The Croatian version of diagnostic interview for genetic studies

Diagnostic Interview for Genetic Studies (DIGS) is a modern structured interview schedule that has been in use since 1994. Main purpose of the DIGS is to record information regarding to a subject's functioning and psychopathology and it was specifically designed for psychiatric genetic studies. The DIGS is also suitable for making diagnosis, evaluation of comorbidity and other researches. It contents items and sections and has a semi-structured design that gives interviewers the freedom needed to extract the best in formation possible. The validity of a Croatian version of the DIGS was investigated. The original English version was initially translated into Croatian. The Croatian version was then back-translated and compared with the original. In this paper we will describe each item that DIGS contents as well as the use of this diagnostic instrument.

Association between depression and anxiety in high-functioning children with autism spectrum disorders and maternal mood symptoms

Research suggests that children with autism spectrum disorders (ASDs) and their relatives have high rates of depression and anxiety. However, relatively few studies have looked at both factors concurrently. This study examined the potential relationship between maternal mood symptoms and depression and anxiety in their children with ASD. Participants were 31 10- to 17-year-old children with an ASD diagnosis that was supported by gold-standard measures and their biological mothers. Mothers completed the Autism Comorbidity Interview to determine whether the child with ASD met criteria for any depressive or anxiety diagnoses and a questionnaire of their own current mood symptoms. As expected, many children with ASD met criteria for lifetime diagnoses of depressive (32%) and anxiety disorders (39%). Mothers' report of their own current mood symptoms revealed averages within the normal range, though there was significant variability. Approximately 75% of children with ASD could be correctly classified as having a depressive or anxiety disorder history or not based on maternal symptoms of interpersonal sensitivity, hostility, phobic anxiety, depression, and anxiety. The results provide preliminary evidence that maternal mood symptoms may be related to depression and anxiety in their children with ASD. Although the design did not allow for testing of heritability per se, the familial transmission patterns were generally consistent with research in typical populations. While larger follow-up studies are needed, this research has implications for prevention and intervention efforts.

The storm and stress of adolescence: insights from human imaging and mouse genetics

The characterization of adolescence as a time of "storm and stress" remains an open debate. Intense and frequent negative affect during this period has been hypothesized to explain the increased rates of affective disorders, suicide, and accidental death during this time of life. Yet some teens emerge from adolescence with minimal turmoil. We provide a neurobiological model of adolescence that proposes an imbalance in the development of subcortical limbic (e.g., amygdala) relative to prefrontal cortical regions as a potential mechanism for heightened emotionality during this period. Empirical support for this model is provided from recent behavioral and human imaging studies on the development of emotion regulation. We then provide examples of environmental factors that may exacerbate imbalances in amygdala-ventrofrontal function increasing risk for anxiety related behaviors. Finally we present data from human and mouse studies to illustrate how genetic factors may enhance or diminish this risk. Together, these studies provide a converging methods approach for understanding the highly variable stress and turmoil experienced in adolescence.

Parental psychiatric hospitalisation and offspring schizophrenia

The risk of schizophrenia has been linked with a family history of schizophrenia and less strongly with other psychiatric disorders in family members. Using data from the Copenhagen Perinatal Cohort and from the Danish Psychiatric Case Register, we studied the relationship between offspring risk of schizophrenia and a range of psychotic and non-psychotic psychiatric diagnoses in parents. Psychiatric admission data after 1969 were available for 7047 cohort members born between 1959 and 1961, and for 7006 mothers and 6993 fathers. Univariate analysis showed that neurosis, alcohol and substance dependence in both parents were associated with elevated risk of offspring schizophrenia; in addition, maternal schizophrenia, affective disorder and personality disorder were associated with elevated risk. Controlling for parental age, parental social status, and parental psychiatric co-diagnosis, offspring risk of schizophrenia was associated with maternal schizophrenia (OR = 15.41 with 95% CI 5.96-39.81) and, independently, with paternal hospitalisation with neurosis (OR = 5.90 with 95% CI 2.23-15.62). The risk of schizophrenia associated with paternal neurosis remained significant after excluding offspring of parents with non-affective psychosis from the sample. These findings suggest that genetic and family studies should not only focus on parental history of schizophrenia since the simple distinction between positive and negative family history could not accurately describe offspring risk in this sample.

Meta-analysis of genome-wide association data identifies a risk locus for major mood disorders on 3p21.1

The major mood disorders, which include bipolar disorder and major depressive disorder (MDD), are considered heritable traits, although previous genetic association studies have had limited success in robustly identifying risk loci. We performed a meta-analysis of five case-control cohorts for major mood disorder, including over 13,600 individuals genotyped on high-density SNP arrays. We identified SNPs at 3p21.1 associated with major mood disorders (rs2251219, P = 3.63 x 10(-8); odds ratio = 0.87; 95% confidence interval, 0.83-0.92), with supportive evidence for association observed in two out of three independent replication cohorts. These results provide an example of a shared genetic susceptibility locus for bipolar disorder and MDD.

The MCP-1 gene (SCYA2) and mood disorders: preliminary results of a case-control association study

The aim of this case-control study was to investigate the potential role of the A-2518G polymorphism of the gene of monocyte chemoattractant protein 1 (MCP-1, a cytokine playing an important role in innate immunity) in conferring susceptibility to mood disorders. The sample studied included 96 outpatients with DSM-IV-TR diagnosis of major depressive disorder, bipolar disorder I (BD I) or BD II and 161 matched healthy controls. All subjects were genotyped for the A-2518G polymorphism of the MCP-1 gene. Genotypic and allelic associations were explored between patients and controls and across the different diagnostic groups (chi(2) tests). No genotypic (chi(2) = 8.215, d.f. = 6, p = 0.223) or allelic (chi(2) = 5.058, d.f. = 3, p = 0.168) association for the A-2518G polymorphism of SCYA2 was found considering cases and controls. Nevertheless, important correlations were observed when patients were divided into diagnostic subgroups. A significantly higher frequency of the AA genotype (chi(2) = 7.233, d.f. = 2, p = 0.027) and of the A allele (chi(2) = 4.730, d.f. = 1, p = 0.030) was observed in subjects with BD. In addition, independently from diagnosis, a higher number of lifetime suicide attempts was found in subjects with the AA genotype of the A-2518G polymorphism of the MCP-1 gene (F = 3.802, p = 0.026). The present preliminary results, though limited by the relatively small sample, suggest a possible role of the SCYA2 in conferring susceptibility to BD and, if confirmed, may represent a biological discriminative influence between mood disorder subtypes.

Circadian rhythms and clock genes in psychotic disorders

Numerous lines of evidence suggest that a disordered circadian system contributes to the etiology and symptomatology of major psychiatric disorders. Sleep disturbances, particularly rapid eye movement (REM) sleep, have been observed in bipolar affective disorder (BPD) and schizophrenia. Therapies aimed at altering the timing and duration of sleep and realigning circadian rhythms, including sleep scheduling, wake extension, light therapy and drug therapies that alter sleep and circadian rhythms appear beneficial for affective disorders. Interventional studies aiming to correct sleep and circadian disturbances in schizophrenia are scarce, although exogenous melatonin has been shown to improve both sleep structure and psychotic symptoms. The study of molecular clock mechanisms in psychiatric disorders is also gaining interest. Genetics studies have found associations with CLOCK, PERIOD1, PERIOD3, and TIMELESS in schizophrenia. Most research on BPD has focused on polymorphisms of CLOCK, but the lithium target GSK-3 may also be significant. New research examining the role of circadian rhythms and clock genes in major mental illness is likely to produce rapid advances in circadian-based therapeutics.

Comorbidity in anxiety disorders

Ever since Feinstein coined the term "comorbidity", referring to the presence of any additional coexisting ailment in a patient with a particular index disease (J Chronic Dis 23:455-468, 1970), aspects of the phenomenon have been extensively studied. The aims of this chapter are: (1) to summarize the evidence of psychiatric comorbidity in anxiety disorders from adult population-based studies; (2) to present findings from the National Comorbidity Survey Replication (NCS-R); (3) to summarize evidence of psychiatric comorbidity in anxiety disorders from child and adolescent population-based samples; (4) to provide a summary of evidence on comorbidity from family and genetic studies; and (5) to examine patterns of comorbidity between anxiety disorders and medical conditions. Throughout each of these aims, implications of the comorbidity are explored, including whether these patterns reflect a need for redefining the disorders or rather an etiologic or even causal path.

The serotonin transporter gene (5-HTT) variant and psychiatric disorders: review of current literature

Both serotonin and the serotonin transporter, which transports the neurotransmitter serotonin from synaptic spaces into presynaptic neurons, play an important role in the pathophysiology of several psychiatric disorders. Mutations associated with the serotonin transporter gene may result in changes in serotonin transporter function. The serotonin transporter gene promoter variant, consisting of a long (L) and a short (S) variant, is one of the major factors which contribute to the etiology of many psychiatric disorders. In this regard, many studies have been published on association of this variant with various psychiatric disorders. This repeat length variant in the promoter region of this gene has been shown to affect the rate of serotonin uptake and may play a role in post-traumatic stress disorder and depression-susceptibility in people experiencing emotional trauma. Associations between a functional variant in the serotonin transporter anxiety-related personality traits were found, as well as the risk of developing depression, alcoholism or suicidal behavior. Understanding of possible associations of these variants and psychiatric disorders would bring progress in principles and treatment of many disorders.

5-HTTLPR polymorphism, mood disorders and MDMA use in a 3-year follow-up study

A 3-year longitudinal prospective study was conducted to compare the incidence of substance use disorders (SUD) and non-substance use disorders (NSUD) among ecstasy users and two control groups: one of cannabis users and the other of non-drug users. The 5-HTTLPR polymorphism related to NSUD was also studied. A total of 94 subjects were included: 37 ecstasy users, 23 cannabis users and 34 non-drug users. SUD and NSUD disorders were diagnosed according to the fourth edition of the Diagnostic and Statistical Manual of Mental Health Disorders criteria using the Psychiatric Research Interview for Substance and Mental Disorders. Incidence Rates (IR) are presented. The 5-HTTLPR polymorphism was analyzed. Hardy-Weinberg equilibrium was studied. The results of the study showed that the highest IR of SUD was cannabis abuse/dependence in both the ecstasy (IR: 48.6/100 person-year) and cannabis (IR: 2.5/100 person-year) groups. There were no new cases of SUD in non-drug users at follow-up. The highest IR of NSUD was primary mood disorder in both the ecstasy (IR: 4.2/100 person-year) and in the non-drug (IR: 1.3/100 person-year) groups (P < 0.282). There were no new cases of NSUD in the cannabis group at follow-up. 5-HTTLPR polymorphism was associated with lifetime of primary mood disorders in ecstasy group (P = 0.018). Ecstasy use was associated with a higher rate of cannabis abuse/dependence disorders and mood disorders than cannabis use. In the ecstasy users, 5-HTTLPR polymorphism may result in a high vulnerability to primary mood disorders.

Interspecies trait genetics reveals association of Adcy8 with mouse avoidance behavior and a human mood disorder

BACKGROUND

Identifying susceptibility genes for endophenotypes by studying analogous behaviors across species is an important strategy for understanding the pathophysiology underlying psychiatric disorders. This approach provides novel biological pathways plus validated animal models critical for selective drug development. One such endophenotype is avoidance behavior.

METHODS

In the present study, novel automated registration methods for longitudinal behavioral assessment in home cages are used to screen a panel of recently generated mouse chromosome substitution strains that are very powerful in quantitative trait loci (QTL) detection of complex traits. In this way, we identified chromosomes regulating avoidance behavior (increased sheltering preference) independent of motor activity levels (horizontal distance moved). Genetic information from the mouse QTL-interval was integrated with that from the homologous human linkage region for a mood disorder.

RESULTS

We genetically mapped a QTL for avoidance behavior on mouse chromosome 15, homologous with a human genome region (8q24) linked to bipolar disorder. Integrating the syntenic mouse QTL-interval with genotypes of 1868 BPD cases versus 14,311 control subjects revealed two associated genes (ADCY8 and KCNQ3). Adenylyl cyclase 8 (Adcy8) was differentially expressed in specific brain regions of mouse strains that differ in avoidance behavior levels. Finally, we showed that chronic infusion of the human mood stabilizer carbamazepine (that acts via adenylyl cyclase activity) significantly reduced mouse avoidance behavior, providing a further link between human mood disorders and this mouse home cage behavior.

CONCLUSIONS

Our data suggest that Adcy8 might encode a translational behavioral endophenotype of bipolar disorder.

Maternal separation alters nerve growth factor and corticosterone levels but not the DNA methylation status of the exon 1(7) glucocorticoid receptor promoter region

Separating rat pups from their mothers during the early stages of life is an animal model commonly used to study the development of psychiatric disorders such as anxiety and depression. The present study investigated how soon after the termination of the maternal separation period behavioural and neuroendocrine abnormalities relevant to above-mentioned illnesses would manifest. Sprague Dawley rat pups were subjected to maternal separation (3 h per day from postnatal day 2 through 14) and their behaviour and HPA axis activity determined 7 d later. We also measured nerve growth factor levels in their hippocampi and assessed the DNA methylation status of the promoter region of exon 1(7) of the glucocorticoid receptor in this brain region. As early as 7 d after the termination of the adverse event, a change in behaviour was observed that was associated with increased plasma corticosterone release and elevated nerve growth factor levels in the hippocampus. No alteration in the methylation status of the exon 1(7) glucocorticoid receptor promoter region was observed. Our data indicate that early life adversity may lead to the rapid development of abnormal behaviours and HPA axis dysregulation though no epigenetic changes to the exon 1(7) glucocorticoid receptor promoter region occurred. We further propose that the observed increased neurotrophin levels reflect compensatory mechanisms that attempt to combat the long-term deleterious effects of maternal separation.

Emotional disorders: cluster 4 of the proposed meta-structure for DSM-V and ICD-11

BACKGROUND

The extant major psychiatric classifications DSM-IV, and ICD-10, are atheoretical and largely descriptive. Although this achieves good reliability, the validity of a medical diagnosis would be greatly enhanced by an understanding of risk factors and clinical manifestations. In an effort to group mental disorders on the basis of aetiology, five clusters have been proposed. This paper considers the validity of the fourth cluster, emotional disorders, within that proposal.

METHOD

We reviewed the literature in relation to 11 validating criteria proposed by a Study Group of the DSM-V Task Force, as applied to the cluster of emotional disorders.

RESULTS

An emotional cluster of disorders identified using the 11 validators is feasible. Negative affectivity is the defining feature of the emotional cluster. Although there are differences between disorders in the remaining validating criteria, there are similarities that support the feasibility of an emotional cluster. Strong intra-cluster co-morbidity may reflect the action of common risk factors and also shared higher-order symptom dimensions in these emotional disorders.

CONCLUSION

Emotional disorders meet many of the salient criteria proposed by the Study Group of the DSM-V Task Force to suggest a classification cluster.

Where should bipolar disorder appear in the meta-structure?

BACKGROUND

The extant major psychiatric classifications, DSM-IV and ICD-10, are purportedly atheoretical and largely descriptive. Although this achieves good reliability, the validity of a medical diagnosis is greatly enhanced by an understanding of both risk factors and clinical history. In an effort to group mental disorders on the basis of risk factors and clinical manifestations, five clusters have been proposed. The purpose of this paper is to consider the position of bipolar disorder (BPD), which could be either with the psychoses, or with emotional disorders, or in a separate cluster.

METHOD

We reviewed the literature on BPD, unipolar depression (UPD) and schizophrenia in relation to 11 validating criteria proposed by the DSM-V Task Force Study Group, and then summarized similarities and differences between BPD and schizophrenia on the one hand, and UPD on the other.

RESULTS

There are differences, often substantial and never trivial, for 10 of the 11 validators between BPD and UPD. There are also important differences between BPD and schizophrenia.

CONCLUSION

BPD has previously been classified together with UPD, but this is the least justifiable place for it. If it is to be recruited to a 'psychotic cluster', there are several important respects in which it differs from schizophrenia, so the cluster would have a division within it. The alternative would be to allow it to be in an intermediate position in a cluster of its own.

The involvement of retinoic acid receptor-alpha in corticotropin-releasing hormone gene expression and affective disorders

BACKGROUND

Corticotropin-releasing hormone (CRH) is considered the central driving force in the stress response and plays a key role in the pathogenesis of depression. Retinoic acid (RA) has been suggested by clinical studies to be associated with affective disorders.

METHODS

First, hypothalamic tissues of 12 patients with affective disorders and 12 matched control subjects were studied by double-label immunofluorescence to analyze the expression of CRH and retinoic acid receptor-alpha (RAR-alpha). Second, critical genes involved in the RA signaling pathways were analyzed in a rat model of depression. Finally, the regulatory effect of RAR-alpha on CRH gene expression was studied in vitro.

RESULTS

We found that the expression of RAR-alpha was colocalized with CRH neurons in human hypothalamic paraventricular nucleus (PVN). The density of RAR-alpha-immunoreactive neurons and CRH-RAR-alpha double-staining neurons was significantly increased in the PVN of patients with affective disorders. The ratio of the CRH-RAR-alpha double-staining neurons to the CRH-immunoreactive neurons in affective disorder patients was also increased. Recruitment of RAR-alpha by the CRH promoter was observed in the rat hypothalamus. A dysregulated RA metabolism and signaling was also found in the hypothalamus of a rat model for depression. Finally, in vitro studies demonstrated that RAR-alpha mediated an upregulation of CRH gene expression.

CONCLUSIONS

These results suggest that RAR-alpha might contribute to regulating the activity of CRH neurons in vivo, and the vulnerable character of the critical proteins in RA signaling pathways might provide novel targets for therapeutic strategies for depression.

Wolframin gene H611R polymorphism: no direct association with suicidal behavior but possible link to mood disorders

Wolframin gene polymorphisms, including the H611R polymorphism, are reportedly associated with mood disorders and psychiatric hospitalization, but there is disagreement about the association of this specific variant with suicidality and impulsive traits. This study tested the association of the H611R polymorphism with mood disorders, suicidal behavior, and aggressive-impulsive traits. Two hundred and one subjects with mood disorders and 113 healthy volunteers were genotyped for the H611R polymorphism and underwent structured interviews for diagnosis and clinical ratings. All were Caucasians. The H611R polymorphism was associated with mood disorders but not suicidal behavior, aggressive/impulsive traits or suicidality in first-degree relatives. The HR heterozygote genotype was more frequent in mood disorder (chi(2)=7.505; df=2; p=.023). If this finding will be replicated, the H611R polymorphism may be a possible marker for mood disorders in a psychiatric population, and not just in relatives of Wolfram syndrome probands.

A complex selection signature at the human AVPR1B gene

BACKGROUND

The vasopressin receptor type 1b (AVPR1B) is mainly expressed by pituitary corticotropes and it mediates the stimulatory effects of AVP on ACTH release; common AVPR1B haplotypes have been involved in mood and anxiety disorders in humans, while rodents lacking a functional receptor gene display behavioral defects and altered stress responses.

RESULTS

Here we have analyzed the two exons of the gene and the data we present suggest that AVPR1B has been subjected to natural selection in humans. In particular, analysis of exon 2 strongly suggests the action of balancing selection in African populations and Europeans: the region displays high nucleotide diversity, an excess of intermediate-frequency alleles, a higher level of within-species diversity compared to interspecific divergence and a genealogy with common haplotypes separated by deep branches. This relatively unambiguous situation coexists with unusual features across exon 1, raising the possibility that a nonsynonymous variant (Gly191Arg) in this region has been subjected to directional selection.

CONCLUSION

Although the underlying selective pressure(s) remains to be identified, we consider this to be among the first documented examples of a gene involved in mood disorders and subjected to natural selection in humans; this observation might add support to the long-debated idea that depression/low mood might have played an adaptive role during human evolution.

Molecular differentiation of schizoaffective disorder from schizophrenia using BDNF haplotypes

BACKGROUND

Allelic variation in the gene encoding brain-derived neurotrophic factor (BDNF) has been associated with affective disorders, but generally not schizophrenia. Brain-derived neurotrophic factor variants may help clarify the status of schizoaffective disorder.

AIMS

To test the hypothesis that BDNF haplotypes are associated with psychiatric illness marked by a prominent affective component.

METHOD

Frequencies of a 5-marker BDNF haplotype were examined in 600 White participants across four diagnostic categories and healthy controls.

RESULTS

Individuals with schizoaffective disorder and other affective disorders were significantly more likely to carry two copies of the most common BDNF haplotype (containing the valine allele of the Val66Met polymorphism) compared with healthy volunteers. Moreover, when compared with people with schizophrenia, individuals with schizoaffective disorder were significantly more likely to carry two copies of the common haplotype.

CONCLUSIONS

To our knowledge, this is the first candidate gene study to demonstrate association with schizoaffective disorder but not schizophrenia. Variation in the BDNF gene may be associated with the clinical phenotype of affective dysregulation across several DSM-IV diagnostic categories.

Cognitive effects of memantine in postmenopausal women at risk of dementia: a pilot study

BACKGROUND

To determine the effects of memantine on cognition in a normal population of postmenopausal women with putative risk factors for Alzheimer's disease (AD) using a built-in control for the genetic risk factor for AD (apoE-epsilon4 status).

METHODS

A prospective, open-label, 6-month pilot medication trial with memantine and follow-up after discontinuance conducted at the Center for Neuroscience in Women's Health, Stanford University School of Medicine. Neuropsychological data were collected on 22 community-dwelling postmenopausal women (11 apoE-epsilon4 carriers and 11 apoE-epsilon4 non-carriers) with at least one putative risk factor for AD.

RESULTS

ApoE-epsilon4 status was not a significant predictor of change in neuropsychological performance. Changes associated with memantine treatment for entire sample included significant declines in some variables associated with verbal learning and memory that improved upon medication withdrawal. A positive medication effect was noted with executive functions and possibly category fluency. Trend-level improvements were seen in motor dexterity of the non-dominant hand and maintained even after drug discontinuance.

CONCLUSIONS

Treatment with memantine appeared to have differential effects on cognitive performance in a population of women with putative risk factors for AD. ApoE-epsilon4 carrier status did not account for observed changes in cognition.

Genomic landscape of a three-generation pedigree segregating affective disorder

Bipolar disorder (BPD) is a common psychiatric illness with a complex mode of inheritance. Besides traditional linkage and association studies, which require large sample sizes, analysis of common and rare chromosomal copy number variants (CNVs) in extended families may provide novel insights into the genetic susceptibility of complex disorders. Using the Illumina HumanHap550 BeadChip with over 550,000 SNP markers, we genotyped 46 individuals in a three-generation Old Order Amish pedigree with 19 affected (16 BPD and three major depression) and 27 unaffected subjects. Using the PennCNV algorithm, we identified 50 CNV regions that ranged in size from 12 to 885 kb and encompassed at least 10 single nucleotide polymorphisms (SNPs). Of 19 well characterized CNV regions that were available for combined genotype-expression analysis 11 (58%) were associated with expression changes of genes within, partially within or near these CNV regions in fibroblasts or lymphoblastoid cell lines at a nominal P value <0.05. To further investigate the mode of inheritance of CNVs in the large pedigree, we analyzed a set of four CNVs, located at 6q27, 9q21.11, 12p13.31 and 15q11, all of which were enriched in subjects with affective disorders. We additionally show that these variants affect the expression of neuronal genes within or near the rearrangement. Our analysis suggests that family based studies of the combined effect of common and rare CNVs at many loci may represent a useful approach in the genetic analysis of disease susceptibility of mental disorders.