Sex differences in schizophrenia: a longitudinal methylome analysis.

DNA methylation analysis at the genome-wide level is a useful tool to explore potential sex differences in SCZ patients. The primary aim of the current study was to identify differentially methylated regions of DNA between males and females with schizophrenia. We collected DNA samples from 134 schizophrenia patients to measure genome-wide methylation at single-base resolution in 96 males and 38 females. We further repeated the analysis in 13 subjects (9 females, 4 males) to confirm the sex differences and to reduce the effect of potential confounders. The longitudinal methylation analysis found significant replication of several genes across the genome. These genes included RFTN1, TLE1, DAZL, PRR4, UTP14C, RNU12, and LOC644649. The overall results showed robust association between autosomal CpG sites and sex. Longitudinal methylation analysis can be used as internal replication to confirm epigenetic variants that are stable over time.

Epigenetics for Drug Discovery: Dissecting the Effect of High Antipsychotic Dosage and D2 Blockage on Peripheral DNA Methylation.

INTRODUCTION: The relationship between genetic polymorphisms of antipsychotic drug-metabolizing agents and drug receptors has been often investigated. DNA methylation is a form of epigenetic modification that regulates gene expression. Few studies have analyzed the relationship between genome-wide methylation patterns and antipsychotic dosage. The primary aim of this pilot study was to investigate the association between antipsychotic dosage and genome-wide DNA methylation in patients with schizophrenia (SCZ). METHODS: Current dosage of antipsychotic medications was assessed in 136 patients with SCZ. Dosage was standardized using three different methods: chlorpromazine equivalent dose (CPZe), defined daily dose (DDD), and percentage of Lexicomp maximum dose (PM%). DNA methylation was measured in white blood cells. Antipsychotic dosage was the primary outcome variable in a model, including genome-wide methylation status as the main predictor. RESULTS: This study did not show any association between DNA methylation and dosage variation for CPZe, PM%, and DDD. However, the probe cg271403389 was consistently associated with antipsychotic dosage across the three standardization methods. When looking at the genomic location of the most significant probes, we found that 15% were intergenic, 23% were in the distal promoter, 9% in the 3'untranslated region, 32% in the gene body, 3% in the 5' untranslated region, 15% in the proximal promoter, and 3% in the first exon. DISCUSSION: This study shows the importance of investigating the relationship between DNA methylation and optimal antipsychotic dosage to personalize treatment in SCZ. Future studies require larger prescription databases to build on the results of this analysis.

Chromosome 22 Deletions and Suicidal Behavior in Schizophrenia.

BACKGROUND: Studies have shown that the overall copy number variant (CNV) load is associated with schizophrenia. Schizophrenia is a mental disorder that is frequently associated with suicidal behavior. METHODS: We recruited 263 patients with schizophrenia from the Centre for Addiction and Mental Health. The Columbia Suicide Severity Rating Scale was used to assess the presence of lifetime suicide attempt. Genotyping was completed using the Illumina Omni 2.5 chip. We tested the association between deletion events on chromosome 22 with suicide attempt in our schizophrenia sample. RESULTS: There was no significant difference between suicide attempters and non-attempters considering the presence/absence of deletion events on chromosome 22. CONCLUSION: Although our results did not show a significant association between deletions on chromosome 22 and suicide attempt in schizophrenia, CNV studies may reveal important, novel insights and open further investigation for the treatment of neuropsychiatric diseases.

Genome-wide methylation association with current suicidal ideation in schizophrenia.

In this study, we investigate the epigenetic mechanisms associated with current suicidal ideation. Gene expression changes have been found in post-mortem brain of suicide victims. However, it is not clear how in-vivo gene expression change confers risk for suicide. DNA methylation is a form of epigenetic modification that regulates gene expression. Our primary aim is to investigate genome-wide methylation in conferring risk for current suicidal ideation (SI) in schizophrenia. The presence of current SI and genome-wide methylation patterns were assessed in 107 patients with schizophrenia. DNA methylation has been measured in white blood cells as a possible peripheral biomarker of SI. SI was the primary outcome variable in a model including methylation status of white blood cells using the Illumina 450 array. We have tested the association with genome-wide methylation levels in 19 subjects with current SI and 88 subjects without current SI and we found that higher methylation level in the CpG cg06121808 located in the gene SLC20A1 on chromosome 2 was associated with current SI (p = 0.000003; beta difference = 0.06). Furthermore, the distal promoter analysis showed that the gene SMPD2 was hypermethylated in suicide ideators (p = 0.0001; beta difference = 0.02). Thus, molecular biomarkers could advance our understanding of the molecular mechanisms of stress-related SI. Furthermore, the methylation sites that we have identified should be replicated in other suicide related phenotypes to generate robust biomarkers with high translational value for proof of concept interventions aiming at reducing SI.

Polygenic Risk Score Effect on Violent Behavior in Schizophrenia.

Previous studies aiming to establish a correlation between schizophrenia (SCZ) and aggressive behavior have resulted in contradictory results. Despite this, a certain degree of evidence suggests a potential underlying genetic component to aggression in SCZ. Polygenic risk score (PRS) analysis is a novel technique to estimate the combined effect of multiple genetic influences on aggression. Our objective was to investigate whether PRS could determine a proclivity toward aggressive behavior in patients with SCZ. Community-dwelling patients diagnosed with a schizophrenia spectrum disorder (n = 205) were recruited from a nonforensic outpatient sample. Participants were assessed for aggression using a cross-sectional and retrospective design, and PRS was calculated using genomic DNA and the Illumina Omni 2.5 array. We did not detect any associations between lifetime physical aggression (P = 32), verbal aggression (P = 24), or aggression against property (P = 24) and the PRS for SCZ risk. There may be several reasons to explain our null findings. We recommend that future interaction analyses of PRSs in SCZ that investigate violence focus on forensic psychiatric patients with higher base rates of violence and use participant interviews to assess aggression.

Head-to-head comparison of various antipsychotic agents on genome-wide methylation in schizophrenia.

Aim: To explore possible differences in genome-wide methylation between schizophrenia patients who consume various antipsychotics. Methods: We compared DNA methylation in leukocytes between the following cohorts: clozapine (n = 19) versus risperidone (n = 19), clozapine (n = 12) versus olanzapine (n = 12), clozapine (n = 9) versus quetiapine (n = 9) and clozapine (n = 33) versus healthy controls (n = 33). Subjects were matched for age, sex, ethnicity, smoking status and leukocyte proportions. Results: No single CpG site reached genome-wide significance for clozapine versus risperidone/olanzapine/quetiapine. For clozapine versus quetiapine, one significantly differentially methylated region was found - ch5: 176797920-176798049 (fwer = 0.075). Clozapine versus healthy controls yielded thousands of significantly differentially methylated CpG sites. Conclusions: Establishing antipsychotic induced genome-wide methylation patterns will further elucidate the biological and clinical effects of antipsychotic administration.

Differential Methylation Analysis of Suicidal Ideation Severity in Schizophrenia with the Illumina MethylationEPIC Array.

There is a multitude of factors that makes difficult to identify those at risk for suicide, especially among schizophrenia patients. Suicide cannot be explained by genetics alone, therefore epigenetic mechanisms including DNA methylation are thought to play a role. DNA methylation could be a valuable tool in helping predict those at-risk individuals. This cross-sectional study comprised 112 subjects diagnosed with schizophrenia spectrum disorders, and were grouped according to the current suicidal ideation severity. DNA methylation across the genome was measured with the Infinium® MethylationEPIC BeadChip. We utilized the dmpFinder and bumphunter functions within the Bioconductor minfi package to identify differentially methylated positions (DMPs) and differentially methylated regions (DMRs), respectively. Following quality control, we removed one sample from the analysis and reported the most significant DMPs and DMRs associated with suicidal ideation severity. All positions and regions identified in this analysis were only found to have suggestive levels of significance at the genome-wide level. The present study was one of the first to investigate genome-wide methylation and suicidal ideation severity. While there were many strengths of our study, including investigating both differentially methylated positions and regions, further larger-scale studies are necessary to replicate, support, and validate our findings presented here.

Childhood trauma exposure and personality traits in schizophrenia patients.

Childhood trauma in schizophrenia (SCZ) is associated with aberrant neurobiological downstream effects and cognitive deficits that markedly hinder patient outcome and functioning. However, the relationship between specific forms of childhood abuse and the tendency for certain personality traits in patients with SCZ has not been comprehensively studied yet. We recruited 374 SCZ patients and screened for history of physical abuse (PA), emotional abuse (EA), sexual abuse (SA), physical neglect (PN) and emotional neglect (EN) using the Childhood Trauma Questionnaire and measured personality traits using the NEO Five-Factor inventory. Using CTQ cut-off scores, the prevalence of EA, PA, SA, EN and PN was 60.7%, 42.0%, 37.7%, 64.2% and 54.3% respectively. Exposure to any form of childhood abuse was associated with increased neuroticism. Exposure to EA, SA, PN and EN was correlated with decreased agreeableness and conscientiousness scores. PN, EN and PA exposure was associated with decreased openness while EA, PN and EN exposure was associated with decreased extraversion. Furthermore, a positive correlation was found between all forms of childhood abuse and trait neuroticism whereas negative correlations were found between certain forms of childhood abuse and all other personality traits. Exposure to specific forms of childhood abuse was associated with specific personality traits in patients with SCZ.

Epigenetic age dysregulation in individuals with bipolar disorder and schizophrenia.

Bipolar disorder (BD) and schizophrenia (SCZ) are debilitating disorders that are associated with significant burden and reduced quality of life. In this study, we leveraged microarray data derived from both the Illumina HumanMethylation450 platform to investigate the epigenetic age of individuals with SCZ (n = 40), BD (n = 40), and healthy controls (n = 38), across five epigenetic clocks. Various statistical metrics were used to identify discrepancies between epigenetic and chronological age across the three groups. We observed a significant increase in epigenetic age compared to chronological age in the BD group. Mean epigenetic age acceleration was also higher in individuals with bipolar disorder compared to healthy controls across four different epigenetic clocks (p<0.05). Despite the study's relatively small sample size, these findings suggest that both individuals with bipolar disorder and schizophrenia may have epigenetic markers associated with a premature aging phenotype, which could be suggestive of negative outcomes associated with the disease. In our future studies, we hope to elucidate this finding further by elucidating the precise link between epigenetic age, symptomatology and disease progression.

Mediating effect of genome-wide DNA methylation on suicidal ideation induced by perceived stress.

Stress is an important risk factor for suicidal ideation, but the mechanisms that link stress, suicidal ideation and neurobiology remain unclear. Epigenetic mechanisms are involved in both vulnerability to suicidal behavior and stress. This is a pilot study of 60 patients with schizophrenia spectrum disorders (36 men and 24 women), with an average age of 43.75 ± 12.24 years. We analyzed the effects of (1) perceived stress and (2) the mediation of genome-wide methylation (~450 000 CpG sites) on suicidal ideation severity. The top CpG site mediating the effect of stress on suicidal ideation was the cg10782349 located in the ZNF701 gene on chromosome 19, facilitating the effect through DNA hypermethylation. These preliminary results indicate that DNA methylation in peripheral tissues can clarify the complex relationship between stress and suicidal ideation in schizophrenia.

Biological aging in schizophrenia and psychosis severity: DNA methylation analysis.

The physiological changes associated with normal aging are known to occur earlier in individuals with schizophrenia (SCZ). One of the phenomena linked with normal aging is the change in patterns of epigenetic modifications. We recruited 138 individuals with SCZ spectrum disorders and extracted DNA from white blood cells. The combinations of pre-selected DNA methylation sites were utilized to estimate the 'methylation age' (DNAm age) and evaluate evidence of epigenetic age acceleration. We investigated the correlation between the epigenetic age acceleration measures and psychosis severity; furthermore, we estimated blood cell counts based on DNA methylation levels. The extrinsic epigenetic age acceleration showed a significant correlation with the Brief Psychiatric Rating Scale (BPRS) disorganization subscale(r=0.222, p=0.039).Both Horvath age acceleration and Hannum age acceleration showed a significant correlation (r=0.221, p=0.029; r=0.242, p=0.017 respectively) with the Symptom Checklist 90 (SCL-90) psychotic domain. Overall, this study shows some evidence of epigenetic age acceleration associated with psychosis severity using two different algorithms for DNAm age analysis.

Global DNA methylation in suicidal ideation and suicide attempt in schizophrenia.

Suicidal behavior is influenced by many risk factors such as childhood trauma, stressful life events, genetic factors, and severe mental illnesses. Suicidal ideation is present in 50% of schizophrenia patients and is associated with an elevated risk of suicide attempt. Studies have shown that epigenetic mechanisms are associated with suicidal behavior in schizophrenia. Although several studies have suggested the importance of epigenetic factors in suicidal ideation and behavior, no studies have investigated global methylation in association with these two phenotypes. This study investigated global methylation level/change in association with current and emergent suicidal ideation and also with suicide attempt. Forty-seven schizophrenia patients were assessed for the association between global methylation and suicide attempt, and a subsample of these patients (n = 27) was assessed for current suicidal ideation. Afterwards, we performed a longitudinal analysis in which global methylation changes during a 3-month follow-up were compared between patients with and without emergent suicidal ideation. This methylation analysis did not find evidence for a significant association between global methylation and suicidal ideation or suicide attempt. To date, there are no robust biomarkers predicting suicidal ideation or behavior in psychotic patients. This study is the first to investigate global methylation in predicting suicidal ideation and behavior. Although we did not find evidence for an association between global methylation and these phenotypes, our findings may offer novel insights into the molecular mechanisms linked to suicide. Future investigation may measure global methylation in association with suicidal ideation or behavior in larger samples.

Romosozumab (sclerostin monoclonal antibody) for the treatment of osteoporosis in postmenopausal women: A review.

Romosozumab (ROMO) is a recently approved monoclonal antibody (approved by the U.S. Food and Drug Administration [FDA] in April 2019 and Health Canada in June 2019) for the treatment of osteoporosis in postmenopausal women. ROMO works by selectively inhibiting sclerostin-a glycoprotein that inhibits osteoblasts and further promotes bone resorption. The authors reviewed three phase III clinical trials (Fracture Study in Postmenopausal Women with Osteoporosis [FRAME], Active-Controlled Fracture Study in Postmenopausal Women with Osteoporosis at High Risk [ARCH], and STudy evaluating the effect of RomosozUmab Compared with Teriparatide in postmenopaUsal women with osteoporosis at high risk for fracture pReviously treated with bisphosphonatE therapy [STRUCTURE]) that demonstrated ROMO's ability to increase bone mineral density (BMD) at the lumbar spine and hip and the risk of vertebral and clinical fractures. Additionally, clinical trials demonstrated the risk for serious cardiovascular events among patients that received ROMO, and these severe adverse reactions deserve further investigation. Although ROMO presents as a potentially exciting therapeutic with serious clinical implications, the authors recommend further analysis using real-world evidence (RWE) studies to fully elucidate the cardiovascular event risk associated with ROMO administration.

Prediction of physical violence in schizophrenia with machine learning algorithms.

Patients with schizophrenia have been shown to have an increased risk for physical violence. While certain features have been identified as risk factors, it has been difficult to integrate these variables to identify violent patients. The present study thus attempts to develop a clinically-relevant predictive tool. In a population of 275 schizophrenia patients, we identified 103 participants as violent and 172 as non-violent through electronic medical documentation, and conducted cross-sectional assessments to identify demographic, clinical, and sociocultural variables. Using these predictors, we utilized seven machine learning classification algorithms to predict for past instances of physical violence. Our classification algorithms predicted with significant accuracy compared to random discrimination alone, and had varying degrees of predictive power, as described by various performance measures. We determined that the random forest model performed marginally better than other algorithms, with an accuracy of 62% and an area under the receiver operator characteristic curve (AUROC) of 0.63. To summarize, machine learning classification algorithms are becoming increasingly valuable, though, optimization of these models is needed to better complement diagnostic decisions regarding early interventional measures to predict instances of physical violence.

Genome-wide association study of aggression and violence in schizophrenia.

Schizophrenia patients are at higher risk of engaging in violent behavior than the general population. Schizophrenia is also regarded as a highly heritable disorder. This study aimed to analyze genome-wide the effect of SNPs on violence in schizophrenia. We recruited 205 subjects between the age of 18-75 from the Centre for Addiction and Mental Health (CAMH), who had a diagnosis of schizophrenia or schizoaffective disorder. We recorded physical, verbal and lifetime violence scores indicating any violent actions to inflict pain, bodily harm, or death on another individual from the standardized scale, Modified Overt Aggression Scale (MOAS). We genotyped each participant's DNA using the Illumina Omni 2.5, and the SNPs were analyzed using the whole genome analysis tool-set, PLINK. We probed for single nucleotide polymorphisms (SNPs) correlated with violence in schizophrenia patients. We found one SNP (rs2188177) on chromosome 7 which showed a trend for association with physical violence (p = 7.80E-06). This study is the first of its kind to investigate genome-wide, the polymorphisms associated with violence in schizophrenia. The findings of this study may promote collaborative efforts to understand the genetic basis of violent behavior in psychosis.

Early-life stressful events and suicide attempt in schizophrenia: Machine learning models.

Childhood abuse and neglect predicts suicide attempt. Furthermore, other early-life stressful events may predict lifetime suicide attempt in psychiatric disorders. We assessed 189 schizophrenics for suicide attempt and stressful life events. Early-life stressful events were used as predictors of lifetime suicide attempt in three machine learning models. In our sample, 38% of the schizophrenics had at least one suicide attempt lifetime. The machine learning models provided an overall significant prediction (accuracy range: 62-69%). Childhood sexual molestation and mental illness were important predictors of suicide attempt. Early-life stressful events should be included in models aiming at predicting suicide attempt in schizophrenia.

Childhood trauma predicts multiple, high lethality suicide attempts in patients with schizophrenia.

Childhood trauma has been shown to increase the risk of suicide attempts in individuals with schizophrenia. However, previous literature has been limited by considerable heterogeneity within the category of suicide attempters. Here we tested the predictive effect of childhood maltreatment on lifetime suicide attempt in a homogeneous sample of 650 patients with schizophrenia spectrum disorders. Childhood trauma was assessed using the Childhood Trauma Questionnaire-Short Form and suicide history was measured using subjective and objective validated scales as well as medical chart reviews. We refined our sample into two homogenous groups: 1) suicide attempters: patients who had attempted suicide multiple times, with highly lethal results (medical hospitalization required) (n = 24); and 2) non-ideators: patients who had no personal history of suicide attempt or ideation, or family history of attempt (n = 25). Binary logistic regression models revealed that total childhood trauma (ß = 0.002; OR: 1.07; 95% CI: 1.00-1.14) and emotional abuse (ß = 0.04; OR: 1.38; 95% CI: 1.08-1.77), but not other trauma subtypes, significantly predicted lifetime multiple, high lethality suicide attempts after adjusting for demographic and clinical covariates. Thus, childhood trauma is a weak, independent risk factor for extreme suicide attempts in patients with schizophrenia spectrum disorders.