression, little is known about possible interplay with genetic liability.Methods: The TwinssCan Study collected data in general population twins, focussing on expression of psychosis at the level of subthreshold psychotic experiences. A multilevel mixed-effects linear regression analysis was performed including 745 subjects to assess the interaction between genetic liability and CT. The Symptom Checklist-90 (SCL-90-R) score of the co-twin was used as an indirect measure of genetic liability to psychopathology, while the Childhood Trauma Questionnaire Short-Form (CTQ-SF) was used to assess CT in the domains of physical, emotional and sexual abuse, as well as physical and emotional neglect. The Community Assessment of Psychic Experience (CAPE) questionnaire was used to phenotypically characterize psychosis expression.Results: In the model using the CAPE total score, the interaction between CT and genetic liability was close to statistical significance (χ2 = 5.6, df = 2, p = 0.06). Analyses of CAPE subscales revealed a significant interaction between CT and genetic liability (χ2 = 8.8, df = 2, p = 0.012) for the CAPE-negative symptoms subscale, but not for the other two subscales (i.e. positive and depressive).Conclusion: The results suggest that the impact of CT on subthreshold expression of psychosis, particularly in the negative subdomain, may be larger in the co-presence of significant genetic liability for psychopathology. [ABSTRACT FROM AUTHOR]

Highlights • Adult 1st-degree relatives of people with schizophrenia demonstrated no dyskinesia. • A sensitive instrumental measurement of dyskinesia was used. • This suggests dyskinesia is not associated with genetic liability for schizophrenia. Abstract There is accruing evidence of spontaneous dyskinesia in individuals with schizophrenia that is independent of medication exposure. Dyskinetic motor behavior is also present in individuals who are at high risk of schizophrenia and appears to have prognostic value for the development of psychosis. Nonetheless, it remains unclear whether dyskinesia is present in first-degree relatives of individuals with schizophrenia and thus associated with genetic liability for schizophrenia (i.e., an endophenotype), or whether the motor abnormality is a biomarker specific to the disease state spectrum. There is also limited information about links between dyskinesia and clinically relevant phenomena such as symptoms and cognition. Because dyskinesia marking genetic liability is likely to be subtle, we used sensitive instrument-based measurement of handwriting fluency to quantify dyskinesia in medicated individuals with schizophrenia or schizoaffective disorder, unaffected first-degree biological relatives of individuals with schizophrenia and schizoaffective disorder, and control participants. Results indicated that medicated individuals with schizophrenia or schizoaffective disorder exhibited more dyskinesia than both relatives and controls, with no difference between relatives and controls. Dyskinesia in individuals with schizophrenia or schizoaffective disorder was unrelated to current antipsychotic medication dosage, but associated with worse working memory function and greater positive formal thought disorder. These results provide evidence that dyskinesia is not associated with unexpressed genetic liability for schizophrenia. [ABSTRACT FROM AUTHOR]

Background: Although alterations in medial temporal lobe structures have been previously associated with use of cannabis, one of the most widely used illicit drugs, whether such alterations are a cause or effect of cannabis use has been unclear. Methods: In this cross-sectional observational study involving 404 twins/siblings, we have compared cortical thickness and surface area between groups of gender-matched sibling-pairs (concordant cannabis unexposed, concordant exposed and discordant for cannabis exposure) using permutation tests after controlling for potential confounds. Bi-variate polygenic model was used to assess the genetic and environmental contributions underlying cortical morphological phenotypes and frequency of cannabis use. Results: Cortical thickness of the right entorhinal cortex was significantly lower in the concordant exposed siblings compared to both discordant unexposed and discordant exposed groups [false discovery rate (FDR)-corrected, q < 0.05]. The association between the right entorhinal cortex thickness and frequency of cannabis use is due to the contribution of significant shared additive genetic (ρ g = −0.19 ± 0.08; p = 0.02) factors but not unique environment (ρ e = 0.05 ± 0.09; p = 0.53). Significantly lower surface area of the right entorhinal cortex in discordant exposed group compared with the discordant unexposed group furnishes preliminary evidence in support of causal effect of cannabis use (FDR-corrected, q < 0.05). However, bi-variate polygenic model-based analysis did not show any significant effect. Conclusions: Shared genetic liability may underlie the association between cannabis exposure and thinner right entorhinal cortex. Prospective longitudinal studies are necessary to definitively disentangle the cause–effect relationships of cannabis use. [ABSTRACT FROM AUTHOR]

Objective: Children of mothers with severe mental illness are at significantly increased risk of developing intellectual disability. Obstetric complications are also implicated in the risk for intellectual disability. Moreover, children of mothers with severe mental illness are more likely to be exposed to obstetric complications. The purpose of this study was to examine the independent and joint contributions of familial severe mental illness and obstetric complications to the risk of intellectual disability.Method: Record linkage across Western Australian whole-population psychiatric, inpatient, birth, and midwives' registers identified 15,351 children born between 1980 and 2001 to mothers with severe mental illness and 449,229 children born to mothers with no mental illness. Multivariable models were adjusted for paternal psychiatric status, parental intellectual disability, and other family and sociodemographic covariates.Results: The risk of intellectual disability was increased among children of mothers with severe mental illness compared with children of unaffected mothers. The impact varied across maternal diagnostic groups. For children of mothers with schizophrenia, the unadjusted odds ratio was 3.8 (95% CI=3.0, 4.9) and remained significant after simultaneous adjustment for exposure to obstetric complications and other covariates (odds ratio=1.7, 95% CI=1.3, 2.3). The odds ratio for exposure to obstetric complications also remained significant after adjustment (odds ratio=1.7, 95% CI=1.6, 1.8). For intellectual disability of a genetic basis, the adjusted odds ratio for maternal schizophrenia was elevated but not statistically significant. Among children with intellectual disability, 4.2% later developed a psychotic disorder, compared with 1.1% of children without intellectual disability.Conclusions: Maternal severe mental illness and exposure to obstetric complications contribute separately to the risk of intellectual disability, suggesting potentially different causal pathways. [ABSTRACT FROM AUTHOR]

This review focuses on the viability of working memory impairment as an endophenotypic marker of a schizophrenia diathesis. It begins with an introduction of the construct of working memory. It follows with a consideration of the operational criteria for defining an endophenotype. Research findings regarding the working memory performance of schizophrenia and schizophrenia-spectrum patients, first-degree relatives of schizophrenia patients and healthy controls, are reviewed in terms of the criteria for being considered an endophenotypic marker. Special attention is paid to specific components of the working memory deficit (namely, encoding, maintenance, and manipulation), in terms of which aspects are likely to be the best candidates for endophenotypes. We examine the extant literature regarding working memory performance in bipolar disorder and major depression in order to address the issue of relative specificity to schizophrenia. Despite some unresolved issues, it appears that working memory impairment is a very promising candidate for an endophenotypic marker of a schizophrenia diathesis but not for mood disorders. Throughout this review, we identify future directions for research in this exciting and dynamic area of research and evaluate the contribution of working memory research to our understanding of schizophrenia.

Treatment-resistant schizophrenia (TRS) affects around one-third of individuals with schizophrenia. Although a number of sociodemographic and clinical predictors of TRS have been identified, data on the genetic risk of TRS are sparse. We aimed to investigate the association between a polygenic risk score for schizophrenia and treatment resistance in patients with schizophrenia. We conducted a nationwide, population-based follow-up study among all Danish individuals born after 1981 and with an incident diagnosis of schizophrenia between 1999 and 2007. Based on genome-wide data polygenic risk scores for schizophrenia were calculated in 862 individuals with schizophrenia. TRS was defined as either clozapine initiation or at least 2 periods of different antipsychotic monotherapies and still being hospitalized. We estimated hazard rate ratios (HRs) for TRS in relation to the polygenic risk score while adjusting for population stratification, age, sex, geographical area at birth, clinical treatment setting, psychiatric comorbidity, and calendar year. Among the 862 individuals with schizophrenia, 181 (21.0%) met criteria for TRS during 4674 person-years of follow-up. We found no significant association between the polygenic risk score and TRS, adjusted HR = 1.13 (95% CI: 0.95-1.35). Based on these results, the use of the polygenic risk score for schizophrenia to identify individuals with TRS is at present inadequate to be of clinical utility at the individual patient level. Future research should include larger genetic samples in combination with non-genetic markers. Moreover, a TRS-specific developed polygenic risk score would be of great interest towards early prediction of TRS. [ABSTRACT FROM AUTHOR]

Background: Previous research indicates that liability to disability pension (DP) due to mental diagnoses is moderately influenced by genetic factors. This study investigates whether genetic contributions to the liability to DP due to mood and neurotic diagnoses overlap with the genetic influences on major depression (MD), generalized anxiety disorder (GAD), or chronic fatigue (CF).Method: A prospective cohort study including 9,985 female twins born in Sweden 1933-1958. The presence of MD, GAD, and CF was assessed by computer-assisted telephone interviews conducted in 1998-2002. Data on DP due to mood and neurotic diagnoses were obtained from nationwide registers for the years 1998-2010. Common genetic and environmental influences on the phenotypes were estimated by applying structural equation modeling.Results: The prevalence of MD/GAD was 30%, CF 8%, and DP due to mood and neurotic diagnoses 3% in 2010. Genetic effects on MD/GAD explained 31% of the total genetic variation in DP, whereas genetic contributions in common with CF were small and not significant. The majority of the total non-shared environmental variance in DP (85%) was explained by the factors that were unique to DP.Conclusions: Large proportions of genetic and non-shared environmental influences in DP due to mood and neurotic diagnoses were not explained by the contributions from MD/GAD or CF. The results suggest that the process leading to DP is complex and influenced by factors other than those related to the disorder underlying DP. [ABSTRACT FROM AUTHOR]

Background.The salience of a visual stimulus is often reduced by nearby stimuli, an effect known as surround suppression of perceived contrast, which may help in locating the borders of an object. Weaker surround suppression has been observed in schizophrenia but it is unclear whether this abnormality is present in other mental disorders with similar symptomatology, or is evident in people with genetic liability for schizophrenia.Method.By examining surround suppression among subjects with schizophrenia or bipolar affective disorder, their unaffected biological relatives and healthy controls we sought to determine whether diminished surround suppression was specific to schizophrenia, and if subjects with a genetic risk for either disorder would show similar deficits. Measuring perceived contrast in different surround conditions also allowed us to investigate how this suppression depends on the similarity of target and surrounding stimuli.Results.Surround suppression was weaker among schizophrenia patients regardless of surround configuration. Subjects with bipolar affective disorder showed an intermediate deficit, with stronger suppression than in schizophrenia but weaker than control subjects. Surround suppression was normal in relatives of both patient groups. Findings support a deficit in broadly tuned (rather than sharply orientation- or direction-selective) suppression mechanisms.Conclusions.Weak broadly tuned suppression during visual perception is evident in schizophrenia and bipolar affective disorder, consistent with impaired gain control related to the clinical expression of these conditions. [ABSTRACT FROM PUBLISHER]

Background: Deficits in facial emotion perception in schizophrenia may be a marker of disorder liability. Previous functional magnetic resonance imaging (fMRI) studies investigating these deficits have been limited by task demands that may recruit other impaired cognitive processes in schizophrenia.Methods: We used a family study design along with a passive viewing task during fMRI to investigate brain activation abnormalities underlying facial emotion perception in schizophrenia and examine whether such abnormalities are associated with the genetic liability to the disorder. Twenty-eight schizophrenia patients, 27 nonpsychotic relatives, and 27 community controls passively viewed images of facial emotions during an fMRI scan.Results: Analyses revealed hypoactivation in face processing areas for both patients and relatives compared to controls, and hyperactivation in relatives compared to both patients and controls for frontal regions implicated in emotion processing.Conclusions: Results suggest that activation abnormalities during facial emotion perception are manifestations of the genetic liability to schizophrenia, and may be accompanied by compensatory mechanisms in relatives. Studying mechanisms in nonpsychotic relatives is a valuable way to examine effects of the unexpressed genetic liability to schizophrenia on the brain and behaviour. [ABSTRACT FROM AUTHOR]

Impaired functional connectivity has been hypothesized as a potential source of the cognitive deficits routinely observed in patients with schizophrenia. Additionally, these deficits may be manifestations of the genetic liability to schizophrenia and present in the non-psychotic first-degree relatives of that group. However, no study has examined task-based functional connectivity in schizophrenia relatives using independent component analysis (ICA). We employed group ICA to test the hypothesis that the unexpressed genetic liability to schizophrenia is reflected in the functional connectivity between brain regions during a task measuring context processing. We compared 20 schizophrenia patients and 32 patients' first-degree relatives to 22 controls demographically matched to the patients and 28 controls' relatives, respectively. The group ICA showed differential connectivity between patients and controls in a task-related network constituting right middle frontal gyrus (MFG) and right posterior parietal lobe. A network constituting left MFG and left posterior parietal, which was also related to the context processing task, did not differ between groups. These findings demonstrate that connectivity abnormalities associated with the genetic liability to schizophrenia are most strongly expressed in a right lateralized executive fronto-parietal network, and that these abnormalities are linked to context processing impairments. [ABSTRACT FROM AUTHOR]

The article examines the comorbidity between multiple sclerosis (MS) and schizophrenia, depression and bipolar disorder in Sweden. The study shows the increase of MS risk in patients having bipolar disorder and depression, but decrease in patients with schizophrenia. It indicates the positive association of MS with depression and bipolar disorder.