A genome-wide linkage study of bipolar disorder and co-morbid migraine: replication of migraine linkage on chromosome 4q24, and suggestion of an overlapping susceptibility region for both disorders on chromosome 20p11

Risk of major mental disorders in the offspring of parents with migraine

BACKGROUND

Migraine has been associated with mental disorders, however whether parental migraine is associated with an increased risk of major mental disorders (MMDs) in offspring has not been investigated. We aimed to examine the risk of the development of MMDs in the offspring of parents with migraine compared with those of parents without migraine.

METHODS

This study used data derived from the Taiwan National Health Insurance Research Database. Offspring of parents with migraine and a control group consisting of offspring of parents without migraine matched for demographic and parental mental disorders were included. Cox regression was used to estimate the risk of MMDs, including schizophrenia, depressive disorder, bipolar disorder, autistic spectrum disorder (ASD), and attention deficit/hyperactivity disorder (ADHD). Sub-analyses stratified by the fathers and mothers were further performed to separately clarify the risks of MMDs among the offspring.

RESULTS

We included 22,747 offspring of parents with migraine and 227,470 offspring of parents without migraine as the controls. Parental migraine was significantly associated with an increased risk of ADHD (reported as hazard ratios with 95% confidence intervals: 1.37, 1.25-1.50), bipolar disorder (1.35, 1.06-1.71), and depressive disorder (1.33, 1.21-1.47) compared to the offspring of parents without migraine. Importantly, sub-analyses showed that only maternal migraine was significantly associated with these risks.

CONCLUSIONS

Due to the heavy burden of MMDs, healthcare workers should be aware of the risk of MMDs in the offspring of parents with migraine, particular in mothers.

A population-health approach to characterizing migraine by comorbidity: Results from the Mindfulness and Migraine Cohort Study

BACKGROUND

The heterogeneity of migraine has been reported extensively, with identified subgroups usually based on symptoms. Grouping individuals with migraine and similar comorbidity profiles has been suggested, however such segmentation methods have not been tested using real-world clinical data.

OBJECTIVE

To gain insights into natural groupings of patients with migraine using latent class analysis based on electronic health record-determined comorbidities.

METHODS

Retrospective electronic health record data analysis of primary-care patients at Sutter Health, a large open healthcare system in Northern California, USA. We identified migraine patients over a five-year time period (2015-2019) and extracted 29 comorbidities. We then applied latent class analysis to identify comorbidity-based natural subgroups.

RESULTS

We identified 95,563 patients with migraine and found seven latent classes, summarized by their predominant comorbidities and population share: fewest comorbidities (61.8%), psychiatric (18.3%), some comorbidities (10.0%), most comorbidities - no cardiovascular (3.6%), vascular (3.1%), autoimmune/joint/pain (2.2%), and most comorbidities (1.0%). We found minimal demographic differences across classes.

CONCLUSION

Our study found groupings of migraine patients based on comorbidity that have the potential to be used to guide targeted treatment strategies and the development of new therapies.

Lithium use associated with symptom severity in comorbid bipolar disorder I and migraine

INTRODUCTION

Bipolar disorder (BD) and migraine headaches are frequently comorbid. The common etiological features are unknown, however cortical hyperexcitability (EEG) of migraines, and the report of hyperexcitability in pluripotent stem cell-derived neurons from lithium responsive BD subjects offers a physiological hypothesis of excitable neurons linking these disorders. However, clinical studies suggest that a history of migraine is associated with higher rates of relapse in those with BD taking lithium. Lithium use and history of migraine in this prospective longitudinal study of BD find that lithium use is associated with a greater symptom severity in BD.

METHODS

Data on longitudinal outcome from 538 patients with BD I were categorized according to treatment with lithium and comorbidity with migraine. Clinical outcome measures on depression, mania, and quality of life over the most recent 2-year period compared the BD and BD/migraine cohort according to lithium treatment status.

RESULTS

A history of migraines was associated with worse clinical outcomes of depression (p = .002), mania (p = .005), and mental and physical quality of life (p = .004 and p = .005, respectively), independent of lithium use. The BD/migraine cohort treated with lithium was associated with worse symptoms of mania, whereas those without migraine and lithium use were associated with milder manic symptoms (p = .026).

CONCLUSIONS

Herein, we replicate the relatively worse outcome in BD with comorbid migraine. We find evidence to suggest that lithium use is associated with more severe symptoms of mania among those with BD and a history of migraine and conclude that lithium is contraindicated in BD comorbid with migraine.

Markedly increased prevalence of migraine headaches in adolescents with bipolar disorder

OBJECTIVE

There is substantial evidence of increased prevalence of migraines, and negative psychiatric correlates of migraines, in adults with bipolar disorder (BD). Given the paucity of data on this topic in youth, we investigated the prevalence and correlates of migraine in a large sample of adolescents with BD.

METHOD

The study included 165 adolescents with BD-I, -II, or -not otherwise specified (NOS), diagnosed via the KSADS-PL semi-structured interview, and 89 healthy controls (HCs). Non-migraine headache and migraine headache was evaluated using the validated ID-Migraine 3-item screener.

RESULTS

Although the prevalence of non-migraine headaches did not differ between adolescents with BD (24.2%) and HCs (32.6%; P = .15), migraine was significantly more prevalent among adolescents with BD (38.2%) compared to HCs (3.4%; adjusted odds ratio 14.76, 95% confidence interval 4.39-49.57; P < .001). Within BD, migraine was associated with female sex, BD-II/-NOS subtype, less severe worst past functioning, higher past depression severity, higher self-reported affective lability, higher body mass index, and less use of lithium and second-generation antipsychotics.

DISCUSSION

Migraine is much more prevalent among adolescents with BD compared to HCs; the magnitude of this association exceeds what has been reported in adult samples. Correlates of migraine in youth BD are similar to those found for adults, including the link with the depressive polarity of BD. Future prospective studies are warranted to evaluate temporal associations between migraine and mood symptoms, and to evaluate neurobiological and cardiovascular underpinnings of these associations.

Financial Stress Interacts With CLOCK Gene to Affect Migraine

Previous studies suggested that both maladaptive stress response and circadian dysregulation might have a role in the background of migraine. However, effects of circadian genes on migraine have not been tested yet. In the present study, we investigated the main effect of rs10462028 of the circadian locomotor output cycles kaput (CLOCK) gene and its interaction with different stress factors on migraine. In our cross-sectional study 2,157 subjects recruited from Manchester and Budapest completed the ID-Migraine questionnaire to detect migraine type headaches (migraineID). Additional stress factors were assessed by a shortened version of the Childhood Trauma Questionnaire, the List of Threatening Experiences questionnaire, and a validated questionnaire to identify financial difficulties. Rs10462028 showed no main genetic effect on migraineID. However, chronic stress indexed by financial difficulties showed a significant interaction effect with rs10462028 (p = 0.006 in recessive model) on migraineID. This result remained significant after correction for lifetime bipolar and unipolar depression and was replicated in both subsamples, although only a trend effect was reached after Bonferroni-correction, which is the strictest correction not considering interdependences. Childhood adversity (CHA) and Recent negative life events (RLE) showed no significant gene × stress interaction with rs10462028. In addition, in silico analysis demonstrated that the genetic region tagged by rs10462028 alters the binding of several miRNAs. Our exploratory study suggests that variations in the CLOCK gene, with moderating effect on gene function through miRNA binding, in interaction with financial difficulties might influence the risk of migraine-type headaches. Thus, financial hardship as a chronic stress factor may affect migraine through altering circadian rhythms.

Comorbid Bipolar Disorder and Migraine: From Mechanisms to Treatment

Bipolar disorder (BD) is a severe psychiatric disorder characterized by recurrent episodes of manic/hypomanic or depressive symptoms and euthymic periods, with some patients suffering a gradual deterioration of illness and consequent cognitive deficits during the late stage. Migraine is a disease generally without abnormal medical examinations, neurological examinations or laboratory studies, and the diagnosis is made based on the retrospective demonstration of headache features and groupings of disease-associated symptoms. The epidemiology of comorbid BD and migraine is high and it is obligatory to find effective treatments to improve the prognosis. Recent investigations demonstrated that the close relationship between BD and migraine significantly increased the rapid cycling rates of both BD and migraine in patients. Although the detailed mechanism is complex and largely unclear in comorbid BD and migrain, genetic factors, neurotransmitters, altered signaling pathways, disturbances of inflammatory cytokines, and mitochondrial dysfunction are risk factors of BD and migraine. Particularly these two diseases share some overlapping mechanisms according to previous studies. To this end, we call for further investigations of the potential mechanisms, and more efforts are underway to improve the treatment of people with comorbid BD and migraine. In this review, we provide an overview of the potential mechanisms in patients with BD or migraine and we further discuss the treatment strategies for comorbid BD and migraine and it is obligatory to find effective treatments to improve the prognosis. This work will provide insights for us to know more about the mechanisms of comorbid BD and migraine, provides new therapeutic targets for the treatment and give clinicians some guidance for more appropriate and beneficial treatment.

Understanding the nature of psychiatric comorbidity in migraine: a systematic review focused on interactions and treatment implications

BACKGROUND

Migraine is a highly prevalent and disabling neurological disorder which is commonly linked with a broad range of psychiatric comorbidities, especially among subjects with migraine with aura or chronic migraine. Defining the exact nature of the association between migraine and psychiatric disorders and bringing out the pathophysiological mechanisms underlying the comorbidity with psychiatric conditions are relevant issues in the clinical practice.

METHODS

A systematic review of the most relevant studies about migraine and psychiatric comorbidity was performed using "PubMed", "Scopus", and "ScienceDirect" electronic databases from 1 January 1998 to 15 July 2018. Overall, 178 studies met our inclusion criteria and were included in the current review.

RESULTS

According to the most relevant findings of our overview, the associations with psychiatric comorbidities are complex, with a bidirectional association of major depression and panic disorder with migraine. Importantly, optimizing the pharmacological and non-pharmacological treatment of either migraine or its psychiatric comorbidities might help clinicians to attenuate the burden of both these conditions.

CONCLUSIONS

The available data highlight the need for a comprehensive evaluation of psychiatric disorders in migraine in order to promote an integrated model of care and carefully address the burden and psychosocial impairment related to psychiatric comorbidities in migraine.

Parental and comorbid migraine in individuals with bipolar disorder: A nationwide register study

BACKGROUND

Genetic studies imply a shared genetic etiology between bipolar disorder (BD) and migraine. Epidemiological studies have demonstrated elevated comorbidity between these disorders, but haven't controlled for parental psychopathology. No previous nationally representative studies exist on familial clustering of BD and migraine. This study examines the association between parental and comorbid migraine and BD, controlling for potential confounders.

METHODS

We identified 1861 cases aged ≤25 years, 3643 matched controls, and their parents from Finnish national registers. Conditional logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs) and two-sided significance limits of p<0.05.

RESULTS

Parental migraine, controlling for parental BD, was associated with offspring BD diagnosed at age ≥18 years (OR 1.52, 95%CI: 1.08-2.14). Associations between BD and comorbid migraine persisted following adjustment for parental BD and parental migraine in all subjects (OR=2.46, 95% CI: 1.76-3.42), both age groups of BD-diagnosis (<18 years,≥18 years) and both sexes.

LIMITATIONS

The diagnoses were register-based, not directly ascertained.

CONCLUSIONS

This study indicates that parental migraine, even in the absence of parental BD, is a risk factor for offspring BD. Thus, a genetic link between BD and migraine could potentially explain some of the elevated comorbidity between these disorders. However, BD shows a stronger association with comorbid migraine than with parental migraine, suggesting that much of the elevated comorbidity is related to non-genetic factors. Increased understanding of mechanisms underlying the comorbidity of BD and migraine is important since it is associated with poorer health-related outcomes compared with BD alone.

Migraine headache and bipolar disorder comorbidity: A systematic review of the literature and clinical implications

BACKGROUND AND AIMS

Psychiatric disorders, e.g., depression, are often comorbid with, and can complicate the treatment of, patients with migraine headache. Although empirical work has increasingly focused on the association between migraine and bipolar disorder, this topic has received little attention in the pain literature. Bipolar disorder is a chronic and recurrent mood disorder characterized by cyclic occurrence of elevated (i.e., manic or hypomanic) and depressed mood states. Bipolar I disorder is diagnosed when patients present with at least one abnormally and persistently elevated manic episode; bipolar II disorder is characterized by the presence of hypomanic episodes. Bipolar disorder warrants attention as depressive phases of the disorder can prevail and are often misconstrued by the unwary clinician as unipolar depression. However, treatment for bipolar disorder is distinct from that of unipolar depression and use of antidepressants, which are often invoked in migraine prophylaxis as well as the treatment of depression, may precipitate significant mood changes among bipolar disorder patients. A systematic review of the literature addressing the co-occurrence of bipolar disorder and migraine was conducted. The treatment of dually affected patients is also discussed.

METHODS

In order to review the literature to date on migraine and bipolar disorder co-occurrence, a comprehensive search of MEDLINE, EMBASE, PubMed, PsycINFO, Web of Science, and CINAHL for clinic-based and epidemiological studies was conducted using terms related to migraine and bipolar disorder. Studies were selected for review if they included subjects meeting validated diagnostic criteria for bipolar disorder as well as migraine headache and if a quantitative description of prevalence rates of comorbid bipolar disorder and migraine were reported. Weighted means of the prevalence rates were calculated to compare with general epidemiological prevalence trends for migraine and bipolar disorder, respectively.

RESULTS

Eleven studies met inclusion criteria. Although findings were constrained by methodological limitations and several low quality studies, clinic- and epidemiological cross-sectional investigations demonstrated a high rate of comorbidity between bipolar disorder and migraine. The weighted mean prevalence rate for migraine headache among bipolar disorder patients was 30.7%; for bipolar disorder among migraineurs, the weighted mean prevalence rates were 9% and 5.9% in clinic-based and epidemiological studies, respectively. The association between bipolar disorder and migraine was most notable among women and patients with the bipolar II disorder subtype.

CONCLUSIONS

High rates of comorbidity exist between migraine and bipolar disorder, exceeding estimated prevalence rates for those conditions in the general population. Comorbidity may portend a more serious clinical course for dually afflicted individuals.

IMPLICATIONS

Clinicians need to structure treatment approaches to address concurrent migraine and bipolar disorder in dually afflicted individuals. Although further evidence-based investigation is warranted to inform optimal treatment approaches for both conditions concurrently, anticonvulsants (e.g., valproate, lamotrigine and topiramate); atypical antipsychotics (e.g., olanzapine or quetiapine); and calcium channel blockers (e.g., verapamil) may be considered.

MOLECULAR GENETIC STUDIES OF COMORBIDITY

This review focuses at the problem of the genetic basis of comorbidity. We discuss the concepts and terms relating to combinations of diseases. The guidelines of the study of comorbidity using modern high throughput methods and approaches of genetics, molecular biology and bioinformatics are designated. In this review we present results of studies showing genetic specificity for the combined phenotypes dif-ferent from the isolated disease, we considergene-gene and gene-environment interactions in comorbidity. We also discuss the role of single nucleotide polymorphisms and structural genome variations in the development of comorbidity. Own results of researching shared genes of inversely comorbid diseases like as bronchial asthma and tuberculosis are presented.

Rapid cycling as a feature of bipolar disorder and comorbid migraine

BACKGROUND

Previous research has suggested the clinical profile of individuals with bipolar disorder (BD) differs according to the presence or absence of comorbid migraine. We aimed to determine the clinical characteristics that differentiate individuals with BD with and without comorbid migraine in a large, representative, clinically well-characterised UK sample.

METHODS

The lifetime clinical characteristics of 1488 individuals with BD (BPI n=1120, BPII n=368) with and without comorbid migraine were compared (n=375 vs. n=1113 respectively).

RESULTS

Individuals with BD and comorbid migraine had a distinctive set of lifetime clinical characteristics. A multivariate model showed that consistent with previous studies those with comorbid migraine were significantly more likely to be female (OR=2.099, p=0.005) and have comorbid panic attacks (OR=1.842, p=0.004). A novel finding was that even after controlling for other differences, the individuals with BD and comorbid migraine were more likely to have a rapid cycling illness course (OR=1.888, p=0.002).

LIMITATIONS

Presence of migraine was assessed using self report measures. Cross-sectional study design limits investigations of bidirectional associations between migraine and bipolar disorder.

CONCLUSIONS

Comorbid migraine in BD may represent a more homogenous subtype of BD with an unstable rapid cycling course. Identifying individuals with BD and comorbid migraine may be of use in a clinical setting and this subgroup could be the focus of future aetiological studies.

Genetic influences on response to novel objects and dimensions of personality in Papio baboons

Behavioral variation within and between populations and species of the genus Papio has been studied extensively, but little is known about the genetic causes of individual- or population-level differences. This study investigates the influence of genetic variation on personality (sometimes referred to as temperament) in baboons and identifies a candidate gene partially responsible for the variation in that phenotype. To accomplish these goals, we examined individual variation in response to both novel objects and an apparent novel social partner (using a mirror test) among pedigreed baboons (n = 578) from the Southwest National Primate Research Center. We investigated the frequency and duration of individual behaviors in response to novel objects and used multivariate factor analysis to identify trait-like dimensions of personality. Exploratory factor analysis identified two distinct dimensions of personality within this population. Factor 1 accounts for 46.8 % of the variance within the behavioral matrix, and consists primarily of behaviors related to the "boldness" of the subject. Factor 2 accounts for 18.8 % of the variation, and contains several "anxiety" like behaviors. Several specific behaviors, and the two personality factors, were significantly heritable, with the factors showing higher heritability than most individual behaviors. Subsequent analyses show that the behavioral reactions observed in the test protocol are associated with animals' social behavior observed later in their home social groups. Finally we used linkage analysis to map quantitative trait loci for the measured phenotypes. Single nucleotide polymorphisms in a positional candidate gene (SNAP25) are associated with variation in one of the personality factors, and CSF levels of homovanillic acid and 3-methoxy-4-hydroxyphenylglycol. This study documents heritable variation in personality among baboons and suggests that sequence variation in SNAP25 may influence differences in behavior and neurochemistry in these nonhuman primates.

Somatic and cognitive symptoms as indicators of potential endophenotypes in bipolar spectrum disorders: an exploratory and proof-of-concept study comparing bipolar II disorder with recurrent brief depression and healthy controls

BACKGROUND

We examined whether somatic symptoms reported by patients with bipolar spectrum disorder (BSD), in this study defined as bipolar II (BD-2) or recurrent brief depression with (RBD-H) or without (RBD-O) a history of hypomanic symptoms might point to the possible underlying disease markers (endophenotypes). We hypothesized that somatic symptoms that are possible indirect indicators of endophenotypes should be more prevalent among patients than among healthy controls; should not correlate with neuroticism; should not correlate with the severity of current mental status (e.g., anxiety, depression); and should not correlate with the use of psychotropic drugs including antiepileptics or be explained by co-morbid medical diseases.

METHODS

Sixty-one patients (BD-2: n=21; RBD-H: n=19; RBD-O: n=21) were compared with 21 healthy controls. Assessments included a 123-item somatic symptom checklist; assessments for neuroticism, anxiety and depression. Candidate somatic symptoms were selected using a 4-step inclusion/exclusion procedure.

RESULTS

Seven symptoms survived in all three groups: general (fatigue, feeling exhausted); sensory (leaden sensation in legs, pain in the body, impaired sense of smell); cognitive (loss of memory) and autonomic (excessive perspiration). In addition 15 symptoms survived in one or two groups (examples: impaired hearing, hypersensitivity to sound, inability to find words).

LIMITATIONS

Possible selection bias and small sample size precludes firm conclusions with regards to specific symptoms.

CONCLUSION

Our approach identified symptoms for which an association with BSDs has been suggested previously, as well as symptoms not commonly associated with BSDs. The findings support the feasibility and validity of using assessment of somatic symptoms as an approach to identify potential endophenotypes in BSDs.

Studies on the pathophysiology and genetic basis of migraine

Migraine is a neurological disorder that affects the central nervous system causing painful attacks of headache. A genetic vulnerability and exposure to environmental triggers can influence the migraine phenotype. Migraine interferes in many facets of people's daily life including employment commitments and their ability to look after their families resulting in a reduced quality of life. Identification of the biological processes that underlie this relatively common affliction has been difficult because migraine does not have any clearly identifiable pathology or structural lesion detectable by current medical technology. Theories to explain the symptoms of migraine have focused on the physiological mechanisms involved in the various phases of headache and include the vascular and neurogenic theories. In relation to migraine pathophysiology the trigeminovascular system and cortical spreading depression have also been implicated with supporting evidence from imaging studies and animal models. The objective of current research is to better understand the pathways and mechanisms involved in causing pain and headache to be able to target interventions. The genetic component of migraine has been teased apart using linkage studies and both candidate gene and genome-wide association studies, in family and case-control cohorts. Genomic regions that increase individual risk to migraine have been identified in neurological, vascular and hormonal pathways. This review discusses knowledge of the pathophysiology and genetic basis of migraine with the latest scientific evidence from genetic studies.

Migraine genes and the relation to gender

Migraine is an episodic brain disorder that is characterized by recurrent attacks of severe unilateral headache that are accompanied by various neurological symptoms. In addition, many patients have what is called an aura with visual and sensory disturbances. The majority of patients are female, suggesting that female hormones play an important role in the pathophysiology of the disorder. The molecular mechanisms, however, underlying this female preponderance are not well understood. It can be expected that the field of genetics that aims at identifying genetic factors that cause migraine by lowering the threshold for attacks will unravel some of these mechanisms. The 3 best known migraine genes encode ion transporters and were identified in families with familial hemiplegic migraine (FHM), a rare subtype of migraine with aura. FHM gene mutations cause alterations in mechanisms that control and modulate the neurotransmitter balance in the brain. Transgenic mice knock-in with human pathogenic mutations that were shown to exhibit some migraine-relevant features were very helpful in dissecting molecular mechanisms of migraine and pointed to a central role for cortical glutamate. In addition, transgenic mice that overexpress human RAMP1 exist and exhibit an increased sensitivity to calcitonin gene-related peptide. Findings from genetic and animal experiments on gender differences in migraine are discussed. Recently, a role for glutamate also came forward from a genome-wide association study in common migraine. By deciphering genetic and pathogenic migraine pathways, it can be expected that in the near future we will better understand mechanisms behind the female preponderance in migraine.

Prevalence, correlates, comorbidity and severity of bipolar disorder: results from the Singapore Mental Health Study

BACKGROUND

Bipolar disorder (BPD) is a serious mental disorder and a leading cause of premature mortality worldwide. Prevalence and risk factors of BPD have not been well studied in multi-ethnic Asian populations. The study aimed to establish the prevalence of BPD and examine the associated socio-demographic correlates, comorbidity, severity, impairment and treatment contact in the Singapore resident population.

METHODS

The Singapore Mental Health Study was a cross-sectional epidemiological survey of a nationally representative sample of the resident (citizens and permanent residents) population in Singapore. The diagnoses were established using the World Mental Health Composite International Diagnostic Interview version 3.0 (CIDI 3.0) diagnostic modules for lifetime and 12-month prevalence of select mental illnesses including BPD.

RESULTS

The lifetime and 12-month prevalence estimates for BPD were 1.2% and 0.6%, respectively. More than two-thirds (69.4%) of respondents with lifetime BPD had other lifetime mental disorders, and approximately half (52.6%) of respondents with lifetime BPD also had at least one chronic physical condition; chronic pain was the most prevalent comorbid condition.

LIMITATIONS

The data was based on respondents' self-report and there could be an element of recall bias and under-reporting. We also did not obtain information on mixed episodes and rapid cycling disorders.

CONCLUSIONS

The high comorbidity, clinical severity, and role impairment associated with BPD exert a heavy toll at an individual and societal level.

A bivariate mann-whitney approach for unraveling genetic variants and interactions contributing to comorbidity

Although comorbidity among complex diseases (e.g., drug dependence syndromes) is well documented, genetic variants contributing to the comorbidity are still largely unknown. The discovery of genetic variants and their interactions contributing to comorbidity will likely shed light on underlying pathophysiological and etiological processes, and promote effective treatments for comorbid conditions. For this reason, studies to discover genetic variants that foster the development of comorbidity represent high-priority research projects, as manifested in the behavioral genetics studies now underway. The yield from these studies can be enhanced by adopting novel statistical approaches, with the capacity of considering multiple genetic variants and possible interactions. For this purpose, we propose a bivariate Mann-Whitney (BMW) approach to unravel genetic variants and interactions contributing to comorbidity, as well as those unique to each comorbid condition. Through simulations, we found BMW outperformed two commonly adopted approaches in a variety of underlying disease and comorbidity models. We further applied BMW to datasets from the Study of Addiction: Genetics and Environment, investigating the contribution of 184 known nicotine dependence (ND) and alcohol dependence (AD) single nucleotide polymorphisms (SNPs) to the comorbidity of ND and AD. The analysis revealed a candidate SNP from CHRNA5, rs16969968, associated with both ND and AD, and replicated the findings in an independent dataset with a P-value of 1.06 × 10(-03) .

Genetic variants affecting the neural processing of human facial expressions: evidence using a genome-wide functional imaging approach

Human faces present crucial visual information for social interaction. Specialized brain regions are involved in the perception of faces, with the fusiform face area (FFA) a key neuronal substrate. Face processing is genetically controlled, but by which specific genes is unknown. A genome-wide approach identified common single nucleotide polymorphisms (SNPs) associated with areas of increased brain activity in response to affective facial expressions, measured with functional magnetic resonance imaging. SNPs in 20 genetic regions were linked with neural responses to negative facial expressions in a Norwegian sample (n=246), which included patients with mental illness. Three genetic regions were linked with FFA activation in a further discovery experiment using positive facial expressions and involving many of the same individuals (n=284). Two of these three regions showed significant association with right FFA activation to negative facial expressions in an independent North American replication sample of healthy Caucasians (n=85, 3q26.31, P=0.004; 20p12.3, P=0.045). The activation patterns were particularly striking for the SNP in 3q26.31, which lies in a gene TMEM212; only the FFA was activated. The specialized function of this brain region suggests that TMEM212 could contribute to the innate architecture of face processing.

Bipolar affective disorder and migraine

This paper consists of a case history and an overview of the relationship, aetiology, and treatment of comorbid bipolar disorder migraine patients. A MEDLINE literature search was used. Terms for the search were bipolar disorder bipolar depression, mania, migraine, mood stabilizer. Bipolar disorder and migraine cooccur at a relatively high rate. Bipolar II patients seem to have a higher risk of comorbid migraine than bipolar I patients have. The literature on the common roots of migraine and bipolar disorder, including both genetic and neuropathological approaches, is broadly discussed. Moreover, bipolar disorder and migraine are often combined with a variety of other affective disorders, and, furthermore, behavioural factors also play a role in the origin and course of the diseases. Approach to treatment options is also difficult. Several papers point out possible remedies, for example, valproate, topiramate, which acts on both diseases, but no first-choice treatments have been agreed upon yet.

Comprehensive gene-based association study of a chromosome 20 linked region implicates novel risk loci for depressive symptoms in psychotic illness

BACKGROUND

Prior genomewide scans of schizophrenia support evidence of linkage to regions of chromosome 20. However, association analyses have yet to provide support for any etiologically relevant variants.

METHODS

We analyzed 2988 LD-tagging single nucleotide polymorphisms (SNPs) in 327 genes on chromosome 20, to test for association with schizophrenia in 270 Irish high-density families (ISHDSF, N = 270 families, 1408 subjects). These SNPs were genotyped using an Illumina iSelect genotyping array which employs the Infinium assay. Given a previous report of novel linkage with chromosome 20p using latent classes of psychotic illness in this sample, association analysis was also conducted for each of five factor-derived scores based on the Operational Criteria Checklist for Psychotic Illness (delusions, hallucinations, mania, depression, and negative symptoms). Tests of association were conducted using the PDTPHASE and QPDTPHASE packages of UNPHASED. Empirical estimates of gene-wise significance were obtained by adaptive permutation of a) the smallest observed P-value and b) the threshold-truncated product of P-values for each locus.

RESULTS

While no single variant was significant after LD-corrected Bonferroni-correction, our gene-dropping analyses identified loci which exceeded empirical significance criteria for both gene-based tests. Namely, R3HDML and C20orf39 are significantly associated with depressive symptoms of schizophrenia (P(emp)<2×10⁻⁵) based on the minimum P-value and truncated-product methods, respectively.

CONCLUSIONS

Using a gene-based approach to family-based association, R3HDML and C20orf39 were found to be significantly associated with clinical dimensions of schizophrenia. These findings demonstrate the efficacy of gene-based analysis and support previous evidence that chromosome 20 may harbor schizophrenia susceptibility or modifier loci.

White matter hyperintensities: from medical comorbidities to bipolar disorders and back

White matter hyperintensities (WMHs) are among the most replicated neuroimaging findings in studies of patients with bipolar disorders (BD). Despite the high rates of WMHs, their role and etiology in BD are not well understood. WMHs occur in multiple other conditions frequently co-morbid with BD. From the available studies it seems that WMHs are not a primary risk factor/endophenotype for BD. More likely, these lesions indicate the presence of medical co-morbidities with specific links to BD. Furthermore, the etiology of the WMHs in BD may represent different processes depending on age. In certain forms of BD, such as pediatric BD, WMHs may represent co-morbidity with developmental disorders. High frequency of migraine in BD and high prevalence of WMHs in migraine may suggest that a substantial proportion of WMHs in early adulthood to midlife BD subjects may be related to co-morbidity with migraine. Among elderly subjects with BD, or those with late-onset BD, WMHs are likely related to the presence of cardiovascular/metabolic disorders. With further research WMHs may enhance our knowledge about various pathological pathways involved in BD, help in decreasing the etiological heterogeneity of BD, and become useful as markers of severity or subtype of BD.

Are migraine and bipolar disorders comorbid phenomena?: findings from a pharmacoepidemiological study using the Norwegian Prescription Database

OBJECTIVES

Clinical, epidemiological, and, recently, genome-wide linkage and genome-wide association studies suggest migraine and bipolar disorder are comorbid phenomena. The objective of this study was to determine whether there is also evidence that this comorbidity exists by virtue of there being a positive relationship between the prescription of medications used to treat migraine and mood-stabilizing agents using the National Norwegian Prescription Database.

METHODS

Data allowing ascertainment of the concurrence of prescriptions for migraine and mood-stabilizing agents were gleaned from the Norwegian Prescription Database for calendar year 2006, covering the total population (N = 4,640,219). Results were obtained using logistic regression analyses and were expressed by odds ratios (ORs).

RESULTS

A total of 81,225 persons (1.8% of the population) received medications for migraine and 19,517 (0.45%) received a mood-stabilizing agent for a bipolar disorder; 843 persons received both types of medications. The OR expressing the relationship between the concurrent use of both categories of medications was 2.55 (95% confidence interval [CI], 2.38-2.73, P < 0.001, z score = 26.44), significant for all mood stabilizers (lithium: OR = 1.82 [95% CI, 1.58-2.10], P < 0.001, z score = 8.31; carbamazepine: OR = 2.48 [95% CI, 2.01-3.06], P < 0.001, z score = 8.42; valproic acid: OR = 2.26 [95% CI, 1.89-2.70], P < 0.001, z score = 8.96; and lamotrigine: OR = 3.50 [95% CI, 3.14-3.90], P < 0.001, z score = 22.68). The association was significantly higher for men (OR = 3.16 [95% CI, 2.74-3.66], P < 0.001, z score = 15.53) than for women (OR = 2.21 [95% CI, 2.04-2.39], P < 0.001, z score = 19.61) and was most pronounced in younger age groups and for lamotrigine.

CONCLUSIONS

There was a strong positive association between the prescription of medications used to treat migraine and mood-stabilizing agents. This is compatible with the hypothesis that migraine and bipolar disorders are associated with one another.

Meta-analysis of genome-wide association for migraine in six population-based European cohorts

Migraine is a common neurological disorder with a genetically complex background. This paper describes a meta-analysis of genome-wide association (GWA) studies on migraine, performed by the Dutch–Icelandic migraine genetics (DICE) consortium, which brings together six population-based European migraine cohorts with a total sample size of 10 980 individuals (2446 cases and 8534 controls). A total of 32 SNPs showed marginal evidence for association at a P-value<10⁻⁵. The best result was obtained for SNP rs9908234, which had a P-value of 8.00 × 10⁻⁸. This top SNP is located in the nerve growth factor receptor (NGFR) gene. However, this SNP did not replicate in three cohorts from the Netherlands and Australia. Of the other 31 SNPs, 18 SNPs were tested in two replication cohorts, but none replicated. In addition, we explored previously identified candidate genes in the meta-analysis data set. This revealed a modest gene-based significant association between migraine and the metadherin (MTDH) gene, previously identified in the first clinic-based GWA study (GWAS) for migraine (Bonferroni-corrected gene-based P-value=0.026). This finding is consistent with the involvement of the glutamate pathway in migraine. Additional research is necessary to further confirm the involvement of glutamate.

No association between bipolar disorder risk polymorphisms in ANK3 and CACNA1C and common migraine

BACKGROUND

Migraine and bipolar disorder are characterized by a high level of co-morbidity, and a common familial-genetic basis has recently been hypothesized for the 2 disorders. Genome-wide association studies have reported strong evidence of association between the polymorphisms rs10994336[T] in the ANK3 gene and rs1006737[A] in the CACNA1C gene and risk of bipolar disorder.

OBJECTIVE

The aim of this study was to evaluate the hypothesis of a genetic linkage between migraine and bipolar disorder by investigating the familial transmission of the 2 bipolar disorder risk polymorphisms, in a sample of family trios with probands with childhood migraine, and unrelated controls.

METHODS

Our sample comprised 192 family trios, each with a proband with childhood migraine (137 migraine without aura, 44 migraine with aura) and 228 unrelated controls. The markers rs10994336 and rs1006737 were genotyped using a TaqMan single nucleotide polymorphism Genotyping Assay. The transmission disequilibrium test analysis for the family trios and the case-control analysis were performed using the program UNPHASED.

RESULTS

The allelic and genotypic transmission disequilibrium test analysis did not show any evidence of transmission distortion of the 2 markers in both migraine overall (rs10994336: OR = 1.61, P = .11; rs1006737: OR = 1.12, P = .49) and in the migraine without aura and migraine with aura subgroups. Likewise, the case-control analysis of alleles and genotypes frequencies did not show any evidence of association.

CONCLUSION

In the present study, we did not find evidence for association between the bipolar disorder risk polymorphisms rs10994336 in the ANK3 gene and rs1006737 in the CACNA1C gene in migraine. However, as these are variants that have a small effect on the risk of bipolar disorder (OR < 1.5), we cannot exclude a similar small effect on migraine susceptibility with the present sample size.

A pharmaco-epidemiological study of migraine and antidepressant medications: complete one year data from the Norwegian population

BACKGROUND

Migraine, depression and anxiety disorders have been associated with one another in several epidemiological studies. However, it is not known if or how these associations are reflected in the concurrent use of medications for migraine and depressive/anxiety disorders in the general population. The purpose of the present study was to identify groups of patients particularly likely to receive clinical treatment for both conditions.

METHODS

Data from the Norwegian Prescription Database for 2006 were analysed for the purpose of ascertaining concurrence of prescriptions for migraine and depression/anxiety disorders. Data were subjected to analysis testing deviation from unity for the OR performed by a chi-square test.

RESULTS

In the total Norwegian population (N=4,640,219) migraine drugs were prescribed to 81,225 persons (1.8% of the population), antidepressant drugs to 257,700 persons (5.6% of the population), and 11,269 persons were prescribed both types of drugs. The prescription of antidepressants was significantly increased in patients receiving a prescription for a medication used to treat migraine (OR=2.82 (95% CI=2.76-2.88); chi-square p<0.001), and this association was stronger for men than for women. Teenage women carried the highest risk for this co-morbid constellation (OR=3.89 CI=3.17-4.77); chi-square p<0.001).

CONCLUSION

This study revealed a strong positive association between the prescription of migraine and antidepressant medications, and this association was generally most pronounced in men. However, teenage girls carried the highest risk of receiving both kinds of prescriptions, suggesting particular attentiveness is required in the clinical management of these patients.

Adult attention deficit hyperactivity disorder is associated with migraine headaches

Attention deficit hyperactivity disorder (ADHD) is now recognized as a common disorder both in child and adult psychiatry. Adult patients with a diagnosis of ADHD (n = 572) and community controls (n = 675) responded to auto-questionnaires rating past and present symptoms of ADHD, co-morbid conditions, including migraine, treatment history and work status. The prevalence of migraine was significantly higher in the patient group compared to the controls (28.3% vs. 19.2%, P < 0.001, OR = 1.67, CI 1.28-2.17). The difference from controls was particularly marked for men (22.5% vs. 10.7%, P < 0.001, OR = 2.43, CI 1.51-3.90) but was also significant for women (34.4% vs. 24.9%, P = 0.008, OR = 1.58, CI 1.13-2.21). In both patients and controls, migraine was associated with symptoms of mood and anxiety disorders. These findings point to a co-morbidity of migraine with ADHD, and it is possible that these patients represent a clinical and biological subgroup of adult patients with ADHD.

A genome-wide association study of bipolar disorder and comorbid migraine

Both migraine and bipolar affective disorder (BPAD) are complex phenotypes with significant genetic and nongenetic components. Epidemiological and clinical studies have showed a high degree of comorbidity between migraine and BPAD, and overlapping regions of linkage have been shown in numerous genome-wide linkage studies. To identify susceptibility factors for the BPAD/migraine phenotype, we conducted a genome-wide association study (GWAS) in 1001 cases with bipolar disorder collected through the NIMH Genetics Initiative for Bipolar Disorder and genotyped at 1 m single-nucleotide polymorphisms (SNPs) as part of the Genetic Association Information Network (GAIN). We compared BPAD patients without any headache (n = 699) with BPAD patients with doctor diagnosed migraine (n = 56). The strongest evidence for association was found for several SNPs in a 317-kb region encompassing the uncharacterized geneKIAA0564 {e.g. rs9566845 [OR = 4.98 (95% CI: 2.6-9.48), P = 7.7 × 10(-8)] and rs9566867 (P = 8.2 × 10(-8))}. Although the level of significance was significantly reduced when using the Fisher's exact test (as a result of the low count of cases with migraine), rs9566845 P = 1.4 × 10(-5) and rs9566867 P = 1.5 × 10(-5), this region remained the most prominent finding. Furthermore, marker rs9566845 was genotyped and found associated with migraine in an independent Norwegian sample of adult attention deficit hyperactivity disorder (ADHD) patients with and without comorbid migraine (n = 131 and n = 324, respectively), OR = 2.42 (1.18-4.97), P = 0.013. This is the first GWAS examining patients with bipolar disorder and comorbid migraine. These data suggest that genetic variants in the KIAA0564 gene region may predispose to migraine headaches in subgroups of patients with both BPAD and ADHD.

Cross-prevalence of migraine and bipolar disorder

OBJECTIVE

In two related studies, we explored the prevalence of migraine and its associated clinical characteristics in patients with bipolar disorder (BD) as well as psychiatric morbidity in patients treated for migraine.

METHOD

The first study included 323 subjects with BD type I (BD I) or BD type II (BD II), diagnosed using the Schedule for Affective Disorders and Schizophrenia, Lifetime version (SADS-L) format, or the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID). Migraine history was assessed by means of a structured questionnaire. In a second sample of 102 migraine patients, we investigated current and lifetime psychiatric morbidity using the SADS-L. Statistical analyses were conducted using nonparametric analysis and log-linear models.

RESULTS

A total of 24.5% of BD patients had comorbid migraine; those with BD II had a higher prevalence (34.8%) compared to BD I (19.1%) (p < 0.005). BD patients with comorbid migraine had significantly higher rates of suicidal behaviour, social phobia, panic disorder, generalized anxiety disorder, and obsessive-compulsive disorder (all p < 0.05). In the sample of migraine patients, 34.3% had a current psychiatric diagnosis, and 73.5% had a lifetime psychiatric diagnosis. The prevalence of BD I was 4.9%, and 7.8% for BD II.

DISCUSSION

Migraine is prevalent within the BD population, particularly among BD II subjects. It is associated with an increased risk of suicidal behaviour and comorbid anxiety disorders. Conversely, migraine sufferers have high rates of current and lifetime psychopathology. A greater understanding of this comorbidity may contribute to our knowledge of the underlying mechanisms of BD.