ABSTRACT
OBJECTIVE: To investigate external factors that trigger manic and hypomanic relapses and how this is associated with personality and clinical outcome measured as number of affective episodes over a 7-year period. METHOD: This is a prospective cohort study of 204 meticulously characterized Swedish bipolar disorder patients. Personality was evaluated at baseline using the Swedish universities Scales of Personality in 170 patients, and 90 patients were followed up after approximately 7 years in order to evaluate clinical outcomes. RESULTS: We found that 44% of the patients reported trigger factors, including sleep disturbance, work- or family-related issues, medication, and illicit drug use. There were no significant differences in any of the personality traits when comparing the 74 patients that reported triggers with the 90 patients that did not. At 7-year follow-up, there was no difference between the groups in number of affective episodes (depressive, hypomanic, manic, or mixed), involuntary commitments, suicide attempts, or self-harm incidents since baseline. CONCLUSIONS: Around 40% of the patients reported external triggers for manic and hypomanic episodes. However, this was neither associated with personality traits nor number of affective episodes at 7-year follow-up.
Subject(s)
Bipolar Disorder/psychology , Mania/etiology , Mania/psychology , Personality , Adult , Female , Humans , Male , Prognosis , Prospective Studies , SwedenABSTRACT
Major mood disorders, which primarily include bipolar disorder and major depressive disorder, are the leading cause of disability worldwide and pose a major challenge in identifying robust risk genes. Here, we present data from independent large-scale clinical data sets (including 29 557 cases and 32 056 controls) revealing brain expressed protocadherin 17 (PCDH17) as a susceptibility gene for major mood disorders. Single-nucleotide polymorphisms (SNPs) spanning the PCDH17 region are significantly associated with major mood disorders; subjects carrying the risk allele showed impaired cognitive abilities, increased vulnerable personality features, decreased amygdala volume and altered amygdala function as compared with non-carriers. The risk allele predicted higher transcriptional levels of PCDH17 mRNA in postmortem brain samples, which is consistent with increased gene expression in patients with bipolar disorder compared with healthy subjects. Further, overexpression of PCDH17 in primary cortical neurons revealed significantly decreased spine density and abnormal dendritic morphology compared with control groups, which again is consistent with the clinical observations of reduced numbers of dendritic spines in the brains of patients with major mood disorders. Given that synaptic spines are dynamic structures which regulate neuronal plasticity and have crucial roles in myriad brain functions, this study reveals a potential underlying biological mechanism of a novel risk gene for major mood disorders involved in synaptic function and related intermediate phenotypes.
Subject(s)
Cadherins/genetics , Mood Disorders/genetics , Adult , Amygdala/physiopathology , Bipolar Disorder/genetics , Brain/physiopathology , Cadherins/metabolism , Cognition/physiology , Dendrites , Dendritic Spines , Depressive Disorder, Major/genetics , Female , Genetic Predisposition to Disease/genetics , Genotype , Humans , Male , Middle Aged , Neuronal Plasticity , Neurons , Personality/genetics , Polymorphism, Single Nucleotide/genetics , Risk Factors , Synapses/genetics , Synapses/metabolismABSTRACT
OBJECTIVE: Electroconvulsive therapy (ECT) is used in patients with severe forms of bipolar depression. ECT is effective but not all patients respond. The aim of this study was to determine prognostic factors for response to ECT in patients hospitalized for bipolar depression. METHODS: Data were obtained from several national Swedish registers. All patients with bipolar depression treated with ECT in any hospital in Sweden between 2011 and 2016 for whom information about ECT response was available were included (n = 1251). Response was defined as a score on the Clinical Global Impression - Improvement scale of one or two. Univariate and multivariate logistic regression were conducted to investigate associations between socio-demographic and clinical factors and response. RESULTS: Response was achieved in 80.2% patients. Older age was associated with higher response rate to ECT. Patients with comorbid obsessive-compulsive disorder or personality disorder, and patients previously treated with lamotrigine had lower response rate. CONCLUSION: Electroconvulsive therapy for bipolar depression was associated with very high response rates. The strongest prognostic factors were higher age, absence of comorbid obsessive-compulsive disorder or personality disorder, and less prior pharmacologic treatment.
Subject(s)
Bipolar Disorder/therapy , Electroconvulsive Therapy , Outcome Assessment, Health Care , Registries , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Prognosis , Sweden , Young AdultABSTRACT
This corrects the article DOI: 10.1038/mp.2015.165.
ABSTRACT
OBJECTIVE: Bipolar disorder carries a high risk of suicide. Identification of risk factors is important. The aim of this study was to study risk factors for suicide in a large cohort of men and women with bipolar disorder. METHOD: A prospective cohort study using clinical data from the Swedish National Quality Register for Bipolar Affective Disorder (BipoläR). The outcome variable was suicide captured in the Cause of Death Register between 2004 and 2014. Hazard ratios (HR) were calculated using Cox proportional hazards models. RESULTS: Of 12 850 persons (4844 men and 8006 women) with bipolar disorder, 90 (55 men and 35 women) died by suicide during the follow-up period (between 1 and 10 years). Male sex (HR 2.56), living alone (HR 2.45), previous suicide attempts (HR 4.10), comorbid psychiatric disorder (HR 2.64), recent affective episodes (HR 2.39), criminal conviction (HR 4.43), psychiatric inpatient care (HR 2.79), and involuntary commitment (HR 3.50) were significant risk factors for suicide. Several of the statistically significant risk factors for suicide in bipolar disorder differed between men and women. CONCLUSIONS: Risk factors for suicide in bipolar disorder include factors associated with suicide in general, but also diagnosis-specific factors.
Subject(s)
Bipolar Disorder/epidemiology , Commitment of Mentally Ill/statistics & numerical data , Hospitalization/statistics & numerical data , Hospitals, Psychiatric/statistics & numerical data , Mental Disorders/epidemiology , Registries/statistics & numerical data , Suicide/statistics & numerical data , Adult , Aged , Comorbidity , Female , Humans , Longitudinal Studies , Male , Middle Aged , Risk Factors , Sex Factors , Suicide, Attempted/statistics & numerical data , Sweden/epidemiologyABSTRACT
OBJECTIVE: Frontal cortical abnormalities and executive function impairment co-occur in bipolar disorder. Recent studies have shown that bipolar subtypes differ in the degree of structural and functional impairments. The relationships between cognitive performance and cortical integrity have not been clarified and might differ across patients with bipolar disorder type I, II, and healthy subjects. METHOD: Using a vertex-wise whole-brain analysis, we investigated how cortical integrity, as measured by cortical thickness, correlates with executive performance in patients with bipolar disorder type I, II, and controls (N = 160). RESULTS: We found focal associations between executive function and cortical thickness in the medial prefrontal cortex in bipolar II patients and controls, but not in bipolar I disorder. In bipolar II patients, we observed additional correlations in lateral prefrontal and occipital regions. CONCLUSIONS: Our findings suggest that bipolar disorder patients show altered structure-function relationships, and importantly that those relationships may differ between bipolar subtypes. The findings are line with studies suggesting subtype-specific neurobiological and cognitive profiles. This study contributes to a better understanding of brain structure-function relationships in bipolar disorder and gives important insights into the neuropathophysiology of diagnostic subtypes.
Subject(s)
Bipolar Disorder , Cognitive Dysfunction , Executive Function/physiology , Prefrontal Cortex , Adult , Bipolar Disorder/classification , Bipolar Disorder/complications , Bipolar Disorder/pathology , Bipolar Disorder/physiopathology , Cognitive Dysfunction/etiology , Cognitive Dysfunction/pathology , Cognitive Dysfunction/physiopathology , Cross-Sectional Studies , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Prefrontal Cortex/diagnostic imaging , Prefrontal Cortex/pathology , Prefrontal Cortex/physiopathologyABSTRACT
BACKGROUND: Advanced paternal age at childbirth is associated with psychiatric disorders in offspring, including schizophrenia, bipolar disorder and autism. However, few studies have investigated paternal age's relationship with eating disorders in offspring. In a large, population-based cohort, we examined the association between paternal age and offspring eating disorders, and whether that association remains after adjustment for potential confounders (e.g. parental education level) that may be related to late/early selection into fatherhood and to eating disorder incidence. METHOD: Data for 2 276 809 individuals born in Sweden 1979-2001 were extracted from Swedish population and healthcare registers. The authors used Cox proportional hazards models to examine the effect of paternal age on the first incidence of healthcare-recorded anorexia nervosa (AN) and all eating disorders (AED) occurring 1987-2009. Models were adjusted for sex, birth order, maternal age at childbirth, and maternal and paternal covariates including country of birth, highest education level, and lifetime psychiatric and criminal history. RESULTS: Even after adjustment for covariates including maternal age, advanced paternal age was associated with increased risk, and younger paternal age with decreased risk, of AN and AED. For example, the fully adjusted hazard ratio for the 45+ years (v. the 25-29 years) paternal age category was 1.32 [95% confidence interval (CI) 1.14-1.53] for AN and 1.26 (95% CI 1.13-1.40) for AED. CONCLUSIONS: In this large, population-based cohort, paternal age at childbirth was positively associated with eating disorders in offspring, even after adjustment for potential confounders. Future research should further explore potential explanations for the association, including de novo mutations in the paternal germline.
Subject(s)
Feeding and Eating Disorders/epidemiology , Paternal Age , Registries/statistics & numerical data , Adolescent , Adult , Cohort Studies , Feeding and Eating Disorders/etiology , Female , Humans , Male , Middle Aged , Proportional Hazards Models , Sweden/epidemiology , Young AdultABSTRACT
Although evidence for mitochondrial dysfunction in the pathogenesis of bipolar disorder (BD) has been reported, the precise biological basis remains unknown, hampering the search for novel biomarkers. In this study, we performed metabolomics of cerebrospinal fluid (CSF) from male BD patients (n=54) and age-matched male healthy controls (n=40). Subsequently, post-mortem brain analyses, genetic analyses, metabolomics of CSF samples from rats treated with lithium or valproic acid were also performed. After multivariate logistic regression, isocitric acid (isocitrate) levels were significantly higher in the CSF from BD patients than healthy controls. Furthermore, gene expression of two subtypes (IDH3A and IDH3B) of isocitrate dehydrogenase (IDH) in the dorsolateral prefrontal cortex from BD patients was significantly lower than that of controls, although the expression of other genes including, aconitase (ACO1, ACO2), IDH1, IDH2 and IDH3G, were not altered. Moreover, protein expression of IDH3A in the cerebellum from BD patients was higher than that of controls. Genetic analyses showed that IDH genes (IDH1, IDH2, IDH3A, IDH3B) and ACO genes (ACO1, ACO2) were not associated with BD. Chronic (4 weeks) treatment with lithium or valproic acid in rats did not alter CSF levels of isocitrate, and mRNA levels of Idh3a, Idh3b, Aco1 and Aco2 genes in the rat brain. These findings suggest that abnormality in the metabolism of isocitrate by IDH3A in the mitochondria plays a key role in the pathogenesis of BD, supporting the mitochondrial dysfunction hypothesis of BD. Therefore, IDH3 in the citric acid cycle could potentially be a novel therapeutic target for BD.
Subject(s)
Bipolar Disorder/metabolism , Isocitrate Dehydrogenase/metabolism , Adult , Animals , Bipolar Disorder/cerebrospinal fluid , Brain/metabolism , Gene Expression/genetics , Humans , Isocitrate Dehydrogenase/cerebrospinal fluid , Isocitrates/metabolism , Male , Metabolomics/methods , Mitochondria/metabolism , RatsABSTRACT
Elevated cerebrospinal fluid (CSF) levels of the glia-derived N-methyl-D-aspartic acid receptor antagonist kynurenic acid (KYNA) have consistently been implicated in schizophrenia and bipolar disorder. Here, we conducted a genome-wide association study based on CSF KYNA in bipolar disorder and found support for an association with a common variant within 1p21.3. After replication in an independent cohort, we linked this genetic variant-associated with reduced SNX7 expression-to positive psychotic symptoms and executive function deficits in bipolar disorder. A series of post-mortem brain tissue and in vitro experiments suggested SNX7 downregulation to result in a caspase-8-driven activation of interleukin-1ß and a subsequent induction of the brain kynurenine pathway. The current study demonstrates the potential of using biomarkers in genetic studies of psychiatric disorders, and may help to identify novel drug targets in bipolar disorder.
Subject(s)
Bipolar Disorder/genetics , Kynurenic Acid/metabolism , Psychotic Disorders/genetics , Adult , Aged , Bipolar Disorder/cerebrospinal fluid , Bipolar Disorder/metabolism , Brain/metabolism , Chromosomes, Human, Pair 1/genetics , Cognition Disorders/complications , Cognitive Dysfunction/genetics , Cognitive Dysfunction/metabolism , Female , Genome-Wide Association Study , Humans , Kynurenic Acid/cerebrospinal fluid , Male , Middle Aged , Psychotic Disorders/complications , Psychotic Disorders/metabolism , Sorting Nexins/geneticsABSTRACT
Considerable uncertainty exists about the defining brain changes associated with bipolar disorder (BD). Understanding and quantifying the sources of uncertainty can help generate novel clinical hypotheses about etiology and assist in the development of biomarkers for indexing disease progression and prognosis. Here we were interested in quantifying case-control differences in intracranial volume (ICV) and each of eight subcortical brain measures: nucleus accumbens, amygdala, caudate, hippocampus, globus pallidus, putamen, thalamus, lateral ventricles. In a large study of 1710 BD patients and 2594 healthy controls, we found consistent volumetric reductions in BD patients for mean hippocampus (Cohen's d=-0.232; P=3.50 × 10-7) and thalamus (d=-0.148; P=4.27 × 10-3) and enlarged lateral ventricles (d=-0.260; P=3.93 × 10-5) in patients. No significant effect of age at illness onset was detected. Stratifying patients based on clinical subtype (BD type I or type II) revealed that BDI patients had significantly larger lateral ventricles and smaller hippocampus and amygdala than controls. However, when comparing BDI and BDII patients directly, we did not detect any significant differences in brain volume. This likely represents similar etiology between BD subtype classifications. Exploratory analyses revealed significantly larger thalamic volumes in patients taking lithium compared with patients not taking lithium. We detected no significant differences between BDII patients and controls in the largest such comparison to date. Findings in this study should be interpreted with caution and with careful consideration of the limitations inherent to meta-analyzed neuroimaging comparisons.
Subject(s)
Bipolar Disorder/physiopathology , Brain/physiopathology , Adult , Brain/anatomy & histology , Case-Control Studies , Female , Humans , Magnetic Resonance Imaging/methods , Male , Middle Aged , Organ Size/physiology , Retrospective StudiesABSTRACT
Lithium is the mainstay prophylactic treatment for bipolar disorder (BD), but treatment response varies considerably across individuals. Patients who respond well to lithium treatment might represent a relatively homogeneous subtype of this genetically and phenotypically diverse disorder. Here, we performed genome-wide association studies (GWAS) to identify (i) specific genetic variations influencing lithium response and (ii) genetic variants associated with risk for lithium-responsive BD. Patients with BD and controls were recruited from Sweden and the United Kingdom. GWAS were performed on 2698 patients with subjectively defined (self-reported) lithium response and 1176 patients with objectively defined (clinically documented) lithium response. We next conducted GWAS comparing lithium responders with healthy controls (1639 subjective responders and 8899 controls; 323 objective responders and 6684 controls). Meta-analyses of Swedish and UK results revealed no significant associations with lithium response within the bipolar subjects. However, when comparing lithium-responsive patients with controls, two imputed markers attained genome-wide significant associations, among which one was validated in confirmatory genotyping (rs116323614, P=2.74 × 10(-8)). It is an intronic single-nucleotide polymorphism (SNP) on chromosome 2q31.2 in the gene SEC14 and spectrin domains 1 (SESTD1), which encodes a protein involved in regulation of phospholipids. Phospholipids have been strongly implicated as lithium treatment targets. Furthermore, we estimated the proportion of variance for lithium-responsive BD explained by common variants ('SNP heritability') as 0.25 and 0.29 using two definitions of lithium response. Our results revealed a genetic variant in SESTD1 associated with risk for lithium-responsive BD, suggesting that the understanding of BD etiology could be furthered by focusing on this subtype of BD.
Subject(s)
Bipolar Disorder/genetics , Carrier Proteins/genetics , Adult , Antimanic Agents/therapeutic use , Biomarkers, Pharmacological/blood , Bipolar Disorder/metabolism , Carrier Proteins/metabolism , Female , Genetic Predisposition to Disease/genetics , Genetic Variation , Genome-Wide Association Study/methods , Genotype , Humans , Lithium/metabolism , Lithium/therapeutic use , Lithium Compounds/therapeutic use , Male , Middle Aged , Polymorphism, Single Nucleotide/genetics , Risk Factors , Self Report , Sweden , United KingdomABSTRACT
OBJECTIVE: Our aim was to investigate the prevalence and magnitude of weight gain in-patients with bipolar disorder when treated with a second-generation antipsychotic as an add-on treatment to a mood stabilizer in routine clinical practice. METHODS: Data were derived from the quality register for bipolar disorder in Sweden (BipoläR). Patients with bipolar disorder who started add-on treatment with a SGA (n = 575) were compared at next yearly follow-up with age and sex matched patients who were only treated with a mood stabilizer (n = 566). The primary outcome measure was change in body weight and body mass index (BMI). We also assessed the prevalence of clinically significant weight gain defined as ≥7% gain in body weight. RESULTS: The group that received add-on treatment with antipsychotics neither gained more weight nor were at higher risk for a clinically significant weight gain than the reference group. Instead, factors associated with clinically significant weight gain were female sex, young age, low-baseline BMI, and occurrence of manic/hypomanic episodes. CONCLUSION: We found no evidence of an overall increased risk of weight gain for patients with bipolar disorder after receiving add-on SGA to a mood stabilizer in a routine clinical setting.
Subject(s)
Antipsychotic Agents/adverse effects , Bipolar Disorder/drug therapy , Weight Gain/drug effects , Antipsychotic Agents/administration & dosage , Antipsychotic Agents/therapeutic use , Body Mass Index , Case-Control Studies , Drug Therapy, Combination/adverse effects , Female , Humans , Male , Middle AgedABSTRACT
OBJECTIVE: To confirm prior findings that the larger the maximum monthly increase in solar insolation in springtime, the younger the age of onset of bipolar disorder. METHOD: Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density. RESULTS: There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001). CONCLUSION: A large increase in springtime solar insolation may impact the onset of bipolar disorder, especially with a family history of mood disorders. Recent societal changes that affect light exposure (LED lighting, mobile devices backlit with LEDs) may influence adaptability to a springtime circadian challenge.
Subject(s)
Bipolar Disorder/epidemiology , Electromagnetic Radiation , Internationality , Seasons , Adolescent , Adult , Africa/epidemiology , Age of Onset , Asia/epidemiology , Australia/epidemiology , Europe/epidemiology , Female , Humans , Male , Middle Aged , North America/epidemiology , Solar System , South America/epidemiology , Sunlight , Young AdultABSTRACT
BACKGROUND: The concept of cognitive reserve (CR) hypothesizes that intellectually stimulating activities provide resilience against brain pathology/disease. Whereas brain abnormalities and cognitive impairment are frequently reported in bipolar disorder (BD), it is unknown whether the impact of brain alterations can be lessened by higher CR in BD. METHOD: We tested if higher CR would reduce the influence of total volumes of deep white matter hypointensities (WMH), ventricular cerebrospinal fluid (CSF), and prefrontal cortex on memory, executive, and attention/speed functions in patients with BD (n = 75). Linear regression models with interaction terms for CR and brain volumes were applied to directly test if CR reduces the influence of brain pathology on cognitive domains. RESULTS: CR reduced the influence of total volumes of deep WMH (ß = -0.38, Q = 0.003) and ventricular CSF (ß = -41, Q = 006) on executive functions. CONCLUSIONS: The interactions between CR and total volumes of deep WMH/ventricular CSF appear to account for executive functioning in BD. The results suggest that the concept of CR is applicable in BD. Higher reserve capacity in BD alters the relationship between brain pathology and clinical presentation.
Subject(s)
Bipolar Disorder/psychology , Brain/diagnostic imaging , Cerebrospinal Fluid/diagnostic imaging , Cognitive Dysfunction/psychology , Cognitive Reserve , Prefrontal Cortex/diagnostic imaging , White Matter/diagnostic imaging , Adult , Attention/physiology , Bipolar Disorder/diagnostic imaging , Bipolar Disorder/physiopathology , Brain/pathology , Case-Control Studies , Cognitive Dysfunction/diagnostic imaging , Cognitive Dysfunction/physiopathology , Executive Function , Female , Humans , Linear Models , Magnetic Resonance Imaging , Male , Memory/physiology , Middle Aged , Organ Size , Prefrontal Cortex/pathology , Reaction Time , White Matter/pathology , Young AdultABSTRACT
BACKGROUND: Major depressive disorder (MDD) is moderately heritable, however genome-wide association studies (GWAS) for MDD, as well as for related continuous outcomes, have not shown consistent results. Attempts to elucidate the genetic basis of MDD may be hindered by heterogeneity in diagnosis. The Center for Epidemiological Studies Depression (CES-D) scale provides a widely used tool for measuring depressive symptoms clustered in four different domains which can be combined together into a total score but also can be analysed as separate symptom domains. METHOD: We performed a meta-analysis of GWAS of the CES-D symptom clusters. We recruited 12 cohorts with the 20- or 10-item CES-D scale (32 528 persons). RESULTS: One single nucleotide polymorphism (SNP), rs713224, located near the brain-expressed melatonin receptor (MTNR1A) gene, was associated with the somatic complaints domain of depression symptoms, with borderline genome-wide significance (p discovery = 3.82 × 10-8). The SNP was analysed in an additional five cohorts comprising the replication sample (6813 persons). However, the association was not consistent among the replication sample (p discovery+replication = 1.10 × 10-6) with evidence of heterogeneity. CONCLUSIONS: Despite the effort to harmonize the phenotypes across cohorts and participants, our study is still underpowered to detect consistent association for depression, even by means of symptom classification. On the contrary, the SNP-based heritability and co-heritability estimation results suggest that a very minor part of the variation could be captured by GWAS, explaining the reason of sparse findings.
Subject(s)
Depression/genetics , Depressive Disorder, Major/genetics , Receptor, Melatonin, MT1/genetics , Somatoform Disorders/genetics , Depression/physiopathology , Depression/psychology , Depressive Disorder, Major/physiopathology , Depressive Disorder, Major/psychology , Genome-Wide Association Study , Humans , Polymorphism, Single Nucleotide , Somatoform Disorders/physiopathology , Somatoform Disorders/psychologyABSTRACT
Historically, American Indian/Alaska Native (AI/AN) populations have suffered excess morbidity and mortality from influenza. We investigated the risk factors for death from 2009 pandemic influenza A(H1N1) in persons residing in five states with substantial AI/AN populations. We conducted a case-control investigation using pandemic influenza fatalities from 2009 in Alaska, Arizona, New Mexico, Oklahoma and Wyoming. Controls were outpatients with influenza. We reviewed medical records and interviewed case proxies and controls. We used multiple imputation to predict missing data and multivariable conditional logistic regression to determine risk factors. We included 145 fatal cases and 236 controls; 22% of cases were AI/AN. Risk factors (P 45 years vs. <18 years], pre-existing medical conditions (mOR 7·1), smoking (mOR 3·0), delayed receipt of antivirals (mOR 6·5), and barriers to healthcare access (mOR 5·3). AI/AN race was not significantly associated with death. The increased influenza mortality in AI/AN individuals was due to factors other than racial status. Prevention of influenza deaths should focus on modifiable factors (smoking, early antiviral use, access to care) and identifying high-risk persons for immunization and prompt medical attention.
Subject(s)
Influenza A Virus, H1N1 Subtype/physiology , Influenza, Human/mortality , Pandemics , Adolescent , Adult , Aged , Case-Control Studies , Child , Child, Preschool , Humans , Indians, North American , Infant , Infant, Newborn , Influenza, Human/virology , Middle Aged , Risk Factors , United States/epidemiology , Young AdultABSTRACT
The kynurenine pathway metabolite kynurenic acid (KYNA), modulating glutamatergic and cholinergic neurotransmission, is increased in cerebrospinal fluid (CSF) of patients with schizophrenia or bipolar disorder type 1 with psychotic features. KYNA production is critically dependent on kynurenine 3-monooxygenase (KMO). KMO mRNA levels and activity in prefrontal cortex (PFC) are reduced in schizophrenia. We hypothesized that KMO expression in PFC would be reduced in bipolar disorder with psychotic features and that a functional genetic variant of KMO would associate with this disease, CSF KYNA level and KMO expression. KMO mRNA levels were reduced in PFC of bipolar disorder patients with lifetime psychotic features (P=0.005, n=19) or schizophrenia (P=0.02, n=36) compared with nonpsychotic patients and controls. KMO genetic association to psychotic features in bipolar disorder type 1 was studied in 493 patients and 1044 controls from Sweden. The KMO Arg(452) allele was associated with psychotic features during manic episodes (P=0.003). KMO Arg(452) was studied for association to CSF KYNA levels in an independent sample of 55 Swedish patients, and to KMO expression in 717 lymphoblastoid cell lines and 138 hippocampal biopsies. KMO Arg(452) associated with increased levels of CSF KYNA (P=0.03) and reduced lymphoblastoid and hippocampal KMO expression (P≤0.05). Thus, findings from five independent cohorts suggest that genetic variation in KMO influences the risk for psychotic features in mania of bipolar disorder patients. This provides a possible mechanism for the previous findings of elevated CSF KYNA levels in those bipolar patients with lifetime psychotic features and positive association between KYNA levels and number of manic episodes.
Subject(s)
Bipolar Disorder/genetics , Bipolar Disorder/metabolism , Kynurenic Acid/cerebrospinal fluid , Kynurenine 3-Monooxygenase/biosynthesis , Kynurenine 3-Monooxygenase/genetics , Psychotic Disorders/genetics , Psychotic Disorders/metabolism , Adult , Aged , Alleles , Bipolar Disorder/complications , Bipolar Disorder/diagnosis , Case-Control Studies , Cell Line , Female , Gene Expression , Genetic Predisposition to Disease/genetics , Hippocampus/metabolism , Humans , Male , Middle Aged , Prefrontal Cortex/metabolism , Psychotic Disorders/complications , Schizophrenia/cerebrospinal fluid , Schizophrenia/metabolism , Young AdultABSTRACT
Bipolar disorder (BD) is a polygenic disorder that shares substantial genetic risk factors with major depressive disorder (MDD). Genetic analyses have reported numerous BD susceptibility genes, while some variants, such as single-nucleotide polymorphisms (SNPs) in CACNA1C have been successfully replicated, many others have not and subsequently their effects on the intermediate phenotypes cannot be verified. Here, we studied the MDD-related gene CREB1 in a set of independent BD sample groups of European ancestry (a total of 64,888 subjects) and identified multiple SNPs significantly associated with BD (the most significant being SNP rs6785[A], P=6.32 × 10(-5), odds ratio (OR)=1.090). Risk SNPs were then subjected to further analyses in healthy Europeans for intermediate phenotypes of BD, including hippocampal volume, hippocampal function and cognitive performance. Our results showed that the risk SNPs were significantly associated with hippocampal volume and hippocampal function, with the risk alleles showing a decreased hippocampal volume and diminished activation of the left hippocampus, adding further evidence for their involvement in BD susceptibility. We also found the risk SNPs were strongly associated with CREB1 expression in lymphoblastoid cells (P<0.005) and the prefrontal cortex (P<1.0 × 10(-6)). Remarkably, population genetic analysis indicated that CREB1 displayed striking differences in allele frequencies between continental populations, and the risk alleles were completely absent in East Asian populations. We demonstrated that the regional prevalence of the CREB1 risk alleles in Europeans is likely caused by genetic hitchhiking due to natural selection acting on a nearby gene. Our results suggest that differential population histories due to natural selection on regional populations may lead to genetic heterogeneity of susceptibility to complex diseases, such as BD, and explain inconsistencies in detecting the genetic markers of these diseases among different ethnic populations.
Subject(s)
Bipolar Disorder/ethnology , Bipolar Disorder/genetics , Cyclic AMP Response Element-Binding Protein/genetics , Gene Expression Regulation/genetics , Genetic Predisposition to Disease , Hippocampus/pathology , Polymorphism, Single Nucleotide/genetics , Adult , Age Factors , Aged , Aged, 80 and over , Asian People/genetics , Case-Control Studies , Computational Biology , Female , Gene Frequency/genetics , Genetic Association Studies , Humans , Male , Middle Aged , Neuroimaging , Neuropsychological Tests , Phenotype , RNA, Messenger/metabolism , White People/geneticsABSTRACT
BACKGROUND: Darier disease is an autosomal dominant skin disorder caused by mutations in the ATP2A2 gene. Anecdotal reports suggest a relationship between Darier disease and intellectual disabilities, but these reports are based on small clinical samples and limited by absence of control populations. OBJECTIVES: To examine the risk of intellectual disability and subclinical impairments in cognitive ability in Darier disease. METHODS: We conducted a matched cohort study based on Swedish Population-, Patient- and Conscript Registers. The risk of being diagnosed with intellectual disability was estimated in 770 individuals with Darier disease, compared with matched comparison individuals without Darier disease. Associations were examined with risk ratios from conditional logistic regressions. In addition, we analysed test-based cognitive ability data (i.e. IQ data) from the Swedish conscript examination, for a subset of patients without diagnosed intellectual disability. RESULTS: Individuals with Darier disease had a sixfold increased risk of being diagnosed with intellectual disability (risk ratio 6.2, 95% confidence interval 3.1-12.4). For conscripted individuals with Darier disease but no diagnosed intellectual disability, mean cognitive ability scores were about half a standard deviation lower than for comparison subjects. CONCLUSIONS: Darier disease is associated with intellectual disability and subclinical impairments in cognitive ability. The Darier-causing mutations merit further attention in molecular genetic research on intellectual disability and cognitive ability.
Subject(s)
Cognition Disorders/etiology , Darier Disease/psychology , Intellectual Disability/etiology , Adolescent , Cognition Disorders/epidemiology , Darier Disease/epidemiology , Genetic Markers , Genotype , Humans , Intellectual Disability/epidemiology , Male , Risk Factors , Sarcoplasmic Reticulum Calcium-Transporting ATPases/genetics , Sweden/epidemiology , Young AdultABSTRACT
OBJECTIVE: To investigate whether persons with bipolar disorder and their siblings have leadership traits and are overrepresented in executive professions. METHOD: A nested case-control study based on longitudinal Swedish total population registries. Data from officer suitability interviews (n=1,126,519), and information on occupations were collected. Bipolar patients (n=68,915) and their healthy siblings were compared with controls. RESULTS: Bipolar patients without comorbidity (pure; n=22,980) were overrepresented in both the highest and lowest strata of officer suitability; their healthy siblings in the highest strata only. Patients with pure bipolar disorder were underrepresented in executive professions, whereas their siblings were overrepresented in these professions (particularly political professions). Patients with general bipolar disorder (including those with comorbidities) and their healthy siblings were overrepresented only in the lowest strata of officer suitability ratings. General bipolar patients were underrepresented in executive professions, whereas their siblings had similar rates of executive professions as controls. Adjusting results for IQ slightly attenuated point estimates, but resulted in pure bipolar patients and their siblings no longer being significantly overrepresented in superior strata of officer suitability, and siblings no longer being overrepresented in executive professions. CONCLUSION: Results support that traits associated with bipolar disorder are linked to superior leadership qualities.