Genetic correlates of medical comorbidity associated with schizophrenia and treatment with antipsychotics

Multimorbidity and the Etiology of Schizophrenia

PURPOSE OF REVIEW

A global study of multimorbidity in schizophrenia, especially of the association with physical conditions, might offer much needed etiological insights.

RECENT FINDINGS

Our review suggests that life-style factors and medication related to schizophrenia are only part of the explanation of the increase in risk for cardiovascular, metabolic, pulmonary disorders, and some cancers. Positive associations with autoimmune disorders (with the exception of rheumatoid arthritis) and epilepsy are promising avenues of research but to date have not been fully exploited. The same holds for the negative comorbidity seen for rheumatoid arthritis and some cancers (e.g., prostate). As a whole, our review suggests that most of the explored conditions have a different prevalence in schizophrenia than in the general population. Several hypotheses emerged from this review such as the role of immune and genetic factors, of sex hormones, and of more general variability factors.

The volume of gray matter mediates the relationship between glucolipid metabolism and neurocognition in first-episode, drug-naïve patients with schizophrenia

We aimed to examine the hypotheses that glucolipid metabolism is linked to neurocognition and gray matter volume (GMV) and that GMV mediates the association of glucolipid metabolism with neurocognition in first-episode, drug-naïve (FEDN) patients with schizophrenia. Parameters of glucolipid metabolism, neurocognition, and magnetic resonance imaging were assessed in 63 patients and 31 controls. Compared to controls, patients exhibited higher levels of fasting glucose, triglyceride, and insulin resistance index, lower levels of cholesterol and high-density lipoprotein cholesterol, poorer neurocognitive functions, and decreased GMV in the bilateral insula, left middle occipital gyrus, and left postcentral gyrus. In the patient group, triglyceride levels and the insulin resistance index exhibited a negative correlation with Rapid Visual Information Processing (RVP) mean latency, a measure of attention within the Cambridge Neurocognitive Test Automated Battery (CANTAB), while showing a positive association with GMV in the right insula. The mediation model revealed that triglyceride and insulin resistance index had a significant positive indirect (mediated) influence on RVP mean latency through GMV in the right insula. Glucolipid metabolism was linked to both neurocognitive functions and GMV in FEDN patients with schizophrenia, with the effect pattern differing from that observed in chronic schizophrenia or schizophrenia comorbid with metabolic syndrome. Moreover, glucolipid metabolism might indirectly contribute to neurocognitive deficits through the mediating role of GMV in these patients.

Deep Brain Stimulation in the Treatment of Tardive Dyskinesia

Tardive dyskinesia (TD) is a phenomenon observed following the predominantly long-term use of dopamine receptor blockers (antipsychotics) widely used in psychiatry. TD is a group of involuntary, irregular hyperkinetic movements, mainly in the muscles of the face, eyelid, lips, tongue, and cheeks, and less frequently in the limbs, neck, pelvis, and trunk. In some patients, TD takes on an extremely severe form, massively disrupting functioning and, moreover, causing stigmatization and suffering. Deep brain stimulation (DBS), a method used, among others, in Parkinson's disease, is also an effective treatment for TD and often becomes a method of last resort, especially in severe, drug-resistant forms. The group of TD patients who have undergone DBS is still very limited. The procedure is relatively new in TD, so the available reliable clinical studies are few and consist mainly of case reports. Unilateral and bilateral stimulation of two sites has proven efficacy in TD treatment. Most authors describe stimulation of the globus pallidus internus (GPi); less frequent descriptions involve the subthalamic nucleus (STN). In the present paper, we provide up-to-date information on the stimulation of both mentioned brain areas. We also compare the efficacy of the two methods by comparing the two available studies that included the largest groups of patients. Although GPi stimulation is more frequently described in literature, our analysis indicates comparable results (reduction of involuntary movements) with STN DBS.

Prenatal and Childhood Immuno-Metabolic Risk Factors for Adult Depression and Psychosis

Depression and psychosis have a developmental component to their origin. Epidemiologic evidence, which we synthesize in this nonsystematic review, suggests that early-life infection, inflammation, and metabolic alterations could play a role in the etiology of these psychiatric disorders. The risk of depression and psychosis is associated with prenatal maternal and childhood infections, which could be mediated by impaired neurodevelopment. Evidence suggests linear dose-response associations between elevated concentrations of circulating inflammatory markers in childhood, particularly the inflammatory cytokine interleukin 6, and the risk for depression and psychosis subsequently in early adulthood. Childhood inflammatory markers are also associated with persistence of depressive symptoms subsequently in adolescence and early adulthood. Developmental trajectories reflecting persistently high insulin levels during childhood and adolescence are associated with a higher risk of psychosis in adulthood, whereas increased adiposity during and after puberty is associated with the risk of depression. Together, these findings suggest that higher levels of infection, inflammation, and metabolic alterations commonly seen in people with depression and psychosis could be a cause for, rather than simply a consequence of, these disorders. Therefore, early-life immuno-metabolic alterations, as well as factors influencing these alterations such as adversity or maltreatment, could represent targets for prevention of these psychiatric disorders. Inflammation could also be an important treatment target for depression and psychosis. The field requires further research to examine sensitive periods when exposure to such immuno-metabolic alterations is most harmful. Interventional studies are also needed to test the potential usefulness of targeting early-life immuno-metabolic alterations for preventing adult depression and psychosis.

Comorbidity and Treatment in Older Psychiatric In-patients-A Retrospective Study in a Chinese Psychiatric Hospital

Background: Comorbid somatic diseases increase the death risk and affect the condition, treatment, and prognosis of older psychiatric patients. We investigated the comorbidity and drug treatment in older patients with psychosis. Methods: This retrospective study used data from 3,115 older psychiatric in-patients hospitalized at the Shanghai Mental Health Center Affiliated to Shanghai Jiaotong University School of Medicine, China discharged from 2005 to 2015. Descriptive analyses of patients' age, sex, treatment drugs, diagnoses (based on ICD-10), and time trend were performed. Results: Patients' median age was 56 (range, 50-98) years; 1,824 (58.6%) were female. The top five first-level diagnoses were schizophrenia (F20) (n = 1,818, 58.3%), depressive episode (F32) (n = 457, 14.6%), bipolar affective disorder (F31) (n = 151, 4.8%), manic episode (F30), (n = 143, 4.6%), and vascular dementia (F01) (n = 136, 4.4%). Mental (99.9%), central nervous system (85.2%), digestive system (83.5%), cardiovascular system (72.5%), and anti-infective (59.6%) drugs had the highest prescription rates. The combined use of antidepressants, anti-anxiety, anti-arrhythmic, hormones and endocrine system drugs were significantly higher in female than in male patients, while mood stabilizers and genitourinary system drugs significantly more frequent in men. With increasing age, the F20-F29 patients decreased, while F00-F09 patients increased, with the corresponding changes to prescription in those patients. In comparison to that in 2005-2010, the combined prescriptions for genitourinary and cardiovascular drugs increased between 2011 and 2015, and F00-F09 and F40-F48 older patients doubled, accordingly anti-Alzheimer's disease drugs and antidepressants more than doubled. F30-F39 patients increased by 49.1%, and anti-anxiety drugs, mood stabilizers, etc. increased by ≥50%; F20-F29 older patients decreased by 26.7%, while antipsychotics only increased by 4.4%. Conclusions: This study found the combined drug treatment of somatic diseases, particularly for central nervous, digestive, cardiovascular, respiratory and genitourinary drugs were extremely common among older psychiatric in-patients in China. With increasing age, the F20-F29 patients decreased, while F00-F09 patients increased; the antipsychotics prescriptions decreased, and almost all comorbidity drugs increased. Compared with that in 2005-2010, the older patients with all diagnosis except F20-F29 increased in 2011-2015, and the prescriptions for psychotropic, genitourinary, and cardiovascular drugs increased.

Comorbid physical illnesses in adult outpatients with psychotic disorders: risk factors, psychological functioning, and quality of life outcomes

PURPOSE

In contrast to global research, where physical comorbidity in psychotic disorders is established, only a few studies have been conducted in Southeast Asia. With a concerning trend of chronic physical illnesses emerging in adults below the age of 65, an investigation into comorbid chronic physical illnesses in adults diagnosed with psychotic disorders is necessary. This study aims to explore the risk factors, psychological functioning, and quality of life outcomes associated with comorbidity in adults below the age of 65, diagnosed with psychotic disorders, in a multi-ethnic non-Western setting.

METHODS

Electronic medical records of 364 patients with psychotic disorders who had provided written consent to participate were screened for co-occurring physical conditions. The majority of participants were female (53.7%), Chinese (69%), single (74.5%), and had tertiary and above education (43%). They were approximately 35 years old on average and the mean age of onset for psychosis was 26.7 years old.

RESULTS

Comorbid physical illnesses were present in approximately a third of adults with psychotic disorders (28%). They typically reported cardiovascular-related diseases, respiratory, and skin conditions. Comorbidity was significantly related to lower physical quality of life. As compared to other types of psychotic disorders, schizophrenia was significantly related to a greater frequency of comorbid physical conditions. Multinomial regression analyses revealed that age, age of onset, Malay and Indian ethnicities were significant factors.

CONCLUSION

Physical comorbidity in adults below the age of 65 is common, signifying an emerging need to place greater attention into the screening and emphasis on the physical care needs of this age group. Finally, more research is needed to understand the impact of common co-occurring acute and chronic cardiovascular, skin, and respiratory diseases locally.

Common mechanisms for type 2 diabetes and psychosis: Findings from a prospective birth cohort

BACKGROUND

Psychosis and type 2 diabetes mellitus (T2DM) are commonly comorbid and may share pathophysiologic mechanisms. To investigate shared genetic variation and inflammation as potential common mechanisms, we tested: (i) associations between genetic predisposition for T2DM and psychotic experiences and psychotic disorder in young adults; (ii) the association between genetic predisposition for schizophrenia and insulin resistance (IR), a precursor of T2DM; and (iii) whether these associations are mediated by childhood inflammation.

METHODS

Psychotic experiences (PEs), psychotic disorder and IR were assessed at age 18. Polygenic risk scores (PRS) for T2DM and schizophrenia were derived based on large genome-wide association studies. Associations between PRS and psychotic/IR outcomes were assessed using regression analysis based on 3768 ALSPAC birth cohort participants with complete data. Inflammatory markers C-reactive protein (CRP) and interleukin 6 (IL-6) measured at age 9 were used in regression and mediation analyses.

RESULTS

Genetic predisposition for T2DM was associated with PEs (adjusted OR = 1.21; 95% CI, 1.01-1.45) and psychotic disorder (adjusted OR = 1.51; 95% CI, 1.04-2.03) at age 18 in a linear dose-response fashion. Genetic predisposition for schizophrenia was weakly associated with IR (adjusted OR = 1.10; 95% C·I, 0.99-1.22) at age 18. The association between genetic risk for T2DM and PEs was partly mediated by childhood CRP (p = .040).

CONCLUSIONS

Comorbidity between psychosis and T2DM may be partly underpinned by shared genes and inflammation. A summation of minor genetic variation representing lifetime risk for T2DM at conception may predispose individuals to psychosis in adulthood by influencing physiologic changes, such as low-grade inflammation, detectable as early as childhood.

Association of physical health multimorbidity with mortality in people with schizophrenia spectrum disorders: Using a novel semantic search system that captures physical diseases in electronic patient records

OBJECTIVE

Single physical comorbidities have been associated with the premature mortality in people with schizophrenia-spectrum disorders (SSD). We investigated the association of physical multimorbidity (≥two physical health conditions) with mortality in people with SSD.

METHODS

A retrospective cohort study between 2013 and 2017. All people with a diagnosis of SSD (ICD-10: F20-F29), who had contact with secondary mental healthcare within South London during 2011-2012 were included. A novel semantic search system captured conditions from electronic mental health records, and all-cause mortality were retrieved. Hazard ratios (HRs) and population attributable fractions (PAFs) were calculated for associations between physical multimorbidity and all-cause mortality.

RESULTS

Among the 9775 people with SSD (mean (SD) age, 45.9 (15.4); males, 59.3%), 6262 (64%) had physical multimorbidity, and 880 (9%) died during the 5-year follow-up. The top three physical multimorbidity combinations with highest mortality were cardiovascular-respiratory (HR: 2.23; 95% CI, 1.49-3.32), respiratory-skin (HR: 2.06; 95% CI, 1.31-3.24), and respiratory-digestive (HR: 1.88; 95% CI, 1.14-3.11), when adjusted for age, gender, and all other physical disease systems. Combinations of physical diseases with highest PAFs were cardiovascular-respiratory (PAF: 35.7%), neurologic-respiratory (PAF: 32.7%), as well as respiratory-skin (PAF: 29.8%).

CONCLUSIONS

Approximately 2/3 of patients with SSD had physical multimorbidity and the risk of mortality in these patients was further increased compared to those with none or single physical conditions. These findings suggest that in order to reduce the physical health burden and subsequent mortality in people with SSD, proactive coordinated prevention and management efforts are required and should extend beyond the current focus on single physical comorbidities.

Glucose metabolism dysregulation at the onset of mental illness is not limited to first episode psychosis: A systematic review and meta-analysis

AIM

To compare the differences of glucose metabolism outcomes between treatment-naïve, patients with first episode psychosis (FEP) and mood disorders.

METHODS

We conducted a systematic review and meta-analysis of glucose intolerance in treatment-naïve, first episode patients with severe mental illnesses (SMIs).

RESULTS

We identified 31 eligible studies. Compared to healthy controls, FEP group have higher insulin and insulin resistance levels, and both groups have higher glucose tolerance test results. No significant differences were found in glucose metabolism outcomes between FEP and mood disorder groups.

CONCLUSIONS

Our results highlight impaired glucose metabolism at the onset of SMIs, suggesting both patients with psychosis and mood disorders are high-risk groups for diabetes development.

Prediction of Schizophrenia Diagnosis by Integration of Genetically Correlated Conditions and Traits

Schizophrenia is genetically heterogeneous and comorbid with many conditions. In this study, we explored polygenic scores (PGSs) from genetically related conditions and traits to predict schizophrenia diagnosis using both logistic regression and deep neural network (DNN) models. We used the combined Molecular Genetics of Schizophrenia and Swedish Schizophrenia Case Control Study (MGS + SSCCS) data for training and testing the models, and used the Clinical Antipsychotic Trials for Intervention Effectiveness (CATIE) data as independent validation. We screened 28 conditions and traits comorbid with schizophrenia to identify traits as potential predictors and used LASSO regression to select predictors for model construction. We investigated how PGS calculation influenced model performance. We found that the inclusion of comorbid traits improved model performance and PGSs calculated from two traits were more generalizable in independent validation. With a DNN model using 19 PGS predictors, we accomplished a prediction accuracy of 0.813 and an AUC of 0.905 in the MGS + SSCCS data. When this model was validated with the CATIE data, it achieved an accuracy of 0.721 and AUC of 0.747. Our results indicate that PGSs alone may not be sufficient to predict schizophrenia accurately and the inclusion of behavioral and clinical data may be necessary for more accurate prediction model.

Valbenazine as the first and only approved treatment for adults with tardive dyskinesia

INTRODUCTION

Valbenazine is a selective VMAT2 inhibitor that the FDA approved in April 2017 for the specific treatment of tardive dyskinesia (TD), a movement disorder commonly caused by dopamine blocking agents. Valbenazine acts to decrease dopamine release, reducing excessive movement found in TD. Areas covered: This drug profile reviews the development of valbenazine and the clinical trials that led to its approval as the first treatment specific to TD. The literature search was performed with the PubMed online database. Expert commentary: Two clinical trials assessing the efficacy of valbenazine have shown the reduction of antipsychotic-induced involuntary movement. No life threatening adverse effects were found. Data from a 42-week extension study demonstrated sustained response.

A polygenic score for schizophrenia predicts glycemic control

Schizophrenia is substantially comorbid with type 2 diabetes (T2D), but the molecular basis of this effect is incompletely understood. Here, we show that a cortical schizophrenia expression score predicts glycemic control from pancreatic islet cell expression. We used machine learning to identify a cortical expression signature in 212 schizophrenia patients and controls, which explained ~25% of the illness-associated variance. The algorithm was predicted in expression data from 51 subjects (9 with T2D), explained up to 26.3% of the variance in the glycemic control indicator HbA_1c and could significantly differentiate T2D patients from controls. The cross-tissue prediction was driven by processes previously linked to diabetes. Genes contributing to this prediction were involved in the electron transport chain as well as kidney development and support oxidative stress as a molecular process underlying the comorbidity between both conditions. Together, the present results suggest a molecular commonality between schizophrenia and glycemic markers of type 2 diabetes.

Impaired glucose tolerance in first-episode drug-naïve patients with schizophrenia: relationships with clinical phenotypes and cognitive deficits

BACKGROUND

Schizophrenia patients have a higher prevalence of type 2 diabetes mellitus with impaired glucose tolerance (IGT) than normals. We examined the relationship between IGT and clinical phenotypes or cognitive deficits in first-episode, drug-naïve (FEDN) Han Chinese patients with schizophrenia.

METHOD

A total of 175 in-patients were compared with 31 healthy controls on anthropometric measures and fasting plasma levels of glucose, insulin and lipids. They were also compared using a 75 g oral glucose tolerance test and the homeostasis model assessment of insulin resistance (HOMA-IR). Neurocognitive functioning was assessed using the MATRICS Consensus Cognitive Battery (MCCB). Patient psychopathology was assessed using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Of the patients, 24.5% had IGT compared with none of the controls, and they also had significantly higher levels of fasting blood glucose and 2-h glucose after an oral glucose load, and were more insulin resistant. Compared with those patients with normal glucose tolerance, the IGT patients were older, had a later age of onset, higher waist or hip circumference and body mass index, higher levels of low-density lipoprotein and triglycerides and higher insulin resistance. Furthermore, IGT patients had higher PANSS total and negative symptom subscale scores, but no greater cognitive impairment except on the emotional intelligence index of the MCCB.

CONCLUSIONS

IGT occurs with greater frequency in FEDN schizophrenia, and shows association with demographic and anthropometric parameters, as well as with clinical symptoms but minimally with cognitive impairment during the early course of the disorder.

Metabolic dysregulation in first-episode schizophrenia patients with respect to genetic variation in one-carbon metabolism

The aim of this study was to investigate the prevalence of metabolic disturbances in patients with first-episode schizophrenia (FES) and test the hypothesis that genetic variation in one-carbon metabolism may account for metabolic dysregulation in early psychosis. We measured fasting glucose, lipid profile parameters, homocysteine, folate and vitamin B12 in 135 patients with FES and 146 healthy controls (HCs). Polymorphisms in the following genes were determined: MTHFR (C677T and A1298C), MTHFD1 (G1958A), MTRR (A66G) and BHMT (G742A). Serum levels of folate and high-density lipoproteins (HDL) were significantly lower in patients with FES compared to HCs. In turn, serum levels of homocysteine and triglycerides were significantly higher in patients with FES than in HCs. Prevalence of hyperhomocysteinemia, low folate and HDL levels together with dyslipidemia was significantly higher in patients with FES compared to HCs. Higher homocysteine levels, lower vitamin B12 levels and the presence of metabolic syndrome were associated with higher severity of negative symptoms. None of studied polymorphisms was associated with schizophrenia risk. Several associations between studied polymorphisms and cardio-metabolic parameters were found. None of them remained significant after Bonferroni correction. Our results indicate that metabolic dysregulation in patients with FES is not associated with genetic variation in one-carbon metabolism.

Therapeutic Perspective on Tardive Syndrome with Special Reference to Deep Brain Stimulation

Tardive syndrome (TDS) is a potentially permanent and irreversible hyperkinetic movement disorder caused by exposure to dopamine receptor blocking agents. Guidelines published by the American Academy of Neurology recommend pharmacological first-line treatment for TDS with clonazepam (level B), ginkgo biloba (level B), amantadine (level C), and tetrabenazine (level C). Recently, a class II study provided level C evidence for use of deep brain stimulation (DBS) of the globus pallidus internus (GPi) in patients with TDS. Although the precise pathogenesis of TDS remains to be elucidated, the beneficial effects of GPi-DBS in patients with TDS suggest that the disease may be a basal ganglia disorder. In addition to recent advances in understanding the pathophysiology of TDS, this article introduces the current use of DBS in the treatment of medically intractable TDS.

Searching human brain for mechanisms of psychiatric disorders. Implications for studies on schizophrenia

In the past 25years, research on the human brain has been providing a clear path toward understanding the pathophysiology of psychiatric illnesses. The successes that have been accrued are matched by significant difficulties identifying and controlling a large number of potential confounding variables. By systematically and effectively accounting for unwanted variance in data from imaging and postmortem human brain studies, meaningful and reliable information regarding the pathophysiology of human brain disorders can be obtained. This perspective paper focuses on postmortem investigations to discuss some of the most challenging sources of variance, including diagnosis, comorbidity, substance abuse and pharmacological treatment, which confound investigations of the human brain.

Drug-induced movement disorders

Movement disorders are frequently a result of prescription drugs or of illicit drug use. This article focuses on prescribed drugs but briefly mentions drugs of abuse. The main emphasis is on movement disorders caused by dopamine receptor-blocking agents. However, movement disorders caused by other drugs are also briefly discussed.

Diabetes mellitus onset in geriatric patients: does long-term atypical antipsychotic exposure increase risk?

BACKGROUND

Diabetes mellitus (DM) in common in adults using psychotropic medications. However, it remains largely unknown whether there is an additional risk of diabetes mellitus (DM) in elderly psychiatric outpatients, particularly those with long-term exposure to atypical antipsychotics (AP).

METHODS

In this retrospective longitudinal study, 61 atypical AP-exposed and 64 atypical AP-unexposed geriatric psychiatric patients were compared to a group of 200 psychotropic-naïve controls. Our main composite outcome was diabetes incidence over a 4-year period, defined by fasting blood glucose ≥ 7.0 mmol/L or a new-onset oral hypoglycaemic or insulin prescription during the 4-year period.

RESULTS

The 4-year incidence of DM did not differ significantly between groups: 12.3%, 6.7%, and 11.9% in the atypical AP-exposed, atypical AP-unexposed, and control groups, respectively (χ(2) = 1.40, P = 0.50). Depression and antidepressant, cholinesterase inhibitor, and valproate use were independently associated with increases in fasting glucose. However, hyperglycaemia and hypoglycaemic prescriptions were not more common in geriatric psychiatric patients.

CONCLUSIONS

DM does not appear to be more common in geriatric psychiatric patients than similarly aged controls and is not more common in atypical AP users. However, depression and antidepressant, cholinesterase inhibitor, and valproate use may increase fasting glucose levels, and the clinical significance of this warrants further investigation. Nonetheless, given the rates of untreated and undertreated fasting hyperglycaemia in both our geriatric psychiatric and control samples (>10% of all patients), we recommend regular screening for DM in these populations.

Pharmacogenetics of second-generation antipsychotics

This review considers pharmacogenetics of the so called 'second-generation' antipsychotics. Findings for polymorphisms replicating in more than one study are emphasized and compared and contrasted with larger-scale candidate gene studies and genome-wide association study analyses. Variants in three types of genes are discussed: pharmacokinetic genes associated with drug metabolism and disposition, pharmacodynamic genes encoding drug targets, and pharmacotypic genes impacting disease presentation and subtype. Among pharmacokinetic markers, CYP2D6 metabolizer phenotype has clear clinical significance, as it impacts dosing considerations for aripiprazole, iloperidone and risperidone, and variants of the ABCB1 gene hold promise as biomarkers for dosing for olanzapine and clozapine. Among pharmacodynamic variants, the TaqIA1 allele of the DRD2 gene, the DRD3 (Ser9Gly) polymorphism, and the HTR2C -759C/T polymorphism have emerged as potential biomarkers for response and/or side effects. However, large-scale candidate gene studies and genome-wide association studies indicate that pharmacotypic genes may ultimately prove to be the richest source of biomarkers for response and side effect profiles for second-generation antipsychotics.

Genome-wide association study supports the role of the immunological system and of the neurodevelopmental processes in response to haloperidol treatment

AIM

The aim of the study was to detect the genetic predictors of reseponse to haloperidol.

BACKGROUND

Haloperidol is a benchmark drug for the pharmacological treatment of schizophrenia, but the genetics of its efficacy is yet to be elucidated.

METHODS

A genome-wide association analysis was carried out in a small sample of patients treated with haloperidol (n=96) and the results were replicated in a larger sample of patients treated with second-generation antipsychotics or perphenazine (final n=169, available from the Clinical Antipsychotic Trials for Intervention Effectiveness study). The Positive and Negative Symptom Scale % score decrease was the outcome in both samples. The period of observation was restricted to 1 month in the replication sample and the most severe cases were included to best balance the replication. The quality control (QC) for the investigation and replication sample included a minor allele frequency at least 0.01, call rate at least 0.95, and Hardy-Weinberg equilibrium P at least 0.0001. The source for imputation was the 1000 Genomes Pilot+HapMap 3 dataset. In total 1 080 870 single nucleotide polymorphisms (SNPs) were available after imputation and QC in the investigation sample. After QC of real genotypes, locus-targeted imputations were restricted to windows of 10 kb on either side of the sentinel SNP in the replication sample. Sentinel SNPs were the most significant findings in the investigation sample. Analysis of variance was the test of choice, PLINK, SNPTEST, and GTOOL were used in the analysis.

RESULTS

Two SNPs (rs7912580 and rs2412459) were associated with response in both samples, respectively, located in an intergenic region between the AT-rich interactive domain 5B (ARID5B, MRF1-like) gene and rhotekin 2 (RTKN2) gene, an intronic region located in the eukaryotic translation initiation factor 2α kinase 4 (EIF2AK4) gene (P=1.358e-06 and 0.015 for the Positive and Negative Symptom Scale % total score decrease in the investigation and replication samples, respectively). The direction of association was opposite in the two samples, a finding that is sometimes reported as a flip-flop association.

CONCLUSION

Heterozygosis for the ancestral allele was associated with the best improvement in the investigation sample and with poorer outcome in the replication sample. This discrepancy can be because of differences in the replication and investigation sample including the drugs used and the severity at baseline. Nevertheless, this finding is in line with two relevant hypothesis of schizophrenia, related to alterations in the immunological system (RTKN2) and in the neurodevelopment of the central nervous system (EIF2AK4). More studies are warranted to further investigate these associations.

Modeling heterogeneous patients with a clinical diagnosis of schizophrenia with induced pluripotent stem cells

Schizophrenia (SZ) is a devastating complex genetic mental condition that is heterogeneous in terms of clinical etiologies, symptoms, and outcomes. Despite decades of postmortem, neuroimaging, pharmacological, and genetic studies of patients, in addition to animal models, much of the biological mechanisms that underlie the pathology of SZ remain unknown. The ability to reprogram adult somatic cells into human induced pluripotent stem cells (hiPSCs) provides a new tool that supplies live human neurons for modeling complex genetic conditions such as SZ. The purpose of this review is to discuss the technical and clinical constraints currently limiting hiPSC-based studies. We posit that reducing the clinical heterogeneity of hiPSC-based studies, by selecting subjects with common clinical manifestations or rare genetic variants, will help our ability to draw meaningful insights from the necessarily small patient cohorts that can be studied at this time.

Analysis of schizophrenia and hepatocellular carcinoma genetic network with corresponding modularity and pathways: novel insights to the immune system

Background

Schizophrenic patients show lower incidences of cancer, implicating schizophrenia may be a protective factor against cancer. To study the genetic correlation between the two diseases, a specific PPI network was constructed with candidate genes of both schizophrenia and hepatocellular carcinoma. The network, designated schizophrenia-hepatocellular carcinoma network (SHCN), was analysed and cliques were identified as potential functional modules or complexes. The findings were compared with information from pathway databases such as KEGG, Reactome, PID and ConsensusPathDB.

Results

The functions of mediator genes from SHCN show immune system and cell cycle regulation have important roles in the eitology mechanism of schizophrenia. For example, the over-expressing schizophrenia candidate genes, SIRPB1, SYK and LCK, are responsible for signal transduction in cytokine production; immune responses involving IL-2 and TREM-1/DAP12 pathways are relevant for the etiology mechanism of schizophrenia. Novel treatments were proposed by searching the target genes of FDA approved drugs with genes in potential protein complexes and pathways. It was found that Vitamin A, retinoid acid and a few other immune response agents modulated by RARA and LCK genes may be potential treatments for both schizophrenia and hepatocellular carcinoma.

Conclusions

This is the first study showing specific mediator genes in the SHCN which may suppress tumors. We also show that the schizophrenic protein interactions and modulation with cancer implicates the importance of immune system for etiology of schizophrenia.

Psychotic symptoms are associated with physical health problems independently of a mental disorder diagnosis: results from the WHO World Health Survey

This study explored whether physical health problems are related to psychotic symptoms independently of a mental disorder diagnosis. A total of 224,254 subjects recruited for the World Health Organization World Health Survey were subdivided into those with both a lifetime diagnosis of psychosis and at least one psychotic symptom in the 12 months prior to the evaluation, those with at least one psychotic symptom in the past 12 months but no lifetime diagnosis of psychosis, and those without psychotic symptoms in the past 12 months and without a lifetime diagnosis of psychosis. The three groups were compared for the presence of medical conditions, health problems, and access to health care. Medical conditions and health problems (angina, asthma, arthritis, tuberculosis, vision or hearing problems, mouth/teeth problems, alcohol consumption, smoking, and accidents), medication consumption, and hospital admissions (but not regular health care visits) were more frequent in individuals with psychotic symptoms but no psychosis diagnosis, compared to those with no symptoms and no diagnosis. The number of medical conditions increased with the number of psychotic symptoms. Given the sample analyzed, this trend seems to be independent from the socio-economic development of the country or the specific health care system.