Genetics of fear and anxiety disorders

The Influence of HLA Alleles on the Affective Distress Profile

(1) Background: Affective distress can be triggered by aggressive stimuli with an unfavorable role for the individual. Some of the factors that lead to the development and evolution of a mental disorder can be genetic. The aim of this study is to determine some correlations between the human leukocyte antigen (HLA) genes and the affective distress profile (PDA). (2) Methods: A psychological assessment and testing tool for anxiety was applied to 115 people. The low-resolution HLA alleles of class I (HLA-A, HLA-B, and HLA-C) and class II (HLA-DRB1 and HLA-DQB1) were identified by the PCR technique after DNA extraction from the blood. Depending on the PDA, the subjects were divided into two groups: a group with a low PDA and another one with a medium and high PDA. The IBM SPSS software was used to compare the frequency of HLA alleles between the two groups. (3) Results: The univariate analysis revealed a significant association of the HLA-A locus (A*01, A*30), HLA-B (B*08), and HLA-DRB1 (DRB1*11) with the low PDA group and of the HLA-A locus (A*32), HLA-B (B*52), and HLA-C (C*12) with the medium and high PDA group. (4) Conclusions: The present study highlighted potential associations between HLA alleles and anxiety disorders.

An Eye Tracking and Event-Related Potentials Study With Visual Stimuli for Adolescents Emotional Issues

BACKGROUND

Psychological issues are common among adolescents, which have a significant impact on their growth and development. However, the underlying neural mechanisms of viewing visual stimuli in adolescents are poorly understood.

MATERIALS AND METHODS

This study applied the Chinese version of the DSM-V self-assessment scales to evaluate 73 adolescents' psychological characteristics for depressive and manic emotional issues. Combined with eye-tracking and event-related potential (ERP), we explored the characteristics of their visual attention and neural processing mechanisms while freely viewing positive, dysphoric, threatening and neutral visual stimuli.

RESULTS

Compared to controls, adolescents with depressive emotional tendencies showed more concentrated looking behavior with fixation distribution index than the controls, while adolescents with manic emotional tendencies showed no such trait. ERP data revealed individuals with depressive tendencies showed lower arousal levels toward emotional stimuli in the early stage of cognitive processing (N1 amplitude decreased) and with prolonged reaction time (N1 latency increased) than the control group. We found no significant difference between the manic group and the control group. Furthermore, the depression severity scores of the individuals with depressive tendencies were negatively correlated with the total fixation time toward positive stimuli, were negatively correlated with the fixation distribution index toward threatening stimuli, and were positively correlated with the mean N1 amplitudes while viewing dysphoric stimuli. Also, for the individuals with depressive tendencies, there was a positive correlation between the mean N1 amplitudes and the fixation time on the area of interest (AOI) while viewing dysphoric stimuli. For the individuals with manic tendencies, the manic severity scores of the individuals with manic tendencies were positively correlated with the total fixation time toward the positive stimuli. However, no significant correlations were found between the manic severity scores and N1 amplitudes, and between N1 amplitudes and eye-tracking output variables.

CONCLUSION

This study proposes the application of eye-tracking and ERP to provide better biological evidence to alter the neural processing of emotional stimuli for adolescents with emotional issues.

Human-Specific Neuropeptide S Receptor Variants Regulate Fear Extinction in the Basal Amygdala of Male and Female Mice Depending on Threat Salience

BACKGROUND

A nonsynonymous single nucleotide polymorphism in the neuropeptide S receptor 1 (NPSR1) gene (rs324981) results in isoleucine-to-asparagine substitution at amino acid 107. In humans, the ancestral variant (NPSR1 I107) is associated with increased anxiety sensitivity and risk of panic disorder, while the human-specific variant (NPSR1 N107) is considered protective against excessive anxiety. In rodents, neurobiological constituents of the NPS system have been analyzed in detail and their anxiolytic-like effects have been endorsed. However, their implication for anxiety and related disorders in humans remains unclear, as rodents carry only the ancestral NPSR1 I107 variant.

METHODS

We hypothesized that phenotypic correlates of NPSR1 variants manifest in fear-related circuits in the amygdala. We used CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/Cas9)-mediated gene editing to generate a "humanized" mouse strain, in which individuals express either NPSR1 I107 or NPSR1 N107.

RESULTS

Stimulation of NPSR1 evoked excitatory responses in principal neurons of the anterior basal amygdala with significant differences in magnitude between genotypes, resulting in synaptic disinhibition of putative extinction neurons in the posterior basal amygdala in mice expressing the human-specific hypofunctional N107 but not the ancestral I107 variant. N107 mice displayed improved extinction of conditioned fear, which was phenocopied after pharmacological antagonism of NPSR1 in the anterior basal amygdala of I107 mice. Differences in fear extinction between male and female mice were related to an interaction of Npsr1 genotype and salience of fear training.

CONCLUSIONS

The NPS system regulates extinction circuits in the amygdala depending on the Npsr1 genotype, contributing to sex-specific differences in fear extinction and high anxiety sensitivity of individuals bearing the ancestral NPSR1 I107 variant.

The Potential Role of Epigenetic Drugs in the Treatment of Anxiety Disorders

There is increasing evidence that abnormalities in epigenetic mechanisms of gene expression contribute to the pathogenesis of anxiety disorders (ADs). This article discusses the role of epigenetic mechanisms of gene expression in the pathogenesis of ADs. It also discusses the data so far obtained from preclinical and clinical trials on the use of epigenetic drugs for treating ADs. Most drug trials investigating the use of epigenetic drugs for treating ADs have used histone deacetylase inhibitors (HDACi). HDACi are showing favorable results in both preclinical and clinical drug trials for treating ADs. However, at present the mode of action of HDACi in ADs is not clear. More work needs to be done to elucidate how epigenetic dysregulation contributes to the pathogenesis of ADs. More work also needs to be done on the mode of action of HDACi in alleviating the signs and symptoms of ADs.

Accumulation of sensory difficulties predicts fear of falling in older women

OBJECTIVE

To explore whether the accumulation of sensory difficulties predicts fear of falling (FOF), and whether the traits correlate with each other regardless of familial factors.

METHODS

Self-reported hearing, vision and balance difficulties, and FOF were assessed using structured questionnaires at the baseline and after a 3-year follow-up in 63- to 76-year-old women (n = 434).

RESULTS

Among the women without FOF at baseline (n = 245), 41% reported FOF at follow-up. Increasing numbers of sensory difficulties at baseline predicted higher incidence of FOF. The relationship between accumulated sensory difficulties and FOF was not mediated by familial factors.

DISCUSSION

The accumulation of multiple sensory difficulties may hinder older people from receiving compensatory information about body position and environment, thus jeopardizing a person's confidence in maintaining a balanced position. Regular screening of sensory functions followed by appropriate actions may prevent the development of FOF, and thus contribute to prevention of falls and promotion of healthy aging.

Cognitive-behavioural Treatment of Blood-Injury-Injection Phobia: A Case Study

This single case study examined the treatment of blood-injury-injection (BII) phobia in a 14-year-old female. Thirteen 1-hour sessions of cognitive behavioural therapy were conducted. The intervention included a combination of exposure, applied tension, and cognitive restructuring in an effort to produce clinically significant reductions in anxiety and fainting in response to BII stimuli. Results did indeed show dramatic reductions in subjective distress in BII situations from baseline to post-treatment. This was supported by small reductions in phobic anxiety and general anxiety on self-report measures. In contrast to baseline, fainting did not occur during treatment. The subject rated cognitive restructuring as the most effective treatment component for the latter half of therapy. It is suggested that, to date, the importance of cognitive therapy for the treatment of BII phobia has been overlooked.

Vulnerability factors for anxiety disorders in children and adolescents

With the maturation of community studies of adults in the past decade, there has been growing awareness of the importance of the magnitude and impact of anxiety disorders in the general population. The convergence of findings from adult and child epidemiology reveals that the onset of anxiety disorders occurs in childhood, and a substantial proportion of youth with anxiety continues to manifest lifelong problems with anxiety and other mental disorders. In this article, the major risk factors for the development of anxiety disorders in childhood and adolescence are reviewed.

Genetic epidemiology of anxiety disorders

This chapter reviews the genetic epidemiology of the major subtypes of anxiety disorders including panic disorder, phobic disorders, generalized anxiety disorder, and obsessive-compulsive disorder. Controlled family studies reveal that all of these anxiety subtypes are familial, and twin studies suggest that the familial aggregation is attributable in part to genetic factors. Panic disorder and, its spectrum have the strongest magnitude of familial clustering and genetic underpinnings. Studies of offspring of parents with anxiety disorders an increased risk of mood and anxiety disorders, but there is far less specificity of the manifestations of anxiety in children and young adolescents. Although there has been a plethora of studies designed to identify genes underlying these conditions, to date, no specific genetic loci have been identified and replicated in independent samples.

Family and high-risk studies of social anxiety disorder

OBJECTIVE

To present data on the role of familial factors in the etiology of social anxiety disorder.

METHOD

Findings presented from a family/high-risk study (the Yale Family Study) and a prospective community study of youth (the Munich Early Developmental Stages of Psychopathology (EDSP) Study).

RESULTS

The Yale Family Study demonstrated a substantial degree of familial aggregation of social anxiety disorder and specificity with respect to other anxiety subtypes among adult relatives. The Yale high-risk component and the EDSP Study confirm the association between parental and offspring social anxiety, but did not yield consistent evidence for an association between familial environmental factors and social anxiety.

CONCLUSION

Future studies are needed to examine mechanisms for the specificity of social anxiety disorder aggregation, to identify vulnerability factors for its development and to pinpoint environmental conditions that may enhance or suppress expression of underlying vulnerability.

The heritability of common phobic fear: a twin study of a clinical sample

The aim of this study was to investigate the genetic and environmental contribution to common phobic fears, and to relate the findings to contemporary theories about the etiology of common phobic fears. Self-reported common phobic fear was studied in a treatment sample of 23 monozygotic and 38 same-sex dizygotic twin pairs. Heritability of .47 was observed for common phobic fear of small animals and social fear, and a heritability of .30 in common agoraphobic fear. For common fear of nature phenomena and situational fear, the heritability was 0. The finding that common nature and situational fears were solely caused by environmental factors is in support of learning theory, whereas results for animal, social, and other common phobic fear are in support of an integrative theory of biological preparedness, learning history, and a cognitive style of fearful expectation.

Vulnerability factors among children at risk for anxiety disorders

BACKGROUND

The high-risk strategy is one of the most powerful approaches for identifying premorbid risk factors and reducing etiologic and phenotypic heterogeneity characteristic of the major psychiatric disorders.

METHODS

This paper reviews the methods of high-risk research and findings from previous high-risk studies of anxiety. The preliminary results of the 6-8 year follow-up of a high-risk study of 192 offspring of probands with anxiety disorders, substance abuse, and unaffected controls are presented. The key study measures include comprehensive diagnostic interviews, symptom ratings, indirect measures of brain functioning (neuropsychologic, neurologic and psychophysiologic function), developmental measures, and family functioning measures.

RESULTS

The major findings reveal that there is specificity of familial aggregation of anxiety disorders among parents and children; children at high risk for anxiety have increased startle reflex, autonomic reactivity, and stress reactivity, higher verbal IQ, and deficits in paired associative learning as compared to other children.

CONCLUSIONS

The finding that family environment and parenting do not differ between children at risk for anxiety disorders and other children, when taken together with the strong degree of specificity of transmission of anxiety disorders, suggests that there may be temperamental vulnerability factors for anxiety disorders in general that may already manifest in children prior to puberty.

A retrospective study of the learning history origins of anxiety sensitivity

Anxiety sensitivity (AS; the fear of anxiety-related sensations) has been proposed as a risk factor for the development of panic disorder. The present study involved a conceptual replication of Ehlers' (1993, Behaviour Research and Therapy, 31, 269-278) study on childhood learning experiences and panic attacks, but also extended her work by investigating the relationship between early learning experiences and the development of AS, in a non-clinical sample. A sample of 551 university students participated in a retrospective assessment of their childhood and adolescent instrumental and vicarious learning experiences with respect to somatic symptoms (i.e. anxiety and cold symptoms, respectively) using an expanded version of Ehler's (1993) Learning History Questionnaire. AS levels were assessed using the Anxiety Sensitivity Index, and panic history was obtained using the Panic Attack Questionnaire, Revised. Contrary to hypotheses, the learning experiences of high AS individuals were not found to be specific to anxiety symptoms, but involved parental reinforcement of sick-role behavior related to somatic symptoms in general. High AS subjects reported both more anxiety and cold symptoms prior to age 18 than individuals with lower levels of AS. In addition, both cold and anxiety symptoms elicited more special attention and/or instructions from parents for high AS individuals to take special care of themselves. These findings are contrasted with the results for self-reported panickers who reported more learning experiences (modeling and parental reinforcement) specific to anxiety-related symptoms, than the non-panickers. The results suggest that higher-than-normal levels of AS may arise from learning to catastrophize about the occurrence of bodily symptoms in general, rather than anxiety-related symptoms in particular.

Autonomic balance revisited: panic anxiety and heart rate variability

The analysis of heart rate variability (HRV) is becoming widely used in clinical research to provide a window into autonomic control of HR. This technique has been valuable in elucidating the autonomic underpinnings of panic disorder (PD), a condition that is marked by reports of heart palpitations. A body of research has emerged that implicates a relative reduction in HRV and cardiac vagal tone in PD, as indicated by various HRV measures. These data are consistent with the cardiac symptoms of panic attacks, as well as with developmental evidence that links high vagal tone with enhanced attention, effective emotion regulation, and organismic responsivity. Implications of these findings for nosology and pathophysiology are discussed. Reports of reduced HRV in PD contrast with portrayals of excess autonomic lability in anxiety. This contradiction is addressed in the context of traditional homeostatic models versus a systems perspective that views physiologic variability as essential to overall stability.

Science, "schizophrenia," and genetics: The creation of myths

Marshall's paper delves into the myths about schizophrenia and the growth of biologic and genetic explanations based on political manufacture of "knowledge."

Somatic symptoms and panic attacks: a retrospective study of learning experiences

Individuals with panic attacks evaluate physical anxiety symptoms as dangerous and tend to respond to them with fear. In a retrospective questionnaire study, we explored childhood and adolescent learning experiences with respect to somatic symptoms of panickers. Compared to normal controls (N = 61), patients with panic disorder (N = 121), infrequent panickers (N = 86) and patients with other anxiety disorders (N = 38) reported more frequent instances prior to age 18 when they had experienced symptoms like dizziness, shortness of breath, palpitations or nausea, accompanied by special attention from their parents and instructions to restrain from strenuous or social activities. The differences were due to higher symptom frequencies in the anxiety groups. All anxiety groups reported more frequent uncontrolled behavior of their parents than controls. Patients with panic disorder and infrequent panickers reported that their parents had suffered more frequently from physical symptoms typical of anxiety than patients with other anxiety disorders or normal controls. Panickers, but not patients with other anxiety disorders, had observed sick-role behavior related to panic symptoms in their parents more often than controls. Panic attack Ss reported a higher number of household members suffering from chronic illnesses than controls and patients with other anxiety disorders. No group differences were found in the reported behavior of parents when Ss had colds. Overall, the results point to the role of severe illnesses and physical symptoms typical of anxiety in significant others in the history of Ss with panic attacks. These experiences during childhood and adolescence may contribute to their belief that physical symptoms are dangerous. In contrast, there was no specificity for panic with respect to the Ss' own physical symptoms or cold-related symptoms.

The genetics of personality disorder

Most measurable aspects of normal personality appear to be at least moderately heritable, with direct evidence coming from family, twin and adoption studies and indirect support deriving from psychophysiological research and breeding experiments on animals. Interestingly, genetic studies also shed light on the environmental sources of variation in personality and suggest that shared family environment rarely, if ever, has any positive effect on similarity between relatives. Despite problems of classification, and variations in the use of terms, a survey of the literature provides reasonably consistent evidence of a genetic contribution to several categories of abnormal personality, which we here divide into three groups, antisocial, anxious/avoidant, and schizoid-schizotypal personalities. However, personality disorders are complex traits that do not show simple mendelian patterns of inheritance and so far molecular genetics has been of no help in understanding their aetiology. Fortunately, techniques are now becoming available that enable the detection and potential localisation of genes of small effect and which may help elucidate the molecular basis even of (probably) polygenic traits such as abnormal personality.

Pattern of obsessive-compulsive disorder in eastern Saudi Arabia

In 32 Muslim Saudis with obsessive-compulsive disorder, compulsive acts (78%) and doubts (66%) were the commonest forms. Religious themes predominated in both the obsessions and compulsions.

Phobic anxiety and clumsiness in a 10-year-old girl

During assessment of a girl with a long-standing phobic state, it was found that she also had previously unrecognised perceptuo-motor problems, which were associated with continuing problems in balance and spatial awareness. Her phobia improved after a desensitisation programme, but the physical disorder persisted, despite physiotherapy. The authors conclude that the girl's phobic anxiety may have had its origin in her experience of the perceptual disorder during development.

Panic disorder in children and adolescents

Panic disorder is a common and well-known psychiatric disorder which commonly has its onset during adolescence. However, the disorder has only recently been described in children and adolescents. The clinical literature describing panic disorder in children and adolescents is reviewed, and six cases are presented. Future directions for research are suggested.

Psychoanalysis today

Psychoanalysis as a theory has permeated Western culture in a way that often no longer is conscious. Psychoanalysis as a practice has had a more visible and stormy progress. A similar fate has befallen behavioural, biological, cognitive and social psychology, and it is argued that the attractiveness of reductionism acts to prevent critical appraisal of psychoanalysis and of the other paradigms.

Aetiology and mechanisms of anxiety disorders

Theories on the aetiology of pathological anxiety abound. A critical review is given of the most influential approaches (e.g. psychoanalytical, "somatogenic", behavioural, psychophysiological and "biological" theories), with emphasis on panic and agoraphobic disorders. Evidence is presented from epidemiological and genetic research and from observations on the course of illness. A surprisingly constant prevalence of anxiety syndromes, and a familial distribution suggesting a pivotal importance of genetic factors, speak in favour of a biological model. The course of illness, however, points to the importance of environmental influences as triggering factors, and to cognitive and behavioural mechanisms for the perpetuation of the symptoms. Treatment responses hitherto documented support the biological and behavioural concepts, but the cognitive and psychophysiological theories are also supported to some extent. An attempt is made to combine these findings with biochemical and pharmacological findings in an integrated model of panic and agoraphobia. This model takes the form of a vicious circle, and is compatible with biological and neuropharmacological as well as evolutionary and psychological concepts.