A multivariate genetic analysis of specific phobia, separation anxiety and social phobia in early childhood

The genetic and environmental hierarchical structure of anxiety and depression in the UK Biobank

BACKGROUND

Anxiety and depressive disorders can be classified under a bidimensional model, where depression and generalized anxiety disorder are represented by distress and the other anxiety disorders, by fear. The phenotypic structure of this model has been validated, but twin studies only show partial evidence for genetic and environmental distinctions between distress and fear. Moreover, the effects of genetic variants are mostly shared between anxiety and depression, but the genome-wide genetic distinction between distress and fear remains unexplored. This study aimed to examine the degree of common genetic variation overlap between distress and fear, and their associations with the psychosocial risk factors of loneliness and social isolation.

METHODS

We used genome-wide data from 157,366 individuals in the UK Biobank who answered a mental health questionnaire.

RESULTS

Genetic correlations indicated that depression and generalized anxiety had a substantial genetic overlap, and that they were genetically partially distinct from fear disorders. Associations with loneliness, but not social isolation, showed that loneliness was more strongly associated with both distress disorders than with fear.

CONCLUSIONS

Our findings shed light on genetic and environmental mechanisms that are common and unique to distress and fear and contribute to current knowledge on individuals' susceptibility to anxiety and depression.

The genetic and environmental structure of fear and anxiety in juvenile twins

Fear and anxiety are conceptualized as responses to acute or potential threat, respectively. Adult twin studies found substantial interplay between genetic and environmental factors influencing fear disorders (phobias) and anxiety disorders. Research in children, however, has largely examined these factors independently. Thus, there exists a substantial knowledge gap regarding the underlying etiologic structure of these closely-related constructs during development. Symptom counts for five fear (criticism, the unknown, death, animal, medical) and four anxiety (generalized, panic, separation, social) dimensions were obtained for 373 twin pairs ages 9-14. Multivariate twin modeling was performed to elucidate the genetic and environmental influences distributed amongst these dimensions. The best fitting model contained one genetic, two familial environmental, and two unique environmental factors shared between fear and anxiety symptoms plus dimension-specific genetic and unique environmental factors. Although several environmental factors were shared between fear and anxiety dimensions, one latent factor accounted for genetic influences across both domains. While adult studies find somewhat distinct etiological differences between anxiety and phobic disorders, the current results suggest that their relative genetic and environmental influences are not as clearly demarcated in children. These etiological distinctions are more nuanced, likely contributing to the highly diffuse symptom patterns seen during development.

Specific phobias

Anxiety disorders are among the most prevalent mental disorders, but the subcategory of specific phobias has not been well studied. Phobias involve both fear and avoidance. For people who have specific phobias, avoidance can reduce the constancy and severity of distress and impairment. However, these phobias are important because of their early onset and strong persistence over time. Studies indicate that the lifetime prevalence of specific phobias around the world ranges from 3% to 15%, with fears and phobias concerning heights and animals being the most common. The developmental course of phobias, which progress from fear to avoidance and then to diagnosis, suggests the possibility that interrupting the course of phobias could reduce their prevalence. Although specific phobias often begin in childhood, their incidence peaks during midlife and old age. Phobias persist for several years or even decades in 10-30% of cases, and are strongly predictive of onset of other anxiety, mood, and substance-use disorders. Their high comorbidity with other mental disorders, especially after onset of the phobia, suggests that early treatment of phobias could also alter the risk of other disorders. Exposure therapy remains the treatment of choice, although this approach might be less effective in the long term than previously believed. This Review discusses the literature regarding the prevalence, incidence, course, risk factors, and treatment of specific phobias, and presents epidemiological data from several population-based surveys.

Anxiety disorders in children and adolescents: aetiology, diagnosis and treatment

The presentation of anxiety disorders in children and adolescents shares similarities and differences with that in adults, and may vary significantly, depending on the age of the individual. Assessment must differentiate anxiety disorders from developmentally appropriate fears as well as medical conditions and drugs that can mimic anxiety states. Aetiology of anxiety disorders in this group encompasses complex genetic and environmental influences. Additional insight into causation is provided by neuroimaging and research into temperament. Recommended interventions include both cognitive-behavioural therapy and pharmacology. Although childhood anxiety disorders generally remit, there remains an increased risk for anxiety and depressive disorders to emerge in adulthood, most likely through heterotypical continuity.

The scientific legacy of Little Hans and Little Albert: future directions for research on specific phobias in youth

We review issues associated with the phenomenology, etiology, assessment, and treatment of specific phobias in children and adolescents and provide suggestions for future research and clinical practice. In doing so, we highlight the early case studies of Little Hans and Little Albert and the advances that have been made following the publication of these seminal cases. In recent years, we have witnessed a deeper understanding of the etiology of specific phobias and developed a rich array of evidence-based assessments and treatments with which to address specific phobias in youth. Although much has been accomplished in this area of inquiry, we also note that much remains to be done before we can advance more fully our understanding, assessment, and treatment of specific phobias in youth. It will be important for future work to build more firmly on these developments and to better determine the moderators and mediators of change with our evidence-based treatments and to more vigorously pursue their dissemination in real-word settings.

Relations Between Parental and Child Separation Anxiety: The Role of Dependency-Oriented Psychological Control

Although separation anxiety is prevalent in young children, it remains unclear whether and how maternal separation anxiety is related to separation anxiety in children. This study examined associations between maternal separation anxiety and separation anxiety in children, and the potential effect psychologically controlling parenting. Mothers (N = 269) and children (N = 287) recruited for a community sample participated in two 1-year interval data-waves. Children were aged five-eight and were interviewed using an age-appropriate method for obtaining self-reports of separation anxiety and perceptions of dependency-oriented psychologically controlling parenting. Mothers reported on their feelings of separation anxiety regarding their child via a questionnaire. We found that maternal separation anxiety was positively related to separation anxiety in children within, but not over time. We did not find psychologically controlling parenting to mediate this association. Studying other factors than parenting may be an important avenue for future research in explaining separation anxiety in children.

Genetic and environmental contributions to social anxiety across different ages: a meta-analytic approach to twin data

Social anxiety disorder (SAD) and social anxiety symptoms (SAS) have been largely studied both epidemiologically and genetically, however, estimates of genetic and environmental influences for these phenotypes widely vary across reports. Based upon available literature, 13 cohorts (42,585 subjects) were included in 3 meta-analytic estimates of the standardized variance components of aetiological influences on SAD/SAS, on the effect of age and of phenotype (symptoms vs. diagnosis). The proportions of variance accounted for by genetic and environmental factors were calculated by averaging estimates among studies, and pondered by the number of individuals in each sample. Meta-analytic estimations showed that genetic and non-shared environmental factors explain most of individual differences for SAD/SAS. In adults, the genetic contribution was half than that in younger patients, with higher contribution of non-shared environmental influences. In contrast, the shared environmental factors seem to be less relevant.

Beliefs regarding child anxiety and parenting competence in parents of children with separation anxiety disorder

BACKGROUND AND OBJECTIVES

Despite the fact that numerous developmental models have highlighted the role of parental cognitive processes in connection with anxiety disorders in children and adolescents, the role of parents' beliefs about their children and parenting remains largely unexplored. This study investigated the specific association between parental beliefs and child separation anxiety.

METHOD

Parents of children with a diagnosis of Separation Anxiety Disorder (SAD) reported on beliefs and expectations related to their child's fears and own parenting competence. To study the potential specificity of relationships, a clinical control group of mothers of children with social phobia (SoP) and a group of mothers of children without a mental disorder (healthy controls, HC) were included.

RESULTS

Results indicated that parents of anxious children had significantly higher levels of dysfunctional beliefs than the parents in the HC group. Mothers of children with SAD showed lower levels of parenting self-efficacy than mothers of children with SoP. They also demonstrated lower parenting self-efficacy and satisfaction compared to mothers of healthy children. Parental dysfunctional beliefs about child anxiety and paternal parenting self-efficacy were significantly positively associated with child anxiety. The effects remained significant after controlling for parental anxiety and depression.

LIMITATIONS

Due to the cross-sectional design of the study, causality of the found effects cannot be inferred.

DISCUSSION

Data suggest that children's anxiety and parents' beliefs about their child's anxiety, coping skills and parenting are strongly associated. Further research is needed to investigate whether addressing parental cognitions in addition to parents' anxiety may improve prevention and intervention of child anxiety.

Bringing a developmental perspective to anxiety genetics

Despite substantial recent advancements in psychiatric genetic research, progress in identifying the genetic basis of anxiety disorders has been limited. We review the candidate gene and genome-wide literatures in anxiety, which have made limited progress to date. We discuss several reasons for this hindered progress, including small samples sizes, heterogeneity, complicated comorbidity profiles, and blurred lines between normative and pathological anxiety. To address many of these challenges, we suggest a developmental, multivariate framework that can inform and enhance anxiety phenotypes for genetic research. We review the psychiatric and genetic epidemiological evidence that supports such a framework, including the early onset and chronic course of anxiety disorders, shared genetic risk factors among disorders both within and across time, and developmentally dynamic genetic influences. We propose three strategies for developmentally sensitive phenotyping: examination of early temperamental risk factors, use of latent factors to model underlying anxiety liability, and use of developmental trajectories as phenotypes. Expanding the range of phenotypic approaches will be important for advancing studies of the genetic architecture of anxiety disorders.

Genetics of pediatric anxiety disorders

This article reviews the familiality, linkage, candidate gene, and genomewide association studies of obsessive-compulsive disorder, panic disorder, posttraumatic stress disorder, and other anxiety disorders (ie, generalized anxiety disorder, separation anxiety disorder, social phobia, and specific phobia). Studies involving children and adolescents are highlighted. Clinical and research implications are discussed.

Integrating etiological models of social anxiety and depression in youth: evidence for a cumulative interpersonal risk model

Models of social anxiety and depression in youth have been developed separately, and they contain similar etiological influences. Given the high comorbidity of social anxiety and depression, we examine whether the posited etiological constructs are a correlate of, or a risk factor for, social anxiety and/or depression at the symptom level and the diagnostic level. We find core risk factors of temperament, genetics, and parent psychopathology (i.e., depression and anxiety) are neither necessary nor sufficient for the development of social anxiety and/or depression. Instead, aspects of children's relationships with parents and/or peers either mediates (i.e., explains) or moderates (i.e., interacts with) these core risks being related to social anxiety and/or depression. We then examine various parent- and peer-related constructs contained in the separate models of social anxiety and depression (i.e., parent-child attachment, parenting, social skill deficits, peer acceptance and rejection, peer victimization, friendships, and loneliness). Throughout our review, we report evidence for a Cumulative Interpersonal Risk model that incorporates both core risk factors and specific interpersonal risk factors. Most studies fail to consider comorbidity, thus little is known about the specificity of these various constructs to depression and/or social anxiety. However, we identify shared, differential, and cumulative risks, correlates, consequences, and protective factors. We then put forth demonstrated pathways for the development of depression, social anxiety, and their comorbidity. Implications for understanding comorbidity are highlighted throughout, as are theoretical and research directions for developing and refining models of social anxiety, depression, and their comorbidity. Prevention and treatment implications are also noted.

A twin study of computer anxiety in Turkish adolescents

The present study investigated computer anxiety within a sample of Turkish twins aged 10-18. A total of 185 twin-pairs participated in the study. Of the twins, 64 pairs (34.6 percent) were monozygotic (MZ) and 121 pairs (65.4 percent) were dizygotic (DZ). Of the 121 DZ twins, 54 pairs (44.63 percent) were same-sex twins and 67 pairs (55.37 percent) were opposite-sex twins. Computer anxiety was assessed using Computer Anxiety Rating Scale-Turkish Version (CARS-TV), one of the three main scales of "Measuring Technophobia Instruments" developed by Rosen and Weil. The results of paired t test comparisons showed no significant differences in MZ and same-sex DZ twin-pairs' levels of computer anxiety. On the other hand, a significant difference was found in opposite-sex DZ twin-pairs' level of computer anxiety. Interesting enough, males appeared to be more computer anxious than their female co-twins. In the present study, using Falconer's formula, heritability estimate for computer anxiety was derived from correlations based on MZ and DZ twins' mean scores on CARS-TV. The results showed that 57 percent of the variance in computer anxiety was from genetics and 41.5 percent was from nonshared environmental factors. Shared environmental influence, on the other hand, was very small and negligible. Interpretations of results and potential directions for future research are presented.

Social and non-social behavioral inhibition in preschool-age children: differential associations with parent-reports of temperament and anxiety

Behavioral inhibition (BI) has generally been treated as a unitary construct and assessed by combining ratings of fear, vigilance, and avoidance to both novel social and non-social stimuli. However, there is evidence suggesting that BI in social contexts is not correlated with BI in non-social contexts. The present study examined the distinction between social and non-social BI in a community sample of 559 preschool-age children using a laboratory assessment of child temperament, a diagnostic interview, and parent-completed questionnaires. Social and non-social BI were not significantly correlated and exhibited distinct patterns of associations with parent reports of temperament and anxiety symptoms. This study suggests that BI is heterogeneous, and that distinguishing between different forms of BI may help account for the variation in trajectories and outcomes exhibited by high BI children.

The role of genes and environment in shaping co-occurrence of DSM-IV defined anxiety dimensions among Italian twins aged 8-17

This study investigated the ultimate causes of co-variation between symptoms of four common DSM-IV anxiety dimensions - Generalized Anxiety, Panic, Social Phobia and Separation Anxiety disorder - assessed with the Italian version of the Screen for Child Anxiety-Related Emotional Disorders questionnaire in a sample of 378 twin pairs aged 8-17 from the population-based Italian Twin Register. Genetic and environmental proportions of covariance between the targeted anxiety dimensions were estimated by multivariate twin analyses. Genetic influences (explaining from 58% to 99% of covariance) and unique environmental factors were the sole sources of co-variation for all phenotypes under study. Genetic influences associated with different anxiety dimensions coincide remarkably, as indicated by genetic correlations ranging from 0.40 to 0.61, while unique environmental overlap is less substantial. Thus, while additive genetic effects are important in explaining why children report symptoms from multiple anxiety disorders, environmental idiosyncratic factors seem to play a marginal role in shaping the co-occurrence of different anxiety dimensions in childhood.

Neurodevelopmental disorders: cluster 2 of the proposed meta-structure for DSM-V and ICD-11

BACKGROUND

DSM-IV and ICD-10 are atheoretical and largely descriptive. Although this achieves good reliability, the validity of diagnoses can be increased by an understanding of risk factors and other clinical features. In an effort to group mental disorders on this basis, five clusters have been proposed. We now consider the second cluster, namely neurodevelopmental disorders.

METHOD

We reviewed the literature in relation to 11 validating criteria proposed by a DSM-V Task Force Study Group.

RESULTS

This cluster reflects disorders of neurodevelopment rather than a 'childhood' disorders cluster. It comprises disorders subcategorized in DSM-IV and ICD-10 as Mental Retardation; Learning, Motor, and Communication Disorders; and Pervasive Developmental Disorders. Although these disorders seem to be heterogeneous, they share similarities on some risk and clinical factors. There is evidence of a neurodevelopmental genetic phenotype, the disorders have an early emerging and continuing course, and all have salient cognitive symptoms. Within-cluster co-morbidity also supports grouping these disorders together. Other childhood disorders currently listed in DSM-IV share similarities with the Externalizing and Emotional clusters. These include Conduct Disorder, Attention Deficit Hyperactivity Disorder and Separation Anxiety Disorder. The Tic, Eating/Feeding and Elimination disorders, and Selective Mutisms were allocated to the 'Not Yet Assigned' group.

CONCLUSION

Neurodevelopmental disorders meet some of the salient criteria proposed by the American Psychiatric Association (APA) to suggest a classification cluster.

Phenotypic and genetic differentiation of anxiety-related behaviors in middle childhood

BACKGROUND

Anxiety-related behaviors (ARBs) are commonly observed during typical development, yet few studies have investigated their etiology in middle childhood. This study aimed to examine both the phenotypic and genetic differentiation of ARB subtypes within the general population at age 7 and 9. It constituted a follow-up to an earlier study of ARBs in preschool children.

METHODS

We investigated the phenotypic structure of ARBs in a large population-based twin sample, comprising 7,834 twin pairs at age 7 and 3,644 twin pairs at age 9. Quantitative genetic modeling techniques were then used to determine the relative influences of genetic and environmental factors upon different types of ARB and upon the covariation between them.

RESULTS

Factor analysis supported the presence of five ARB factors at both ages: negative cognitions, negative affect, fear, obsessive-compulsive behaviors, and social anxiety. Multivariate genetic analyses revealed significant genetic effects and a small but significant influence of shared environment for all ARB subtypes. There was a moderate level of genetic specificity for each subtype as well as some shared genetic effects. Shared environmental influences correlated highly across all types of ARB, whereas nonshared environmental effects were largely subtype specific.

CONCLUSIONS

The current results suggest that ARBs can be differentiated both phenotypically and genetically within middle childhood, with subtypes reflecting symptom groupings of diagnosable disorders but also aspects of temperament. Although some etiological risk factors lead to a generalized vulnerability to anxiety, others may serve to differentiate between different types of ARBs.

Social Anxiety Disorder: Recent Developments in Psychological Approaches to Conceptualization and Treatment

The aim of the present study was to identify and synthesize recent research findings in the aetiology and psychological treatment of social anxiety disorder and consider how these might improve outcome through more effective intervention. The electronic databases Medline, EMBASE and PsychInfo were searched for January 2000–December 2008. Publications of interest referred to in relevant articles were also reviewed. Case reports and publications not in English were excluded. The greatest variance in social anxiety disorder is accounted for by temperamental and personality factors and these may be associated with significant heritability. The environmental contribution is smaller and mainly due to non-shared factors, with a small contribution from shared environmental factors. Epidemiological research confirms that social anxiety disorder is chronic, and among the anxiety disorders has the lowest rates of treatment seeking, receipt of evidence-based treatments and recovery. Effective psychological treatments have been available for some time, and the research emphasis is on increasing the efficacy of treatments through innovations in programme content and delivery. Cognitive science research has contributed a better understanding of cognitive factors that maintain social anxiety disorder and informed enhancement of the cognitive elements of therapy. Internet-based programmes show promise as a novel way to deliver and improve access to effective therapy. Genetic, personality and temperamental factors contribute to the risk for social anxiety disorder. Given the associated comorbidity and disability, energy needs to be directed towards early recognition and treatment, and to increasing engagement and retention in effective therapy. Ongoing professional education is required to ensure that the disorder is recognized and evidence-based treatments received by patients who do seek help. Current cognitive behavioural treatments are being enhanced as the results of cognitive science research are being applied, and novel forms of treatment delivery show promise in increasing access.