Aetiological overlap between obsessive-compulsive related and anxiety disorder symptoms: multivariate twin study

Practitioner Review: Assessment and treatment of body dysmorphic disorder in young people

Body dysmorphic disorder (BDD) is a relatively common and highly impairing mental disorder that is strikingly underdiagnosed and undertreated in Child and Adolescent Mental Health Services (CAMHS). The only clinical guidelines for the management of BDD in youth were published nearly 20 years ago, when empirical knowledge was sparse. Fortunately, there has been a surge in research into BDD over the last 10 years, shedding important insights into the phenomenology, epidemiology, assessment and treatment of the disorder in young people. This review aimed to provide an overview of recent research developments of relevance to clinicians and healthcare policymakers. We summarise key findings regarding the epidemiology of BDD in youth, which indicate that the disorder usually develops during teenage years and affects approximately 2% of adolescents at any one point in time. We provide an overview of aetiological research, highlighting that BDD arises from an interplay between genetic and environmental influences. We then focus on screening and assessment strategies, arguing that these are crucial to promote detection and diagnosis of this under-recognised condition. Additionally, we summarise the recommended treatment approaches for BDD in youth, namely cognitive behaviour therapy with or without selective serotonin reuptake inhibitors. The review concludes by highlighting key knowledge gaps and priorities for future research including, but not limited to, better understanding aetiological factors, long-term consequences and treatment.

Epidemiology of Body Dysmorphic Disorder and Appearance Preoccupation in Youth: Prevalence, Comorbidity and Psychosocial Impairment

OBJECTIVE

Little is known about how common and impairing body dysmorphic disorder (BDD) is in the general population of youth. We evaluated the prevalence, comorbidity, and psychosocial impairment associated with BDD and more broadly defined appearance preoccupation in young people.

METHOD

Data were drawn from the 2017 Mental Health of Children and Young People in England survey. BDD and psychiatric comorbidity were assessed in individuals 5 to 19 years of age (N = 7,654) according to DSM-5 criteria, using a clinician-rated standardized diagnostic assessment. Psychosocial impairment was measured with a quantitative scale and was indexed by reported self-harm and suicide attempts, as well as service use, assessed using structured interviews.

RESULTS

The point prevalence of BDD was 1.0% (95% CI = 0.8%-1.3%). BDD was significantly more common among adolescents than children (1.9 vs 0.1%; OR = 22.5, p < .001), and among female than male participants (1.8% vs 0.3%; OR = 7.3, p < .001). Approximately 70% of young people with BDD had psychiatric comorbidity, most commonly internalizing disorders. BDD was associated with self- and parent-reported psychosocial impairment, self-harm and suicide attempts, and service utilization. Appearance preoccupation was more common than full-syndrome BDD, but showed similar age and sex effects, patterns of comorbidity, and associated impairment.

CONCLUSION

BDD and appearance preoccupation are relatively common, especially among adolescent girls, and are associated with substantial co-occurring psychopathology, impairment, and risk. Improved screening is needed to increase detection and diagnosis of BDD, and to facilitate access to evidence-based treatment.

STUDY PREREGISTRATION INFORMATION

The epidemiology of body dysmorphic disorder the youth: prevalence, comorbidity and psychosocial impact; https://osf.io/g83jy.

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.

A network perspective on cognitive function and obsessive-compulsive related symptoms

BACKGROUND

The relationship between cognitive function and psychopathological symptoms has been an important research field in recent years. Previous studies have typically applied case-control designs to explore differences in certain cognitive variables. Multivariate analyses are needed to deepen our understanding of the intercorrelations among cognitive and symptom phenotypes in OCD.

METHODS

The present study used network analysis to construct networks of cognitive variables and OCD-related symptoms in patients with OCD and healthy controls (N = 226), aiming to explore the relationship among numerous cognitive function variables and OCD-related symptoms in detail and compare the network features between the two groups.

RESULTS

In the network of cognitive function and OCD-related symptoms, nodes representing IQ, letter/number span test, accuracy of task switching test and obsession were much important in the network in terms of their larger strengths and edges. By constructing the networks of these two groups respectively, there was a strong similarity except that the symptom's network in healthy group had a higher degree of overall connectivity.

LIMITATIONS

Due to the small sample size, the stability of the network cannot be guaranteed. Due to the cross-sectional nature of the data, we were unable to determine how the cognitive-symptom network would change with disease deterioration or treatment.

CONCLUSIONS

The present study highlights the important role of variables such as obsession and IQ from a network perspective. These results deepen our understanding of the multivariate relationship between cognitive dysfunction and OCD symptoms, and may promote the prediction and diagnosis of OCD.

Measuring symptoms of obsessive-compulsive and related disorders using a single dimensional self-report scale

BACKGROUND

Obsessions and compulsions are heterogenous but can be classified into obsessive-compulsive disorder (OCD), body dysmorphic disorder (BDD), hoarding disorder (HD), hair-pulling disorder (HPD), and skin-picking disorder (SPD). OCD is in itself heterogenous, with symptoms clustering around four major symptom dimensions: contamination/cleaning, symmetry/ordering, taboo obsessions, and harm/checking. No single self-report scale captures the full heterogeneity of OCD and related disorders, limiting assessment in clinical practice and research on nosological relations among the disorders.

METHODS

To provide a single self-report scale of OCD and related disorders that respects the heterogeneity of OCD, we expanded the DSM-5-based Obsessive-Compulsive and Related Disorders-Dimensional Scales (OCRD-D) so that is also includes the four major symptom dimensions of OCD. A psychometric evaluation and an exploration of the overarching relations among the dimensions were conducted using an online survey which was completed by 1,454 Spanish adolescents and adults (age span = 15-74 years). Approximately 8 months after the initial survey, 416 participants completed the scale again.

RESULTS

The expanded scale showed excellent internal psychometric properties, adequate test-retest correlations, known groups validity, and correlations in the expected directions with well-being, depression/anxiety symptoms, and satisfaction with life. The higher-order structure of the measure indicated that harm/checking and taboo obsessions formed a common disturbing thoughts factor and that HPD and SPD formed a common body-focused repetitive behaviors factor.

CONCLUSION

The expanded OCRD-D (OCRD-D-E) shows promise as a unified way to assess symptoms across the major symptom dimensions of OCD and related disorders. The measure may be useful in clinical practice (e.g., screening) and research, but more research on construct validity, incremental validity, and clinical utility is needed.

Internet addiction among teenagers in a Chinese population: Prevalence, risk factors, and its relationship with obsessive-compulsive symptoms

BACKGROUND AND AIMS

Internet addiction (IA) among teenagers has been reported frequently in China, although research has seldom focused on vocational high school students. This study investigated the prevalence and risk factors among this special adolescent population. Moreover, we illustrate the complex relationship between obsessive-compulsive (OC) symptoms, insomnia, psychological states, and IA.

METHODS

A cross-sectional design was applied to collect information from three different vocational high schools in Hunan Province, China. Socio-demographic characteristics, OC symptoms, insomnia, depression, anxiety, and stress symptoms were compared between the IA and non-IA groups. Then, a structural equation model (SEM) was established to test our hypothesis regarding different paths from OC symptoms to IA.

RESULTS

IA prevalence was 13.4% among 7990 vocational high school students. Individuals with IA were more likely to be male and students with more severe depression, stress, anxiety, and insomnia symptoms (all p < 0.001). SEM verified that OC symptoms were related to IA both directly and indirectly, where the latter relationship was mediated through insomnia or mental disorders.

LIMITATIONS

This study cannot confirm the causal relationships among the variables and should be generalized cautiously to other groups.

CONCLUSIONS

More attention should be paid to Chinese vocational high school students, especially those with more severe OC symptoms, poor mental health, and insomnia. We should consider OC symptoms, insomnia, psychological suffering, and IA together when addressing related problems.

Impact of the fear of Covid-19 infection on intent to breastfeed; a cross sectional survey of a perinatal population in Qatar

Objectives

Infection control measures during the Covid-19 pandemic have focused on limiting physical contact and decontamination by observing cleaning and hygiene rituals. Breastfeeding requires close physical contact and observance of hygienic measures like handwashing. Worries around contamination increase during the perinatal period and can be expressed as increase in obsessive compulsive symptoms. These symptoms have shown to impact breastfeeding rates. This study attempts to explore any relationship between the Covid-19 pandemic and perinatal obsessive–compulsive symptomatology and whether the Covid-19 pandemic has any impact on intent to breastfeed.

Methods

A cross sectional survey of perinatal women attending largest maternity centre in Qatar was carried out during the months of October to December 2020. Socio-demographic information, intent to breastfeed and information around obsessive compulsive thoughts around Covid-19 pandemic were collected using validated tools.

Results

15.7% respondents report intent to not breastfeed. 21.4% respondents reported obsessive–compulsive symptoms. 77.3% respondents believed the biggest source of infection was from others while as only 12% of the respondents believed that the source of infection was through breastfeeding and 15.7% believed the vertical transmission as the main source of risk of transmission.

Conclusions

The rates of Obsessive–compulsive symptoms were increased and the rates of intent to breastfeed were decreased when compared with pre pandemic rates. The obsessive–compulsive symptoms and the intent to not breastfeed were significantly associated with fear of infection to the new-born.

Obsessive–compulsive symptoms were not significantly correlated with intent to breastfeed and can be seen as adaptive strategies utilized by women to continue breastfeeding in the context of fear of infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04446-z.

Posttraumatic Stress Disorder and Anxiety-Related Conditions

PURPOSE OF REVIEW

This article provides a synopsis of current assessment and treatment considerations for posttraumatic stress disorder (PTSD) and related anxiety disorder characteristics. Epidemiologic and neurobiological data are reviewed as well as common associated symptoms, including sleep disruption, and treatment approaches to these conditions.

RECENT FINDINGS

PTSD is no longer considered an anxiety-related disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition classification and instead is associated with trauma/stressor-related disorders. PTSD symptoms are clustered into four domains including intrusive experiences, avoidance, mood, and arousal symptoms. Despite this reclassification, similarities exist in consideration of diagnosis, treatment, and comorbidities with anxiety disorders. PTSD and anxiety-related disorders are heterogeneous, which is reflected by the neural circuits involved in the genesis of symptoms that may vary across symptom domains. Treatment is likely to benefit from consideration of this heterogeneity.Research in animal models of fear and anxiety, as well as in humans, suggests that patients with PTSD and generalized anxiety disorder have difficulty accurately determining safety from danger and struggle to suppress fear in the presence of safety cues.Empirically supported psychotherapies commonly involved exposure (fear extinction learning) and are recommended for PTSD. Cognitive-behavioral therapy has been shown to be effective in other anxiety-related disorders. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) are commonly used in the treatment of PTSD and anxiety disorders in which pharmacologic intervention is supported. Treating sleep disruption including sleep apnea (continuous positive airway pressure [CPAP]), nightmares, and insomnia (preferably via psychotherapy) may improve symptoms of PTSD, as well as improve mood in anxiety disorders.

SUMMARY

PTSD has a lifetime prevalence that is close to 10% and shares neurobiological features with anxiety disorders. Anxiety disorders are the most common class of mental conditions and are highly comorbid with other disorders; treatment considerations typically include cognitive-behavioral therapy and pharmacologic intervention. Developing technologies show some promise as treatment alternatives in the future.

Transdiagnostic dimensions in obsessive-compulsive and related disorders: associations with internalizing and externalizing symptoms

BACKGROUND

Hierarchical structural models of psychopathology rarely extend to obsessive-compulsive spectrum disorders. The current study sought to examine the higher-order structure of the obsessive-compulsive and related disorders (OCRDs) in DSM-5: obsessive-compulsive disorder (OCD), hoarding disorder (HD), body dysmorphic disorder (BDD), trichotillomania (hair-pulling disorder; HPD) and excoriation (skin-picking) disorder (SPD).

METHODS

Adult patients in a partial hospital program (N = 532) completed a dimensional measure of the five OCRDs. We used confirmatory factor analysis to identify the optimal model of the comorbidity structure. We then examined the associations between the transdiagnostic factors and internalizing and externalizing symptoms (i.e. depression, generalized anxiety, neuroticism, and drug/alcohol cravings).

RESULTS

The best fitting model included two correlated higher-order factors: an obsessions-compulsions (OC) factor (OCD, BDD, and HD), and a body-focused repetitive behavior (BFRB) factor (HPD and SPD). The OC factor, not the BFRB factor, had unique associations with internalizing symptoms (standardized effects = 0.42-0.66) and the BFRB factor, not the OC factor, had small marginally significant unique association with drug/alcohol cravings (standardized effect = 0.22, p = 0.088).

CONCLUSIONS

The results mirror findings from twin research and indicate that OCD, BDD, and HD share liability that is significantly associated with internalizing symptoms, but this liability may be relatively less important for BFRBs. Further research is needed to better examine the associations between BFRBs and addictive disorders.

The comorbidity structure of fear, distress and compulsive disorders in an acute psychiatric sample

Body dysmorphic disorder (BDD) and obsessive-compulsive disorder (OCD), collectively referred to as compulsive disorders, have typically not been included in structural research on the internalizing spectrum due to low prevalence in community samples. The current study examined the higher-order structure of anxiety, depressive and compulsive disorders among patients in a psychiatric partial hospital program (N = 2,178). We applied confirmatory factor analysis to diagnostic data obtained at admission and compared several competing models of the comorbidity structure. A one-factor model accounted well for the co-occurrence of all the disorders. A two-factor model comprised of fear and distress factors, wherein compulsive disorders loaded on fear, also fit the data well. However, a very large factor correlation (r = 0.86) suggested limited discriminant validity of fear and distress in the sample. Alternate models that featured a distinct compulsivity factor were not viable owing to large correlations between fear and compulsive disorders. Overall, our findings indicate that a broad internalizing dimensions underlies not only anxiety and depression, but also compulsive disorders, in an acute psychiatric population. Future studies using symptom-level data are needed to replicate these results and determine the structure of internalizing disorders from the bottom up, starting with narrowly defined symptom components.

A short form of the Recovery Assessment Scale-Domains and Stages: Development and validation among adults with anxiety disorders

The Recovery Assessment Scale-Domains and Stages (RAS-DS) is a 38-item self-report instrument measuring recovery from serious mental illness. We explored the suitability of the RAS-DS for individuals with anxiety disorders. A parsimonious short form of the scale was developed. Participants with anxiety disorder symptoms (N = 295) completed the RAS-DS, DASS-21 and GAD-7. Confirmatory factor analysis supported the expected four-factor structure. Associations with related scales exhibited the expected pattern supporting construct validity in this population. The Recovery Assessment Scale-Short Form (RAS-SF) was derived by inspection of factor loadings and modification indices, yielding a 20-item scale with five items per subscale. Strong correlations between subscales confirmed the total score represented a valid overarching measure of recovery. The present study indicates that recovery is pertinent to individuals with anxiety disorders. Development of the short-form RAS-SF affords opportunity for routine measurement of recovery in populations with anxiety and other high prevalence conditions.

Involvement of fear, incompleteness, and disgust during symptoms of pediatric obsessive-compulsive disorder

Fear has been assigned a central role in models of obsessive-compulsive disorder (OCD), but empirical investigations into the emotions that underpin OCD symptoms are few, especially in pediatric samples. Using validated, clinician-led structured interviews, 124 youth with OCD reported on the presence and severity of symptoms across the main symptom dimensions of OCD (aggressive, symmetry, contamination) and the degree to which fear, incompleteness, and disgust accompanied these symptoms. For comparison purposes, the degree of fear, incompleteness, and disgust during symptoms was obtained also from youth with social anxiety disorder (SAD; n = 27) and generalized anxiety disorder (GAD; n = 28). Participants with OCD reported that all three emotions were involved in their symptoms; however, fear was most strongly linked to aggressive symptoms, incompleteness to symmetry symptoms, and disgust to contamination symptoms. Incompleteness differentiated youth with OCD from those with SAD and GAD. No differences for these emotions were found for youth with OCD with versus without the tic-disorder subtype or comorbid autism. A positive association between incompleteness and self-reported hoarding emerged among youth with OCD. Further studies of the emotional architecture of pediatric OCD, and its relationship to etiology and treatment, are warranted.

Internalized psychopathology dimensions in middle childhood: Cross-sectional and temporal associations

BACKGROUND

Anxiety, depression, and obsessive-compulsive symptoms often onset during middle childhood and are major causes of disability in young individuals. A better understanding of how these symptoms are linked and unfold over time is important to develop valid etiological models and effective prevention and treatment.

METHODS

In the present study, 950 community children (8-14 years) reported on a broad range of internalised symptoms at three time points over the course of a year. First, factor analysis was used to examine the overarching dimensions of these symptoms. Second, network analysis was used to examine unique cross-sectional associations among these empirically supported symptom dimensions. Last, longitudinal structural equation models (SEMs) were used to examine temporal associations among the symptom dimensions.

RESULTS

Six broad symptom dimensions fitted the self-report data well at all time points. These dimensions were conceptualized as depression, general anxiety, situational fears, compulsivity, intrusive thoughts, and somatic anxiety. Network analysis showed that these dimensions formed a highly interconnected network with general anxiety and somatic anxiety being most central (i.e., most strongly associated with other dimensions) at all time points. Longitudinal SEMs supported the central role played by general anxiety in the temporal associations among these dimensions.

CONCLUSIONS

Overarching expressions of internalized psychopathology are highly interconnected in middle childhood with possible central roles played by general and somatic anxiety. Interventions aimed at a general proneness for anxiety may be warranted in preventing and treating internalizing symptoms in middle childhood.

COVID-19 Pandemic and Mental Health: Prevalence and Correlates of New-Onset Obsessive-Compulsive Symptoms in a Canadian Province

Background: This cross-sectional online survey investigates the prevalence of obsessive-compulsive disorder (OCD) symptoms at an early stage of the COVID-19 pandemic in Canada. Methods: OCD symptoms, moderate/high stress, likely generalized anxiety disorder (GAD) and likely major depressive disorder (MDD) were assessed with the Brief Obsessive-Compulsive Scale (BOCS), Perceived Stress Scale (PSS), Generalized Anxiety Disorder 7-item (GAD-7) scale, and Patient Health Questionnaire-9 (PHQ-9) scale, respectively. Results: Out of 32,805 individuals subscribed to Text4Hope, 6041 completed an online survey; the response rate was 18.4%. Overall, 60.3% of respondents reported onset of OCD symptoms and 53.8% had compulsions to wash hands during the COVID-19 pandemic. Respondents who showed OCD symptoms only since the start of COVID-19 were significantly more likely to have moderate/high stress (z = 6.4, p < 0.001), likely GAD (z = 6.0, p < 0.001), and likely MDD (z = 2.7, p < 0.01). Similarly, respondents who engaged in compulsive hand washing were significantly more likely to have moderate/high stress (z = 4.6, p < 0.001) and likely GAD (z = 4.6 p < 0.001), but not likely MDD (z = 1.4, p = 0.16). Conclusion: The prevalence of OCD symptoms increased during the COVID-19 pandemic, at a rate significantly higher than pre-pandemic rates reported for the sample population. Presenting with OCD symptoms increased the likelihood of presenting with elevated stress, likely GAD, and likely MDD.

Heritability of overlapping impulsivity and compulsivity dimensional phenotypes

Impulsivity and compulsivity are traits relevant to a range of mental health problems and have traditionally been conceptualised as distinct constructs. Here, we reconceptualised impulsivity and compulsivity as partially overlapping phenotypes using a bifactor modelling approach and estimated heritability for their shared and unique phenotypic variance within a classical twin design. Adult twin pairs (N = 173) completed self-report questionnaires measuring psychological processes related to impulsivity and compulsivity. We fitted variance components models to three uncorrelated phenotypic dimensions: a general impulsive-compulsive dimension; and two narrower phenotypes related to impulsivity and obsessiveness.There was evidence of moderate heritability for impulsivity (A² = 0.33), modest additive genetic or common environmental effects for obsessiveness (A² = 0.25; C² = 0.23), and moderate effects of common environment (C² = 0.36) for the general dimension, This general impulsive-compulsive phenotype may reflect a quantitative liability to related mental health disorders that indexes exposure to potentially modifiable environmental risk factors.

Obsessive-compulsive symptoms and their links to depression and anxiety in clinic- and community-based pediatric samples: A network analysis

BACKGROUND

Symptoms of depression and anxiety are common in children with obsessive-compulsive disorder (OCD) and associated with more severe OCD, greater impairment, and worse treatment outcome. Beyond twin studies showing that genetic factors contribute to the high co-occurrence, few studies have examined how OCD, depression, and anxiety are linked in youth, and current studies often fail to account for OCD and anxiety heterogeneity.

METHODS

Network analysis was used to investigate how OCD were linked to depression and anxiety in multinational youth diagnosed with OCD (total n = 419) and in school-recruited, community-based samples of youth (total n = 2 991).

RESULTS

Initial results aligned with earlier work showing that severity of obsession-related symptoms are important in linking OCD to depression in youth with OCD. However, when symptom content of OCD (e.g., washing, ordering) was fully taken into account and when measures of anxiety were included, specific OCD symptom dimensions (primarily obsessing and doubting/checking) were linked to specific anxiety dimensions (primarily panic and generalized anxiety) which in turn were linked to depression. These results were replicated in three separate community-based samples from Chile, Italy, and Spain using different measures of anxiety and depression.

LIMITATIONS

Cross-sectional data were analyzed which precludes causal inference. Self-report measures were used.

CONCLUSIONS

Youth with OCD with symptoms related to doubting/checking and obsessing should be carefully assessed for symptoms of panic and generalized anxiety. Non-responders to standard OCD treatment may benefit from interventions targeting panic and generalized anxiety, but more research is needed to test this hypothesis.

Obsessive-Compulsive Symptoms in Obsessive-Compulsive Disorder and in Generalized Anxiety Disorder: Occurrence and Correlations

OBJECTIVE

Because of the heterogeneity of obsessive-compulsive disorders (OCDs) and their co-occurrence with anxiety disorders, we investigated the prevalence, severity, and correlations between obsessive and compulsive symptoms reported by patients diagnosed with OCD or generalized anxiety disorder (GAD).

METHODS

A retrospective study was conducted in 2 groups of patients: 76 patients diagnosed with OCD [F42 according to the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10)], and 186 patients diagnosed with GAD (F41.1 according to ICD-10), who had presented for therapy at the day ward. The Symptom Questionnaire "O," based on the Symptom Checklist 90-Revised (SCL-90-R) questionnaire, was used to assess obsessive, compulsive, and anxiety symptoms. The analysis took into account the impact of sex and the presence or absence of cognitive dysfunction (as assessed using the Bender Benton Visual Retention and Bender-Gestalt tests) on the associations being investigated.

RESULTS

We observed that obsessive and compulsive symptoms were more prevalent and more strongly expressed in the group with OCD than in the group with GAD. However, almost all patients with GAD (94%) confirmed the presence of some obsessive-compulsive symptoms. The study revealed differences in correlations with obsessions and compulsions between the OCD and GAD groups. In the group with OCD, no significant correlation between the severity of obsessions and compulsions was identified, whereas in the group with GAD, a significant positive correlation was found between the severity of those symptoms. In both the GAD and OCD groups, a greater intensity of obsessive-compulsive symptoms was accompanied by an increase in the severity of anxiety symptoms (with this effect noted to a greater extent with obsessions than compulsions).

CONCLUSIONS

The study revealed that patients with GAD often have coexisting obsessive-compulsive symptoms, which may not be identified during routine psychiatric examination. Obsessive-compulsive symptoms observed in patients with GAD may show a different structure than obsessive-compulsive symptoms in patients with OCD. The results of this study suggest that compulsions are more specific for the diagnosis of OCD than obsessions. Compulsions, such as counting related to the need for order and symmetry, may be associated with some cognitive dysfunctions and male sex, a finding that requires further research.

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.

Assessing the evidence for shared genetic risks across psychiatric disorders and traits

Genetic influences play a significant role in risk for psychiatric disorders, prompting numerous endeavors to further understand their underlying genetic architecture. In this paper, we summarize and review evidence from traditional twin studies and more recent genome-wide molecular genetic analyses regarding two important issues that have proven particularly informative for psychiatric genetic research. First, emerging results are beginning to suggest that genetic risk factors for some (but not all) clinically diagnosed psychiatric disorders or extreme manifestations of psychiatric traits in the population share genetic risks with quantitative variation in milder traits of the same disorder throughout the general population. Second, there is now evidence for substantial sharing of genetic risks across different psychiatric disorders. This extends to the level of characteristic traits throughout the population, with which some clinical disorders also share genetic risks. In this review, we summarize and evaluate the evidence for these two issues, for a range of psychiatric disorders. We then critically appraise putative interpretations regarding the potential meaning of genetic correlation across psychiatric phenotypes. We highlight several new methods and studies which are already using these insights into the genetic architecture of psychiatric disorders to gain additional understanding regarding the underlying biology of these disorders. We conclude by outlining opportunities for future research in this area.

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.

The classification of body dysmorphic disorder symptoms in male and female adolescents

BACKGROUND

Body dysmorphic disorder (BDD) was categorised in DSM-5 within the newly created 'obsessive-compulsive and related disorders' chapter, however this classification remains subject to debate. Confirmatory factor analysis was used to test competing models of the co-occurrence of symptoms of BDD, obsessive-compulsive disorder, unipolar depression, anxiety, and eating disorders in a community sample of adolescents, and to explore potential sex differences in these models.

METHODS

Self-report questionnaires assessing disorder symptoms were completed by 3149 Australian adolescents. The fit of correlated factor models was calculated separately in males and females, and measurement invariance testing compared parameters of the best-fitting model between males and females.

RESULTS

All theoretical models of the classification of BDD had poor fit to the data. Good fit was found for a novel model where BDD symptoms formed a distinct latent factor, correlated with affective disorder and eating disorder latent factors. Metric non-invariance was found between males and females, and the majority of factor loadings differed between males and females. Correlations between some latent factors also differed by sex.

LIMITATIONS

Only cross-sectional data were collected, and the study did not assess a broad range of DSM-5 defined eating disorder symptoms or other disorders in the DSM-5 obsessive-compulsive and related disorders chapter.

CONCLUSIONS

This study is the first to statistically evaluate competing models of BDD classification. The findings highlight the unique features of BDD and its associations with affective and eating disorders. Future studies examining the classification of BDD should consider developmental and sex differences in their models.

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.