Segregation analysis of obsessive-compulsive disorder using symptom-based factor scores

Clinical characteristics of probands with obsessive-compulsive disorder from simplex and multiplex families

Genetic and non-genetic factors contribute to obsessive-compulsive disorder (OCD), with strong evidence of familial clustering. Genomic studies in psychiatry have used the concepts of families that are "simplex" (one affected) versus "multiplex" (multiple affected). Our study compares demographic and clinical data from OCD probands in simplex and multiplex families to uncover potential differences. We analyzed 994 OCD probands (501 multiplex, 493 simplex) from the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders (C-TOC). Clinicians administered the Structured Clinical Interview for DSM-IV (SCID-IV) to diagnose, Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) to assess severity, and Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) to assess symptom dimensionality. Demographics, clinical history, and family data were collected. Compared to simplex probands, multiplex probands had earlier onset, higher sexual/religious and hoarding dimensions severity, increased comorbidity with other obsessive-compulsive-related disorders (OCRD), and higher family history of psychiatric disorders. These comparisons provide the first insights into demographic and clinical differences between Latin American simplex and multiplex families with OCD. Distinct clinical patterns may suggest diverse genetic and environmental influences. Further research is needed to clarify these differences, which have implications for symptom monitoring and management.

Bidirectional Behavioral Selection in Mice: A Novel Pre-clinical Approach to Examining Compulsivity

Obsessive-compulsive disorder (OCD) and related disorders (OCRD) is one of the most prevalent neuropsychiatric disorders with no definitive etiology. The pathophysiological attributes of OCD are driven by a multitude of factors that involve polygenic mechanisms, gender, neurochemistry, physiological status, environmental exposures and complex interactions among these factors. Such complex intertwining of contributing factors imparts clinical heterogeneity to the disorder making it challenging for therapeutic intervention. Mouse strains selected for excessive levels of nest- building behavior exhibit a spontaneous, stable and predictable compulsive-like behavioral phenotype. These compulsive-like mice exhibit heterogeneity in expression of compulsive-like and other adjunct behaviors that might serve as a valuable animal equivalent for examining the interactions of genetics, sex and environmental factors in influencing the pathophysiology of OCD. The current review summarizes the existing findings on the compulsive-like mice that bolster their face, construct and predictive validity for studying various dimensions of compulsive and associated behaviors often reported in clinical OCD and OCRD.

A dimensional perspective on the genetics of obsessive-compulsive disorder

This review covers recent findings in the genomics of obsessive-compulsive disorder (OCD), obsessive-compulsive symptoms, and related traits from a dimensional perspective. We focus on discoveries stemming from technical and methodological advances of the past five years and present a synthesis of human genomics research on OCD. On balance, reviewed studies demonstrate that OCD is a dimensional trait with a highly polygenic architecture and genetic correlations to multiple, often comorbid psychiatric phenotypes. We discuss the phenotypic and genetic findings of these studies in the context of the dimensional framework, relying on a continuous phenotype definition, and contrast these observations with discoveries based on a categorical diagnostic framework, relying on a dichotomous case/control definition. Finally, we highlight gaps in knowledge and new directions for OCD genetics research.

Neurocognitive Endophenotypes of OCD

In this chapter, I address the concept of endophenotypes for obsessive-compulsive disorder (OCD). Endophenotypes are objective and heritable quantitative traits hypothesized to be more biologically tractable than distal clinical phenotypes. This approach has been adopted to gain a better understanding of psychiatric conditions in general. It is theorized that endophenotypes will particularly assist in clarifying both the diagnostic status and aetiological origins of complex neuropsychiatric conditions such as OCD. At the cognitive level, separable constructs of relevance for OCD have been identified. The prevailing model for OCD assumes the development of abnormalities within fronto-striatal neural circuits leading to impairment of executive functions and their neuropsychological subcomponents. Here, I address whether this model can guide towards the identification of endophenotypes for this condition and discuss possible implications.

Are There Familial Patterns of Symptom Dimensions in Obsessive-Compulsive Disorder?

Background: Obsessive-compulsive disorder (OCD) is a heterogeneous illness, and emerging evidence suggests that different symptom dimensions may have distinct underlying neurobiological mechanisms. We aimed to look for familial patterns in the occurrence of these symptom dimensions in a sample of families with at least two individuals affected with OCD. Methods: Data from 153 families (total number of individuals diagnosed with DSM-5 OCD = 330) recruited as part of the Accelerator Program for Discovery in Brain Disorders using Stem Cells (ADBS) was used for the current analysis. Multidimensional Item Response Theory (IRT) was used to extract dimensional scores from the Yale-Brown Obsessive-Compulsive Scale (YBOCS) checklist data. Using linear mixed-effects regression models, intra-class correlation coefficients (ICC), for each symptom dimension, and within each relationship type were estimated. Results: IRT yielded a four-factor solution with Factor 1 (Sexual/Religious/Aggressive), Factor 2 (Doubts/Checking), Factor 3 (Symmetry/Arranging), and Factor 4 (Contamination/Washing). All except for Factor 1 were found to have significant ICCs, highest for Factor 3 (0.41) followed by Factor 4 (0.29) and then Factor 2 (0.27). Sex-concordant dyads were found to have higher ICC values than discordant ones, for all the symptom dimensions. No major differences in the ICC values between parent-offspring and sib-pairs were seen. Conclusions: Our findings indicate that there is a high concordance of OCD symptom dimensions within multiplex families. Symptom dimensions of OCD might thus have significant heritability. In view of this, future genetic and neurobiological studies in OCD should include symptom dimensions as a key parameter in their analyses.

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.

Compulsivity is measurable across distinct psychiatric symptom domains and is associated with familial risk and reward-related attentional capture

BACKGROUND

Compulsivity can be seen across various mental health conditions and refers to a tendency toward repetitive habitual acts that are persistent and functionally impairing. Compulsivity involves dysfunctional reward-related circuitry and is thought to be significantly heritable. Despite this, its measurement from a transdiagnostic perspective has received only scant research attention. Here we examine both the psychometric properties of a recently developed compulsivity scale, as well as its relationship with compulsive symptoms, familial risk, and reward-related attentional capture.

METHODS

Two-hundred and sixty individuals participated in the study (mean age = 36.0 [SD = 10.8] years; 60.0% male) and completed the Cambridge-Chicago Compulsivity Trait Scale (CHI-T), along with measures of psychiatric symptoms and family history thereof. Participants also completed a task designed to measure reward-related attentional capture (n = 177).

RESULTS

CHI-T total scores had a normal distribution and acceptable Cronbach's alpha (0.84). CHI-T total scores correlated significantly and positively (all p < 0.05, Bonferroni corrected) with Problematic Usage of the Internet, disordered gambling, obsessive-compulsive symptoms, alcohol misuse, and disordered eating. The scale was correlated significantly with history of addiction and obsessive-compulsive related disorders in first-degree relatives of participants and greater reward-related attentional capture.

CONCLUSIONS

These findings suggest that the CHI-T is suitable for use in online studies and constitutes a transdiagnostic marker for a range of compulsive symptoms, their familial loading, and related cognitive markers. Future work should more extensively investigate the scale in normative and clinical cohorts, and the role of value-modulated attentional capture across compulsive disorders.

Obsessive-compulsive personality disorder traits and personality dimensions in parents of children with obsessive-compulsive disorder

Purpose

To compare patterns of temperament and character and the prevalence of Obsessive-Compulsive Personality Disorder (OCPD) and OCPD traits in parents of children with OCD and parents of healthy controls.

Methods

TCI and SCID-II were administered to 63 parents of 32 children with OCD and 63 parents of age- and sex-matched controls with no psychiatric diagnosis. Interviewers were not blind to proband status. Personality dimension scores and frequencies of OCPD criteria in both groups were compared after excluding parents with a diagnosis of OCD. Relationships between TCI dimensions and OCPD symptoms in parents and the clinical characteristics of OCD children were also studied.

Results

Parents of OCD children presented significantly higher scores in harm avoidance and lower scores in self-directedness, cooperativeness and reward dependence than parents of healthy children. A higher incidence of OCPD was found in parents of probands (p < 0.02). Hoarding, perfectionism and preoccupation with details were significantly more frequent in parents of OCD children. Counting, ordering and cleaning compulsions in OCD children predicted elevated odds of perfectionism and rigidity in their parents.

Conclusions

The existence of the dimensional personality profile associated with OCD in parents of children with OCD and the higher number of OCPD criteria in these parents in comparison to parents of healthy children highlight the importance of the role of personality factors in familial OCD.

What is at the core of OCD? A network analysis of selected obsessive-compulsive symptoms and beliefs

BACKGROUND

Obsessive-compulsive disorder (OCD) is a heterogeneous condition that consists of distinct subtypes, and identification of its core symptoms may inform how to best conceptualize the heterogeneity. Accordingly, we used network analysis to evaluate which symptoms (and associations between symptoms) are most central to OCD symptoms and beliefs.

METHODS

Participants consisted of a combined sample of adults with a primary diagnosis of OCD (N = 150), those with other primary diagnoses (N = 114), and an unselected nonclinical sample (N = 310). Network analysis was used to identify the most central symptoms (nodes) and associations between symptoms (edges) assessed by the Obsessive-Compulsive Inventory-Revised and the Obsessional Beliefs Questionnaire-44.

RESULTS

The most central symptoms in the network were negative appraisals of intrusive thoughts (i.e., Having intrusive thoughts means I'm out of control). Some of the strongest associations between symptoms were also observed for those pertaining to intrusive thoughts and their negative appraisal. Furthermore, central symptoms in the network predicted depression and anxiety (over and above peripheral symptoms) among those with a primary diagnosis of OCD, but not the severity of OCD symptoms.

LIMITATIONS

The approach was exploratory rather than experimental and relied solely on self-report measures of OCD symptoms and beliefs.

CONCLUSIONS

Negative appraisals of intrusive thoughts were the most central symptoms in the OCD network, and they uniquely predict co-occurring symptoms of anxiety and depression, suggesting that these symptoms should be prioritized in theoretical and treatment models of OCD.

No Association of Variants of the NPY-System With Obsessive-Compulsive Disorder in Children and Adolescents

Obsessive-compulsive disorder (OCD) causes severe distress and is therefore counted by the World Health Organisation (WHO) as one of the 10 most impairing illnesses. There is evidence for a strong genetic underpinning especially in early onset OCD (eoOCD). Though several genes involved in neurotransmission have been reported as candidates, there is still a need to identify new pathways. In this study, we focussed on genetic variants of the Neuropeptide Y (NPY) system. NPY is one of the most abundant neuropeptides in the human brain with emerging evidence of capacity to modulate stress response, which is of high relevance in OCD. We focussed on tag-SNPs of NPY and its receptor gene NPY1R in a family-based approach. The sample comprised 86 patients (children and adolescents) with eoOCD with both their biological parents. However, this first study on genetic variants of the NPY-system could not confirm the association between the investigated SNPs and eoOCD. Based on the small sample size results have to be interpreted as preliminary and should be replicated in larger samples. However, also in an additional GWAS analysis in a large sample, we could not observe an associations between NPY and OCD. Overall, these preliminary results point to a minor role of NPY on the stress response of OCD.

Association of HTR1A gene polymorphisms with obsessive-compulsive disorder and its treatment response: the influence of sex and clinical characteristics

OBJECTIVE

There have been controversial results in the literature on the association between HTR1A polymorphisms (rs10042486, C-1019G, and Gly272Asp) and obsessive-compulsive disorder (OCD). Here, the plausibility for such genetic and pharmacogenetic association was investigated by assessing a sample of Iranian OCD patients.

METHOD

OCD patients had fulfilled the criteria for DSM-IV-TR with Y-BOCS scores higher than 9. A total of 207 controls and 205 patients' blood samples were genotyped by means of PCR-RFLP.

RESULTS

The results showed that there was no association between these three SNPs and the treatment response. The distribution of rs10042486 genotypes was significantly different in the patients compared to the controls. The association analyses of the C-1019G showed significant differences in the genotypic frequency of the patients with or without a positive family history of psychiatric disorders. Similar differences in female patients were also observed. We found that the age of onset also associates with the C-1019G polymorphism but only in the female patients. No association of Gly272Asp polymorphism and OCD was observed in this study.

CONCLUSION

We concluded that among the HTR1A polymorphisms, only the association of rs10042486 CT genotype and OCD was statistically significant. The association of C-1019G with OCD by considering the age of onset and family history was just significant in the female patients. No significant association between the studied HTR1A SNPs with treatment response was observed. Acquiring both positive and negative pharmacogenetic outcomes in each population helps to select the appropriate medication for a particular patient with fewer side effects.

Genetic susceptibility in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is present in 1.5-2.5% of the population and can result in substantial lifelong disability. It is characterized by intrusive thoughts, sensations, and urges and by repetitive behaviors that are difficult to control despite, in most cases, preserved insight as to their excessive or irrational nature. The causes and underlying pathophysiology of OCD are not well understood, which has limited the development of new treatments and interventions. Despite evidence for a substantial genetic contribution to disease risk, identification and replication of genetic variants associated with OCD have been challenging. Decades of candidate gene association studies have provided little insight. They are now being supplanted by modern genomewide approaches to discover both common and rare sequence and structural variants. Studies to date suggest potential novel therapeutic avenues such as modulators of glutamatergic and immune pathways; however, individual genetic findings are not yet statistically robust or replicated. Further efforts are clearly needed to identify specific risk variants and to confirm vulnerable pathways by studying much larger cohorts of patients with comprehensive variant discovery approaches. Mouse knockout models have already made notable inroads into our understanding of OCD pathology; their utility will only increase as specific risk alleles are identified.

Exploring yale-brown obsessive-compulsive scale symptom structure in Iranian OCD patients using item-based factor analysis

Obsessive compulsive disorder (OCD) is a heterogeneous psychiatric disorder. This study aimed to reach a comprehensive perspective of OCD symptoms in Iranian patients. Item-based factor analysis of Y-BOCS checklist from 216 outpatients resulted in five factors including aggression/checking, contamination/cleaning, symmetry/ordering/repeating/counting/hoarding, sexual and somatic. Regression analyses showed that miscellaneous items can be predicted by these factors. Results showed that OCD subtypes in Iranian patients resemble to those of other nations except the aggressive, sexual and religious obsessions; demonstrating the influence of the culture on obsession manifestation. The correlation analyses of factors and clinical characteristics demonstrated that aggression/checking was associated with high obsession scores and more avoidance. Contamination/cleaning was correlated with higher compulsion score. Patients with higher scores on symmetry/ordering/counting/repeating/hoarding had familial OCD pattern with earlier age of onset, lower age at assessment, higher obsession and more avoidance. Sexual factor was associated with less compulsion scores and somatic factor was associated with higher obsessions and compulsions as well as less familial history and more avoidance. These findings provide a comprehensive view of OCD symptom structure in Iranian OCD patients and will be of value to studies using symptom factor to lead investigation of its causes, correlates and treatment strategies considering cross-cultural differences.

The familiality of specific symptoms of obsessive-compulsive disorder

This study aimed to assess whether a family history of specific OCD symptoms was associated with the same OCD symptoms in study participants. Participants were sampled from the Nepean OCD study (N=206) and were assessed with the Yale-Brown Obsessive-Compulsive Scale Symptom Checklist (YBOCS-SC) and the Vancouver Obsessional Compulsive Inventory (VOCI) in order to determine their OCD symptoms. A family history screen was used to determine whether participants had a first-degree relative with a history of any of the following specific symptoms: hoarding, contamination/cleaning, symmetry/ordering, doubt/checking and/or other OCD symptoms. The characteristics of participants with a family history of a specific OCD symptom were compared to those of participants with a family history of any other OCD symptom. This was repeated for each specific OCD symptom. The roles of co-occurring tics and age of onset of OCD were also assessed. Distinct familial associations were detected for the symptoms of hoarding and contamination/cleaning. Age of onset of OCD was significantly younger in participants who reported a family history of "other" symptoms. These findings suggest that certain OCD symptom dimensions are more familial than others, which has significant implications for aetiology of OCD.

Clinical significance of psychiatric comorbidity in children and adolescents with obsessive-compulsive disorder: subtyping a complex disorder

A promising approach in relation to reducing phenotypic heterogeneity involves the identification of homogeneous subtypes of OCD based on age of onset, gender, clinical course and comorbidity. This study aims to assess the sociodemographic characteristics and clinical features of OCD patients in relation to gender and the presence or absence of another comorbid disorder. The sample comprised 112 children and adolescents of both sexes and aged 8-18 years, all of whom had a diagnosis of OCD. Overall, 67 % of OCD patients had one comorbid diagnosis, 20.5 % had two such diagnoses and 2.6 % had three comorbid diagnoses. The group of OCD patients with a comorbid neurodevelopmental disorder had significantly more family history of OCD in parents (p = .049), as compared with the no comorbidity group and the group with a comorbid internalizing disorder, and they also showed a greater predominance of males (p = .013) than did the group with a comorbid internalizing disorder. The group of OCD patients with internalizing comorbidity had a later age of onset of OCD (p = .001) compared with both the other groups. Although the initial severity was similar in all three groups, the need for pharmacological treatment and for hospitalization due to OCD symptomatology was greater in the groups with a comorbid neurodevelopmental disorder (p = .038 and p = .009, respectively) and a comorbid internalizing disorder (p = .008 and p = .004, respectively) than in the group without comorbidity. Our findings suggest that two subtypes of OCD can be defined on the basis of the comorbid pathology presented. The identification of different subtypes according to comorbidity is potentially useful in terms of understanding clinical variations, as well as in relation to treatment management and the use of therapeutic resources.

Psychometric properties of the DY-BOCS in a Turkish sample of children and adolescents

BACKGROUND

Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS) is a promising scale for assessing frequency and severity of symptom dimensions. The main objective of the study was to assess the psychometric properties of the DY-BOCS in a large sample of children and adolescents from Turkey.

METHODS

We studied 143 children and adolescents, 7-18years, with well characterized DSM-IV-R OCD, ascertained from seven collaborating university or state hospital sites. We compared the DY-BOCS scores with the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS), the Children's Depression Inventory (CDI), the Yale Global Tic Severity Scale (YGTSS) and the Child Behavior Checklist 6-18years (CBCL 6-18).

RESULTS

The internal consistency of the DY-BOCS symptom dimensions and inter-rater agreement of component scores were excellent. The agreement between global DY-BOCS score and the total CY-BOCS score was highly significant (Pearson's r=0.55, p<0.0001). Severity scores for individual symptom dimensions were independent of one another, only modestly correlating with the global ratings, and were also differentially related to ratings of depression, anxiety and tic severity.

CONCLUSION

The DY-BOCS is a reliable and valid instrument for assessing multiple aspects of OCD symptom severity in children and adolescents from Turkey.

Incompleteness, aesthetic sensitivity, and the obsessive-compulsive need for symmetry

BACKGROUND AND OBJECTIVES

The "need for symmetry" is a well recognized yet little understood feature of obsessive-compulsive (OC) experience. In light of the strong associations between the OC-related trait of incompleteness and symmetry-related behaviors and symptoms, and between perceptual symmetry and aesthetic judgments, this study examined whether trait incompleteness is associated with enhanced natural aesthetic skill and/or aesthetic sensitivity, particularly as they pertain to visual symmetry.

METHODS

A quasi-experimental design was used to compare the responses of nonclinical individuals with high versus average levels of trait incompleteness on self-report measures and two performance measures of aesthetic judgment.

RESULTS

Compared to controls, participants high in incompleteness reported higher levels of self-perceived symmetry-related concerns and behaviors, and displayed greater aesthetic sensitivity in the form of substantially heightened preferences for symmetry in images. Contrary to the hypothesis relating to aesthetic skill, however, the two groups did not differ in their capacity to estimate accurately the objective aesthetic value of images. Nor did they differ in self-reported aesthetics interests and background.

LIMITATIONS

A clinical sample was not included.

CONCLUSIONS

Findings provide evidence that high trait incompleteness is associated not just with symptomatic symmetry-related concerns but with a nonspecific heightened preference for visual symmetry. Conceptual implications are discussed, particularly the potential value of the perceptual fluency theory of symmetry and aesthetic response for explaining the association between incompleteness and symmetry preferences and symptoms.

Obsessive-compulsive symptom dimensions in a population-based, cross-sectional sample of school-aged children

BACKGROUND

Obsessive-compulsive disorder can be expressed as four potentially overlapping obsessive-compulsive symptom (OCS) dimensions (OCSD) ("symmetry/ordering", "contamination/cleaning", "aggressive/sexual/religious" and "collecting/hoarding"). In clinical samples, some dimensions are more familial and associated with increased psychiatric comorbidity and malfunctioning. However, data concerning OCS and OCSD are scarce in non-clinical samples, particularly among children. The present study aims to estimate: (1) the prevalence and sex/age distribution of OCS/OCSD in a community-based sample of schoolchildren; (2) the association between OCS and additional clinical factors; and (3) the degree of familial aggregation of OCS/OCSD.

METHODS

OCS and OCSD were evaluated in 9937 Brazilian school-children (6-12 years-old) and their biological relatives using the Family History Screen. Data analyses included gradient estimated equations and post-hoc tests.

RESULTS

We included data on 9937 index-children, 3305 siblings (13-18 years-old), and 16,218 parents. Biological mothers were the informants in 87.6% of the interviews. OCS were present in 14.7% of the index-children; 15.6% of their siblings; 34.6% of their mothers and 12.1% of their fathers. The prevalence of OCS and each of the OCSD gradually increased from ages 6 to 12 years. Overall, OCS in children were associated with the presence of other psychiatric symptoms, as well as behavioral/school impairment. OCS and each of the four OCSD aggregated significantly within families.

CONCLUSIONS

OCS are prevalent and associated with psychiatric symptoms and clinical impairment among school-aged children. OCSD aggregate within families in a dimension-specific fashion. These findings suggest a natural continuum between OCS and OCD with regard to their dimensional character.

Microstructural brain abnormalities and symptom dimensions in child and adolescent patients with obsessive-compulsive disorder: a diffusion tensor imaging study

BACKGROUND

The aims of this study were to determine white matter (WM) microstructure abnormalities in obsessive-compulsive disorder (OCD) using diffusion tensor imaging, and to investigate whether these abnormalities differ according to OCD symptom dimensions.

METHODS

Sixty-three child and adolescent OCD patients (11-18 years old) and 37 healthy subjects matched for gender, age, and estimated intelligence quotient were assessed by means of psychopathology scales and diffusion tensor magnetic resonance imaging.

RESULTS

Compared with healthy controls OCD patients showed a significant decrease (t = 3.79, P = .049 FDR-corrected) in fractional anisotropy (FA) in the anterior region of the corpus callosum (CC). In addition, mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) values were significantly increased in OCD compared with controls in the CC and in several WM regions of the cingulate, frontal and occipital lobes, basal ganglia, cerebellum, and pons. Compared with healthy controls, OCD patients presenting the harm/checking dimension showed decreased FA in the CC and in the left anterior cingulate gyrus and caudate nucleus, whereas patients with a predominant contamination/washing symptom dimension presented significantly decreased FA in the left midbrain, lentiform nucleus, insula, and thalamus, and increased MD, AD, and RD in both the anterior lobes of cerebellum and in the pons.

CONCLUSIONS

The findings suggest WM abnormalities at the microstructural level in the pathogenesis of OCD. Moreover, WM abnormalities in OCD may vary according to the specific OCD symptom dimensions, thus indicating the clinical heterogeneity of the condition.

White matter structural alterations in pediatric obsessive-compulsive disorder: relation to symptom dimensions

The aims of this study were to identify gray matter (GM) and white matter (WM) volume abnormalities in pediatric obsessive-compulsive patients, to examine their relationship between these abnormalities and the severity of disorder, and to explore whether they could be explained by the different symptom dimensions.

METHODS

62 child and adolescent OCD patients (11-18years old) and 46 healthy subjects of the same gender and similar age and estimated intellectual quotient were assessed by means of psychopathological scales and magnetic resonance imaging (MRI). Axial three-dimensional T1-weighted images were obtained in a 3T scanner and analyzed using optimized voxel-based morphometry (VBM).

RESULTS

Compared with healthy controls, OCD patients showed lower white matter (WM) volume in the left dorsolateral and cingulate regions involving the superior and middle frontal gyri and anterior cingulate gyrus (t=4.35, p=0.049 FWE (family wise error)-corrected). There was no significant correlation between WM and the severity of obsessive-compulsive symptomatology. There were no regions with lower gray matter (GM) volume in OCD patients than in controls. Compared with healthy controls, only the "harm/checking" OCD dimension showed a cluster with a near significant decrease in WM volume in the right superior temporal gyrus extending into the insula (t=5.61, p=.056 FWE-corrected).

CONCLUSION

The evidence suggests that abnormalities in the dorsolateral prefrontal cortex, anterior cingulate cortex, temporal and limbic regions play a central role in the pathophysiology of OCD. Moreover, regional brain volumes in OCD may vary depending on specific OCD symptom dimensions, indicating the clinical heterogeneity of the condition.

Comparison of clinical characteristics of familial and sporadic obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a heterogeneous condition with evidence of familiality in a considerable proportion of patients. A classification into familial and sporadic forms has been proposed to explain the heterogeneity. The current study aims to compare the demographic, clinical and comorbidity patterns of patients with and without a family history of OCD in first-degree relatives.

METHOD

802 consecutive patients who consulted a specialty OCD Clinic at a tertiary care psychiatric hospital in India were evaluated with the Mini-International Neuropsychiatric Interview, the Yale-Brown Obsessive-Compulsive Scale, and the Clinical Global Impression Scale. Family history was assessed by interviewing patients and at least one first-degree relative.

RESULTS

Family history of OCD was seen in 152 patients (19%). Family history was associated with juvenile onset (Χ(2)=19.472, p<0.001), obsessions of contamination (Χ(2)=6.658, p=0.01), hoarding (Χ(2)=4.062, p=0.032), need for symmetry (Χ(2)=3.95, p=0.047), washing compulsion (Χ(2)=7.923, p=0.005), ordering compulsions (Χ(2)=6.808, p=0.009), repeating compulsions (Χ(2)=4.950, p=0.026) and compulsions by proxy (Χ(2)=7.963, p=0.005). Family history was also associated with greater severity of OCD (t=-2.31, p=0.022) and compulsions (t=-3.09, p=0.002) and longer duration of illness at presentation (t=-2.93, p=0.004).

CONCLUSION

Our findings suggest that familial OCD may have distinctive clinical features. Studying familial forms of OCD may offer unique insight in to understanding the genetic basis of OCD.

Distinct functional connectivity of limbic network in the washing type obsessive-compulsive disorder

Neurobiological models of obsessive-compulsive disorder (OCD) emphasize disturbances of the corticostriatal circuit, but it remains unclear as to how these complex network dysfunctions correspond to heterogeneous OCD phenotypes. We aimed to investigate corticostriatal functional connectivity alterations distinct to OCD characterized predominantly by contamination/washing symptoms. Functional connectivity strengths of the striatal seed regions with remaining brain regions during the resting condition and the contamination symptom provocation condition were compared among 13 OCD patients with predominant contamination/washing symptoms (CON), 13 OCD patients without these symptoms (NCON), and 18 healthy controls. The CON group showed distinctively altered functional connectivity between the ventral striatum and the insula during both the resting and symptom-provoking conditions. Also, the connectivity strength between the ventral striatum and the insula significantly correlated with contamination/washing symptom severity. As common connectivity alterations of the whole OCD subjects, corticostriatal circuits involving the orbitofrontal and temporal cortices were again confirmed. To our knowledge, this is the first study that examined specific abnormalities in functional connectivity of contamination/washing symptom dimension OCD. The findings suggest limbic network dysfunctions to play a pivotal role in contamination/washing symptoms, possibly associated with emotionally salient error awareness. Our study sample allowed us to evaluate the corticostriatal network dysfunction underlying the contamination/washing symptom dimension, which leaves other major symptom dimensions to be explored in the future.

Differential Parental Influence in the Familial Aggregation of Obsessive Compulsive Disorder

The familial nature of OCD has been well established. Clinical characteristics such as early age of onset, comorbidity with tic disorders, and higher rates of symmetry symptoms have been associated with the familial aggregation of OCD, though little research has examined the differential impact of paternal and maternal OCD. The current study explored parental influence on the expression of these characteristics and reports on 310 probands diagnosed with OCD as well as 1,580 of their biological first-degree relatives. The probands were evaluated by trained clinical raters using semi-structured assessments, and relative diagnoses were obtained based on probands' reports. Similar to previous findings, 10.13% of the 1,580 relatives (n = 160) were reported to have significant OCD symptoms. Only probands who reported having a father with OCD, rather than any first-degree relative, were more likely to have an early age of onset, symmetry and exactness obsessions, and higher rates of comorbidity. No significant differences were found with respect to the probands who reported their mothers as having OCD. These findings suggest that paternal OCD, rather than simply any first-degree relative having OCD, may influence whether probands exhibit the clinical characteristics commonly associated with the familial subtype of OCD.

Latent class analysis of obsessive-compulsive symptoms in a clinical sample

OBJECTIVE

Obsessive-compulsive disorder (OCD) is probably a heterogeneous condition. To date, research investigating the symptom structure of OCD has generally focused on variable-classification approaches, primarily factor analysis. Our aim was to use the latent class analysis, an advanced individual-classification method, in order to define homogeneous sub-groups based on the Yale-Brown Obsessive-Compulsive Scale Check List (Y-BOCS CL) assessments within 193 outpatients with OCD.

METHOD

Latent class analysis of 13 obsessive-compulsive symptom-clusters measured by the Yale-Brown Obsessive-Compulsive Scale Check List was performed. Associations of demographic and clinical features with latent class membership were tested by using logistic regression models. Differences in severity of obsessive-compulsive symptoms, obsessive beliefs, and depressive symptomotology between latent classes were evaluated with the chi-square likelihood test.

RESULTS

Latent class analysis models of best fit yielded 3 latent classes: "autogenous obsessions", "reactive obsessive-compulsive", and "reactive obsessions". Outpatients in reactive obsessive-compulsive group reported significantly higher scores on the Y-BOCS global, obsessions, and compulsions scales than outpatients in other two sub-groups. Participants in reactive obsessive-compulsive group were predominantly female, single, and had a history of family psychopathology; whereas autogenous and reactive obsessions groups were predominantly male. There were no differences in severity of depression and obsessive belief domains.

CONCLUSIONS

The results provide support for the validity of autogenous/reactive distinction for OCD. These three classes may have important implications for research and clinical purposes.

Genetics of obsessive–compulsive disorder: a research update

The genetic study of obsessive-compulsive disorder (OCD) has made significant gains in the past decade. However, etiological gene findings are still elusive. Epidemiological studies, including family and twin studies, strongly support a genetic component for OCD. In addition, complex segregation analyses suggest the presence of at least one major gene. The neurobiology of OCD also lends support to the notion that programmed CNS-based biological processes underlie OCD symptom expression, with mapping of brain circuits to fronto-subcortical circuits in a consistent manner. Genetic linkage studies of OCD, using families with multiple affected relatives, have generated several suggestive linkage peaks, regions that may harbor a gene or genes for OCD. However, the presence of multiple linkage peaks has added to the complexity of OCD genetics, suggesting that the exploration of gene-gene interactions and gene-environment interactions, in addition to the exploration of alternate phenotypes based on symptom expression, age at onset or comorbid conditions, may be key in locating etiologic genes. Finally, candidate gene studies, while promising, are not yet associated with linkage regions, except in the case of the glutamate transporter gene SLC1A1 in 9p24. While OCD appears to have a genetic component, additional innovative research is needed to unravel the genetic influences in the disorder.

Development and validation of a computer-based measure of symmetry and arranging behavior in obsessive-compulsive disorder: a preliminary study

OBJECTIVE

While compulsive ordering and arranging, and a preoccupation with symmetry are common presentations of obsessive-compulsive disorder (OCD), little attention has been given to these types of symptoms in the assessment of patients with OCD. The goal of the present study was to develop and evaluate psychometric properties for the objective and quantitative measurement of compulsive symptoms related to symmetry and arranging.

METHODS

Thirty-five normal volunteers performed computer-simulated environment tasks under four different conditions with or without a target and distraction. Primary dependent variables included several indices of time and manipulation of arranging behaviors. We evaluated the validity of the task by comparing the novel behavioral measures with standardized measures such as the Symmetry, Ordering and Arranging Questionnaire (SOAQ), Obsessive Compulsive Inventory-Revised (OCI-R), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Barratt Impulsiveness Scale (BIS-11), and Quality of Life Scale (WHOQOL).

RESULTS

We found a significant positive correlation between the arrangement time (time to complete the task) with the SOAQ score and the "ordering" subscore of the OCI-R. In addition, the number of manipulations was positively correlated with the SOAQ score and the "ordering" subscore of the OCI-R. There were no significant correlations between behavioral parameters and other scales measuring constructs less relevant to the symptoms of OCD related to ordering/symmetry. There was only a significant main effect of the target on the arrangement time.

CONCLUSION

This study demonstrates the good convergent and discriminant validity of this task as a novel behavioral measure for the assessment of arranging compulsion symptoms. We can infer from the results that subjects are likely to spend more time in compulsive arranging when the target for the task is given.

DRD4 gene and obsessive compulsive disorder: do symptom dimensions have specific genetic correlates?

INTRODUCTION

The dopamine D4 receptor (DRD4) is a promising candidate gene in obsessive compulsive disorder (OCD). A 48-bp variable number of tandem repeats (VNTR) sequence in exon 3 has been studied previously, and alleles containing 2-11 repeats (2R-11R) have been identified. We investigated the association of DRD4 VNTR polymorphism with OCD and its relationship with various clinical parameters (age of onset, gender, family history, co-morbidity, factor-analyzed symptom dimensions and insight).

METHODOLOGY

One hundred and seventy three South Indian OCD patients (DSM-IV) recruited from a specialty OCD clinic were evaluated using the Yale-Brown obsessive compulsive scale (YBOCS), YBOCS item-11 for insight, Mini International Neuropsychiatric Interview (MINI) plus, tic disorder subsection of the MINI-KID and Clinical Global Impression scale. 201 healthy controls were evaluated using MINI plus. All subjects were genotyped for the DRD4 VNTR polymorphism.

RESULTS

Genotype frequencies did not deviate significantly from the Hardy-Weinberg equilibrium. Case-control association analysis revealed that the 7R allele frequency was significantly greater in OCD patients than controls. This difference was restricted to the women subsample when performing the gender sub-analysis. Among other clinical variables examined, factor 3 (symmetry) was associated with presence of 2R allele. Linear regression analysis confirmed the association of symmetry dimension with the 2R allele (Beta=0.23, t=2.96, p=0.004, CI=0.19-0.95).

CONCLUSIONS

Our data provides further evidence that DRD4 VNTR polymorphism is associated with OCD. Furthermore, the presence of the 2R allele was significantly associated with the symmetry dimension. This dimension may represent a more homogeneous subtype of OCD with a genetic etiology.

Anxiety and affective disorder comorbidity related to serotonin and other neurotransmitter systems: obsessive-compulsive disorder as an example of overlapping clinical and genetic heterogeneity

Individuals with obsessive-compulsive disorder (OCD) have also been shown to have comorbid lifetime diagnoses of major depressive disorder (MDD; rates greater than 70%), bipolar disorder (rates greater than 10%) and other anxiety disorders (e.g. panic disorder, post-traumatic stress disorder (PTSD)). In addition, overlap exists in some common genetic variants (e.g. the serotonin transporter gene (SLC6A4), the brain-derived neurotrophic factor (BDNF) gene), and rare variants in genes/chromosomal abnormalities (e.g. the 22q11 microdeletion syndrome) found across the affective/anxiety disorder spectrums. OCD has been proposed as a possible independent entity for DSM-5, but by others thought best retained as an anxiety disorder subtype (its current designation in DSM-IV), and yet by others considered best in the affective disorder spectrum. This review focuses on OCD, a well-studied but still puzzling heterogeneous disorder, regarding alterations in serotonergic, dopaminergic and glutamatergic neurotransmission in addition to other systems involved, and how related genes may be involved in the comorbidity of anxiety and affective disorders. OCD resembles disorders such as depression, in which gene × gene interactions, gene × environment interactions and stress elements coalesce to yield OC symptoms and, in some individuals, full-blown OCD with multiple comorbid disorders.

Association between the NMDA glutamate receptor GRIN2B gene and obsessive-compulsive disorder

BACKGROUND

Recent data from neuroimaging, genetic and clinical trials and animal models suggest a role for altered glutamatergic neuro transmission in the pathogenesis of obsessive-compulsive disorder (OCD). The aim of this study was to investigate whether variants in the GRIN2B gene, the gene encoding the NR2 subunit of the N-methyl-D-aspartate (NMDA) glutamate receptor, may contribute to genetic susceptibility to OCD or to different OCD subphenotypes.

METHODS

Between 2003 and 2008, we performed a case-control association study in which we genotyped 10 tag single-nucleotide polymorphisms (SNPs) in the 3' untranslated region (3' UTR) of GRIN2B. We performed SNP association and haplotype analysis considering the OCD diagnosis and different OCD subphenotypes: early-onset OCD, comorbid tic disorders and OCD clinical symptom dimensions.

RESULTS

We enrolled 225 patients with OCD and 279 controls recruited from the OCD Clinic at Bellvitge Hospital (Barcelona, Spain). No significant difference in the distribution of alleles or genotypes was detected between patients with OCD and controls. Nonetheless, on analyzing OCD subphenotypes, the rs1805476 SNP in male patients (95% confidence interval [CI] 1.37-4.22, p = 0.002) and a 4-SNP haplotype in the whole sample (rs1805476, rs1805501, rs1805502 and rs1805477; odds ratio 1.92, 95% CI 1.22-3.01; permutation p = 0.023) were significantly associated with the presence of contamination obsessions and cleaning compulsions.

LIMITATIONS

Study limitations included the risk of population stratification associated with the case-control design, use of psychiatrically unscreened blood donors as the control group, reduced sample size of participants with certain OCD subphenotypes and tested polymorphisms limited to 3' UTR and exon 13 of GRIN2B.

CONCLUSION

Our results converge with recent data suggesting a possible contribution of glutamatergic variants to the genetic vulnerability to OCD or at least to certain OCD manifestations. The dissection of OCD into more homogeneous subphenotypes may constitute a useful tool to disentangle the complex genetic basis of the disorder.

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.

Impact of obsessive-compulsive symptoms in Tourette's syndrome on neuropsychological performance

AIM

Although inconsistencies in neuropsychological impairments in Tourette's syndrome (TS) have been discussed with respect to comorbid disorders, such as obsessive-compulsive disorder, few studies have focused on the specific dimensions of obsessive-compulsive symptoms (OCS) related to TS, such as aggression and symmetry. The aim of this study was to explore the impact of specific TS-related OCS on neuropsychological performance.

METHODS

A series of neuropsychological tasks examining attention and executive functioning were performed in groups of 33 TS participants and 18 healthy controls. The neuropsychological performance of TS with Aggression OCS (n = 11) were compared to TS without Aggression OCS (n = 22) and controls by using MANCOVA controlling for age. In the same way as Aggression, we compared the performance of three groups by Symmetry: TS with Symmetry OCS (n = 14), TS without Symmetry OCS (n = 19) and controls.

RESULTS

TS participants with Aggression OCS tended to make more perseverative errors than those without. Global OCS severity and tic severity did not correlate with any neuropsychological performances. No significant differences were detected between TS participants with and without Symmetry OCS.

CONCLUSION

Neuropsychological deficits in TS might be affected not by global OCS severity but by specific TS-related OCS.

Risk factors prospectively associated with adult obsessive-compulsive symptom dimensions and obsessive-compulsive disorder

BACKGROUND

Very few longitudinal studies have evaluated prospective neurodevelopmental and psychosocial risk factors for obsessive-compulsive disorder (OCD). Furthermore, despite the heterogeneous nature of OCD, no research has examined risk factors for its primary symptom dimensions, such as contamination/washing.

METHOD

Potential risk factors for symptoms or diagnosis of OCD in adulthood and for specific adult obsessive-compulsive (OC) symptom dimensions were examined in the Dunedin Study birth cohort. The presence of obsessions and compulsions and psychological disorders was assessed using the Diagnostic Interview Schedule (DIS) at ages 26 and 32 years. Individuals with a diagnosis of OCD at either age (n=36) were compared to both a healthy control group (n=613) and an anxious control group (n=310) to determine whether associations between a risk factor and an OCD diagnosis were specific.

RESULTS

Childhood neurodevelopmental, behavioral, personality and environmental risk factors were associated with a diagnosis of OCD and with OC symptoms at ages 26 and 32. Social isolation, retrospectively reported physical abuse and negative emotionality were specific predictors of an adult OCD diagnosis. Of note, most risk factors were associated with OC symptoms in adulthood and several risk factors predicted specific OCD dimensions. Perinatal insults were linked to increased risk for symmetry/ordering and shameful thoughts dimensions, whereas poor childhood motor skills predicted the harm/checking dimension. Difficult temperament, internalizing symptoms and conduct problems in childhood also predicted specific symptom dimensions and lower IQ non-specifically predicted increased risk for most dimensions.

CONCLUSIONS

The current findings underscore the need for a dimensional approach in evaluating childhood risk factors for obsessions and compulsions.

Impaired executive functions in paediatric obsessive-compulsive disorder patients

Isık Taner Y, Erdogan Bakar E, Oner O. Impaired executive functions in paediatric obsessive-compulsive disorder patients.

Objective: There are only few studies which investigated the neuropsychological performances of paediatric patients with obsessive-compulsive disorder (OCD). Previous studies show that most of adult OCD patients had an onset of their first symptoms before the age of 15. Our objective was to evaluate the neuropsychological functions in paediatric patients with OCD.

Methods: We compared the executive functions and general intelligence of child and adolescent OCD patients (n = 20) with age- and gender-matched healthy controls (n = 20). To compare mentioned skills, a neuropsychological test battery including Wechsler Intelligence Scale for Children-Revised (WISC-R), Wisconsin Card Sorting Test (WCST), Stroop Test and Verbal Fluency Test was performed.

Result: Performances of the OCD and control subjects on neuropsychological tests were statistically analysed by using multivariate analysis of covariance (MANCOVA), in which Full Scale Intelligence Quotient (FSIQ) results were taken into consideration as a covariate to observe FSIQ's effect on test scores. Our results showed that the differences in WISC-R Picture Arrangement and Coding scores remained significant when co-analysed with FSIQ scores. In a similar manner, the OCD group exhibited worse performances on STR1-duration, STR3-duration, STR3-error, STR4-duration, STR4-error, STR5-correct response, and STR5-error as compared with the control group when FSIQ scores were taken into calculation. Some variables of the WCST (perseverative responses, percent errors, abstraction-flexibility and categories completed) also yield lower test scores in the OCD group. There was no significant difference between the groups regarding Verbal Fluency Test scores.

Conclusion: Our results suggested that paediatric OCD patients had worse abstraction-flexibility, mental set-shifting, verbal comprehension and visuospatial/construction abilities.

Functional neuroimaging in obsessive-compulsive disorder

BACKGROUND AND AIM

Obsessive-compulsive disorder (OCD) is a severe, highly prevalent and chronically disabling psychiatric disorder that usually emerges during childhood or adolescence. This paper aims to review the literature on functional neuroimaging in OCD, analysing the reported dysfunctional connectivity in the corticostriatothalamocortical circuitry.

METHOD

This study included papers published in peer-reviewed journals dealing with functional imaging in OCD.

RESULTS

Striatal dysfunction, mainly of the caudate nucleus, leads to inefficient thalamic gating, resulting in hyperactivity within the orbitofrontal cortex (intrusive thoughts) and the anterior cingulate cortex (non-specific anxiety). Compulsions consist of ritualistic behaviours performed to recruit the inefficient striatum and neutralise unwanted thoughts and anxiety. Functional neuroimaging findings are discussed against the background of specific cognitive impairments, mainly regarding visuospatial processing, executive functioning and motor speed. Cognitive deficits are partial and specific, matching imaging data.

CONCLUSIONS

Several studies have targeted brain regions hypothesised to be involved in the pathogenesis of OCD, showing the existence of dysfunctional connectivity in the corticostriatothalamocortical circuitry. Improvements in spatial resolution of neuroimaging techniques may contribute to a better understanding of the neurocircuitry of OCD and other anxiety disorders.

Obsessive-compulsive disorder in children and adolescents: symptom dimensions in a naturalistic setting

BACKGROUND

Obsessive-compulsive disorder (OCD) is a frequent and clinically heterogeneous disorder. The complex clinical presentation can be summarized using a few consistent and temporally stable symptom dimensions. Only few studies in children and adolescents have examined the importance of symptom dimensions.

AIMS

This retrospective study was undertaken to describe the relation between symptom dimensions, pattern of comorbidity and family disposition, in a sample of Danish children and adolescents with OCD assessed in a naturalistic setting.

METHODS

A retrospective study of children and adolescents (n=83) diagnosed with OCD in the period 1998-2004, at the Psychiatric Hospital for Children and Adolescents, Risskov, Denmark. Information from clinical records was systematically collected and Children's Yale-Brown Obsessive-compulsive Scale (CY-BOCS) scores and symptom checklists were obtained.

RESULTS

High scores on the symmetry/ordering dimension were related to OCD in first-degree relatives and high scores on the aggressive/checking dimension were associated to comorbidity with tic disorders. We showed a correlation between limited insight and younger age.

CONCLUSION

This is one of the first studies to examine symptom dimensions in children and adolescents in naturalistic settings. The results were comparable with those in adult studies, showing an association between the occurrence of the symmetry/ordering dimension and family OCD and the occurrence of the aggressive/checking dimension and comorbid tic disorders. In small children, insight into symptoms may be limited.

The involvement of distinct neural systems in patients with obsessive-compulsive disorder with autogenous and reactive obsessions

OBJECTIVE

To investigate the regional metabolite abnormalities and changes after treatment in patients with OCD with autogenous and reactive obsessions.

METHOD

We assessed right anterior cingulate cortex (ACC) and amygdala-hippocampal region (Am + Hpp) N-acetyl-aspartate (NAA), choline (Cho) and creatine (Cr) concentrations and NAA/Cr and Cho/Cr ratios using single-voxel proton magnetic resonance spectroscopy in 15 patients with autogenous obsessions (OCD-A), 15 patients with reactive obsessions (OCD-R) and 15 healthy controls (HC). Measurements were repeated after 16 weeks of fluoxetine treatment.

RESULTS

Baseline ACC NAA/Cr ratios of both OCD groups were significantly lower than HC. OCD-A group had significantly lower baseline NAA/Cr ratios in the Am + Hpp than other groups. These differences were more likely to be explained by higher Cr levels in ACC. We found no significant differences and changes for Cho levels and Cho/Cr ratios between groups and within groups. Significant increase in NAA/Cr ratios of OCD-A group found in the Am + Hpp was more likely to be explained by increased NAA levels. No significant changes were found in ACC NAA/Cr ratios.

CONCLUSION

While disturbed energy metabolism in ACC might reflect a common pathology in patients with OCD regardless of symptom dimension, alterations in mesiotemporal lobe are more likely for autogenous obsessions.

Serotonin transporter gene polymorphism implicates reduced orbito-frontal cortex in obsessive-compulsive disorder

Although a number of magnetic resonance imaging (MRI) and genetic studies have been performed on obsessive-compulsive disorder (OCD), only limited studies in which genetic and neuroanatomical variables are evaluated concurrently have been performed. Therefore, the aim of our present study is (to understand) better understanding how genetic variation in the promoter region of the 5-HTT gene (5-HTTLPR) is associated with key brain structures in OCD, orbito-frontal cortex (OFC), thalamus and anterior cingulate. 5-HTT genotypes (SS, SL, LL) were determined for 40 patients with OCD and the same number of healthy controls. MRI-derived volumes of the OFC, thalamus, and anterior cingulate were determined by reliable tracing techniques. Volumetric measurements were made with T1-weighted coronal MRI images, with 1.5-mm-thick slices, at 1.5T, and were done blindly. In comparison with controls, OCD patients demonstrated volumes reduction in OFC, increased volumes of thalamus and total white matter volumes, but no difference in total brain volume, total gray matter volumes and anterior cingulate volumes. No significant difference was observed in allelic frequencies between the patients and controls. The stronger effects of 5-HTT polymorphism on brain morphology in OCD than those in controls were determined in the both OFC and thalamus. On the other hand, for the OCD patients, ANCOVA revealed a significant main effect of genotype for both the OFC and thalamus and a significant genotype-by-side interaction for the OFC, demonstrating that the short variants had a smaller right OFC than the long variants. In conclusion, we found a significant genotype-diagnosis interaction effects on key brain structures, with a stronger effects of 5-HTT polymorphism in OFC and thalamus of OCD patients, whereas no morphological changes related to the polymorphism were found in normal individuals.

Variants in estrogen receptor alpha gene are associated with phenotypical expression of obsessive-compulsive disorder

Compelling data from animal and clinical studies suggest that sex steroids may play a role in the etiopathology of obsessive-compulsive disorder (OCD). The aim of this study was to investigate whether variants in estrogen receptor genes ESR1 and ESR2 may contribute to the genetic susceptibility to OCD, through a case-control association study using an extensive linkage disequilibrium-mapping approach. Twenty tag single-nucleotide polymorphisms (tagSNPs) covering the ESR2 region and nine tagSNPS from regions of ESR1 reported to be related to transcriptional control were genotyped in 229 OCD patients and 279 controls. SNP association and haplotype analysis were performed. The association of these genes and OCD subphenotypes was tested, considering early-onset OCD, comorbid tic and affective disorders, and OCD symptom dimensions. No significant difference in the distribution of alleles or genotypes was detected between controls and OCD subjects. Nevertheless, on analyzing OCD subphenotypes, SNP rs34535804 in ESR1 and a five SNPs haplotype, located at the 5' end of intron 1 of ESR1, were associated with the presence of contamination obsessions and cleaning compulsions. Specifically, carriers of the ACCCG haplotype, a combination of functional alleles related to higher ER alpha expression, showed a reduced risk of suffering from these symptoms. Our results suggest that the ESR1 gene may contribute to the genetic vulnerability to certain OCD manifestations. The dissection of OCD into more homogeneous subphenotypes may well help to identify susceptibility genes for the disorder.

Latent class analysis of the Yale-Brown Obsessive-Compulsive Scale symptoms in obsessive-compulsive disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is phenomenologically heterogeneous, and findings of underlying structure classification based on symptom grouping have been ambiguous to date. Variable-centered approaches, primarily factor analysis, have been used to identify homogeneous groups of symptoms; but person-centered latent methods have seen little use. This study was designed to uncover sets of homogeneous groupings within 1611 individuals with OCD based on symptoms.

METHOD

Latent class analysis models using 61 obsessive-compulsive symptoms collected from the Yale-Brown Obsessive-Compulsive Scale were fit. Relationships between latent class membership and treatment response, sex, symptom severity, and comorbid tic disorders were tested for relationship to class membership.

RESULTS

Latent class analysis models of best fit yielded 3 classes. Classes differed only in frequency of symptom endorsement. Classes with higher symptom endorsement were associated with earlier age of onset, being male, higher Yale-Brown Obsessive-Compulsive Scale symptom severity scores, and comorbid tic disorders. There were no differences in treatment response between classes.

CONCLUSIONS

These results provide support for the validity of a single underlying latent OCD construct, in addition to the distinct symptom factors identified previously via factor analyses.

The genetics of obsessive-compulsive disorder: a review

Obsessive-compulsive disorder (OCD) is a serious psychiatric disorder that affects approximately 2% of the populations of children and adults. Family aggregation studies have demonstrated that OCD is familial, and results from twin studies demonstrate that the familiality is due in part to genetic factors. Only three genome-wide linkage studies have been completed to date, with suggestive but not definitive results. In addition, over 80 candidate gene studies have been published. Most of these studies have focused on genes in the serotonergic and dopaminergic pathways. Unfortunately, none have achieved genome-wide significance, and, with the exception of the glutamate transporter gene, none have been replicated. Future research will require the collaboration of multidisciplinary teams of investigators to (i) achieve sufficiently large samples of individuals with OCD; (ii) apply the state-of-the-art laboratory techniques; and (iii) perform the bioinformatic analyses essential to the identification of risk loci.

Obsessive-compulsive symptom dimensions in the general population: results from an epidemiological study in six European countries

BACKGROUND

The prevalence of obsessive-compulsive symptom dimensions and their sociodemographic and psychopathological correlates at the population level are unknown.

METHOD

Obsessive-compulsive symptom dimensions and mental disorders were assessed with the Composite International Diagnostic Interview 3.0 in a random subsample (n=2804) of individuals participating in a cross-sectional survey of the adult general population of six European countries.

RESULTS

The lifetime prevalence of any obsessive-compulsive symptom dimension was 13%. Harm/Checking was the most prevalent dimension (8%) followed by Somatic obsessions (5%) and Symmetry/Ordering (3%). Females were more likely to have symptoms in Contamination/Cleaning (OR=3, 95%CI=1.06-8.51) and Somatic obsessions (OR=1.88, 95%CI=1.05-3.37). All symptom dimensions were associated with an increased risk of most mental (but not physical) disorders. There were some differences in prevalence between countries.

LIMITATIONS

The interference associated with each symptom dimension could not be assessed. Few direct data are available on the validity of the CIDI to assess obsessive-compulsive symptom dimensions.

CONCLUSIONS

Obsessive-compulsive symptom dimensions are relatively frequent in the general population. Their sociodemographic and psychopathological correlates may be slightly different in clinical and community samples. They are associated with an increased risk of most mental disorders.

Suicide in patients treated for obsessive-compulsive disorder: a prospective follow-up study

BACKGROUND

To describe the occurrence of persistent suicidal ideation and suicide attempts in a sample of obsessive-compulsive patients followed-up prospectively during 1 to 6years, and to determine the existence of predictors of suicide behavior.

METHOD

Two hundred and eighteen outpatients with DSM-IV OCD, recruited from a specialized OCD Unit in Barcelona, Spain, between February 1998 and December 2007, were included in the study. Suicide ideation was assessed by item 3 of the Hamilton Depression Rating Scale. Suicide attempts were evaluated by the Beck Suicide Intent Scale. Patients with and without persistent suicidal thoughts and suicide attempters and non-attempters were compared on sociodemographic and clinical variables. A Cox proportional hazards regression analysis was used to estimate potential predictors of suicide.

RESULTS

Patients completed a mean follow-up period of treatment of 4.1years (SD: 1.7; range: 1-6years). During this period, eighteen patients (8.2%) reported persistent suicidal ideation, two patients (0.91%) committed suicide and 11 (5.0%) attempted suicide. Being unmarried, presenting higher basal scores in the HDRS, current or previous history of affective disorders and symmetry/ordering obsessions were independently associated with suicidal behaviors.

LIMITATIONS

Patients were recruited from a specialized OCD clinic and received exhaustive treatment. Influence of variables including social support, life events, hopelessness and substance abuse/dependence was not assessed.

CONCLUSIONS

Suicide behavior is not a highly common phenomenon in OCD, but it should not be disregarded, especially in unmarried patients, with comorbid depression and symmetry/ordering obsessions and compulsions, who appear to be at a greater risk for suicide acts.

Obsessive-compulsive disorder: a review of the diagnostic criteria and possible subtypes and dimensional specifiers for DSM-V

BACKGROUND

Since the publication of the DSM-IV in 1994, research on obsessive-compulsive disorder (OCD) has continued to expand. It is timely to reconsider the nosology of this disorder, assessing whether changes to diagnostic criteria as well as subtypes and specifiers may improve diagnostic validity and clinical utility.

METHODS

The existing criteria were evaluated. Key issues were identified. Electronic databases of PubMed, ScienceDirect, and PsycINFO were searched for relevant studies.

RESULTS

This review presents a number of options and preliminary recommendations to be considered for DSM-V. These include: (1) clarifying and simplifying the definition of obsessions and compulsions (criterion A); (2) possibly deleting the requirement that people recognize that their obsessions or compulsions are excessive or unreasonable (criterion B); (3) rethinking the clinical significance criterion (criterion C) and, in the interim, possibly adjusting what is considered "time-consuming" for OCD; (4) listing additional disorders to help with the differential diagnosis (criterion D); (5) rethinking the medical exclusion criterion (criterion E) and clarifying what is meant by a "general medical condition"; (6) revising the specifiers (i.e., clarifying that OCD can involve a range of insight, in addition to "poor insight," and adding "tic-related OCD"); and (7) highlighting in the DSM-V text important clinical features of OCD that are not currently mentioned in the criteria (e.g., the major symptom dimensions).

CONCLUSIONS

A number of changes to the existing diagnostic criteria for OCD are proposed. These proposed criteria may change as the DSM-V process progresses.

Comorbidity of obsessive-compulsive disorder with obsessive-compulsive personality disorder: Does it imply a specific subtype of obsessive-compulsive disorder?

The present study examined whether the comorbidity of obsessive-compulsive personality disorder (OCPD) and obsessive-compulsive disorder (OCD) constitute a specific subtype of OCD. The study sample consisted of 146 consecutive outpatients with a DSM-IV diagnosis of OCD. Diagnoses were established using MINI, IPDE, YBOCS and YBOCS-SC. OCD patients with comorbid OCPD were compared with OCD patients without OCPD on various sociodemographic and clinical variables. Almost one third of the OCD subjects met criteria for comorbid OCPD. OCD+OCPD patients had a significantly earlier age at onset of initial OC symptoms, earlier age at onset of OCD and more obsessions and compulsions than pure obsessions compared to the patients with OCDOCPD. OCD+OCPD patients also had a higher rate of comorbidity with avoidant personality disorder and showed more impairment in global functioning. There were not differences between the two sub-groups on severity of OCD symptoms and also on type of OCD onset. Our results indicate that the comorbidity of OCD with OCPD is associated with a number of specific clinical characteristics of OCD. These findings in conjunction with of current clinical, family and genetic studies provide some initial evidence that OCD comorbid with OCPD constitute a specific subtype of OCD.

The Genetics of Obsessive-Compulsive Disorder

OCD is a psychiatric disorder with a lifetime prevalence of 1-3% and is a significant cause of disability worldwide. Family studies indicate that OCD has a significant hereditable component, with relatives of OCD cases being 4 times more likely to develop the disorder than the general population. Linkage studies in OCD have generally been underpowered and have failed to reach the statistical threshold for genome-wide significance, but they have nevertheless been useful for revealing potential regions of interest for future candidate gene studies. Candidate gene studies in OCD have thus far focused on genes involved in the serotonergic, dopaminergic, and glutamatergic pathways. These studies have been for the most part inconclusive, and failures to replicate have been the norm until very recently. The only genetic association replicated by multiple groups was with a glutamate transporter gene (SLC1A1). Genome-wide association studies in OCD are in progress, but final results have not yet been reported. As with the study of many other psychiatric disorders, an improved understanding of OCD will only be achieved (1) with larger collaborative efforts involving more probands, (2) the use of probands and controls drawn from epidemiologically-based populations rather than clinical samples, (3) developing a more precise phenotypic description of OCD and (4) measuring important environmental influences that affect OCD pathogenesis and severity.

Symptom dimensions in OCD: item-level factor analysis and heritability estimates

To reduce the phenotypic heterogeneity of obsessive-compulsive disorder (OCD) for genetic, clinical and translational studies, numerous factor analyses of the Yale-Brown Obsessive Compulsive Scale checklist (YBOCS-CL) have been conducted. Results of these analyses have been inconsistent, likely as a consequence of small sample sizes and variable methodologies. Furthermore, data concerning the heritability of the factors are limited. Item and category-level factor analyses of YBOCS-CL items from 1224 OCD subjects were followed by heritability analyses in 52 OCD-affected multigenerational families. Item-level analyses indicated that a five factor model: (1) taboo, (2) contamination/cleaning, (3) doubts, (4) superstitions/rituals, and (5) symmetry/hoarding provided the best fit, followed by a one-factor solution. All 5 factors as well as the one-factor solution were found to be heritable. Bivariate analyses indicated that the taboo and doubts factor, and the contamination and symmetry/hoarding factor share genetic influences. Contamination and symmetry/hoarding show shared genetic variance with symptom severity. Nearly all factors showed shared environmental variance with each other and with symptom severity. These results support the utility of both OCD diagnosis and symptom dimensions in genetic research and clinical contexts. Both shared and unique genetic influences underlie susceptibility to OCD and its symptom dimensions.