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To date, bipolar disorder (BD) genetic studies and polygenic risk scores (PRSs) for BD are based primarily on populations of European descent (EUR) and lack representation from other ancestries including Latin American (LAT). Here, we describe a new LAT cohort from the Mayo Clinic Bipolar Biobank (MCBB), a multisite collaboration with recruitment sites in the United States (EUR; 1,443 cases and 777 controls) and Mexico and Chile (LAT; 211 cases and 161 controls) and use the sample to explore the performance of a BD-PRS in a LAT population. Using results from the largest genome-wide association study of BD in EUR individuals, PRSice2 and LDpred2 were used to compute BD-PRSs in the LAT and EUR samples from the MCBB. PRSs explained up to 1.4% (PRSice) and 4% (LDpred2) of the phenotypic variance on the liability scale in the LAT sample compared to 3.8% (PRSice2) and 3.4% (LDpred2) in the EUR samples. Future larger studies should further explore the differential performance of different PRS approaches across ancestries. International multisite studies, such as this one, have the potential to address diversity-related limitations of prior genomic studies and ultimately contribute to the reduction of health disparities., (© 2023 Wiley Periodicals LLC.)

Individuals with bipolar disorder (BD) require chronic pharmacotherapy, typically including medication switches or polypharmacy due to persisting symptoms or intolerable side effects. Here, we quantified pharmacotherapy exposure (PE) of Mayo Clinic BD Biobank participants using the number of cross-sectional (at enrollment) and lifetime BD-specific medications and medication classes, to understand the relationship between PE and markers of disease severity or treatment failure, psychiatric comorbidities, and polygenic risk scores (PRS) for six major psychiatric disorders. Being female (p < 0.05), older (p < 0.01), having history of suicide attempts (p < 0.0001), and comorbid attention-deficit/hyperactivity disorder (p < 0.05) or generalized anxiety disorder (p < 0.05) were uniformly associated with higher PE. Lifetime exposure to unique medication classes among participants with BD-I was significantly lower than for those with schizoaffective disorder (estimate = -2.1, p < 0.0001) while significantly higher than for those with BD-II (estimate = 0.5, p < 0.01). Further, higher PRS for schizophrenia (SCZ) and anxiety resulted in greater lifetime medication counts (p < 0.01), both driven by antipsychotic (p < 0.001) and anxiolytic use (p < 0.05). Our results provide initial evidence of the utility of PE as a measure of disease complexity or treatment resistance, and that PE may be predicted by higher genetic risk for SCZ and anxiety., Competing Interests: Declaration of Competing Interests SLM reports receiving personal fees for advisory boards and/or consultation from Idorsia, Levo, Novo Nordisk, Otsuka, Sunovion, and Takeda; receiving grant support from Idorsia, Janssen, Marriott Foundation, Myriad, National Institute of Mental Health, Novo Nordisk, Otsuka, and Sunovion; and receiving payments from Johnson & Johnson for being an inventor on US Patent No. 6323,236 B2. ABCB has received lecture and consulting fees from Asofarma and Exeltis. MLP has served on an advisory board for Janssen and has received grant support from ANID FONDECYT Regular 1181365, FONDEF ID19I10116 and Basal Funding for Scientific and Technological Center of Excellence, IMPACT, #FB210024. MAF reports the following conflicts of interest: grant support from Assurex Health and Mayo Foundation; CME/travel/honoraria from Carnot Laboratories, American Physician Institute; and financial interest/stock ownership/royalties in Chymia LLC., (Copyright © 2023. Published by Elsevier B.V.)

Background: Bipolar disorder (BD) presents with high obesity and type 2 diabetes (T2D) and pathophysiological and phenomenological abnormalities shared with cardiometabolic disorders. Genomic studies may help define if they share genetic liability. This selective review of BD with obesity and T2D will focus on genomic studies, stress their current limitations and guide future steps in developing the field., Methods: We searched electronic databases (PubMed, Scopus) until December 2021 to identify genome-wide association studies, polygenic risk score analyses, and functional genomics of BD accounting for body mass index (BMI), obesity, or T2D., Results: The first genome-wide association studies (GWAS) of BD accounting for obesity found a promising genome-wide association in an intronic gene variant of TCF7L2 that was further replicated. Polygenic risk scores of obesity and T2D have also been associated with BD, yet, no genetic correlations have been demonstrated. Finally, human-induced stem cell studies of the intronic variant in TCF7L2 show a potential biological impact of the products of this genetic variant in BD risk., Limitations: The narrative nature of this review., Conclusions: Findings from BD GWAS accounting for obesity and their functional testing, have prompted potential biological insights. Yet, BD, obesity, and T2D display high phenotypic, genetic, and population-related heterogeneity, limiting our ability to detect genetic associations. Further studies should refine cardiometabolic phenotypes, test gene-environmental interactions and add population diversity., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objectives: Recognizing bipolar disorder as a multi-system metabolic condition driven, in part, by binge eating behavior and atypical depressive symptoms, this study aimed to quantify diet quality and evaluate clinical correlates in a bipolar disorder cohort., Methods: Participants from the Mayo Clinic Bipolar Disorder Biobank (n = 734) completed the Rapid Eating Assessment for Participants - Shortened version (REAP-S) to determine diet quality. The average REAP-S score for a U.S. omnivorous diet is 32 (range 13 to 39) with higher scores indicating healthier diet. Demographic variables were collected in a standardized clinical questionnaire. Depressive symptoms were assessed by the Bipolar Inventory of Symptoms Scale. Cardiometabolic variables were retrieved from the electronic health record. Associations between continuous variables and REAP-S scores (total, 'healthy foods' and 'avoidance of unhealthy foods') were assessed using linear regression., Results: Overall, our sample had a mean REAP-S score of 27.6 (4.9), suggestive of a lower diet quality than the average general population in the US. There was a significant inverse relationship between mean REAP-S lower scores with increased BMI, waist circumference, disordered eating and depression. All these associations were significantly stronger in female participants., Limitations: EHR cross-sectional data., Conclusions: Our data suggest unhealthy diet quality in bipolar disorder is associated with depression, obesity and cardiometabolic abnormalities. Additional work is encouraged to prospectively track mood and diet quality to further understand the bidirectional relationship and clarify if dietary interventions can positively impact mood. Further delineating potential sex differences in diet quality and depression may provide greater appreciation of modifiable risk factors for future cardiometabolic burden., (Copyright © 2022. Published by Elsevier B.V.)

Objective: To evaluate the association between cardiometabolic markers and bipolar disorder (BD), examining the impact of sex and cardiometabolic medication use, from a large case-control biorepository of more than 1300 participants., Patients and Methods: Recruited from July 2009 through September 2017, cardiometabolic markers were harvested from electronic health records (EHR) of participants (n=661) from the Mayo Clinic Individualized Medicine Biobank for Bipolar Disorder and Mayo Clinic Biobank age-sex-matched controls (n=706). Markers were compared between cases and controls using logistic regression, stratified by sex, adjusting for cardiometabolic medications and current smoking status. We studied the effect of psychotropics in case-only analyses., Results: The mean age of the sample was 52.5 ± 11.6 years and 55% were female. BD patients had higher rates of smoking, but lower utilization of lipid-lowering medication compared with controls. After adjustment, BD was associated with obesity [Odds ratio (CI) 1.62 (1.22-2.15)], elevated systolic blood pressure (SBP) [2.18 (1.55-3.06)] and elevated triglycerides [1.58 (1.13-2.2)]. When stratified by sex, obesity [1.8 (1.23-2.66)] and systolic blood pressure [2.32 (1.46-3.7)] were associated with BD females compared to female controls; however, only systolic blood pressure [2.04 (1.23-3.42)] was associated with male bipolars compared to male controls. Psychotropics were marginally associated with mean BMI, abnormal triglycerides, and HbA1c., Limitations: EHR cross-sectional data CONCLUSION: To our knowledge, this is the largest case controlled study to date to explore the association between cardiometabolic markers and bipolar disorder adjusting for utilization of cardiometabolic medication. Identification of significant, non-laboratory based cardiometabolic markers that are associated with increased risk of major cardiovascular adverse events in patients with bipolar disorder, underscores, both the utility and importance of risk monitoring that can be easily done in community mental health centers., (Copyright © 2020. Published by Elsevier B.V.)

Objective: Our aim was to evaluate the relationship between evening chronotype, a proxy marker of circadian system dysfunction, and disordered eating behavior and poor dietary habits in individuals with bipolar disorder (BD)., Methods: In this cross-sectional study, we evaluated 783 adults with BD. Chronotype was determined using item 5 from the reduced Morningness-Eveningness Questionnaire. The Eating Disorder Diagnostic Scale (EDDS) and the Rapid Eating Assessment for Participants-Shortened Version (REAP-S) were used to assess disordered eating behavior and dietary habits respectively. General linear models and logistic regression models were utilized to evaluate differences between chronotype groups., Results: Two hundred and eight (27%) BD participants self-identified as having evening chronotypes. Compared to non-evening types, evening types were younger (P < 0.01) and, after controlling for age, had higher mean EDDS composite z-scores (P < 0.01); higher rates of binge-eating (BE) behavior (P = 0.04), bulimia nervosa (P < 0.01), and nocturnal eating binges (P < 0.01); and a higher body mass index (P = 0.04). Compared to non-evening types, evening chronotypes had a lower REAP-S overall score (P < 0.01) and scored lower on the 'healthy foods' and 'avoidance of unhealthy food' factors. Evening types also skipped breakfast more often (P < 0.01), ate less fruit (P = 0.02) and vegetables (P = 0.04), and consumed more fried foods (P < 0.01), unhealthy snacks (P = 0.02), and soft drinks (P = 0.01)., Conclusions: Our findings suggest that the circadian system plays a role in the disordered eating and unhealthy dietary behaviors observed in BD patients. The circadian system may therefore represent a therapeutic target in BD-associated morbidity that warrants further investigation., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: Our aim was to investigate evening chronotype, a proxy marker of circadian system dysfunction, as a clinical subphenotype in bipolar disorder (BD)., Methods: In this cross-sectional study, 773 BD participants and 146 control subjects were evaluated using the Structured Clinical Interview for DSM-IV and a set of questionnaires. Chronotype was determined using item-5 from the reduced Morningness-Eveningness Questionnaire. Univariate analyses and regression models were used to compare evening and non-evening chronotype in BD and chronotype association with clinical variables., Results: Overall, 205 (27%) of BD patients reported an evening chronotype. Evening chronotype was higher in a matched sub-sample of BD patients (n = 150) than in controls (24% and 5% respectively, OR=5.4, p<0.01). Compared to those with non-evening chronotypes, BD patients with an evening chronotype were younger, had an earlier age of onset of BD, and had more prior depressive and manic episodes, higher rates of rapid cycling, past suicide attempts, more comorbid anxiety and substance use disorders. Multivariate regression showed age, prior suicide attempts, and co-occurring substance use disorder were associated with evening chronotype (OR range of 0.97 to1.59). Hypertension, migraine, asthma, and obstructive sleep apnea were significantly associated with evening chronotype (OR range of 1.56 to 2.0)., Limitation: Limitations include a cross-sectional study design that precludes establishing causality. Analyses did not control for medication use. Younger participant age may prevent evaluation of associations with late-life illnesses., Conclusions: Evening chronotype may be a discrete clinical subphenotype in BD and circadian dysfunction a shared pathophysiological mechanism between psychopathology and medical morbidity., Competing Interests: Declaration of Competing Interest Dr. Romo-Nava reports support from the Brain & Behavior Research Foundation NARSAD Young Investigator Award; receiving nonfinancial support from Soterix Medical outside the submitted work; and having patent 62 581 968 pending. dr. McElroy reported receiving grants and personal fees from Allergan, Avanir, Myriad, Shire, and Sunovion; receiving grants from Brainsway, Marriott Foundation, Medibio, Neurocrine, and Novo Nordisk; receiving personal fees from Bracket, F. Hoffmann-LaRoche Limited, Mitsubishi Tanabe Pharma America, and Opiant; being a consultant to or member of the scientific advisory boards of Bracket, MedAvante, Naurex, Shire, and Sunovion; being a principal or co-investigator on studies sponsored by the Agency for Healthcare Research & Quality, AstraZeneca, Cephalon, Forest, Marriott Foundation, the National Institute of Mental Health, Orexigen Therapeutics Inc, Shire, and Takeda Pharmaceutical Company Ltd; being an inventor on US Patent 6 323 236 B2; and receiving payments from Johnson & Johnson, which has exclusive patent rights. dr.. Frye reported receiving grants from the Marriott Foundation during the conduct of the study; receiving grants from the National Institute of Alcohol Abuse and Alcoholism and National Institute of Mental Health, National Institutes of Health, Assurex Health, Myriad, and Pfizer; being a consultant to Janssen Global Services LLC; receiving other support from Mitsubishi Tanabe Pharma Corporation, Myriad, Sunovion, and Teva Pharmaceuticals; receiving travel and hotel honoraria from CME Outfitters to give a lecture for continuing medical education credit and receiving support for a presentation from Sunovion. No other disclosures are reported., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Bipolar disorder (BD) affects both sexes, but important sex differences exist with respect to its symptoms and comorbidities. For example, rapid cycling (RC) is more prevalent in females, and alcohol use disorder (AUD) is more prevalent in males. We hypothesize that X chromosome variants may be associated with sex-specific characteristics of BD. Few studies have explored the role of the X chromosome in BD, which is complicated by X chromosome inactivation (XCI). This process achieves "dosage compensation" for many X chromosome genes by silencing one of the two copies in females, and most statistical methods either ignore that XCI occurs or falsely assume that one copy is inactivated at all loci. We introduce new statistical methods that do not make these assumptions., Methods: We investigated this hypothesis in 1001 BD patients from the Genetic Association Information Network (GAIN) and 957 BD patients from the Mayo Clinic Bipolar Disorder Biobank. We examined the association of over 14,000 X chromosome single nucleotide polymorphisms (SNPs) with sex-associated BD traits using two statistical approaches that account for whether a SNP may be undergoing or escaping XCI. In the "XCI-informed approach," we fit a sex-adjusted logistic regression model assuming additive genetic effects where we coded the SNP either assuming one copy is expressed or two copies are expressed based on prior knowledge about which regions are inactivated. In the "XCI-robust approach," we fit a logistic regression model with sex, SNP, and SNP-sex interaction effects that is flexible to whether the region is inactivated or escaping XCI., Results: Using the "XCI-informed approach," which considers only the main effect of SNP and does not allow the SNP effect to differ by sex, no significant associations were identified for any of the phenotypes. Using the "XCI-robust approach," intergenic SNP rs5932307 was associated with BD (P = 8.3 × 10 -8 ), with a stronger effect in females (odds ratio in males (OR M ) = 1.13, odds ratio in females for a change of two allele copies (OR W2 ) = 3.86)., Conclusion: X chromosome association studies should employ methods which account for its unique biology. Future work is needed to validate the identified associations with BD, to formally assess the performance of both approaches under different true genetic architectures, and to apply these approaches to study sex differences in other conditions.

Dorsolateral prefrontal cortex (DLPFC) and temporal pole (TP) are brain regions that display abnormalities in bipolar disorder (BD) patients. DNA methylation - an epigenetic mechanism both heritable and sensitive to the environment - may be involved in the pathophysiology of BD. To study BD-associated DNA methylomic differences in these brain regions, we extracted genomic DNA from the postmortem tissues of Brodmann Area (BA) 9 (DLPFC) and BA38 (TP) gray matter from 20 BD, ten major depression (MDD), and ten control age-and-sex-matched subjects. Genome-wide methylation levels were measured using the 850 K Illumina MethylationEPIC BeadChip. We detected striking differences between cortical regions, with greater numbers of between-brain-region differentially methylated positions (DMPs; i.e., CpG sites) in all groups, most pronounced in the BD group, and with substantial overlap across groups. The genes of DMPs common to both BD and MDD (hypothetically associated with their common features such as depression) and those distinct to BD (hypothetically associated with BD-specific features such as mania) were enriched in pathways involved in neurodevelopment including axon guidance. Pathways enriched only in the BD-MDD shared list pointed to GABAergic dysregulation, while those enriched in the BD-only list suggested glutamatergic dysregulation and greater impact on synaptogenesis and synaptic plasticity. We further detected group-specific between-brain-region gene expression differences in ODC1, CALY, GALNT2, and GABRD, which contained significant between-brain-region DMPs. In each brain region, no significant DMPs or differentially methylated regions (DMRs) were found between diagnostic groups. In summary, the methylation differences between DLPFC and TP may provide molecular targets for further investigations of genetic and environmental vulnerabilities associated with both unique and common features of various mood disorders and suggest directions of future development of individualized treatment strategies., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction : Clinical and genetic study of psychiatric conditions has underscored the co-occurrence of complex phenotypes and the need to refine them. Bipolar Disorder (BD) and Binge Eating (BE) behavior are common psychiatric conditions that have high heritability and high co-occurrence, such that at least one quarter of BD patients have BE (BD + BE). Genetic studies of BD alone and of BE alone suggest complex polygenic risk models, with many genetic risk loci yet to be identified. Areas covered : We review studies of the epidemiology of BD+BE, its clinical features (cognitive traits, psychiatric comorbidity, and role of obesity), genomic studies (of BD, eating disorders (ED) defined by BE, and BD + BE), and therapeutic implications of BD + BE. Expert opinion : Subphenotyping of complex psychiatric disorders reduces heterogeneity and increases statistical power and effect size; thus, it enhances our capacity to find missing genetic (and other) risk factors. BD + BE has a severe clinical picture and genetic studies suggests a distinct genetic architecture. Differential therapeutic interventions may be needed for patients with BD + BE compared with BD patients without BE. Recognizing the BD + BE subphenotype is an example of moving towards more precise clinical and genetic entities.

Background: Patients with bipolar disorder demonstrate sex differences in clinical presentation, particularly in the sub-phenotypes related to periodicity of mood episodes, such as rapid cycling. Additionally, recent studies have linked P2RX7 gene variants with the risk of rapid cycling in clinical cohorts of patients with bipolar disorder, as well as other mood disorders. However, little is known about potential sex differences in the relationship between variants in P2RX7 and bipolar disorder., Methods: We investigated sex-specific genetic associations between variants of P2RX7 (rs1621388 and rs2230912) in 756 patients with bipolar disorder and 787 control patients matched on age, sex, and ancestry. We examined sex-specific genetic associations with bipolar disorder by comparing cases and controls, as well as rapid cycling of mood episodes in cases. Findings were replicated in an independent dataset., Results: P2RX7 variants implying an increased pore activity were more common in bipolar disorder, in females but not in males. Neither P2RX7 variants associated with rapid cycling among bipolar patients., Limitations: Low sample size limited power for tests of SNP by sex interaction, and data about the onset of rapid cycling and the timing of medication use were not available., Conclusion: The effects of P2RX7 variants on bipolar disorder may be sex-specific, with increased P2X7 activity potentially elevating risk for bipolar disorder in females. Future research to examine the effect of P2RX7 on bipolar disorder should consider sex-specific effects., (Copyright © 2018. Published by Elsevier B.V.)

Bipolar disorder (BD) is associated with binge eating behavior (BE), and both conditions are heritable. Previously, using data from the Genetic Association Information Network (GAIN) study of BD, we performed genome-wide association (GWA) analyses of BD with BE comorbidity. Here, utilizing data from the Mayo Clinic BD Biobank (969 BD cases, 777 controls), we performed a GWA analysis of a BD subtype defined by BE, and case-only analysis comparing BD subjects with and without BE. We then performed a meta-analysis of the Mayo and GAIN results. The meta-analysis provided genome-wide significant evidence of association between single nucleotide polymorphisms (SNPs) in PRR5-ARHGAP8 and BE in BD cases (rs726170 OR = 1.91, P = 3.05E-08). In the meta-analysis comparing cases with BD with comorbid BE vs. non-BD controls, a genome-wide significant association was observed at SNP rs111940429 in an intergenic region near PPP1R2P5 (p = 1.21E-08). PRR5-ARHGAP8 is a read-through transcript resulting in a fusion protein of PRR5 and ARHGAP8. PRR5 encodes a subunit of mTORC2, a serine/threonine kinase that participates in food intake regulation, while ARHGAP8 encodes a member of the RhoGAP family of proteins that mediate cross-talk between Rho GTPases and other signaling pathways. Without BE information in controls, it is not possible to determine whether the observed association reflects a risk factor for BE in general, risk for BE in individuals with BD, or risk of a subtype of BD with BE. The effect of PRR5-ARHGAP8 on BE risk thus warrants further investigation.

Objective: To determine whether bipolar spectrum disorder with binge eating behavior (BE) is an important clinical sub-phenotype., Methods: Prevalence rates and correlates of different levels of BE were assessed in 1114 bipolar spectrum patients participating in a genetic biobank. BE and eating disorders (EDs) were assessed with the Eating Disorder Diagnostic Scale (EDDS). Psychiatric illness burden was evaluated with measures of suicidality, psychosis, mood instability, anxiety disorder comorbidity, and substance abuse comorbidity. Medical illness burden was evaluated with body mass index (BMI) and the Cumulative Index Rating Scale (CIRS)., Results: Thirty percent of patients had any BE and 27% had BE plus an ED diagnosis. Compared with bipolar spectrum patients without BE, bipolar spectrum patients with BE were younger and more likely to be female; had significantly higher levels of eating psychopathology, suicidality, mood instability, and anxiety disorder comorbidity; had a significantly higher mean BMI and a significantly higher rate of obesity; and had a significantly higher medical illness burden. Bipolar spectrum patients with BE but no ED diagnosis were more similar to bipolar spectrum patients without BE than to those with an ED. Nonetheless, the positive predictive value and specificity of BE predicting an ED was 0.90 and 0.96, respectively., Limitations: As only two patients had co-occurring anorexia nervosa, these results may not generalize to bipolar spectrum patients with restricting EDs., Conclusion: Bipolar spectrum disorder with broadly-defined BE may not be as clinically relevant a sub-phenotype as bipolar spectrum disorder with an ED but may be an adequate proxy for the latter when phenotyping large samples of individuals., (Copyright © 2016. Published by Elsevier B.V.)

Objectives: Bipolar disorder (BD) is a complex disease associated with various hereditary traits, including a higher body mass index (BMI). In a prior genome-wide association study, we found that BMI modified the association of rs12772424 - a common variant in the gene encoding transcription factor 7-like 2 (TCF7L2) - with risk for BD. TCF7L2 is a transcription factor in the canonical Wnt pathway, involved in multiple disorders, including diabetes, cancer and psychiatric conditions. Here, using an independent sample, we evaluated 26 TCF7L2 single nucleotide polymorphisms (SNPs) to explore further the association of BD with the TCF7L2-BMI interaction., Methods: Using a sample of 662 BD cases and 616 controls, we conducted SNP-level and gene-level tests to assess the evidence for an association between BD and the interaction of BMI and genetic variation in TCF7L2. We also explored the potential mechanism behind the detected associations using human brain expression quantitative trait loci (eQTL) analysis., Results: The analysis provided independent evidence of an rs12772424-BMI interaction (p = 0.011). Furthermore, while overall there was no evidence for SNP marginal effects on BD, the TCF7L2-BMI interaction was significant at the gene level (p = 0.042), with seven of the 26 SNPs showing SNP-BMI interaction effects with p < 0.05. The strongest evidence of interaction was observed for rs7895307 (p = 0.006). TCF7L2 expression showed a significant enrichment of association with the expression of other genes in the Wnt canonical pathway., Conclusions: The current study provides further evidence suggesting that TCF7L2 involvement in BD risk may be regulated by BMI. Detailed, prospective assessment of BMI, comorbidity, and other possible contributing factors is necessary to explain fully the mechanisms underlying this association., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To determine prevalence rates and clinical correlates of current DSM-5 eating disorders in patients with bipolar disorder (BP)., Methods: Prevalence rates of current DSM-5- and DSM-IV-defined binge eating disorder (BED), bulimia nervosa (BN), and anorexia nervosa (AN) were assessed with the Eating Disorder Diagnostic Scale (EDDS) in 1092 patients with BP. Psychiatric illness burden was evaluated with five proxy measures of BP illness severity. Medical illness burden was evaluated with the Cumulative Index Rating Scale (CIRS)., Results: Twenty-seven percent of patients had a current DSM-5 eating disorder: 12% had BED, 15% had BN, and 0.2% had AN. Rates of DSM-5-defined BED and BN were higher than clinical diagnosis rates and rates of DSM-IV-defined BED and BN. Compared with BP patients without an eating disorder, BP patients with a DSM-5 eating disorder were younger and more likely to be women; had an earlier age of onset of BP; had higher EDDS composite scores and higher degrees of suicidality, mood instability, and anxiety disorder comorbidity; and had a higher mean BMI, higher rate of obesity, and higher CIRS total scores. In a logistic regression model controlling for previously identified correlates of an eating disorder, younger age, female gender, and higher BMI remained significantly associated with an eating disorder., Limitations: The EDDS has not been validated in BP patients., Conclusion: DSM-5-defined BED and BN are common in BP patients, possibly more common than DSM-IV-defined BED and BN, and associated with greater psychiatric and general medical illness burden. Further studies assessing DSM-5 eating disorders in people with BP are greatly needed., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Objectives: To examine the independent effects of sex on the risk of rapid cycling and other indicators of adverse illness course in patients with bipolar I disorder (BP-I) or bipolar II disorder (BP-II)., Methods: We analyzed data from the first 1,225 patients enrolled in the Mayo Clinic Individualized Medicine Biobank for Bipolar Disorder. Demographic and clinical variables were ascertained using standardized questionnaires; height and weight were assessed to determine body mass index (BMI). Rates of rapid cycling, cycle acceleration, and increased severity of mood episodes over time were compared between women and men overall and within subgroups defined by bipolar disorder subtype (BP-I or BP-II). Multiple logistic regression analysis was used to assess the independent effect of sex on the risk of these indicators of adverse illness course., Results: Women had significantly higher rates of rapid cycling than men. Overall rates of rapid cycling were higher in patients with BP-II than BP-I; and sex differences in the rate of rapid cycling were more pronounced in patients with BP-II than BP-I, although the power to detect statistically significant differences was reduced due to the lower sample size of subjects with BP-II. Female sex was a significant predictor of rapid cycling, cycle acceleration, and increased severity of mood episodes over time after adjusting for age, bipolar disorder subtype, BMI, having any comorbid psychiatric disorder, and current antidepressant use., Conclusions: Female sex was associated with significantly higher risk of rapid cycling, cycle acceleration, and increased severity of mood episodes over time in a sample of 1,225 patients with bipolar disorders., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Bipolar disorder (BD) is associated with higher body mass index (BMI) and increased metabolic comorbidity. Considering the associated phenotypic traits in genetic studies of complex diseases, either by adjusting for covariates or by investigating interactions between genetic variants and covariates, may help to uncover the missing heritability. However, obesity-related traits have not been incorporated in prior genome-wide analyses of BD as covariates or potential interacting factors. To investigate the genetic factors underlying BD while considering BMI, we conducted genome-wide analyses using data from the Genetic Association Information Network BD study. We analyzed 729,454 genotyped single-nucleotide polymorphism (SNP) markers on 388 European-American BD cases and 1020 healthy controls with available data for maximum BMI. We performed genome-wide association analyses of the genetic effects while accounting for the effect of maximum BMI, and also evaluated SNP-BMI interactions. A joint test of main and interaction effects demonstrated significant evidence of association at the genome-wide level with rs12772424 in an intron of TCF7L2 (P=2.85E-8). This SNP exhibited interaction effects, indicating that the bipolar susceptibility risk of this SNP is dependent on BMI. TCF7L2 codes for the transcription factor TCF/LF, part of the Wnt canonical pathway, and is one of the strongest genetic risk variants for type 2 diabetes (T2D). This is consistent with BD pathophysiology, as the Wnt pathway has crucial implications in neurodevelopment, neurogenesis and neuroplasticity, and is involved in the mechanisms of action of BD and depression treatments. We hypothesize that genetic risk for BD is BMI dependent, possibly related to common genetic risk with T2D.

Background: Bipolar disorder (BD) is a highly heritable disease. While genome-wide association (GWA) studies have identified several genetic risk factors for BD, few of these studies have investigated the genetic etiology of specific disease subtypes. In particular, BD is positively associated with eating dysregulation traits such as binge eating behavior (BE), yet the genetic risk factors underlying BD with comorbid BE have not been investigated., Methods: Utilizing data from the Genetic Association Information Network study of BD, which included 729,454 single nucleotide polymorphisms (SNPs) genotyped in 1001 European American bipolar cases and 1034 controls, we performed GWA analyses of bipolar subtypes defined by the presence or absence of BE history, and performed a case-only analysis comparing BD subjects with and without BE history. Association signals were refined using imputation, and network analysis was performed with Ingenuity Pathway Analysis software. Based on these results, candidate SNPs were selected for replication in an independent sample of 855 cases and 857 controls., Results: Top ranking SNPs in the discovery set included rs6006893 in PRR5, rs17045162 in ANK2, rs13233490 near PER4, rs4665788 and rs10198175 downstream of APOB, rs2367911 in CACNA2D1, and rs7249968 near ZNF536. Rs10198175 in APOB also demonstrated evidence of association in the replication sample and a meta-analysis of the two samples., Limitations: Without information of BE history in controls, it is not possible to determine whether the observed association with APOB reflects a risk factor for BE behavior in general or a risk factor for a subtype of BD with BE. Further longitudinal and functional studies are needed to determine the causal pathways underlying the observed associations., Conclusions: This study identified new potential BD-susceptibility genes, highlighting the advantages of phenotypic sub-classification in genetic research and clinical practice., (Copyright © 2014 Elsevier B.V. All rights reserved.)