Polymorphisms of the 5-HT2C receptor and leptin genes are associated with antipsychotic drug-induced weight gain in Caucasian subjects with a first-episode psychosis

Atypical antipsychotic use does not impact weight gain for individuals with extreme anorexia nervosa: a retrospective case-control study

BACKGROUND

There are no U.S. Food and Drug Administration (FDA)-approved medications for the treatment of anorexia nervosa (AN). Various medication classes have been evaluated for benefits in this population, including antipsychotics. Studies focused on use of antipsychotics for assistance with weight restoration in AN produced conflicting results. While current evidence does not suggest that antipsychotic medications can be generally recommended for persons with AN, some individuals might benefit from an antipsychotic medication for anxiety, mood, and the cognitive distortions that accompany the illness. It is well-established that atypical antipsychotics can cause weight gain when taken by other psychiatric populations. This published data can understandably limit the willingness of persons with AN to trial these medications. Given the conflicting results of studies examining antipsychotic-related weight gain in AN, it is currently hypothesized that individuals with extreme anorexia nervosa, restricting type, do not experience the weight gain seen in other psychiatric populations utilizing atypical antipsychotics.

METHODS

Two hundred seventy-six individuals with extreme AN were enrolled in this retrospective, case-control study between April 1, 2016 and June 30, 2022 utilizing study-specific inclusion and exclusion criteria. Clinical and demographic data, including use of atypical antipsychotics and weights, were retrospectively obtained from chart review. Variables were assessed for normality using univariate statistics. Continuous variables were described using means (M) and standard deviations (SD) or medians and interquartile ranges (IQR) based on normality. Differences in weight gain between cohorts was ascertained via independent samples t-test. P values of < 0.05 were considered statistically significant, and all analyses were completed using SAS Enterprise Guide software version 7.1 (SAS Institute, Cary, NC) and R version 4.3.1 (R Core Team, 2023).

RESULTS

Use of antipsychotics in this population of individuals with extreme AN did not impact the rate of weight gain (M: 1.7 kg/week, SD: 0.9 and 0.8, for cases and controls respectively).

CONCLUSIONS

Weight gain is often cited by individuals with AN as a feared side effect of antipsychotic medications. In this study, there was no difference in weight trends for individuals taking atypical antipsychotic medications during the refeeding process compared with individuals who were not.

Longitudinal Gut Microbiota Dysbiosis Underlies Olanzapine-Induced Weight Gain

Olanzapine is one of the most effective medicines available for stabilizing schizophrenia spectrum disorders. However, it has been reported to show the greatest propensity for inducing body weight gain and producing metabolic side effects, which cause a great burden in patients with psychiatric disorders. Since the gut microbiota has a profound impact on the initiation and development of metabolic diseases, we conducted a longitudinal study to explore its role in olanzapine-induced obesity and metabolic abnormalities. Female Sprague-Dawley rats were treated with different doses of olanzapine, and metabolic and inflammatory markers were measured. Olanzapine significantly induced body weight gain (up to a 2.1-fold change), which was accompanied by hepatic inflammation and increased plasma triglyceride levels (up to a 2.9-fold change), as well as gut microbiota dysbiosis. Subsequently, fuzzy c-means clustering was used to characterize three clusters of longitudinal trajectories for microbial fluctuations: (i) genera continuing to increase, (ii) genera continuing to decrease, and (iii) genera temporarily changing. Among them, Enterorhabdus (r = 0.38), Parasutterella (r = 0.43), and Prevotellaceae UCG-001 (r = 0.52) positively correlated with body weight gain. In addition, two MetaCyc metabolic pathways were identified as associated with olanzapine-induced body weight gain, including the superpathway of glucose and xylose degradation and the superpathway of l-threonine biosynthesis. In conclusion, we demonstrate that olanzapine can directly alter the gut microbiota and rapidly induce dysbiosis, which is significantly associated with body weight gain. This may suggest gut microbiota targets in future studies on metabolic abnormalities caused by olanzapine. IMPORTANCE Olanzapine is one of the most effective second-generation antipsychotics for stabilizing schizophrenia spectrum disorders. However, olanzapine has multiple drug-induced metabolic side effects, including weight gain. This study provides insight to the gut microbiota target in olanzapine-induced obesity. Specifically, we explored the longitudinal gut microbiota trajectories of female Sprague-Dawley rats undergoing olanzapine treatment. We showed that olanzapine treatment causes a dynamic alteration of gut microbiota diversity. Additionally, we identified three genera, Parasutterella, Enterorhabdus, and Prevotellaceae UCG-001, that may play an important role in olanzapine-induced obesity. In this case, the supply or removal of specific elements of the gut microbiota may represent a promising avenue for treatment of olanzapine-related metabolic side effects.

Mechanism and treatments of antipsychotic-induced weight gain

The long-term use of antipsychotics (APs) may cause a variety of diseases, such as metabolic syndrome, antipsychotic-induced weight gain (AIWG), and even obesity. This paper reviews the various mechanisms of AIWG and obesity in detail, involving genetics, the central nervous system, the neuroendocrine system, and the gut microbiome. The common drug and non-drug therapies used in clinical practice are also introduced, providing the basis for research on the molecular mechanisms and the future selection of treatments.

Pharmacogenetics and Schizophrenia-Can Genomics Improve the Treatment with Second-Generation Antipsychotics?

Schizophrenia (SCZ) is a complex psychiatric disorder of multifactorial origin, in which both genetic and environmental factors have an impact on its onset, course, and outcome. Large variability in response and tolerability of medication among individuals makes it difficult to predict the efficacy of a chosen therapeutic method and create universal and precise guidelines for treatment. Pharmacogenetic research allows for the identification of genetic polymorphisms associated with response to a chosen antipsychotic, thus allowing for a more effective and personal approach to treatment. This review focuses on three frequently prescribed second-generation antipsychotics (SGAs), risperidone, olanzapine, and aripiprazole, and aims to analyze the current state and future perspectives in research dedicated to identifying genetic factors associated with antipsychotic response. Multiple alleles of genes involved in pharmacokinetics (particularly isoenzymes of cytochrome P450), as well as variants of genes involved in dopamine, serotonin, and glutamate neurotransmission, have already been identified as ones of significant impact on antipsychotic response. It must, however, be noted that although currently obtained results are promising, trials with bigger study groups and unified protocols are crucial for standardizing methods and determining objective antipsychotic response status.

Does the gut microbiome mediate antipsychotic-induced metabolic side effects in schizophrenia?

INTRODUCTION

Second-generation antipsychotics (SGAs) are the most effective treatment for people with schizophrenia. Despite their effectiveness in treating psychotic symptoms, they have been linked to metabolic, cardiovascular and gastrointestinal side-effects. The gut microbiome has been implicated in potentiating symptoms of schizophrenia, response to treatment and medication-induced side effects and thus presents a novel target mediating second-generation antipsychotic-induced side effects in patients.

AREAS COVERED

This narrative review presents evidence from clinical and pre-clinical studies exploring the relationship between the gut microbiome, schizophrenia, second-generation antipsychotics and antipsychotic-induced side-effects. It also covers evidence for psychobiotic treatment as a potential supplementary therapy for people with schizophrenia.

EXPERT OPINION

The gut microbiome has the potential to mediate antipsychotic-induced side-effects in people with schizophrenia. Microbiome-focused treatments should be considered in combination with standard therapy in order to ameliorate debilitating drug-induced side effects, increase quality of life and potentially improve psychotic symptoms. Future studies should aim to collect not only microbiome data, but also metabolomic measures, dietary information and behavioral data.

The pharmacogenetics of treatment with olanzapine

Genetic polymorphism in olanzapine-metabolizing enzymes, transporters and drug targets is associated with alterations in safety and efficacy. The aim of this systematic review is to describe all clinically relevant pharmacogenetic information on olanzapine and to propose clinically actionable variants. Two hundred and eighty-four studies were screened; 76 complied with the inclusion criteria and presented significant associations. DRD2 Taq1A (rs1800497) *A1, LEP -2548 (rs7799039) G and CYP1A2*1F alleles were related to olanzapine effectiveness and safety variability in several studies, with a high level of evidence. DRD2 -141 (rs1799732) Ins, A-241G (rs1799978) G, DRD3 Ser9Gly (rs6280) Gly, HTR2A rs7997012 A, ABCB1 C3435T (rs1045642) T and G2677T/A (rs2032582) T and UGT1A4*3 alleles were related to safety, effectiveness and/or pharmacokinetic variability with moderated level of evidence.

Genetic Polymorphisms Associated With the Pharmacokinetics, Pharmacodynamics and Adverse Effects of Olanzapine, Aripiprazole and Risperidone

Olanzapine, aripiprazole and risperidone are atypical antipsychotics or neuroleptics widely used for schizophrenia treatment. They induce various adverse drug reactions depending on their mechanisms of action: metabolic effects, such as weight gain and alterations of glucose and lipid metabolism; hyperprolactinemia and extrapyramidal effects, such as tremor, akathisia, dystonia, anxiety and distress. In this review, we listed polymorphisms associated with individual response variability to olanzapine, aripiprazole and risperidone. Olanzapine is mainly metabolized by cytochrome P450 enzymes, CYP1A2 and CYP2D6, whereas aripiprazole and risperidone metabolism is mainly mediated by CYP2D6 and CYP3A4. Polymorphisms in these genes and other enzymes and transporters, such as enzymes from the uridine 5'-diphospho-glucuronosyltransferase (UGT) family and ATP-binding cassette sub-family B member 1 (ABCB1), are associated to differences in pharmacokinetics. The three antipsychotics act on dopamine and serotonin receptors, among others, and several studies found associations between polymorphisms in these genes and variations in the incidence of adverse effects and in the response to the drug. Since olanzapine is metabolized by CYP1A2, a lower starting dose should be considered in patients treated with fluvoxamine or other CYP1A2 inhibitors. Regarding aripiprazole, a reduced dose should be administered in CYP2D6 poor metabolizers (PMs). Additionally, a reduction to a quarter of the normal dose is recommended if the patient is treated with concomitant CYP3A4 inhibitors. Risperidone dosage should be reduced for CYP2D6 PMs and titrated for CYPD6 ultrarapid metabolizers (UMs). Moreover, risperidone dose should be evaluated when a CYP2D6, CYP3A4 or ABCB1 inhibitor is administered concomitantly.

Genetic Testing for Antipsychotic Pharmacotherapy: Bench to Bedside

There is growing research interest in learning the genetic basis of response and adverse effects with psychotropic medications, including antipsychotic drugs. However, the clinical utility of information from genetic studies is compromised by their controversial results, primarily due to relatively small effect and sample sizes. Clinical, demographic, and environmental differences in patient cohorts further explain the lack of consistent results from these genetic studies. Furthermore, the availability of psychopharmacological expertise in interpreting clinically meaningful results from genetic assays has been a challenge, one that often results in suboptimal use of genetic testing in clinical practice. These limitations explain the difficulties in the translation of psychopharmacological research in pharmacogenetics and pharmacogenomics from bench to bedside to manage increasingly treatment-refractory psychiatric disorders, especially schizophrenia. Although these shortcomings question the utility of genetic testing in the general population, the commercially available genetic assays are being increasingly utilized to optimize the effectiveness of psychotropic medications in the treatment-refractory patient population, including schizophrenia. In this context, patients with treatment-refractory schizophrenia are among of the most vulnerable patients to be exposed to the debilitating adverse effects from often irrational and high-dose antipsychotic polypharmacy without clinically meaningful benefits. The primary objective of this comprehensive review is to analyze and interpret replicated findings from the genetic studies to identify specific genetic biomarkers that could be utilized to enhance antipsychotic efficacy and tolerability in the treatment-refractory schizophrenia population.

The Burden of Antipsychotic-Induced Weight Gain and Metabolic Syndrome in Children

Antipsychotic medications are critical to child and adolescent psychiatry, from the stabilization of psychotic disorders like schizophrenia, bipolar disorder, and psychotic depression to behavioral treatment of autism spectrum disorder, tic disorders, and pediatric aggression. While effective, these medications carry serious risk of adverse events-most commonly, weight gain and cardiometabolic abnormalities. Negative metabolic consequences affect up to 60% of patients and present a major obstacle to long-term treatment. Since antipsychotics are often chronically prescribed beginning in childhood, cardiometabolic risk accumulates. An increased susceptibility to antipsychotic-induced weight gain (AIWG) has been repeatedly documented in children, particularly rapid weight gain. Associated cardiometabolic abnormalities include central obesity, insulin resistance, dyslipidemia, and systemic inflammation. Lifestyle interventions and medications such as metformin have been proposed to reduce risk but remain limited in efficacy. Furthermore, antipsychotic medications touted to be weight-neutral in adults can cause substantial weight gain in children. A better understanding of the biological underpinnings of AIWG could inform targeted and potentially more fruitful treatments; however, little is known about the underlying mechanism. As yet, modest genetic studies have nominated a few risk genes that explain only a small percentage of the risk. Recent investigations have begun to explore novel potential mechanisms of AIWG, including a role for gut microbiota and microbial metabolites. This article reviews the problem of AIWG and AP metabolic side effects in pediatric populations, proposed mechanisms underlying this serious side effect, and strategies to mitigate adverse impact. We suggest future directions for research efforts that may advance the field and lead to improved clinical interventions.

International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

Association between the -2548G/A polymorphism of the leptin gene and antipsychotic-induced weight gain: Analysis of the CATIE sample and meta-analysis

BACKGROUND

Antipsychotics, especially most of the second-generation antipsychotics, have a high risk for metabolic syndrome and antipsychotic-induced weight gain (AIWG). A promoter variant of the leptin (LEP) gene, -2548G/A (rs7799039), has been associated with AIWG in several studies. The aim of this study was to evaluate this association in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) sample, followed by meta-analysis.

METHODS

We investigated the association between rs7799039 and AIWG in a sub-sample of European (N = 164) individuals from the CATIE study. Body mass index (BMI) change and weight gain (presence or absence) was analyzed using ANCOVA and logistic regression, respectively. For the meta-analysis, a literature search was conducted using MEDLINE, Embase, and PsycINFO up to October 2019. The pooled odds ratio was calculated for presence or absence of weight gain (≥7% weight change) using a random effects model.

RESULTS

We did not detect an association between rs7799039 and BMI change or weight gain (presence or absence) in the CATIE sample. As for the meta-analysis, we included 12 studies. No significant associations between the LEP rs7799039 polymorphism and AIWG were observed under the allelic genetic model (allele A vs. allele G) (OR = 1.10 [0.71, 1.70], p = .68). In the subgroup analyses of first-episode schizophrenia patients, a significant association between the A-allele and weight gain was observed, respectively (OR = 2.32 [1.41, 3.82], p = .0009).

CONCLUSIONS

The present meta-analysis showed no significant effect of rs7799039 on AIWG. However, this variant may influence AIWG in first-episode schizophrenia patients. Further investigation of a larger and more homogenous sample is required to elucidate the role of the LEP gene in AIWG.

Association of the HTR2C-759C/T polymorphism and antipsychotic-induced weight gain: a meta-analysis

Background

Antipsychotic-induced weight gain (AIWG) is a crucial factor for the medication cessation of patients with schizophrenia. Multiple studies have shown that the functional polymorphism -759 C/T (rs3813929) in the HTR2C promoter region could possibly be correlated with AIWG.

Aim

To evaluate the genetic association of the HTR2C-759C/T polymorphism and AIWG in patients with schizophrenia with antipsychotic drugs (APDs) administration.

Methods

Eligible studies were identified by searching the following databases: PubMed, Embase, Web of Science, China Nation Knowledge Infrastructure (CNKI), VIP, Wanfang Data, Chinese Biomedical Literature Database (CBM) and the Airiti Library. The quality of studies was evaluated based on the Newcastle-Ottawa Scale. The pooled OR and 95% CI were calculated for the dominant (CT/TT/T vs CC/C) mode, and subgroup analyses were performed based on ethnicity, antipsychotic medication and gender; all statistical analyses were performed using the statistical software STATA V.12.0.

Result

A total of 17 studies with 3170 patients with schizophrenia were included in our meta-analysis. The result of the meta-analysis has shown that the association between the -759 C/T polymorphism and AIWG is statistically significant (OR 0.34, 95% CI: 0.20 to 0.57, z=4.11, p<0.001). The subgroup analyses revealed significant correlations between the -759 C/T polymorphism and AIWG in the Caucasian population (OR 0.33, 95% CI: 0.14 to 0.77, z=2.55, p=0.011), the Asian population (OR 0.31, 95% CI: 0.18 to 0.52, z=4.46, p<0.001), the patients with APDs administration (CT/TT/T vs CC/C: OR 0.63, 95% CI: 0.40 to 1.00, z=1.97, p=0.049) and the patients with atypical antipsychotic drug administration (CT/TT/T vs CC/C: OR 0.21, 95% CI: 0.09 to 0.47, z=3.83, p<0.001). The sensitivity analysis showed that the results were stable. Begg’s test (after correction z=1.07, p=0.287) and Egger’s test (t=−2.41, p=0.029) show that the included articles have no significant publication bias.

Conclusion

There is a significant genetic association between HTR2C-759C/T and AIWG, and patients with T allele are less likely to have AIWG.

Molecular pathway analysis associates alterations in obesity-related genes and antipsychotic-induced weight gain

OBJECTIVE

Antipsychotics often induce excessive weight gain. We hypothesised that individuals with genetic variations related to known obesity-risk genes have an increased risk of excessive antipsychotic-induced weight gain (AIWG). This hypothesis was tested in a subset of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) trial data set.

METHODS

The CATIE trial compared effects and side effects of five different antipsychotics through an 18-month period. Based on the maximum weight gain recorded, excessive weight gain was defined as >7% weight gain. Cytoscape and GeneMANIA were instrumental in composing a molecular pathway from eight selected genes linked to obesity. Genetic information on a total of 495.172 single-nucleotide polymorphisms (SNPs) were available from 765 (556 males) individuals. Enrichment test was conducted through ReactomePA and Bioconductor. A permutation test was performed, testing the generated pathway against 105 permutated pathways (p ≤ 0.05). In addition, a standard genome-wide association study (GWAS) analysis was performed.

RESULT

GWAS analysis did not detect significant differences related to excessive weight gain. The pathway generated contained 28 genes. A total of 2067 SNPs were significantly expressed (p < 0.01) within this pathway when comparing excessive weight gainers to the rest of the sample. Affected genes including PPARG and PCSK1 were not previously related to treatment-induced weight gain.

CONCLUSIONS

The molecular pathway composed from high-risk obesity genes was shown to overlap with genetics of patients who gained >7% weight gain during the CATIE trial. This suggests that genes related to obesity compose a pathway of increased risk of excessive AIWG. Further independent analyses are warranted that may confirm or clarify the possible reasoning behind.

Leptin and psychiatric illnesses: does leptin play a role in antipsychotic-induced weight gain?

Antipsychotic-induced weight gain is the most prevalent somatic adverse event occurring in patients treated by antipsychotics, especially atypical antipsychotics. It is of particular interest because of its repercussion on cardiovascular morbidity and mortality especially now that the use of second-generation antipsychotics has been extended to other mental health illnesses such as bipolar disorders and major depressive disorder. The mechanism underlying antipsychotics-induced weight gain is still poorly understood despite a significant amount of work on the topic. Recently, there has been an on-going debate of tremendous research interest on the relationship between antipsychotic-induced weight gain and body weight regulatory hormones such as leptin. Given that, researchers have brought to light the question of leptin's role in antipsychotic-induced weight gain. Here we summarize and discuss the existing evidence on the link between leptin and weight gain related to antipsychotic drugs, especially atypical antipsychotics.

Progress in Genetic Polymorphisms Related to Lipid Disturbances Induced by Atypical Antipsychotic Drugs

Metabolic side effects such as weight gain and disturbed lipid metabolism are often observed in the treatment of atypical antipsychotic drugs (AAPDs), which contribute to an excessive prevalence of metabolic syndrome among schizophrenic patients. Great individual differences are observed but the underlying mechanisms are still uncertain. Research on pharmacogenomics indicates that gene polymorphisms involved in the pathways controlling food intake and lipid metabolism may play a significant role. In this review, relevant genes (HTR2C, DRD2, LEP, NPY, MC4R, BDNF, MC4R, CNR1, INSIG2, ADRA2A) and genetic polymorphisms related to metabolic side effects of AAPDs especially dyslipidemia were summarized. Apart from clinical studies, in vitro and in vivo evidence is also analyzed to support related theories. The association of central and peripheral mechanisms is emphasized, enabling the possibility of using peripheral gene expression to predict the central status. Novel methodological development of pharmacogenomics is in urgent need, so as to provide references for individualized medication and further to shed some light on the mechanisms underlying AAPD-induced lipid disturbances.

Leptin gene polymorphisms are associated with weight gain during lithium augmentation in patients with major depression

Weight gain is a common adverse effect of lithium augmentation. Previous studies indicate an impact of genetic variants at the leptin gene on weight gain as a consequence of psychopharmacological treatment. The primary aim of our study was to identify variants at the leptin locus that might predict lithium-induced weight gain. The secondary aim was to investigate if these variants modulate leptin levels. In 180 patients with acute major depressive disorder, body mass index was measured before and after 4 weeks of lithium augmentation, in a subsample also after 4 and/or 7 months. In a subsample of 89 patients, leptin serum concentrations were measured before and during lithium augmentation. We used linear mixed model analyzes to investigate the effects of 2 polymorphisms at the leptin locus (rs4731426 and rs7799039, employing the respective proxy SNPs rs2278815 and rs10487506) on changes in body mass index and leptin levels. For both polymorphisms, which are in high linkage disequilibrium, body mass index was significantly lower in homozygous A-allele carriers than in carriers of other genotypes at baseline. Over the follow-up period, body mass index increased less in homozygous A-allele carriers of rs4731426 than in carriers of other genotypes. This was not the case for rs7799039. Neither polymorphism modulated leptin protein expression. Our study strongly supports the hypothesis that genetic variability at the leptin locus is involved in lithium augmentation-associated weight gain in major depressive disorder. Furthermore, Genotype-Tissue Expression data provide strong evidence that rs4731426 influences the expression of leptin messenger ribonucleic acid in fibroblasts.

Second-Generation Antipsychotics and Dysregulation of Glucose Metabolism: Beyond Weight Gain

Second-generation antipsychotics (SGAs) are the cornerstone of treatment for schizophrenia because of their high clinical efficacy. However, SGA treatment is associated with severe metabolic alterations and body weight gain, which can increase the risk of type 2 diabetes and cardiovascular disease, and greatly accelerate mortality. Several underlying mechanisms have been proposed for antipsychotic-induced weight gain (AIWG), but some studies suggest that metabolic changes in insulin-sensitive tissues can be triggered before the onset of AIWG. In this review, we give an outlook on current research about the metabolic disturbances provoked by SGAs, with a particular focus on whole-body glucose homeostasis disturbances induced independently of AIWG, lipid dysregulation or adipose tissue disturbances. Specifically, we discuss the mechanistic insights gleamed from cellular and preclinical animal studies that have reported on the impact of SGAs on insulin signaling, endogenous glucose production, glucose uptake and insulin secretion in the liver, skeletal muscle and the endocrine pancreas. Finally, we discuss some of the genetic and epigenetic changes that might explain the different susceptibilities of SGA-treated patients to the metabolic side-effects of antipsychotics.

Genome-wide association study on antipsychotic-induced weight gain in Europeans and African-Americans

BACKGROUND

Antipsychotic (AP) medications are the first line of treatment for schizophrenia. However, most conferr a risk of antipsychotic-induced weight gain (AIWG). The objective of this investigation was to conduct a genome-wide association study (GWAS) of AIWG, followed by comprehensive, post-GWAS approaches.

METHODS

We investigated n = 201 schizophrenia or schizoaffective disorder patients of European and African American ancestry who were treated primarily with clozapine or olanzapine. We conducted a genome-wide association analysis for AIWG, defined primarily as a percentage of weight change from baseline.

RESULTS

When examining Europeans (n = 147), we noticed an association between rs62097526 (β = 0.39, p = 3.59 × 10-6, CADD = 2.213) variant, located downstream of the CIDEA gene, which is considered a risk factor for AIWG. In the entire sample, we observed a significant association between rs1525085 (β = 0.411, p = 3.15 × 10-9) variant of the DGKB gene and AIWG. The association was nominally significant in Europeans (β = 0.271, p = 0.002) and African Americans (β = 0.579, p = 5.73 × 10-5) with the same risk allele. Our top genes (p < 5 × 10-5) were enriched in the GWAS catalog for the risk of obesity and interacted with the known risk factors for obesity (G6PD) and diabetes (IRS1). In addition, these genes are targeted by miRNAs related to schizophrenia (mir-34a) and obesity (mir-19b). However, our polygenic risk score analyses did not provide support for major genetic overlap between obesity and the risk of AIWG.

CONCLUSIONS

In summary, we propose that the CIDEA and DGKB genes are risk factors for AIWG in transethnic populations. Additionally, our evidence suggests that the G6PD and IRS1 gene-related pathways might be involved in AIWG.

Association between polymorphisms of LEP, LEPR, DRD2, HTR2A and HTR2C genes and risperidone- or clozapine-induced hyperglycemia

Objective

To determine whether genetic polymorphisms related to pharmacodynamics with metabolic adverse effects, namely leptin promoter (LEP) rs7799039, leptin receptor rs1137101, dopamine D2 rs4436578, serotonin 5-HT2A rs6313, and serotonin 5-HT2C rs518147 and rs12836771, are associated with hyperglycemia induced by risperidone or clozapine in adult Thai patients with psychosis.

Methods

A total of 180 patients treated with risperidone-based (n=130) or clozapine-based (n=50) regimens were included in this study. Blood samples were analyzed for genotyping of the candidate genes and biochemical testing. Genotyping was performed by conducting a TaqMan real-time polymerase chain reaction-based analysis.

Results

The prevalence of hyperglycemia was higher in patients receiving clozapine (64.0%) than in those receiving risperidone (30.8%). Among the candidate genes, only the LEP rs7799039 polymorphism demonstrated a significant association with hyperglycemia (χ²=9.879, P=0.008) in patients treated with risperidone; patients with the AA genotype had the highest risk (41.1%), followed by those with AG (20.8%) and GG (0%) genotypes. Using the recessive genetic model (AA vs AG + GG), the odds ratio and 95% CI were 3.28 and 1.44 −7.50, respectively. None of the genes were associated with hyperglycemia in patients treated with clozapine. A binary logistic regression revealed that the LEP rs7799039 polymorphism demonstrated a significant association with hyperglycemia, independent of body-mass index (BMI) in patients receiving risperidone; the odds ratio (95% CI) was 3.188 (1.399–7.262), P=0.006. By contrast, none of the pharmacodynamic genetic factors, except for BMI, were significantly associated with hyperglycemia in patients receiving clozapine.

Conclusion

The risk of type 2 diabetes mellitus is associated with the LEP rs7799039 polymorphism in Thai adults receiving risperidone but not in those receiving clozapine. Clarifying underlying mechanisms and risk of hyperglycemia provides an opportunity to prevent impaired glucose metabolism in patients receiving risperidone or clozapine.

Appetite regulating hormones in first-episode psychosis: A systematic review and meta-analysis

We aimed to perform a systematic review and meta-analysis of appetite regulating hormones in patients with first-episode psychosis (FEP). Meta-analyses were conducted using random-effects models with Hedges' g as the effect size estimate. We identified 31 eligible studies, investigating the levels of 7 appetite regulating hormones (adiponectin, insulin, leptin, ghrelin, orexin, resistin and visfatin) in 1792 FEP patients and 1364 controls. The insulin levels in FEP patients were higher than in controls (g = 0.34, 95%CI: 0.19 - 0.49, p < 0.001), even considering only antipsychotic-naïve patients (g = 0.39, 95%CI: 0.12 - 0.66, p = 0.005). The severity of negative symptoms was positively associated with the effect size estimates (β = 0.08, 95%CI: 0.01 - 0.16, p = 0.030). Moreover, we found lower levels of leptin in antipsychotic-naïve FEP patients (g = -0.62, 95%CI: -1.11 - 0.12, p = 0.015). Impaired appetite regulation, in terms of elevated insulin levels and decreased leptin levels, occurs in early psychosis, before antipsychotic treatment. Hyperinsulinemia might be related to negative symptoms.

Testing the role of genetic variation of the MC4R gene in Chinese population in antipsychotic-induced metabolic disturbance

Antipsychotic-induced metabolic disturbance (AIMD) is a common adverse effect of antipsychotics with genetics partly underpinning variation in susceptibility among schizophrenia patients. Melanocortin4 receptor (MC4R) gene, one of the candidate genes for AIMD, has been under-studied in the Chinese patients. We conducted a pharmacogenetic study in a large cohort of Chinese patients with schizophrenia. In this study, we investigated the genetic variation of MC4R in Chinese population by genotyping two SNPs (rs489693 and rs17782313) in 1,991 Chinese patients and examined association of these variants with the metabolic effects that were often observed to be related to AIMD. Metabolic measures, including body mass index (BMI), waist circumference (WC), glucose, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels were assessed at baseline and after 6-week antipsychotic treatment. We found that interaction of SNP×medication status (drug-naïve/medicated) was significantly associated with BMI, WC, and HDL change %, respectively. Both SNPs were significantly associated with baseline BMI and WC in the medicated group. Moderate association of rs489693 with WC, Triglyceride, and HDL change % were observed in the whole sample. In the drug-naïve group, we found recessive effects of rs489693 on BMI gain more than 7%, WC and Triglyceride change %, with AA incurring more metabolic adverse effects. In conclusion, the association between rs489693 and the metabolic measures is ubiquitous but moderate. Rs17782313 is less involved in AIMD. Two SNPs confer risk of AIMD to patients treated with different antipsychotics in a similar way.

Associations between the LEP -2548G/A Promoter and Baseline Weight and between LEPR Gln223Arg and Lys656Asn Variants and Change in BMI z Scores in Arab Children and Adolescents Treated with Risperidone

Data on baseline (antipsychotics-naïve) age, weight, and height, and change in these at 3 subsequent follow-up time points up to 313.6 days (95% CI 303.5-323.7) were collected from 181 risperidone-treated children and adolescents (mean age 12.58 years, SD 4.99, range 2.17-17.7) attending a pediatric neurology clinic in Saudi Arabia. Owing to differences in genotypic distributions in the subsamples, results are reported for the white Arab population (n = 144). Age- and gender-normed body mass index (BMI)-standardized z scores (BMI z) were calculated (LMSgrowth program). Linear regression was performed for baseline weight and BMI z, while change in BMI z was assessed using random effects ordered logistic regression. The following single nucleotide polymorphisms (SNPs) were analyzed: rs7799039 in the LEP promoter, rs1805094 (previously rs8179183), rs1137100 and rs1137101 in the LEPR, and rs1414334 in HTR2C. We found a nominally significant association between rs7799309 and baseline weight, adjusting for height, age, gender, and diagnosis (A/G, p = 0.035, β = -3.62 vs. G/G). The rs1137101 (G/G, p = 0.018, odds ratio [OR] = 4.13 vs. A/A) and rs1805094 C allele carriers (p = 0.019, OR = 0.51) showed nominally significant associations with change in BMI z categories. Our data support and replicate previous relevant associations for these variants (including with weight gain when on risperidone), whilst being the first report of such associations in patients of Arab ethnicity.

Decreased 5-HT2cR and GHSR1a interaction in antipsychotic drug-induced obesity

Second generation antipsychotics (SGAs), notably atypical antipsychotics including olanzapine, clozapine and risperidone, can cause weight gain and obesity side effects. Antagonism of serotonin 2c receptors (5-HT2cR) and activation of ghrelin receptor type 1a (GHSR1a) signalling have been identified as a main cause of SGA induced obesity. Here we review the pivotal regulatory role of the 5-HT2cR in ghrelin-mediated appetite signalling. The 5-HT2cR dimerizes with GHSR1a to inhibit orexigenic signalling, while 5-HT2cR antagonism reduces dimerization and increases GHSR1a-induced food intake. Dimerization is specific to the unedited 5-HT2cR isoform. 5-HT2cR antagonism by SGAs may disrupt the normal inhibitory tone on the GHSR1a, increasing orexigenic signalling. The 5-HT2cR and its interaction with the GHSR1a could serve as the basis for discovering novel approaches to preventing and treating SGA-induced obesity.

Genetic polymorphisms of HTR2C, LEP and LEPR on metabolic syndromes in patients treated with atypical antipsychotic drugs

OBJECTIVE

Single nucleotide polymorphisms in serotonin 2C receptor (HTR2C), leptin (LEP), and leptin receptor (LEPR) genes are reportedly associated with the presence of metabolic syndrome (MS). We investigated whether HTR2C:rs518147 (-697G/C), rs12836771 (A/G), LEP: rs7799039 (-2548G/A) and LEPR:rs1137101 (668A/G) are related to MS in psychotic disorder patients treated with atypical antipsychotics.

METHODS

A cross-sectional study including 200 patients was conducted; genetic polymorphisms in HTR2C (rs518147 and rs12836771), LEP (rs7799039) and LEPR (rs1137101) were genotyped. The presence of MS was evaluated according to the 2005 International Diabetes Federation (IDF) Asia criteria. The associations of genetic factors with the presence of MS are analysed.

KEY FINDINGS

Two SNPs in the HTR2C gene but not LEP and LEPR were associated with the presence of MS after adjustment for the combination of atypical antipsychotics. With respect to the effect of gender after treatment with risperidone and clozapine was statistically significant. Moreover, genotype combinations had no effect on MS.

CONCLUSIONS

Therefore, HTR2C genetic variants may be involved in the susceptibility to MS in patients treated with atypical antipsychotics. Additionally, there was a gender effect in the presence of MS. No effect of LEP or LEPR polymorphisms or the combination of HTR2C-LEP and HTR2C-LEPR was observed for the presence of MS.

The potentially beneficial central nervous system activity profile of ivacaftor and its metabolites

Ivacaftor-lumacaftor and ivacaftor are two new breakthrough cystic fibrosis transmembrane conductance modulators. The interactions of ivacaftor and its two metabolites hydroxymethylivacaftor (iva-M1) and ivacaftorcarboxylate (iva-M6) with neurotransmitter receptors were investigated in radioligand binding assays. Ivacaftor displayed significant affinity to the 5-hydroxytryptamine (5-HT; serotonin) 5-HT2C receptor (pKi=6.06±0.03), β3-adrenergic receptor (pKi=5.71±0.07), δ-opioid receptor (pKi=5.59±0.06) and the dopamine transporter (pKi=5.50±0.20); iva-M1 displayed significant affinity to the 5-HT2C receptor (pKi=5.81±0.04) and the muscarinic M3 receptor (pKi=5.70±0.10); iva-M6 displayed significant affinity to the 5-HT2A receptor (pKi=7.33±0.05). The in vivo central nervous system activity of ivacaftor (40 mg·kg-1 intraperitoneally for 21 days) was assessed in a chronic mouse model of depression. In the forced swim test, the ivacaftor-treated group displayed decreased immobility (52.8±7.6 s), similarly to fluoxetine (33.8±11.0 s), and increased climbing/swimming activity (181.5±9.2 s). In the open field test, ivacaftor produced higher locomotor activity than the fluoxetine group, measured both as mean number of paw touches (ivacaftor 81.1±9.6 versus fluoxetine 57.9±9.5) and total distance travelled (ivacaftor 120.6±16.8 cm versus fluoxetine 84.5±16.0 cm) in 600 s. Treatment of 23 cystic fibrosis patients with ivacaftor-lumacaftor resulted in significant improvements in quality of life (including anxiety) in all five domains of the AweScoreCF questionnaire (p=0.092-0.096). Our findings suggest ivacaftor displays potential clinical anxiolytic and stimulating properties, and may have beneficial effects on mood.

Mechanisms underlying metabolic disturbances associated with psychosis and antipsychotic drug treatment

The increase in cardiovascular disease and reduced life expectancy in schizophrenia likely relate to an increased prevalence of metabolic disturbances. Such metabolic risk factors in schizophrenia may result from both symptom-related effects and aetiological factors. However, a major contributory factor is that of treatment with antipsychotic drugs. These drugs differ in effects on body weight; the underlying mechanisms are not fully understood and may vary between drugs, but may include actions at receptors associated with the hypothalamic control of food intake. Evidence supports 5-hydroxytryptamine receptor 2C and dopamine D2 receptor antagonism as well as antagonism at histamine H1 and muscarinic M3 receptors. These M3 receptors may also mediate the effects of some drugs on glucose regulation. Several antipsychotics showing little propensity for weight gain, such as aripiprazole, have protective pharmacological mechanisms, rather than just the absence of a hyperphagic effect. In addition to drug differences, there is large individual variation in antipsychotic drug-induced weight gain. This pharmacogenetic association reflects genetic variation in several drug targets, including the 5-hydroxytryptamine receptor 2C, as well as genes involved in obesity and metabolic disturbances. Thus predictive genetic testing for drug-induced weight gain would represents a first step towards personalised medicine addressing this severe and problematic iatrogenic disease.

Association between antipsychotic treatment and leptin levels across multiple psychiatric populations: An updated meta-analysis

OBJECTIVE

Antipsychotics (APs) are associated with metabolic syndrome, with increases in leptin proposed as an underlying mechanism of AP-induced weight gain. Currently available meta-analyses on this topic have limited their populations of interest to those diagnosed with schizophrenia. The purpose of this meta-analysis is to explore the relationship between leptin levels and AP use across multiple psychiatric diagnoses, and also in healthy controls.

METHOD

Systematic electronic searches were conducted using PubMed and OVID: Medline. Longitudinal studies were included if showing leptin levels before and after AP use. We included participants with any psychiatric disorders and mentally healthy participants, if exposed to AP use. The differences in leptin levels were evaluated using Hedges' g with a random effects model.

RESULTS

Forty-two studies were found (36 schizophrenia, 2 bipolar disorder, 1 anorexia nervosa, and 3 healthy controls), encompassing 66 study arms and 1,156 participants. The meta-analysis showed that regardless of diagnoses, leptin levels increase with AP use (Hedges' g = 0.811, p ≤ .001).

CONCLUSION

Leptin increases induced by APs are present across all diagnoses. More comprehensive research is needed to understand the relationship between AP use and leptin levels across multiple diagnoses.

A short history of the 5-HT2C receptor: from the choroid plexus to depression, obesity and addiction treatment

This paper is a personal account on the discovery and characterization of the 5-HT_2C receptor (first known as the 5-HT_1C receptor) over 30 years ago and how it translated into a number of unsuspected features for a G protein-coupled receptor (GPCR) and a diversity of clinical applications. The 5-HT_2C receptor is one of the most intriguing members of the GPCR superfamily. Initially referred to as 5-HT_1CR, the 5-HT_2CR was discovered while studying the pharmacological features and the distribution of [³H]mesulergine-labelled sites, primarily in the brain using radioligand binding and slice autoradiography. Mesulergine (SDZ CU-085), was, at the time, best defined as a ligand with serotonergic and dopaminergic properties. Autoradiographic studies showed remarkably strong [³H]mesulergine-labelling to the rat choroid plexus. [³H]mesulergine-labelled sites had pharmacological properties different from, at the time, known or purported 5-HT receptors. In spite of similarities with 5-HT₂ binding, the new binding site was called 5-HT_1C because of its very high affinity for 5-HT itself. Within the following 10 years, the 5-HT_1CR (later named 5-HT_2C) was extensively characterised pharmacologically, anatomically and functionally: it was one of the first 5-HT receptors to be sequenced and cloned. The 5-HT_2CR is a GPCR, with a very complex gene structure. It constitutes a rarity in the GPCR family: many 5-HT_2CR variants exist, especially in humans, due to RNA editing, in addition to a few 5-HT_2CR splice variants. Intense research led to therapeutically active 5-HT_2C receptor ligands, both antagonists (or inverse agonists) and agonists: keeping in mind that a number of antidepressants and antipsychotics are 5-HT_2CR antagonists/inverse agonists. Agomelatine, a 5-HT_2CR antagonist is registered for the treatment of major depression. The agonist Lorcaserin is registered for the treatment of aspects of obesity and has further potential in addiction, especially nicotine/ smoking. There is good evidence that the 5-HT_2CR is involved in spinal cord injury-induced spasms of the lower limbs, which can be treated with 5-HT_2CR antagonists/inverse agonists such as cyproheptadine or SB206553. The 5-HT_2CR may play a role in schizophrenia and epilepsy. Vabicaserin, a 5-HT_2CR agonist has been in development for the treatment of schizophrenia and obesity, but was stopped. As is common, there is potential for further indications for 5-HT_2CR ligands, as suggested by a number of preclinical and/or genome-wide association studies (GWAS) on depression, suicide, sexual dysfunction, addictions and obesity. The 5-HT_2CR is clearly affected by a number of established antidepressants/antipsychotics and may be one of the culprits in antipsychotic-induced weight gain.

Theranostic Biomarkers for Schizophrenia

Schizophrenia is a highly heritable, chronic, severe, disabling neurodevelopmental brain disorder with a heterogeneous genetic and neurobiological background, which is still poorly understood. To allow better diagnostic procedures and therapeutic strategies in schizophrenia patients, use of easy accessible biomarkers is suggested. The most frequently used biomarkers in schizophrenia are those associated with the neuroimmune and neuroendocrine system, metabolism, different neurotransmitter systems and neurotrophic factors. However, there are still no validated and reliable biomarkers in clinical use for schizophrenia. This review will address potential biomarkers in schizophrenia. It will discuss biomarkers in schizophrenia and propose the use of specific blood-based panels that will include a set of markers associated with immune processes, metabolic disorders, and neuroendocrine/neurotrophin/neurotransmitter alterations. The combination of different markers, or complex multi-marker panels, might help in the discrimination of patients with different underlying pathologies and in the better classification of the more homogenous groups. Therefore, the development of the diagnostic, prognostic and theranostic biomarkers is an urgent and an unmet need in psychiatry, with the aim of improving diagnosis, therapy monitoring, prediction of treatment outcome and focus on the personal medicine approach in order to improve the quality of life in patients with schizophrenia and decrease health costs worldwide.

Atypical antipsychotics: recent research findings and applications to clinical practice: Proceedings of a symposium presented at the 29th Annual European College of Neuropsychopharmacology Congress, 19 September 2016, Vienna, Austria

Available evidence suggests that second-generation atypical antipsychotics are broadly similar to first-generation agents in terms of their efficacy, but may have a more favourable tolerability profile, primarily by being less likely to cause extrapyramidal symptoms. However, atypical antipsychotics are variably associated with disturbances in the cardiometabolic arena, including increased body weight and the development of metabolic syndrome, which may reflect differences in their receptor binding profiles. Effective management of schizophrenia must ensure that the physical health of patients is addressed together with their mental health. This should therefore involve consideration of the specific tolerability profiles of available agents and individualization of treatment to minimize the likelihood of adverse metabolic sequelae, thereby improving long-term adherence and optimizing overall treatment outcomes. Alongside this, modifiable risk factors (such as exercise, diet, obesity/body weight and smoking status) must be addressed, in order to optimize patients' overall health and quality of life (QoL). In addition to antipsychotic-induced side effects, the clinical management of early nonresponders and psychopharmacological approaches for patients with treatment-resistant schizophrenia remain important unmet needs. Evidence suggests that antipsychotic response starts early in the course of treatment and that early nonresponse accurately predicts nonresponse over the longer term. Early nonresponse therefore represents an important modifiable risk factor for poor efficacy and effectiveness outcomes, since switching or augmenting antipsychotic treatment in patients showing early nonresponse has been shown to improve the likelihood of subsequent treatment outcomes. Recent evidence has also demonstrated that patients showing early nonresponse to treatment with lurasidone at 2 weeks may benefit from an increase in dose at this timepoint without compromising tolerability/safety. However, further research is required to determine whether these findings are generalizable to other antipsychotic agents.

Genetic Determinants of Clozapine-Induced Metabolic Side Effects

OBJECTIVE

Atypical antipychotics are linked to a higher incidence of metabolic side effects, including weight gain, dyslipidemia, and diabetes. In this study, we examined the prevalence and potential genetic predictors of metabolic side effects in 60 adult patients on clozapine.

METHOD

Genetic variants of relevance to clozapine metabolism, clearance, and response were assessed through targeted genotyping of cytochrome P450 enzymes CYP1A2 and CYP2C19, the efflux transporter ABCB1, the serotonin receptor (HTR2C), leptin (LEP), and leptin receptor (LEPR). Clozapine levels and other potential confounders, including concurrent medications, were also included in the analysis.

RESULTS

More than half of the patients were obese (51%), had metabolic syndrome (52.5%), and 30.5% were overweight. There was a high prevalence of antipsychotic polypharmacy (61.9%). With multivariable linear regression analysis, LEP -2548G>A, LEPR c.668A>G, and HTR2C c.551-3008 C>G were identified as genetic predictors of body mass index (BMI) after considering effects of clozapine dose, blood level, and concurrent medications (adjusted R² = 0.305). Metabolic syndrome was found to be significantly associated with clozapine level and CYP2C19*2 and LEPR c.668 G alleles. Clozapine levels in patients with metabolic syndrome were significantly higher compared to those without metabolic syndrome (1886 ± 895 vs. 1283 ± 985 ng/mL, P < 0.01) and were associated with the CYP2C19*2 genotype. No association was found between the genetic variants studied and lipid or glucose levels.

CONCLUSION

This study confirms a high prevalence of metabolic side effects with clozapine and suggests higher clozapine level and pharmacogenetic markers in CYP2C19, LEP, LEPR, and HTR2C receptors as important predictors of BMI and metabolic syndrome.

Pharmacogenetic Associations of Antipsychotic Drug-Related Weight Gain: A Systematic Review and Meta-analysis

Although weight gain is a serious but variable adverse effect of antipsychotics that has genetic underpinnings, a comprehensive meta-analysis of pharmacogenetics of antipsychotic-related weight gain is missing. In this review, random effects meta-analyses were conducted for dominant and recessive models on associations of specific single nucleotide polymorphisms (SNP) with prospectively assessed antipsychotic-related weight or body mass index (BMI) changes (primary outcome), or categorical increases in weight or BMI (≥7%; secondary outcome). Published studies, identified via systematic database search (last search: December 31, 2014), plus 3 additional cohorts, including 222 antipsychotic-naïve youth, and 81 and 141 first-episode schizophrenia adults, each with patient-level data at 3 or 4 months treatment, were meta-analyzed. Altogether, 72 articles reporting on 46 non-duplicated samples (n = 6700, mean follow-up = 25.1wk) with 38 SNPs from 20 genes/genomic regions were meta-analyzed (for each meta-analysis, studies = 2-20, n = 81-2082). Eleven SNPs from 8 genes were significantly associated with weight or BMI change, and 4 SNPs from 2 genes were significantly associated with categorical weight or BMI increase. Combined, 13 SNPs from 9 genes (Adrenoceptor Alpha-2A [ADRA2A], Adrenoceptor Beta 3 [ADRB3], Brain-Derived Neurotrophic Factor [BDNF], Dopamine Receptor D2 [DRD2], Guanine Nucleotide Binding Protein [GNB3], 5-Hydroxytryptamine (Serotonin) Receptor 2C [HTR2C], Insulin-induced gene 2 [INSIG2], Melanocortin-4 Receptor [MC4R], and Synaptosomal-associated protein, 25kDa [SNAP25]) were significantly associated with antipsychotic-related weight gain (P-values < .05-.001). SNPs in ADRA2A, DRD2, HTR2C, and MC4R had the largest effect sizes (Hedges' g's = 0.30-0.80, ORs = 1.47-1.96). Less prior antipsychotic exposure (pediatric or first episode patients) and short follow-up (1-2 mo) were associated with larger effect sizes. Individual antipsychotics did not significantly moderate effect sizes. In conclusion, antipsychotic-related weight gain is polygenic and associated with specific genetic variants, especially in genes coding for antipsychotic pharmacodynamic targets.

Effect of miRNA-27a and Leptin Polymorphisms on Risk of Recurrent Spontaneous Abortion

Background

The aim of this study was to investigate the possible associations of miRNA-27a and Leptin polymorphisms with the risk of recurrent spontaneous abortion (RSA).

Material/Methods

Between May 2013 and April 2015 at Shenzhen Longhua New District Central Hospital, we randomly recruited 138 RSA patients as the case group and another 142 normal pregnancy women as the control group. We used denaturing high-performance liquid chromatography (DHPLC) to determine the genotypes and allele frequencies of miRNA-27a rs895819 A/G and Leptin rs7799039 G/A.

Results

The GG genotype and G allele frequencies of miRNA-27a rs895819 A/G were higher in the case group than in the control group, and the AA genotype and A allele frequencies of Leptin rs7799039 G/A were also higher in the case group than in the control group (all P<0.05). MiRNA-27a rs895819 A/G and Leptin rs7799039 G/A polymorphisms increased the risk of RSA (Exp (B)=2.732, 95% CI=1.625~4.596, P=0.000; Exp (B)=4.081, 95% CI=1.817~9.164, P=0.001). GG-AA or AG-AA carriers had a higher risk of RSA. The miRNA-27a expression of AA carriers of miRNA-27a rs895819 was lower than that of AG+GG carriers both in the case and control groups (all P=0.024). The plasma leptin concentration of GG carriers was lower than that of GA+AA carriers in the case group (P=0.026).

Conclusions

The polymorphisms of miRNA-27a rs895819 A/G and Leptin rs7799039 G/A may contribute to an increased risk of RSA.

Core Concepts Involving Adverse Psychotropic Drug Effects: Assessment, Implications, and Management

Adverse effects from psychiatric drugs can profoundly influence treatment adherence and outcomes. Good care involves addressing adverse effects no differently than any other component of treatment. Knowledge about adverse effect assessment and management fosters a proper context that helps clinicians not sacrifice a drug's potential therapeutic benefits because of greater concerns about its tolerability. This article provides an overview of basic concepts related to the assessment and management of suspected adverse effects from psychotropic drugs. Key points are discussed regarding clinical, pharmacogenetic, pharmacokinetic, and pharmacodynamic risk factors for treatment-emergent adverse effects, alongside recommendations for their systematic assessment.

BAP guidelines on the management of weight gain, metabolic disturbances and cardiovascular risk associated with psychosis and antipsychotic drug treatment

Excess deaths from cardiovascular disease are a major contributor to the significant reduction in life expectancy experienced by people with schizophrenia. Important risk factors in this are smoking, alcohol misuse, excessive weight gain and diabetes. Weight gain also reinforces service users' negative views of themselves and is a factor in poor adherence with treatment. Monitoring of relevant physical health risk factors is frequently inadequate, as is provision of interventions to modify these. These guidelines review issues surrounding monitoring of physical health risk factors and make recommendations about an appropriate approach. Overweight and obesity, partly driven by antipsychotic drug treatment, are important factors contributing to the development of diabetes and cardiovascular disease in people with schizophrenia. There have been clinical trials of many interventions for people experiencing weight gain when taking antipsychotic medications but there is a lack of clear consensus regarding which may be appropriate in usual clinical practice. These guidelines review these trials and make recommendations regarding appropriate interventions. Interventions for smoking and alcohol misuse are reviewed, but more briefly as these are similar to those recommended for the general population. The management of impaired fasting glycaemia and impaired glucose tolerance ('pre-diabetes'), diabetes and other cardiovascular risks, such as dyslipidaemia, are also reviewed with respect to other currently available guidelines.These guidelines were compiled following a consensus meeting of experts involved in various aspects of these problems. They reviewed key areas of evidence and their clinical implications. Wider issues relating to primary care/secondary care interfaces are discussed but cannot be resolved within guidelines such as these.

Pharmacogenetics of Risperidone and Cardiovascular Risk in Children and Adolescents

Objective. To identify the frequency of obesity and metabolic complications in child and adolescent users of risperidone. Potential associations with clinical parameters and SNPs of the HTR2C, DRD2, LEP, LEPR, MC4R, and CYP2D6 genes were analyzed. Methods. Samples from 120 risperidone users (8-20 years old) were collected and SNPs were analyzed, alongside assessment of chronological and bone ages, prescribed and weight-adjusted doses, use of other psychotropic drugs, waist circumference, BMI z-scores, blood pressure, HOMA-IR index, fasting levels of serum glucose, insulin, cholesterol, triglycerides, transaminases, and leptin. Results. Thirty-two (26.7%) patients were overweight and 5 (4.2%) obese. Hypertension was recorded in 8 patients (6.7%), metabolic syndrome in 6 (5%), and increased waist circumference in 20 (16.7%). The HOMA-IR was high for 22 patients (18.3%), while total cholesterol and triglycerides were high in 20 (16.7%) and 41 (34.2%) patients, respectively. SNP associations were found for LEP, HTR2C, and CYP2D6 with BMI; CYP2D6 with blood pressure, ALT, and HOMA-IR; HTR2C and LEPR with leptin levels; MC4R and DRD2 with HOMA-IR; HTR2C with WC; and LEP with ALT. Conclusions. Although not higher than in the general pediatric population, a high frequency of patients was overweight/obese, with abnormalities in metabolic parameters and some pharmacogenetic associations.

A review of genetic alterations in the serotonin pathway and their correlation with psychotic diseases and response to atypical antipsychotics

Serotonin is a neurotransmitter that plays a predominant role in mood regulation. The importance of the serotonin pathway in controlling behavior and mental status is well recognized. All the serotonin elements - serotonin receptors, serotonin transporter, tryptophan hydroxylase and monoamine oxidase proteins - can show alterations in terms of mRNA or protein levels and protein sequence, in schizophrenia and bipolar disorder. Additionally, when examining the genes sequences of all serotonin elements, several single nucleotide polymorphisms (SNPs) have been found to be more prevalent in schizophrenic or bipolar patients than in healthy individuals. Several of these alterations have been associated either with different phenotypes between patients and healthy individuals or with the response of psychiatric patients to the treatment with atypical antipsychotics. The complex pattern of genetic diversity within the serotonin pathway hampers efforts to identify the key variations contributing to an individual's susceptibility to the disease. In this review article, we summarize all genetic alterations found across the serotonin pathway, we provide information on whether and how they affect schizophrenia or bipolar disorder phenotypes, and, on the contribution of familial relationships on their detection frequencies. Furthermore, we provide evidence on whether and how specific gene polymorphisms affect the outcome of schizophrenic or bipolar patients of different ethnic groups, in response to treatment with atypical antipsychotics. All data are discussed thoroughly, providing prospective for future studies.

New therapeutic opportunities for 5-HT2C receptor ligands in neuropsychiatric disorders

The 5-HT2C receptor (R) displays a widespread distribution in the CNS and is involved in the action of 5-HT in all brain areas. Knowledge of its functional role in the CNS pathophysiology has been impaired for many years due to the lack of drugs capable of discriminating among 5-HT2R subtypes, and to a lesser extent to the 5-HT1B, 5-HT5, 5-HT6 and 5-HT7Rs. The situation has changed since the mid-90s due to the increased availability of new and selective synthesized compounds, the creation of 5-HT2C knock out mice, and the progress made in molecular biology. Many pharmacological classes of drugs including antipsychotics, antidepressants and anxiolytics display affinities toward 5-HT2CRs and new 5-HT2C ligands have been developed for various neuropsychiatric disorders. The 5-HT2CR is presumed to mediate tonic/constitutive and phasic controls on the activity of different central neurobiological networks. Preclinical data illustrate this complexity to a point that pharmaceutical companies developed either agonists or antagonists for the same disease. In order to better comprehend this complexity, this review will briefly describe the molecular pharmacology of 5-HT2CRs, as well as their cellular impacts in general, before addressing its central distribution in the mammalian brain. Thereafter, we review the preclinical efficacy of 5-HT2C ligands in numerous behavioral tests modeling human diseases, highlighting the multiple and competing actions of the 5-HT2CRs in neurobiological networks and monoaminergic systems. Notably, we will focus this evidence in the context of the physiopathology of psychiatric and neurological disorders including Parkinson's disease, levodopa-induced dyskinesia, and epilepsy.

Polymorphisms of the leptin and HTR2C genes and clozapine-induced weight change and baseline BMI in patients with chronic schizophrenia

OBJECTIVES

We investigated the associations of the LEP-2548A/G and HTR2C-759C/T polymorphisms with long-term clozapine-induced weight changes and baseline BMI in chronic patients with schizophrenia.

MATERIALS AND METHODS

A total of 113 patients receiving clozapine for at least 1 year were enrolled. Body weight was measured cross-sectionally and data on body weight just before starting clozapine were retrospectively extracted from medical records.

RESULTS

Clozapine-induced change in BMI was correlated inversely with the baseline BMI (P<0.001, ρ=-0.347). The LEP-2548A/G polymorphism was associated significantly with the change in BMI (F=4.380, P=0.015) during clozapine use; those with the AA genotype had the highest BMI gain (1.4±3.1 kg/m), followed by those with the AG (-0.2±3.3 kg/m) and GG (-1.6±3.4 kg/m) genotypes. We also found a significant association between the leptin genotype and BMI at baseline (F=3.499, P=0.034); those with the AA genotype had the lowest baseline BMI (23.4±4.3 kg/m), followed by those with the AG (24.1±4.4 kg/m) and GG (28.8±7.3 kg/m) genotypes. In the case of the HTR2C-759C/T polymorphism, we found a trend in which T alleles were more prevalent in male patients with up to 7% increase in BMI than in those with a greater than 7% increase in BMI [12/54 (22.7%) vs. 1/27 (3.7%); Fisher's exact test: P=0.051].

CONCLUSION

This study shows an inverse correlation between the baseline BMI and change in BMI during long-term clozapine use in patients with schizophrenia, and the LEP-2548A/G polymorphism was associated significantly with both these measures.

Metabolic side effects and pharmacogenetics of second-generation antipsychotics in children

Second-generation antipsychotics (SGAs) are increasingly being used to treat children for a range of mental health conditions, for example, anxiety disorder, attention deficit hyperactivity disorder and bipolar disorder. SGA treatment is associated with weight gain and cardiometabolic side effects such as dyslipidemia, insulin resistance and elevated blood pressure, in some, but not all children. This review provides an overview of the potential role of pharmacogenomics in predisposing a child to unhealthy weight gain and cardiometabolic side effects with SGA treatment. Specifically, the review includes a synopsis of the evidence for cardiometabolic side effects in SGA-treated children, illustrating the extent and depth of the problem; summarizes the potential long-term consequences of developing cardiometabolic risk during childhood and highlights genetic variants that may be useful in predicting cardiometabolic side effects in SGA-treated children.

Association of FTO, LEPR and MTHFR gene polymorphisms with metabolic syndrome in schizophrenia patients receiving antipsychotics

AIM

The occurrence of metabolic syndrome (MS) in schizophrenia patients receiving long-term antipsychotics (APs) contributes to their high mortality rate. We aimed to determine whether genetic polymorphisms of identified candidate genes are associated with MS in our study population.

MATERIALS & METHODS

We recruited 206 schizophrenia patients receiving AP treatment for at least a year. Cross-sectional measurements of weight, height, blood pressure, waist and hip circumference, and other lipid profiles were recorded. Patient DNA was genotyped for 16 candidate gene polymorphisms.

RESULTS

Of these patients, 59.7% were found to have MS while 40.3% did not. All metabolic parameters were significantly different between the two groups. Only three of the 16 polymorphisms studied showed significant association with MS; rs9939609 of the FTO gene confers risk for MS (odds ratio [OR]: 1.73, 95% CI: 1.07-2.78, p = 0.026), while rs1137101 of the LEPR gene (OR: 0.47, 95% CI: 0.28-0.80, p = 0.005) and rs1801133 of the MTHFR gene (OR: 0.59, 95% CI: 0.35-0.99, p = 0.049) are protective against MS.

CONCLUSION

Polymorphisms of the FTO, LEPR and MTHFR genes may play a role in MS in Malaysian schizophrenia patients receiving long-term treatment with APs.

The promise of biological markers for treatment response in first-episode psychosis: a systematic review

Successful treatment of first-episode psychosis is one of the major factors that impacts long-term prognosis. Currently, there are no satisfactory biological markers (biomarkers) to predict which patients with a first-episode psychosis will respond to which treatment. In addition, a non-negligible rate of patients does not respond to any treatment or may develop side effects that affect adherence to the treatments as well as negatively impact physical health. Thus, there clearly is a pressing need for defining biomarkers that may be helpful to predict response to treatment and sensitivity to side effects in first-episode psychosis. The present systematic review provides (1) trials that assessed biological markers associated with antipsychotic response or side effects in first-episode psychosis and (2) potential biomarkers associated with biological disturbances that may guide the choice of conventional treatments or the prescription of innovative treatments. Trials including first-episode psychoses are few in number. Most of the available data focused on pharmacogenetics markers with so far only preliminary results. To date, these studies yielded-beside markers for metabolism of antipsychotics-no or only a few biomarkers for response or side effects, none of which have been implemented in daily clinical practice. Other biomarkers exploring immunoinflammatory, oxidative, and hormonal disturbances emerged as biomarkers of first-episode psychoses in the last decades, and some of them have been associated with treatment response. In addition to pharmacogenetics, further efforts should focus on the association of emergent biomarkers with conventional treatments or with innovative therapies efficacy, where some preliminary data suggest promising results.

Efficacy of adjunctive treatments added to olanzapine or clozapine for weight control in patients with schizophrenia: a systematic review and meta-analysis

Objectives. This study was conducted to review systematically adjunctive treatments for weight reduction in patients with schizophrenia and compare efficacies of clinical trials through meta-analysis, so as to provide effective clinical guideline regarding weight control for patients taking atypical antipsychotics. Methods. Candidate clinical trials were identified through searching the Cochrane Central Register of Controlled Trials, PubMed, and PsycINFO. Fourteen randomized clinical trials were included for systematic review and meta-analysis from 132 potential trials. The Comprehensive Meta-Analysis version 2 was used for meta-analysis. Results. Difference in means and significances from meta-analyses regarding weight control by adjunctive treatments showed that topiramate, aripiprazole, or sibutramine was more effective than metformin or reboxetine. Psychiatric evaluations did not show statistically significant changes between treatment groups and placebo groups except topiramate adjunctive treatments. Adverse effects regarding adjunctive therapies were tolerable and showed statistically no significances compared to control groups. Conclusion. Though having several reports related to exacerbation of psychiatric symptoms, topiramate and aripiprazole are more efficacious than other medications in regard to weight reduction and less burden of critical adverse effects as well as being beneficial for clinical improvement.

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.

Pharmacogenomics in psychiatry: the relevance of receptor and transporter polymorphisms

The treatment of severe mental illness, and of psychiatric disorders in general, is limited in its efficacy and tolerability. There appear to be substantial interindividual differences in response to psychiatric drug treatments that are generally far greater than the differences between individual drugs; likewise, the occurrence of adverse effects also varies profoundly between individuals. These differences are thought to reflect, at least in part, genetic variability. The action of psychiatric drugs primarily involves effects on synaptic neurotransmission; the genes for neurotransmitter receptors and transporters have provided strong candidates in pharmacogenetic research in psychiatry. This paper reviews some aspects of the pharmacogenetics of neurotransmitter receptors and transporters in the treatment of psychiatric disorders. A focus on serotonin, catecholamines and amino acid transmitter systems reflects the direction of research efforts, while relevant results from some genome-wide association studies are also presented. There are many inconsistencies, particularly between candidate gene and genome-wide association studies. However, some consistency is seen in candidate gene studies supporting established pharmacological mechanisms of antipsychotic and antidepressant response with associations of functional genetic polymorphisms in, respectively, the dopamine D2 receptor and serotonin transporter and receptors. More recently identified effects of genes related to amino acid neurotransmission on the outcome of treatment of schizophrenia, bipolar illness or depression reflect the growing understanding of the roles of glutamate and γ-aminobutyric acid dysfunction in severe mental illness. A complete understanding of psychiatric pharmacogenomics will also need to take into account epigenetic factors, such as DNA methylation, that influence individual responses to drugs.

HTR2C polymorphisms, olanzapine-induced weight gain and antipsychotic-induced metabolic syndrome in schizophrenia patients: a meta-analysis

OBJECTIVE

To conduct meta-analyses of all published association studies on the HTR2C -759C/T (rs3813829) polymorphism and olanzapine-induced weight gain in schizophrenia patients and on the HTR2C -759C/T, -697G/C (rs518147) and rs1414334:C> G polymorphisms and olanzapine/clozapine/risperidone-induced metabolic syndrome in schizophrenia patients.

METHODS

Eligible studies were identified by searching PubMed and Web of Science databases. Meta-analyses were performed using Cochrane Review Manager (RevMan, version 5.2) to calculate the pooled odds ratio (OR) and its corresponding 95% confidence interval (CI).

RESULTS

Our meta-analyses revealed both a significant positive association between the rs1414334 C allele and olanzapine/clozapine/risperidone-induced metabolic syndrome and a marginally significant positive association between the -697C allele and the induced metabolic syndrome in schizophrenia patients, but no significant association between the -759C/T polymorphism and the induced metabolic syndrome in schizophrenia patients. Our analysis further revealed a pronounced trend toward a significant negative association between the -759T allele and high olanzapine-induced weight gain and a trend toward a significant positive association between the -759C allele and high olanzapine-induced weight gain in Caucasian schizophrenia patients.

CONCLUSIONS

Our results support that HTR2C polymorphisms play a role in antipsychotic-induced metabolic disturbance. More association studies are needed to further elucidate association of different HTR2C polymorphisms and antipsychotic-induced metabolic disturbance.

Subchronic olanzapine treatment decreases the expression of pancreatic glucose transporter 2 in rat pancreatic β cells

BACKGROUND

Olanzapine is a second generation antipsychotic. A common side effect in humans is weight gain, but the mechanisms are mostly unknown.

AIM

To study the effects of subchronic olanzapine treatment on body weight, fasting plasma glucose (FPG), fasting insulin (FINS), C-peptide, insulin sensitivity index (ISI), and expression of glucose transporter 2 (GLUT2) in rat pancreatic β cells.

MATERIALS AND METHODS

Female Sprague-Dawley rats were randomly divided into two groups: the olanzapine-treated group and the control group (each n = 8). Rats in the olanzapine-treated group intragastrically received olanzapine 5 mg/kg/day for 28 days; the rats in the control group received the same volume of vehicle. FPG and body weight were measured on the 1st, 7th, 14th and 28th day. FINS and C-peptide were measured using immunoradiometric assays at baseline and on the 28th day. GLUT2 mRNA and protein expressions in pancreatic β cells were analyzed by RT-PCR and western blot.

RESULTS

Olanzapine-treated rats had higher body weight (227.4 ± 8.9 vs. 211.0 ± 9.9 g), FPG (5.86 ± 0.42 vs. 4.24 ± 0.29 mmol/L), FINS (17.34 ± 3.64 vs. 10.20 ± 1.50 µIU/mL), and C-peptide (0.154 ± 0.027 vs. 0.096 ± 0.009 ng/mL) than those in controls (all P < 0.05) at the 28th day. Pancreatic β cells of the olanzapine-treated group showed lower ISI (-4.60 ± 0.23 vs. -3.76 ± 0.20) and GLUT2 levels (mRNA: 1.12 ± 0.02 vs. 2.00 ± 0.03; protein: 0.884 ± 0.134 vs. 1.118 ± 0.221) than those in controls (all P < 0.05).

CONCLUSIONS

Subchronic olanzapine treatment inhibited expression of GLUT2 in rat pancreatic β cells. Therefore, it may disturb glucose metabolism via the insulin resistance of β cells, but confirmation in humans is needed.