Prevalence and heritability of obsessive-compulsive spectrum and anxiety disorder symptoms: A survey of the Australian Twin Registry

Adverse Childhood Experiences Among Adolescents With Body Dysmorphic Disorder: Frequency and Clinical Correlates

Increasing empirical attention has been given to the role of adverse childhood experiences (ACEs) in the development and maintenance of body dysmorphic disorder (BDD). Yet, current research has predominantly focused on adult and nonclinical BDD samples, and little is known about relevance of ACEs in adolescent BDD. The present study examined (a) the frequency of ACEs in adolescents with a primary diagnosis of BDD (n = 50) versus obsessive compulsive disorder (OCD) (n = 50) and (b) the clinical profile of ACE-exposed youth with BDD. ACEs were ascertained through a systematic search of electronic patient records, as well as through a parent- and self-report screening item for exposure to traumatic events. Results showed higher rate of peer victimisation (74% vs. 38%) and child maltreatment (44% vs. 24%) among BDD versus OCD youths; sexual abuse was the most common type of child maltreatment documented in the BDD group (28%) according to patient records. Parent-reported exposure to traumatic events was also significantly higher in the BDD than the OCD group (40% vs. 18%, respectively). Clinical presentation and treatment outcomes did not differ between those with versus without a history of ACEs. The current study is the first to demonstrate that a range of ACEs are common in adolescent BDD. Our findings highlight the importance of screening for these experiences. Although further research is needed, our findings also indicate that adolescents with BDD who have a history of ACEs are broadly similar in their clinical presentation to those without, and benefit from BDD-focused treatment.

The genetic epidemiology of obsessive-compulsive disorder: a systematic review and meta-analysis

The first systematic review and meta-analysis of obsessive-compulsive disorder (OCD) genetic epidemiology was published approximately 20 years ago. Considering the relevance of all the studies published since 2001, the current study aimed to update the state-of-art knowledge on the field. All published data concerning the genetic epidemiology of OCD from the CENTRAL, MEDLINE, EMBASE, BVS, and OpenGrey databases were searched by two independent researchers until September 30, 2021. To be included, the articles had to fulfill the following criteria: OCD diagnosis provided by standardized and validated instruments; or medical records; inclusion of a control group for comparison and case-control, cohort or twin study designs. The analysis units were the first-degree relatives (FDRs) of OCD or control probands and the co-twins in twin pairs. The outcomes of interest were the familial recurrence rates of OCD and the correlations of OCS in monozygotic compared with dizygotic twins. Nineteen family, twenty-nine twin, and six population-based studies were included. The main findings were that OCD is a prevalent and highly familial disorder, especially among the relatives of children and adolescent probands, that OCD has a phenotypic heritability of around 50%; and that the higher OCS correlations between MZ twins were mainly due to additive genetic or to non-shared environmental components.

Genomics of Obsessive-Compulsive Disorder and Related Disorders: What the Clinician Needs to Know

A wealth of evidence has shown that genetics plays a major role in susceptibility to obsessive-compulsive disorder (OCD) and all of its related disorders. Several large-scale, collaborative efforts using modern genomic methods are beginning to reveal the genetic architecture of these traits and identify long-sought risk genes. In this article, we summarize current OCD and related disorder genomic knowledge and explain how to communicate this information to patients and their families. The article concludes with a discussion of how genomic discovery in OCD and related disorders can inform our understanding of disease etiology and provide novel targets for therapeutic development.

Meta-analysis of genome-wide association studies of hoarding symptoms in 27,537 individuals

Hoarding Disorder (HD) is a mental disorder characterized by persistent difficulties discarding or parting with possessions, often resulting in cluttered living spaces, distress, and impairment. Its etiology is largely unknown, but twin studies suggest that it is moderately heritable. In this study, we pooled phenotypic and genomic data from seven international cohorts (N = 27,537 individuals) and conducted a genome wide association study (GWAS) meta-analysis of parent- or self-reported hoarding symptoms (HS). We followed up the results with gene-based and gene-set analyses, as well as leave-one-out HS polygenic risk score (PRS) analyses. To examine a possible genetic association between hoarding symptoms and other phenotypes we conducted cross-trait PRS analyses. Though we did not report any genome-wide significant SNPs, we report heritability estimates for the twin-cohorts between 26-48%, and a SNP-heritability of 11% for an unrelated sub-cohort. Cross-trait PRS analyses showed that the genetic risk for schizophrenia and autism spectrum disorder were significantly associated with hoarding symptoms. We also found suggestive evidence for an association with educational attainment. There were no significant associations with other phenotypes previously linked to HD, such as obsessive-compulsive disorder, depression, anxiety, or attention-deficit hyperactivity disorder. To conclude, we found that HS are heritable, confirming and extending previous twin studies but we had limited power to detect any genome-wide significant loci. Much larger samples will be needed to further extend these findings and reach a "gene discovery zone". To move the field forward, future research should not only include genetic analyses of quantitative hoarding traits in larger samples, but also in samples of individuals meeting strict diagnostic criteria for HD, and more ethnically diverse samples.

Genetics of obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a psychiatric disorder with multiple symptom dimensions (e.g. contamination, symmetry). OCD clusters in families and decades of twin studies clearly demonstrate an important role for genetics in the etiology of the disorder.

METHODS

In this review, we summarize the genetic epidemiology and molecular genetic studies of OCD and obsessive-compulsive symptoms.

RESULTS

OCD is a heritable, polygenic disorder with contributions from both common and rare variants, including de novo deleterious variations. Multiple studies have provided reliable support for a large additive genetic contribution to liability to OCD, with discrete OCD symptom dimensions having both shared and unique genetic risks. Genome-wide association studies have not produced significant results yet, likely because of small sample sizes, but larger meta-analyses are forthcoming. Both twin and genome-wide studies show that OCD shares genetic risk with its comorbid conditions (e.g. Tourette syndrome and anorexia nervosa).

CONCLUSIONS

Despite significant efforts to uncover the genetic basis of OCD, the mechanistic understanding of how genetic and environmental risk factors interact and converge at the molecular level to result in OCD's heterogeneous phenotype is still mostly unknown. Future investigations should increase ancestral genetic diversity, explore age and/or sex differences in genetic risk for OCD and expand the study of pharmacogenetics, gene expression, gene × environment interactions and epigenetic mechanisms for OCD.

Associations Between Anxiety Symptoms and Health-Related Quality of Life: A Population-Based Twin Study in Sri Lanka

Anxiety not only concerns mental wellbeing but also negatively impacts other areas of health. Yet, there is limited research on (a) the genetic and environmental aetiology of such relationships; (b) sex differences in aetiology and (c) non-European samples. In this study, we investigated the genetic and environmental variation and covariation of anxiety symptoms and eight components of health-related quality of life (QoL), as measured by the short form health survey (SF-36), using genetic twin model fitting analysis. Data was drawn from the Colombo Twin and Singleton Study (COTASS), a population-based sample in Sri Lanka with data on twins (N = 2921) and singletons (N = 1027). Individual differences in anxiety and QoL traits showed more shared environmental (family) effects in women. Men did not show familial effects. Anxiety negatively correlated with all eight components of QoL, mostly driven by overlapping unique (individual-specific) environmental effects in both sexes and overlapping shared environmental effects in women. This is the first study in a South Asian population supporting the association between poor mental health and reduced QoL, highlighting the value of integrated healthcare services. Associations were largely environmental, on both individual and family levels, which could be informative for therapy and intervention.

Association Between Obsessive-Compulsive Symptom Dimensions in Mothers and Psychopathology in Their Children

Background: The non-clinical presentation of obsessive-compulsive symptoms (OCS) in women may impact not only their daily lives and well-being but also increase the risk for emotional and behavioral problems in their children. This study aims to investigate the OCS dimension distribution in a large sample of mothers from a cohort of school age children and the association between these OCS dimensions with their own psychopathology, and with the presence of OCS and other psychopathology in their children. Method: Our final sample consisted of 2,511 mother-children dyads recruited from the elementary schools of two large cities. Throughout multiple regression analysis, we examined the correlations between demographic and clinical variables of mothers assessed by the Mini International Psychiatric Interview (MINI) and the Dimensional Yale-Brown Obsessive-Compulsive Scale-Short Version (DY-BOCS-SV) with children's psychopathology status reported by the Child Behavior Checklist (CBCL). Results: The overall prevalence of mothers who reported experiencing at least one OCS was 40% (N = 1,004). "Aggression/violence" was the most frequent symptom dimension (32.2%), followed by the "symmetry/ordering" (16.4%) and the "sexual/religious" dimensions (13.8%). There was a significant correlation between the presence of OCS and maternal psychopathology in general (p < 0.001, r = 0.397). Not only the presence but also the severity of the mother's OCS were strongly correlated to the total (p < 0.001), internalizing (p < 0.001), externalizing (p < 0.001), and OCS subscale scores (p < 0.001) on the CBCL. Conclusion: OCS dimensions are highly prevalent in women. Presence and severity of maternal OCS are related to children's psychopathology and behavioral problems.

Prevalence of hoarding disorder among primary care patients

Objectives:

Despite the inclusion of hoarding disorder (HD) in the DSM-5, there is little epidemiological data on hoarding from low and middle-income countries. This study, the first from India, examines the prevalence and correlates of HD among primary care patients in the state of Kerala, India.

Methods:

To assess correlates, the Hoarding Rating Scale-Interview (HRS-I) and other structured instruments were administered to 7,555 subjects selected by stratified random sampling from 71 primary health centers.

Results:

The prevalence of HD was 1.02% (95%CI 0.8-1.3). Those with HD were more likely to be older and live alone. In the binary logistic regression analysis, after controlling for significant sociodemographic variables, subjects with HD had a higher odds of reporting chronic illness, depression, anxiety disorder, alcohol abuse, and tobacco dependence. Subjects with HD had significantly higher disability scores than unaffected individuals.

Conclusion:

Although HD is not uncommon in India, this disorder is rarely reported in specialty settings in India, which suggests that awareness and detection should be improved, considering the co-occurring negative correlates and disability among affected individuals.

Higher Anxiety Is Associated with Lower Cardiovascular Autonomic Function in Female Twins

Anxiety symptoms co-occur with cardiovascular health problems, with increasing evidence suggesting the role of autonomic dysfunction. Yet, there is limited behavior genetic research on underlying mechanisms. In this twin study, we investigated the phenotypic, genetic and environmental associations between a latent anxiety factor and three cardiovascular autonomic function factors: interbeat interval (IBI, time between heart beats), heart rate variability (HRV, overall fluctuation of heart-beat intervals) and baroreflex sensitivity (BRS, efficiency in regulating blood pressure [BP]). Multivariate twin models were fit using data of female twins (N = 250) of the Twin Interdisciplinary Neuroticism Study (TWINS). A significant negative association was identified between latent anxiety and BRS factors (r = -.24, 95% CI [-.40, -.07]). Findings suggest that this relationship was mostly explained by correlated shared environmental influences, and there was no evidence for pleiotropic genetic or unique environmental effects. We also identified negative relationships between anxiety symptoms and HRV (r = -.17, 95% CI [-.34, .00]) and IBI factors (r = -.13, 95% CI [-.29, .04]), though these associations did not reach statistical significance. Findings implicate that higher anxiety scores are associated with decreased efficiency in short-term BP regulation, providing support for autonomic dysfunction with anxiety symptomatology. The baroreflex system may be a key mechanism underlying the anxiety-cardiovascular health relationship.

Intergenerationale Transmission psychischer Auffälligkeiten unter Berücksichtigung von Geschlechtereffekten

Zusammenfassung. Hintergrund: Kinder psychisch kranker Eltern sind eine Hochrisikogruppe. Eine mütterliche Erkrankung scheint sich stärker negativ auf die Nachkommen auszuwirken als eine väterliche Erkrankung. Ob sich die Auswirkungen auf Mädchen und Jungen unterscheiden, ist unklar. Fragestellung: Ziel der Studie ist die Klärung von Geschlechtereffekten bei der intergenerationalen Transmission psychischer Auffälligkeiten. Methode: Es wurden N = 267 Familien untersucht, indem die Depressions- und Angstsymptome von Müttern und Vätern mit einem latenten Wachstumskurvenmodell über vier Messzeitpunkte (zehn Jahre) modelliert wurden. Die Überprüfung erfolgt mittels Strukturgleichungsmodellen. Ergebnisse: Es wurden Zusammenhänge zwischen elterlichen und kindlichen Auffälligkeiten gefunden. Dabei steht eine väterliche depressive Symptomatik stärker mit jugendlichen externalisierenden Auffälligkeiten in Verbindung als eine mütterliche depressive Symptomatik. Mädchen entwickeln tendenziell mehr als Jungen internalisierende Auffälligkeiten bei psychisch belasteten Eltern. Schlussfolgerung: Zukünftige Studien sollten Mütter und Väter gleichermaßen einbeziehen. Weiterhin sollten verstärkt Transmissionsmechanismen inklusive möglicher Mediatoren mit Berücksichtigung des elterlichen und kindlichen Geschlechtes untersucht werden.

Body dysmorphic disorder and facial aesthetic treatments in dental practice

There is a relatively high prevalence of body dysmorphic disorder (BDD) and it is known that this patient group regularly and frequently visit dental practitioners, especially those who advertise themselves as cosmetic or aesthetic practices. The market for facial aesthetics is hugely increasing both generally and within dental practices making it ever more likely that dentists will encounter this patient group frequently. Moreover, due to the nature of their concerns individuals within this group are likely to have contact with dentists (or other medical professionals in the physical health field) prior to any contact with mental health professionals. The aim of this paper is to give an overview of the presentation of BDD, to discuss the changing climate of facial aesthetic treatments and to highlight a care pathway for general dentists. Identification of patients with potential BDD is far more predictable with the use of a validated questionnaire, and the BDD Questionnaire and Dysmorphic Concern Questionnaire are described. A flowchart approach for the management of patients requesting aesthetic improvements is presented as the ideal method for identifying, referring and managing the aesthetic treatment desires of potential BDD patients.

The relationship between obsessive-compulsive disorder and anxiety disorders: A question of diagnostic boundaries or simply severity of symptoms?

BACKGROUND

A growing number of studies are questioning the validity of current DSM diagnoses, either as "discrete" or distinct mental disorders and/or as phenotypically homogeneous syndromes. In this study, we investigated how symptom domains in patients with a main diagnosis of obsessive-compulsive disorder (OCD), panic disorder (PD) and social anxiety disorder (SAD) coaggregate. We predicted that symptom domains would be unrelated to DSM diagnostic categories and less likely to cluster with each other as severity increases.

METHODS

One-hundred eight treatment seeking patients with a main diagnosis of OCD, SAD or PD were assessed with the Dimensional Obsessive-Compulsive Scale (DOCS), the Social Phobia Inventory (SPIN), the Panic and Agoraphobia Scale (PAS), the Anxiety Sensitivity Index-Revised (ASI-R), and the Beck Depression and Anxiety Inventories (BDI and BAI, respectively). Subscores generated by each scale (herein termed "symptom domains") were used to categorize individuals into mild, moderate and severe subgroups through K-means clusterization and subsequently analysed by means of multiple correspondence analysis.

RESULTS

Broadly, we observed that symptom domains of OCD, SAD or PD tend to cluster on the basis of their severities rather than their DSM diagnostic labels. In particular, symptom domains and disorders were grouped into (1) a single mild "neurotic" syndrome characterized by multiple, closely related and co-occurring mild symptom domains; (2) two moderate (complicated and uncomplicated) "neurotic" syndromes (the former associated with panic disorder); and (3) severe but dispersed "neurotic" symptom domains.

CONCLUSION

Our findings suggest that symptoms domains of treatment seeking patients with OCD and anxiety disorders tend to be better conceptualized in terms of severity rather than rigid diagnostic boundaries.

Prevalence of Hoarding Disorder: A systematic review and meta-analysis

Currently there is uncertainty concerning the prevalence of Hoarding Disorder (HD) due to methodological issues in the evidence base. Estimates have widely ranged from between 1.5% and 6% of the general population. This systematic review and meta-analysis therefore aimed to summarise and reliably estimate the prevalence of HD by employing strict inclusion criteria and using studies with sufficiently large samples. A systematic literature search was conducted to identify all relevant prevalence studies. Inclusion criteria were studies that reported working age adult HD prevalence rates and had sample sizes of at least 1009 participants. Eleven studies met criteria (n = 53,378), had low risk of bias and were originally based in developed countries. A random effects meta-analysis was then conducted, with subgroup moderator analysis and meta-regression. The pooled estimated prevalence for HD was 2.5% (CI 1.7-3.6%) and subgroup analyses revealed that prevalence rates were similar for both males and females. Guidance on the manner in which HD is assessed in future prevalence studies is provided and the clinical implications of the results discussed.

Twenty-Five and Up (25Up) Study: A New Wave of the Brisbane Longitudinal Twin Study

The aim of the 25 and Up (25Up) study was to assess a wide range of psychological and behavioral risk factors behind mental illness in a large cohort of Australian twins and their non-twin siblings. Participants had already been studied longitudinally from the age of 12 and most recently in the 19Up study (mean age = 26.1 years, SD = 4.1, range = 20-39). This subsequent wave follows up these twins several years later in life (mean age = 29.7 years, SD = 2.2, range =  22-44). The resulting data set enables additional detailed investigations of genetic pathways underlying psychiatric illnesses in the Brisbane Longitudinal Twin Study (BLTS). Data were collected between 2016 and 2018 from 2540 twins and their non-twin siblings (59% female, including 341 monozygotic complete twin-pairs, 415 dizygotic complete pairs and 1028 non-twin siblings and singletons). Participants were from South-East Queensland, Australia, and the sample was of predominantly European ancestry. The 25Up study collected information on 20 different mental disorders, including depression, anxiety, substance use, psychosis, bipolar and attention-deficit hyper-activity disorder, as well as general demographic information such as occupation, education level, number of children, self-perceived IQ and household environment. In this article, we describe the prevalence, comorbidities and age of onset for all 20 examined disorders. The 25Up study also assessed general and physical health, including physical activity, sleep patterns, eating behaviors, baldness, acne, migraines and allergies, as well as psychosocial items such as suicidality, perceived stress, loneliness, aggression, sleep-wake cycle, sexual identity and preferences, technology and internet use, traumatic life events, gambling and cyberbullying. In addition, 25Up assessed female health traits such as morning sickness, breastfeeding and endometriosis. Furthermore, given that the 25Up study is an extension of previous BLTS studies, 86% of participants have already been genotyped. This rich resource will enable the assessment of epidemiological risk factors, as well as the heritability and genetic correlations of mental conditions.

Prevalence and heritability of body dysmorphic symptoms in adolescents and young adults: a population-based nationwide twin study

BACKGROUND

Body dysmorphic disorder (BDD) usually begins during adolescence but little is known about the prevalence, etiology, and patterns of comorbidity in this age group. We investigated the prevalence of BDD symptoms in adolescents and young adults. We also report on the relative importance of genetic and environmental influences on BDD symptoms, and the risk for co-existing psychopathology.

METHODS

Prevalence of BDD symptoms was determined by a validated cut-off on the Dysmorphic Concerns Questionnaire (DCQ) in three population-based twin cohorts at ages 15 (n = 6968), 18 (n = 3738), and 20-28 (n = 4671). Heritability analysis was performed using univariate model-fitting for the DCQ. The risk for co-existing psychopathology was expressed as odds ratios (OR).

RESULTS

The prevalence of clinically significant BDD symptoms was estimated to be between 1 and 2% in the different cohorts, with a significantly higher prevalence in females (1.3-3.3%) than in males (0.2-0.6%). The heritability of body dysmorphic concerns was estimated to be 49% (95% CI 38-54%) at age 15, 39% (95% CI 30-46) at age 18, and 37% (95% CI 29-42) at ages 20-28, with the remaining variance being due to non-shared environment. ORs for co-existing neuropsychiatric and alcohol-related problems ranged from 2.3 to 13.2.

CONCLUSIONS

Clinically significant BDD symptoms are relatively common in adolescence and young adulthood, particularly in females. The low occurrence of BDD symptoms in adolescent boys may indicate sex differences in age of onset and/or etiological mechanisms. BDD symptoms are moderately heritable in young people and associated with an increased risk for co-existing neuropsychiatric and alcohol-related problems.

Nineteen and Up study (19Up): understanding pathways to mental health disorders in young Australian twins

PURPOSE

The Nineteen and Up study (19Up) assessed a range of mental health and behavioural problems and associated risk factors in a genetically informative Australian cohort of young adult twins and their non-twin siblings. As such, 19Up enables detailed investigation of genetic and environmental pathways to mental illness and substance misuse within the Brisbane Longitudinal Twin Sample (BLTS).

PARTICIPANTS

Twins and their non-twin siblings from Queensland, Australia; mostly from European ancestry. Data were collected between 2009 and 2016 on 2773 participants (age range 18-38, 57.8% female, 372 complete monozygotic pairs, 493 dizygotic pairs, 640 non-twin siblings, 403 singleton twins).

FINDINGS TO DATE

A structured clinical assessment (Composite International Diagnostic Interview) was used to collect lifetime prevalence of diagnostic statistical manual (4th edition) (DSM-IV) diagnoses of major depressive disorder, (hypo)mania, social anxiety, cannabis use disorder, alcohol use disorder, panic disorder and psychotic symptoms. Here, we further describe the comorbidities and ages of onset for these mental disorders. Notably, two-thirds of the sample reported one or more lifetime mental disorder.In addition, the 19Up study assessed general health, drug use, work activity, education level, personality, migraine/headaches, suicidal thoughts, attention deficit hyperactivity disorder (ADHD) symptomatology, sleep-wake patterns, romantic preferences, friendships, familial environment, stress, anorexia and bulimia as well as baldness, acne, asthma, endometriosis, joint flexibility and internet use.The overlap with previous waves of the BLTS means that 84% of the 19Up participants are genotyped, 36% imaged using multimodal MRI and most have been assessed for psychological symptoms at up to four time points. Furthermore, IQ is available for 57%, parental report of ADHD symptomatology for 100% and electroencephalography for 30%.

FUTURE PLANS

The 19Up study complements a phenotypically rich, longitudinal collection of environmental and psychological risk factors. Future publications will explore hypotheses related to disease onset and development across the waves of the cohort. A follow-up study at 25+years is ongoing.

Predictors and consequences of health anxiety symptoms: a novel twin modeling study

OBJECTIVE

The question of how to best conceptualize health anxiety (HA) from a diagnostic and etiological perspective remains debated. The aim was to examine the relationship between HA and the symptoms of anxiety and obsessive-compulsive-related disorders in a normative twin population.

METHOD

Four hundred and ninety-six monozygotic adult twin pairs from the Australian Twin Registry participated in the study (age, 34.4 ± 7.72 years; 59% females). Validated scales were used to assess each domain. We applied a twin regression methodology-ICE FALCON-to determine whether there was evidence consistent with 'causal' relationships between HA and other symptoms by fitting and comparing model estimates.

RESULTS

Estimates were consistent with higher levels of obsessing ('unwanted thoughts') (P = 0.008), social anxiety (P = 0.03), and body dysmorphic symptoms (P = 0.008) causing higher levels of HA symptoms, and with higher levels of HA symptoms causing higher levels of physical/somatic anxiety symptoms (P = 0.001).

CONCLUSION

Obsessional thoughts, body dysmorphic concerns, and social anxiety symptoms may have a causal influence on HA. To report physical/somatic anxiety appears to be a consequence of the underlying presence of HA-related fears. Should our results be confirmed by longitudinal studies, the evaluation and treatment of HA may benefit from the consideration of these identified risk factors.

Anxious attachment and excessive acquisition: The mediating roles of anthropomorphism and distress intolerance

Background and aims Most individuals with hoarding disorder (HD) are prone to excessively acquiring new possessions. Understanding the factors that contribute to this collecting behavior will allow us to develop better treatment approaches for HD. The aim of this study was to test our assumption that an anxious attachment style is associated with a tendency to anthropomorphize comforting objects and an inability to tolerate distress, which in turn leads to excessive acquisition. Methods A total of 361 participants with subclinical to clinical acquisition problems (77.8% female) completed a series of self-report measures. Results As expected, greater anxious attachment was related to greater distress intolerance and stronger tendencies to anthropomorphize inanimate objects. In turn, greater distress intolerance and anthropomorphism were related to more excessive buying and greater acquisition of free items. Examination of the pathways and indirect effects showed support for double mediation rather than serial mediation, as distress intolerance did not predict anthropomorphism. Discussion and conclusion These novel findings, if replicated, suggest that adding treatment modules that target improving distress tolerance and reducing anthropomorphism to standard treatment for HD may lead to further reductions in excessive acquiring.

Recent advances in understanding and managing body dysmorphic disorder

Body dysmorphic disorder (BDD) is a relatively common and disabling psychiatric disorder characterised by excessive and persistent preoccupation with perceived defects or flaws in one's appearance, which are unnoticeable to others, and associated repetitive behaviours (eg, mirror checking). The disorder generally starts in adolescence, but often goes unnoticed and is severely underdiagnosed. Left untreated, BDD typically persists and causes marked functional impairment in multiple domains. This clinical review considers recent advances in the epidemiology and classification of BDD, including its reclassification in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders under the new 'Obsessive-Compulsive and Related Disorders' chapter. Key issues in assessment are outlined including the use of validated screening instruments to minimise misdiagnosis and the importance of risk assessment in this population given the high rates of suicidality and inappropriate use of cosmetic treatments. In addition, current knowledge regarding the causes and mechanisms underlying BDD are summarised. The recommended treatments for BDD are outlined, namely cognitive behavioural therapy (CBT) and antidepressants, such as selective serotonin reuptake inhibitors. Both CBT and pharmacotherapy have been shown to be efficacious treatments for BDD in adult populations, and evidence is emerging to support their use in young people. Although the majority of patients improve with existing evidence-based treatment, a large proportion are left with clinically significant residual symptoms. Priorities for future research are therefore discussed including the need to further refine and evaluate existing interventions with the goal of improving treatment outcomes and to increase their availability.

Age-Specific Prevalence of Hoarding and Obsessive Compulsive Disorder: A Population-Based Study

OBJECTIVE

Little is known about the age-specific prevalence of hoarding and obsessive compulsive symptoms (OCS), particularly in older age groups. The objectives of this study were to estimate the age-specific prevalence, severity, and relationships between hoarding and OCS in males and females using a large population-based sample.

METHODS

We assessed the age-specific prevalence rates of hoarding disorder (HD) and OC disorder (OCD) in males and females (at various age ranges between 15 and 97 years) from the Netherlands Twins Register (N = 15,194). Provisional HD and OCD diagnoses were made according to Diagnostic and Statistical Manual of Mental Health Disorders, 5th Edition, criteria using self-report measures. We also assessed hoarding and OCS severity in the various age groups and explored specific hoarding and OCS patterns (e.g., difficulty discarding, excessive acquisition, clutter, checking, washing, perfectionism, and obsessions) with age.

RESULTS

Prevalence of provisional HD diagnoses (2.12%) increased linearly by 20% with every 5 years of age (z = 13.8, p < 0.0001) and did not differ between males and females. Provisional OCD diagnoses were most common in younger individuals and in individuals over age 65. Co-occurring OCD increased hoarding symptom severity (coefficient: 4.5; SE: 0.2; 95% CI: 4.1-4.9; t = 22.0, p < 0.0001). Difficulty discarding for HD and checking behaviors for OCD appeared to drive most increases in these diagnoses in older ages.

CONCLUSION

Increased prevalence and severity of HD with age appears to be primarily driven by difficulties with discarding. Increases in OCD prevalence with older age were unexpected and of potential clinical relevance.

Health anxiety in obsessive compulsive disorder and obsessive compulsive symptoms in severe health anxiety: An investigation of symptom profiles

Severe health anxiety (SHA) shares features with obsessive-compulsive disorder (OCD) and in recent years there has been a debate as to whether the two disorders may represent two facets of the same condition. Few studies have however investigated the overlap and differences in symptom profiles between the disorders. The primary aim of the present study was to investigate these aspects using one sample of participants with a principal diagnosis of SHA and one sample of participants with a principal OCD diagnosis. The second aim was to examine differences in improvement trajectories on measures of health anxiety and OCD symptoms in patients with SHA receiving treatment with exposure and response prevention. We compared persons participating in clinical trials with a principal diagnosis of SHA (N=290) to persons with a principal diagnosis of OCD (n=95) on measures of health anxiety, OCD symptoms, and depressive symptoms. A subsample of SHA participants (n=99) received exposure and response prevention (ERP) for SHA over 12 weeks and was assessed at baseline and post-treatment. The results showed large and significant differences between SHA and OCD patients on measures of health anxiety (ds=2.99-3.09) and OCD symptoms (ds=1.64-2.14), while they had equivalent levels of depressive symptoms (d=0.19, 95% CI [-0.04, 0.43]). In the SHA sample 7.6% had comorbid OCD, and in the OCD sample 9.5% had SHA. For participants with a principal diagnosis of SHA, ERP led to large reductions of health anxiety, but effects on OCD symptoms were small to moderate. Among participants with comorbid OCD, effect sizes were large on measures of health anxiety and moderate to large on OCD measures. We conclude that SHA and OCD are separate psychiatric disorders with limited overlap in symptom profiles.

The effects of stress-tension on depression and anxiety symptoms: evidence from a novel twin modelling analysis

BACKGROUND

Negative mood states are composed of symptoms of depression and anxiety, and by a third factor related to stress, tension and irritability. We sought to clarify the nature of the relationships between the factors by studying twin pairs.

METHOD

A total of 503 monozygotic twin pairs completed the Depression Anxiety Stress Scales (DASS), an instrument that assesses symptoms of depression, anxiety and stress-tension. We applied a recently developed twin regression methodology - Inference about Causation from Examination of FAmiliaL CONfounding (ICE FALCON) - to test for evidence consistent with the existence of 'causal' influences between the DASS factors.

RESULTS

There was evidence consistent with the stress-tension factor having a causal influence on both the depression (p < 0.0001) and anxiety factors (p = 0.001), and for the depression factor having a causal influence on the anxiety factor (p < 0.001).

CONCLUSIONS

Our findings suggest a critical role for stress-tension in the structure of negative mood states, and that interventions that target it may be particularly effective in reducing depression and anxiety symptoms.

DISTINCT ETIOLOGICAL INFLUENCES ON OBSESSIVE-COMPULSIVE SYMPTOM DIMENSIONS: A MULTIVARIATE TWIN STUDY

BACKGROUND

Obsessive-compulsive disorder (OCD) is characterized by five major dimensions, including contamination/washing, harm/checking, symmetry/ordering, hoarding, and forbidden thoughts. How these dimensions may relate etiologically to the symptoms of other obsessive-compulsive related disorders (OCRDs) and anxiety disorders (ADs) is not well known. The aim of this study was to examine the genetic and environmental overlap between each major obsessive-compulsive dimension with the symptoms of other OCRDs and ADs.

METHODS

Two thousand four hundred ninety-five twins of both sexes, aged between 18 and 45 years, were recruited from the Australian Twin Registry. Measures used scores on four dimensions (obsessing (forbidden thoughts), washing, checking, and ordering) of the Obsessive-Compulsive Inventory-Revised, Dysmorphic Concerns Questionnaire, Hoarding Rating Scale, Anxiety Sensitivity Index, Social Phobia Inventory, and Stress subscale of the Depression, Anxiety, and Stress Scale. Multivariate twin modeling methods using continuous and categorized variables were performed, also controlling for age and gender.

RESULTS

Our findings suggested that forbidden thoughts and washing demonstrated the strongest genetic overlap with other AD symptoms, while ordering was genetically related to OCRD symptoms. Common genetic influences on checking symptoms were best estimated when modeling OCRDs together with AD symptoms. Common environmental factors of ordering and checking were shared with AD symptoms.

CONCLUSIONS

Important shared genetic and environmental risk factors exist between OCD, OCRDs, and ADs, but which vary alongside the expression of its major dimensions.

Developing zebrafish models relevant to PTSD and other trauma- and stressor-related disorders

While post-traumatic stress disorder (PTSD) and other trauma- and stress-related disorders (TSRDs) represent a serious societal and public health concern, their pathogenesis is largely unknown. Given the clinical complexity of TSRD development and susceptibility, greater investigation into candidate biomarkers and specific genetic pathways implicated in both risk and resilience to trauma becomes critical. In line with this, numerous animal models have been extensively used to better understand the pathogenic mechanisms of PTSD and related TSRD. Here, we discuss the rapidly increasing potential of zebrafish as models of these disorders, and how their use may aid researchers in uncovering novel treatments and therapies in this field.