The OCD collaborative genetics study: methods and sample description

Genomics of Obsessive-Compulsive Disorder-Toward Personalized Medicine in the Era of Big Data

Pathogenesis of obsessive-compulsive disorder (OCD) mainly involves dysregulation of serotonergic neurotransmission, but a number of other factors are involved. Genetic underprints of OCD fall under the category of "common disease common variant hypothesis," that suggests that if a disease that is heritable is common in the population (a prevalence >1-5%), then the genetic contributors-specific variations in the genetic code-will also be common in the population. Therefore, the genetic contribution in OCD is believed to come from multiple genes simultaneously and it is considered a polygenic disorder. Genomics offers a number of advanced tools to determine causal relationship between the exposure and the outcome of interest. Particularly, methods such as polygenic risk score (PRS) or Mendelian Randomization (MR) enable investigation of new pathways involved in OCD pathogenesis. This premise is also facilitated by the existence of publicly available databases that include vast study samples. Examples include population-based studies such as UK Biobank, China Kadoorie Biobank, Qatar Biobank, All of US Program sponsored by National Institute of Health or Generations launched by Yale University, as well as disease-specific databases, that include patients with OCD and co-existing pathologies, with the following examples: Psychiatric Genomics Consortium (PGC), ENIGMA OCD, The International OCD Foundation Genetics Collaborative (IOCDF-GC) or OCD Collaborative Genetic Association Study. The aim of this review is to present a comprehensive overview of the available Big Data resources for the study of OCD pathogenesis in the context of genomics and demonstrate that OCD should be considered a disorder which requires the approaches offered by personalized medicine.

General personality dimensions, impairment and treatment response in obsessive-compulsive disorder

General personality dimensions are associated with clinical severity and treatment response in individuals with depression and many anxiety disorders, but little is known about these relationships in individuals with obsessive-compulsive disorder (OCD). Individuals in the current study included 705 adults with OCD who had participated in family and genetic studies of the disorder. Participants self-completed the Neuroticism, Extraversion, Openness Personality Inventory or Neuroticism, Extraversion, Openness Five-Factor Inventory-3. Relationships between personality scores, and subjective impairment and OCD treatment response, were evaluated. The odds of subjective impairment increased with (unit increase in) the neuroticism score (odds ratio, OR = 1.03; 95% CI = 1.01-1.04; p < 0.01) and decreased with extraversion scores (OR = 0.98; 95% CI = 0.96-0.99; p < 0.01). The odds of reporting a good response to serotonin/selective serotonin reuptake inhibitors (OR = 1.02; 95% CI = 1.01-1.04; p < 0.01) or cognitive behavioural therapy (OR = 1.03; 95% CI = 1.01-1.05; p < 0.01) increased with the extraversion score. The magnitude of these relationships did not change appreciably after adjusting for other clinical features related to one or more of the personality dimensions. The findings suggest that neuroticism and extraversion are associated with subjective impairment, and that extraversion is associated with self-reported treatment response, in individuals with OCD. © 2019 John Wiley & Sons, Ltd.

Immune-Related Comorbidities in Childhood-Onset Obsessive Compulsive Disorder: Lifetime Prevalence in the Obsessive Compulsive Disorder Collaborative Genetics Association Study

Objective: To evaluate the lifetime prevalence of infectious, inflammatory, and autoimmune disorders in a multisite study of probands with childhood-onset obsessive compulsive disorder (OCD) and their first-degree relatives. Methods: Medical questionnaires were completed by 1401 probands and 1045 first-degree relatives in the OCD Collaborative Genetics Association Study. Lifetime prevalence of immune-related diseases was compared with the highest available population estimate and reported as a point estimate with 95% adjusted Wald interval. Worst-episode OCD severity and symptom dimensions were assessed with the Yale-Brown Obsessive Compulsive Scale (YBOCS) and Symptom Checklist (YBOCS-CL). Results: Probands reported higher-than-expected prevalence of scarlet fever (4.0 [3.1-5.2]% vs. 1.0%-2.0%, z = 1.491, p < 0.001, n = 1389), encephalitis or meningitis (1.4 [0.9-2.1]% vs. 0.1%-0.4%, z = 5.913, p < 0.001, n = 1393), rheumatoid arthritis (1.1 [0.6-2.0]% vs. 0.2%-0.4%, z = 3.416, p < 0.001, n = 949) and rheumatic fever (0.6 [0.3-1.2]% vs. 0.1%-0.2%, z = 3.338, p < 0.001, n = 1390), but not systemic lupus erythematosus, diabetes, asthma, multiple sclerosis, psoriasis, or inflammatory bowel disease. First-degree relatives reported similarly elevated rates of scarlet fever, rheumatic fever, and encephalitis or meningitis independent of OCD status. There was no association between worst-episode severity and immune-related comorbidities, although probands reporting frequent ear or throat infections had increased severity of cleaning-/contamination-related symptoms (mean factor score 2.5 ± 0.9 vs. 2.3 ± 1.0, t = 3.183, p = 0.002, n = 822). Conclusion: These data suggest high rates of streptococcal-related and other immune-mediated diseases in patients with childhood-onset OCD and are consistent with epidemiological studies in adults noting familial clustering. Limitations include potential reporting bias and absence of a control group, underscoring the need for further prospective studies characterizing medical and psychiatric disease clusters and their interactions in children. Such studies may ultimately improve our understanding of OCD pathogenesis and aid in the development of adjunctive immune-modulating therapeutic strategies.

Trichotillomania comorbidity in a sample enriched for familial obsessive-compulsive disorder

BACKGROUND

This study addresses the strength of associations between trichotillomania (TTM) and other DSM-IV Axis I conditions in a large sample (n = 2606) enriched for familial obsessive-compulsive disorder (OCD), to inform TTM classification.

METHODS

We identified participants with TTM in the Johns Hopkins OCD Family Study (153 families) and the OCD Collaborative Genetics Study, a six-site genetic linkage study of OCD (487 families). We used logistic regression (with generalized estimating equations) to assess the strength of associations between TTM and other DSM-IV disorders.

RESULTS

TTM had excess comorbidity with a number of conditions from different DSM-IV chapters, including tic disorders, alcohol dependence, mood disorders, anxiety disorders, impulse-control disorders, and bulimia nervosa. However, association strengths (odds ratios) were highest for kleptomania (6.6), pyromania (5.8), OCD (5.6), skin picking disorder (4.4), bulimia nervosa (3.5), and pathological nail biting (3.4).

CONCLUSIONS

TTM is comorbid with a number of psychiatric conditions besides OCD, and it is strongly associated with other conditions involving impaired impulse control. Though DSM-5 includes TTM as an OCD-related disorder, its comorbidity pattern also emphasizes the impulsive, appetitive aspects of this condition that may be relevant to classification.

Genetic and pharmacogenetic study of glutamate transporter (SLC1A1) in Iranian patients with obsessive-compulsive disorder

WHAT IS KNOWN AND OBJECTIVE

Obsessive-compulsive disorder (OCD) is a chronic neuropsychiatric disorder. Selective serotonin reuptake inhibitors (SSRIs) are the first line of medication for OCD treatment; however, 40%-60% of patients with OCD do not respond to SSRIs adequately. There are growing pieces of evidence which suggest a significant role for the glutamatergic system in the genesis of OCD and its consequent treatment. In the present study, we aimed to assess the association of SLC1A1 polymorphisms (rs301430, rs2228622 and rs3780413) with OCD and its clinical characteristics, as well as the importance of these SNPs in the response of OCD patients to SSRI pharmacotherapy.

METHODS

Sample study consisted of 243 OCD cases and 221 control subjects. Patients were treated 12 weeks with fluvoxamine (daily dose: 150-300 mg). Based on the reduction in obsessive and compulsive severity scores using Y-BOCS severity scale, patients were classified as responders, non-responders and refractory. A total of 239, 228 and 215 patients were genotyped for rs301430, rs2228622 and rs3780413, respectively, by the means of PCR-RFLP.

RESULTS AND DISCUSSION

No association was detected between SLC1A1 SNPs and OCD, except an association between the familial form of the disease in males with rs2228622 (P = 0.033). The results of pharmacogenetic studies revealed the associations of two SLC1A1 SNPs, rs2228622 (P = 0.031) and rs3780413 (P = 0.008), with treatment response.

WHAT IS NEW AND CONCLUSION

Results of the current study suggest a role for the glutamate transporter in OCD treatment response with SSRIs which should encourage researchers to further investigate the importance of glutamate transporter in OCD pharmacogenetics.

Chronic obsessive-compulsive disorder: prognostic factors

BACKGROUND

The course of illness in obsessive-compulsive disorder (OCD) varies significantly between patients. Little is known about factors predicting a chronic course of illness. The aim of this study is to identify factors involved in inducing and in maintaining chronicity in OCD.

METHODS

The present study is embedded within the Netherlands Obsessive Compulsive Disorder Association (NOCDA) study, an ongoing multicenter naturalistic cohort study designed to identify predictors of long-term course and outcome in OCD. For this study, 270 subjects with a current diagnosis of OCD were included. Chronicity status at 2-year follow-up was regressed on a selection of baseline predictors related to OCD, to comorbidity and to stress and support.

RESULTS

Psychotrauma [odds ratio (OR) 1.98, confidence interval (CI) 1.22-3.22, p = 0.006], recent negative life events (OR 1.42, CI 1.01-2.01, p = 0.043), and presence of a partner (OR 0.28, CI 0.09-0.85, p = 0.025) influenced the risk of becoming chronic. Longer illness duration (OR 1.46, CI 1.08-1.96, p = 0.013) and higher illness severity (OR 1.09, CI 1.03-1.16, p = 0.003) increased the risk of remaining chronic.

CONCLUSIONS

External influences increase the risk of becoming chronic, whereas the factors involved in maintaining chronicity are illness-related. As the latter are potentially difficult to modify, treatment should be devoted to prevent chronicity from occurring in the first place. Therapeutic strategies aimed at alleviating stress and at boosting social support might aid in achieving this goal.

Association of the functional serotonin transporter haplotype with familial form of obsessive compulsive disorder in Iranian patients

OBJECTIVE

Several polymorphisms have been reported in the 5-HTTLPR of the serotonin transporter gene (SLC6A4). Family-based evidences for the association of 5-HTTLPR polymorphisms with OCD were previously reported but results were controversial. The present study investigated the possible correlation of SLC6A4 polymorphisms (5-HTTLPR, rs25532, rs25531) in Iranian OCD patients considering gender, age of onset, family history of psychiatric disorders, obsessive and compulsive subtypes and severities.

METHODS

The included OCD patients fulfilled the criteria for DSM-IV-TR whom Y-BOCS score was more than 9. Blood samples (184 cases and 192 controls) were genotyped by means of PCR-RFLP.

RESULTS

Mean of Y-BOCS scores of included patients was 20.1 ± 0.69. Rs25532 CC genotype showed significant association with OCD in men and were detected more in the patients reported positive family history of psychiatric disorders but the other single loci (5-HTTLPR and rs25531) did not associate with OCD. Haplotype analysis showed significant association of 14-A variant with OCD and revealed the association of 14-A/14-A genotype with familial form of OCD.

CONCLUSIONS

The findings of this study showed the association of SLC6A4 variants with familial form of OCD and proposed stratified analyses in the genetic studies facilitate identification of genetic risk factors for this heterogeneous disorder.

Association of serotonin receptor 2a haplotypes with obsessive-compulsive disorder and its treatment response in Iranian patients: a genetic and pharmacogenetic study

INTRODUCTION

Obsessive-compulsive disorder (OCD) is a debilitating psychiatric disorder causing intrusive thoughts or repetitive behaviors. Serotonin reuptake inhibitors are used for OCD treatment, but 40%-60% of patients do not respond to them adequately. In this study, the associations of serotonin receptor 2a polymorphisms rs6311 and rs6313 with OCD, its familial form and fluvoxamine treatment response in Iranian population were investigated.

PATIENTS AND METHODS

Association analyses were conducted in 293 OCD cases fulfilling the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV-TR and 245 controls. Pharmacotherapy was defined as 12 weeks of treatment with fluvoxamine (150-300 mg). Treatment response was considered as >25% reduction in Yale-Brown Obsessive Compulsive Scale score. Genotyping was performed by means of PCR-RFLP.

RESULTS

The results showed no association of rs6311 or rs6313 with OCD, but their haplotypes had different distribution patterns in cases and controls. Moreover, rs6313 was associated with the familial form of OCD in females significantly (P=0.005) under the recessive genetic model. Moreover, rs6311-rs6313 haplotypes were associated with fluvoxamine treatment response in OCD patients with more AC and less AT in responders.

CONCLUSION

HTR2A haplotypes are associated with OCD and its treatment response with a fluvoxamine in Iranian patients. Furthermore, the observed association of rs6313 with the familial form of OCD in females suggests different genetic background of OCD familial and non-familial forms, which needs further investigation.

An investigation of doubt in obsessive-compulsive disorder

BACKGROUND

Clinicians have long considered doubt to be a fundamental characteristic of obsessive-compulsive disorder (OCD). However, the clinical relevance of doubt in OCD has not been addressed.

METHODS

Participants included 1182 adults with OCD who had participated in family and genetic studies of OCD. We used a clinical measure of the severity of doubt, categorized as none, mild, moderate, severe, or extreme. We evaluated the relationship between doubt and OCD clinical features, Axis I disorders, personality and personality disorder dimensions, impairment, and treatment response.

RESULTS

The severity of doubt was inversely related to the age at onset of OCD symptoms. Doubt was strongly related to the number of checking symptoms and, to a lesser extent, to the numbers of contamination/cleaning and hoarding symptoms. Doubt also was related to the lifetime prevalence of recurrent major depression and generalized anxiety disorder; to the numbers of avoidant, dependent, and obsessive-compulsive personality disorder traits; and to neuroticism and introversion. Moreover, doubt was strongly associated with global impairment and poor response to cognitive behavioral treatment (CBT), even adjusting for OCD severity and other correlates of doubt.

CONCLUSIONS

Doubt is associated with important clinical features of OCD, including impairment and cognitive-behavioral treatment response.

A Multisite Study of Family Functioning Impairment in Pediatric Obsessive-Compulsive Disorder

OBJECTIVE

Familial aspects of pediatric obsessive-compulsive disorder (OCD), including accommodation and treatment, have received notable and warranted attention. However, individual perspectives of its repercussions on family functioning, including emotional and occupational parental burden, have not been closely examined. The present study details this topic using a large multicenter sample.

METHOD

Participants included 354 youth affected with OCD and their mothers and fathers ascertained through OCD programs in Boston, Massachusetts (n = 180) and Vancouver, British Columbia (n = 174). The validated OCD Family Functioning Scale and standard OCD measurements were completed. Descriptive, between-site, and cross-perspective comparative analyses were followed by regression model testing to predict family impairment.

RESULTS

Family functioning was negatively affected from youth, mother, and father perspectives. Impairment was reportedly more extensive at the time of worst OCD severity and was greater from maternal versus paternal viewpoints. Most frequently affected family tasks and implicated OCD symptoms included morning and bedtime routines and intrusive thoughts. Emotional repercussions in all members included stress and anxiety, followed by frustration or anger in youth and sadness in parents. Nearly half of mothers and one third of fathers reported daily occupational impairment. Compared with youth self-report, parents perceived fewer social and academic effects on their child. Family accommodation most consistently predicted family impairment, especially from parent perspectives. OCD and compulsion severity, contamination and religious obsessions, and comorbidities also predicted various perspectives of family subdomain impairment.

CONCLUSION

This study quantitatively details the pervasive burden that pediatric OCD places on families, as reported from complementary relative perspectives. Further attention to this topic is warranted in clinical and research realms.

Parental bonding and hoarding in obsessive-compulsive disorder

BACKGROUND

Hoarding behavior may indicate a clinically and possibly etiologically distinct subtype of obsessive-compulsive disorder (OCD). Empirical evidence supports a relationship between hoarding and emotional over-attachment to objects. However, little is known about the relationship between hoarding and parental attachment in OCD.

METHOD

The study sample included 894 adults diagnosed with DSM-IV OCD who had participated in family and genetic studies of OCD. Participants were assessed for Axis I disorders, personality disorders, and general personality dimensions. The Parental Bonding Instrument (PBI) was used to assess dimensions of perceived parental rearing (care, overprotection, and control). We compared parental PBI scores in the 334 hoarding and 560 non-hoarding participants, separately in men and women. We used logistic regression to evaluate the relationship between parenting scores and hoarding in women, adjusting for other clinical features associated with hoarding.

RESULTS

In men, there were no significant differences between hoarding and non-hoarding groups in maternal or paternal parenting scores. In women, the hoarding group had a lower mean score on maternal care (23.4 vs. 25.7, p<0.01); a higher mean score on maternal protection (9.4 vs. 7.7, p<0.001); and a higher mean score on maternal control (7.0 vs. 6.2, p<0.05), compared to the non-hoarding group. The magnitude of the relationships between maternal bonding dimensions and hoarding in women did not change after adjustment for other clinical features. Women who reported low maternal care/high maternal protection had significantly greater odds of hoarding compared to women with high maternal care/low maternal protection (OR=2.54, 95% CI=1.60-4.02, p<0.001).

CONCLUSIONS

Perceived poor maternal care, maternal overprotection, and maternal overcontrol are associated with hoarding in women with OCD. Parenting dimensions are not related to hoarding in men. These findings provide further support for a hoarding subtype of OCD and for sex-specific differences in etiologic pathways for hoarding in OCD.

ADHD and executive functioning deficits in OCD youths who hoard

Hoarding is common among youth with obsessive compulsive disorder (OCD), with up to 26% of OCD youth exhibiting hoarding symptoms. Recent evidence from adult hoarding and OCD cohorts suggests that hoarding symptoms are associated with executive functioning deficits similar to those observed in subjects with attention deficit hyperactivity disorder (ADHD). However, while hoarding behavior often onsets during childhood, there is little information about executive function deficits and ADHD in affected children and adolescents. The study sample included 431 youths (ages 6-17 years) diagnosed with OCD who participated in the OCD Collaborative Genetics Study and the OCD Collaborative Genetics Association Study and completed a series of clinician-administered and parent report assessments, including diagnostic interviews and measures of executive functioning (Behavior Rating Inventory of Executive Functioning; BRIEF) and hoarding severity (Hoarding Rating Scale-Interview; HRS-I). 113 youths (26%) had clinically significant levels of hoarding compulsions. Youths with and without hoarding differed significantly on most executive functioning subdomains and composite indices as measured by the parent-rated BRIEF. Groups did not differ in the frequency of full DSM-IV ADHD diagnoses; however, the hoarding group had significantly greater number of inattention and hyperactivity symptoms compared to the non-hoarding group. In multivariate models, we found that overall BRIEF scores were related to hoarding severity, adjusting for age, gender and ADHD symptoms. These findings suggest an association between hoarding and executive functioning deficits in youths with OCD, and assessing executive functioning may be important for investigating the etiology and treatment of children and adolescents with hoarding and OCD.

Assessing Sexual Orientation-Related Obsessions and Compulsions in Italian Heterosexual Individuals: Development and Validation of the Sexual Orientation Obsessive-Compulsive Scale (SO-OCS)

Sexual Orientation-Obsessive-Compulsive Disorder (SO-OCD) is characterized by intrusive thoughts, images, and urges related to one's sexual orientation, and by consequent avoidance, reassurance seeking, and overt and covert compulsions. Currently there is no short self-report measure that assesses SO-OCD symptoms. The current article describes two studies that develop and evaluate the first version of the Sexual Orientation Obsessive-Compulsive Scale (SO-OCS), a 14-item Italian self-report measure targeted towards heterosexual individuals. In Study 1, the SO-OCS was developed and refined through item analysis and exploratory factor analysis from an initial pool of 33 items administered to 732 Italian nonclinical participants. The SO-OCS showed a unidimensional structure and an acceptable internal consistency. In Study 2, the factor structure, internal consistency, temporal stability, construct and criterion validity, and diagnostic sensitivity of the SO-OCS were investigated in three samples of Italian participants (294 from the general population, 52 OCD patients who reported sexual orientation-related symptoms or concerns as a primary complaint, and 51 OCD patients who did not report these symptoms as primary complaint). The SO-OCS was again found to have a unidimensional structure and good internal consistency, as well as to exhibit strong construct validity. Specifically, the SO-OCS showed an excellent criterion validity and diagnostic sensitivity, as it successfully discriminated between those with SO-OCD and all other groups of participants. Finally, evidence of temporal stability of the SO-OCS in a nonclinical subsample was found. The SO-OCS holds promise as a measure of SO-OCD symptoms in heterosexual individuals.

Whole-genome association analysis of treatment response in obsessive-compulsive disorder

Up to 30% of patients with obsessive-compulsive disorder (OCD) exhibit an inadequate response to serotonin reuptake inhibitors (SRIs). To date, genetic predictors of OCD treatment response have not been systematically investigated using genome-wide association study (GWAS). To identify specific genetic variations potentially influencing SRI response, we conducted a GWAS study in 804 OCD patients with information on SRI response. SRI response was classified as 'response' (n=514) or 'non-response' (n=290), based on self-report. We used the more powerful Quasi-Likelihood Score Test (the MQLS test) to conduct a genome-wide association test correcting for relatedness, and then used an adjusted logistic model to evaluate the effect size of the variants in probands. The top single-nucleotide polymorphism (SNP) was rs17162912 (P=1.76 × 10(-8)), which is near the DISP1 gene on 1q41-q42, a microdeletion region implicated in neurological development. The other six SNPs showing suggestive evidence of association (P<10(-5)) were rs9303380, rs12437601, rs16988159, rs7676822, rs1911877 and rs723815. Among them, two SNPs in strong linkage disequilibrium, rs7676822 and rs1911877, located near the PCDH10 gene, gave P-values of 2.86 × 10(-6) and 8.41 × 10(-6), respectively. The other 35 variations with signals of potential significance (P<10(-4)) involve multiple genes expressed in the brain, including GRIN2B, PCDH10 and GPC6. Our enrichment analysis indicated suggestive roles of genes in the glutamatergic neurotransmission system (false discovery rate (FDR)=0.0097) and the serotonergic system (FDR=0.0213). Although the results presented may provide new insights into genetic mechanisms underlying treatment response in OCD, studies with larger sample sizes and detailed information on drug dosage and treatment duration are needed.

OBSESSIVE-COMPULSIVE PERSONALITY DISORDER: EVIDENCE FOR TWO DIMENSIONS

BACKGROUND

To determine possible dimensions that underlie obsessive-compulsive personality disorder (OCPD) and to investigate their clinical correlates, familiality, and genetic linkage.

METHODS

Participants were selected from 844 adults assessed with the Structured Instrument for the Diagnosis of DSM-IV Personality Disorders (SIDP) in the OCD Collaborative Genetics Study (OCGS) that targeted families with obsessive-compulsive disorder (OCD) affected sibling pairs. We conducted an exploratory factor analysis, which included the eight SIDP-derived DSM-IV OCPD traits and the indecision trait from the DSM-III, assessed clinical correlates, and estimated sib-sib correlations to evaluate familiality of the factors. Using MERLIN and MINX, we performed genome-wide quantitative trait locus (QTL) linkage analysis to test for allele sharing among individuals.

RESULTS

Two factors were identified: Factor 1: order/control (perfectionism, excessive devotion to work, overconscientiousness, reluctance to delegate, and rigidity); and Factor 2: hoarding/indecision (inability to discard and indecisiveness). Factor 1 score was associated with poor insight, whereas Factor 2 score was associated with task incompletion. A significant sib-sib correlation was found for Factor 2 (rICC = .354, P < .0001) but not Factor 1 (rICC = .129, P = .084). The linkage findings were different for the two factors. When Factor 2 was analyzed as a quantitative trait, a strong signal was detected on chromosome 10 at marker d10s1221: KAC LOD = 2.83, P = .0002; and marker d10s1225: KAC LOD = 1.35, P = .006.

CONCLUSIONS

The results indicate two factors of OCPD, order/control and hoarding/indecision. The hoarding/indecision factor is familial and shows modest linkage to a region on chromosome 10.

Dependent personality, separation anxiety disorder and other anxiety disorders in OCD

BACKGROUND

The purpose of this study was to investigate whether dependent personality and/or general personality dimensions might explain the strong relationships between separation anxiety disorder (Sep-AD) and three other anxiety disorders (agoraphobia, panic disorder and social anxiety disorder) in individuals with obsessive compulsive disorder (OCD).

METHODS

Using data from 509 adult participants collected during the OCD Collaborative Genetic Study, we used logistic regression models to evaluate the relationships between Sep-AD, dependent personality score, general personality dimensions and three additional anxiety disorders.

RESULTS

The dependent personality score was strongly associated with Sep-AD and the other anxiety disorders in models adjusted for age at interview, age at onset of OC symptoms and worst ever OCD severity score. Several general personality dimensions, especially neuroticism, extraversion and conscientiousness, were also related to Sep-AD and the other anxiety disorders. Sep-AD was not independently related to these anxiety disorders, in multivariate models including general personality and dependent personality disorder scores.

CONCLUSIONS

The results suggest that Sep-AD in childhood and these other anxiety disorders in adulthood are consequences of dependent personality disorder (for agoraphobia and panic disorder) or introversion (for social phobia). It is unknown whether these results would be similar in a non-OCD sample.

Domains of distress among people with sexual orientation obsessions

Although sexual obsessions in obsessive-compulsive disorder (OCD) are not uncommon, obsessions about sexual orientation have not been well studied. These obsessions focus on issues such as the fear of being or becoming gay, fear of being perceived by others as gay, and unwanted mental images involving homosexual acts. Sexual orientation obsessions in OCD are particularly distressing due to the ego-dystonic nature of the obsessions and, often, stigma surrounding a same-sex orientation. The purpose of this study was to better understand distress in people suffering from sexual orientation obsessions in OCD. Data were collected online (n = 1,176) and subjects were 74.6% male, 72.0% heterosexual, and 26.4% with an OCD diagnosis from a professional. The survey consisted of 70 novel questions that were assessed using a principal components analysis and the items separated into six components. These components were then correlated to distress among those with a prior OCD diagnosis and sexual orientation obsessions. Results indicated that sexual orientation obsessions in OCD were related to severe distress, including suicidal ideation. Implications of these findings and future directions for research are discussed.

Obsessive-compulsive disorder and female reproductive cycle events: results from the OCD and reproduction collaborative study

BACKGROUND

Women with obsessive-compulsive disorder (OCD) often report that symptoms first appear or exacerbate during reproductive cycle events; however, little is known about these relationships. The goals of this study were to examine, in a US and a European female OCD sample, onset and exacerbation of OCD in reproductive cycle events, and to investigate the likelihood of repeat exacerbation in subsequent pregnancies and postpartum periods.

METHODS

Five hundred forty-two women (United States, n = 352; Dutch, n = 190) who met DSM-IV criteria for OCD, completed self-report questionnaires designed to assess OCD onset and symptom exacerbation associated with reproductive events.

RESULTS

OCD onset occurred within 12 months after menarche in 13.0%, during pregnancy in 5.1%, at postpartum in 4.7%, and at menopause in 3.7%. Worsening of pre-existing OCD was reported by 37.6% of women at premenstruum, 33.0% during pregnancy, 46.6% postpartum, and 32.7% at menopause. Exacerbation in first pregnancy was significantly associated with exacerbation in second pregnancy (OR = 10.82, 95% CI 4.48-26.16), as was exacerbation in first postpartum with exacerbation in second postpartum (OR = 6.86, 95% CI 3.27-14.36). Results were replicated in both samples.

CONCLUSIONS

Reproductive cycle events are periods of increased risk for onset and exacerbation of OCD in women. The present study is the first to provide significant evidence that exacerbation in or after first pregnancy is a substantial risk factor for exacerbation in or after a subsequent pregnancy. Further research is needed to identify factors related to exacerbation, so that physicians may provide appropriate recommendations to women regarding clinical issues involving OCD and reproductive cycle events.

Hoarding in Children and Adolescents with Obsessive-Compulsive Disorder

Compared to studies in adults, there have been few studies of hoarding in children and adolescents with obsessive-compulsive disorder (OCD). In the current study, we evaluated OCD clinical features, Axis I disorders, and social reciprocity scores in 641 children and adolescents with OCD, of whom 163 (25%) had hoarding compulsions and 478 did not. We found that, as a group, youth with hoarding had an earlier age at onset and more severe lifetime OCD symptoms, poorer insight, more difficulty making decisions and completing tasks, and more overall impairment. The hoarding group also had a greater lifetime prevalence of panic disorder, specific phobia, Tourette disorder, and tics. As measured with the Social Reciprocity Scale, the hoarding group had more severe deficits in parent-rated domains of social communication, social motivation, and restricted interests and repetitive behavior. In a multivariable model, the overall social reciprocity score, age at onset of OCD symptoms, symmetry obsessions, and indecision were independently related to hoarding in these children and adolescents with OCD. These features should be considered as candidate risk factors for the development of hoarding behavior in pediatric OCD.

Clinical correlates and genetic linkage of social and communication difficulties in families with obsessive-compulsive disorder: Results from the OCD Collaborative Genetics Study

Some individuals with obsessive-compulsive disorder (OCD) have autistic-like traits, including deficits in social and communication behaviors (pragmatics). The objective of this study was to determine if pragmatic impairment aggregates in OCD families and discriminates a clinically and genetically distinct subtype of OCD. We conducted clinical examinations on, and collected DNA samples from, 706 individuals with OCD in 221 multiply affected OCD families. Using the Pragmatic Rating Scale (PRS), we compared the prevalence of pragmatic impairment in OCD-affected relatives of probands with and without pragmatic impairment. We also compared clinical features of OCD-affected individuals in families having at least one, versus no, individual with pragmatic impairment, and assessed for linkage to OCD in the two groups of families. The odds of pragmatic impairment were substantially greater in OCD-affected relatives of probands with pragmatic impairment. Individuals in high-PRS families had greater odds of separation anxiety disorder and social phobia, and a greater number of schizotypal personality traits. In high-PRS families, there was suggestive linkage to OCD on chromosome 12 at marker D12S1064 and on chromosome X at marker DXS7132 whereas, in low-PRS families, there was suggestive linkage to chromosome 3 at marker D3S2398. Pragmatic impairment aggregates in OCD families. Separation anxiety disorder, social phobia, and schizotypal personality traits are part of a clinical spectrum associated with pragmatic impairment in these families. Specific regions of chromosomes 12 and X are linked to OCD in high-PRS families. Thus, pragmatic impairment may distinguish a clinically and genetically homogeneous subtype of OCD.

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.

The Netherlands Obsessive Compulsive Disorder Association (NOCDA) study: design and rationale of a longitudinal naturalistic study of the course of OCD and clinical characteristics of the sample at baseline

In half of Obsessive Compulsive Disorder (OCD) patients the disorder runs a chronic course despite treatment. The factors determining this unfavourable outcome remain unknown. The Netherlands Obsessive Compulsive Disorder Association (NOCDA) study is a multicentre naturalistic cohort study of the biological, psychological and social determinants of chronicity in a clinical sample. Recruitment of OCD patients took place in mental health organizations. Its design is a six-year longitudinal cohort study among a representative clinical sample of 419 OCD patients. All five measurements within this six-year period involved validated semi-structured interviews and self-report questionnaires which gathered information on the severity of OCD and its co-morbidity as well as information on general wellbeing, quality of life, daily activities, medical consumption and key psychological and social factors. The baseline measurements also include DNA and blood sampling and data on demographic and personality variables. The current paper presents the design and rationale of the study, as well as data on baseline sample characteristics. Demographic characteristics and co-morbidity ratings in the NOCDA sample closely resemble other OCD study samples. Lifetime co-morbid Axis I disorders are present in the majority of OCD patients, with high current and lifetime co-morbidity ratings for affective disorders (23.4% and 63.7%, respectively) and anxiety disorders other than OCD (36% current and 46.5% lifetime).

Homeobox genes in obsessive-compulsive disorder

BACKGROUND

Despite evidence that obsessive-compulsive disorder (OCD) is a familial neuropsychiatric condition, progress aimed at identifying genetic determinants of the disorder has been slow. The OCD Collaborative Genetics Study (OCGS) has identified several OCD susceptibility loci through linkage analysis.

METHODS

In this study we investigate two regions on chromosomes 15q and 1q by first refining the linkage region using additional short tandem repeat polymorphic (STRP) markers. We then performed association analysis on single nucleotide polymorphisms (SNP) genotyped (markers placed every 2-4 kb) in the linkage regions in the OCGS sample of 376 rigorously phenotyped affected families.

RESULTS

Three SNPs are most strongly associated with OCD: rs11854486 (P = 0.00005 [0.046 after adjustment for multiple tests]; genetic relative risk (GRR) = 11.1 homozygous and 1.6 heterozygous) and rs4625687 [P = 0.00007 (after adjustment = 0.06); GRR = 2.4] on 15q; and rs4387163 (P = 0.0002 (after adjustment = 0.08); GRR = 1.97) on 1q. The first SNP is adjacent to NANOGP8, the second SNP is in MEIS2, and the third is 150 kb between PBX1 and LMX1A.

CONCLUSIONS

All the genes implicated by association signals are homeobox genes and are intimately involved in neurodevelopment. PBX1 and MEIS2 exert their effects by the formation of a heterodimeric complex, which is involved in development of the striatum, a brain region involved in the pathophysiology of OCD. NANOGP8 is a retrogene of NANOG, a homeobox transcription factor known to be involved in regulation of neuronal development. These findings need replication; but support the hypothesis that genes involved in striatal development are implicated in the pathogenesis of OCD.

Is obsessive-compulsive disorder an anxiety disorder, and what, if any, are spectrum conditions? A family study perspective

BACKGROUND

Experts have proposed removing obsessive-compulsive disorder (OCD) from the anxiety disorders section and grouping it with putatively related conditions in DSM-5. The current study uses co-morbidity and familiality data to inform these issues.

METHOD

Case family data from the OCD Collaborative Genetics Study (382 OCD-affected probands and 974 of their first-degree relatives) were compared with control family data from the Johns Hopkins OCD Family Study (73 non-OCD-affected probands and 233 of their first-degree relatives).

RESULTS

Anxiety disorders (especially agoraphobia and generalized anxiety disorder), cluster C personality disorders (especially obsessive-compulsive and avoidant), tic disorders, somatoform disorders (hypochondriasis and body dysmorphic disorder), grooming disorders (especially trichotillomania and pathological skin picking) and mood disorders (especially unipolar depressive disorders) were more common in case than control probands; however, the prevalences of eating disorders (anorexia and bulimia nervosa), other impulse-control disorders (pathological gambling, pyromania, kleptomania) and substance dependence (alcohol or drug) did not differ between the groups. The same general pattern was evident in relatives of case versus control probands. Results in relatives did not differ markedly when adjusted for demographic variables and proband diagnosis of the same disorder, though the strength of associations was lower when adjusted for OCD in relatives. Nevertheless, several anxiety, depressive and putative OCD-related conditions remained significantly more common in case than control relatives when adjusting for all of these variables simultaneously.

CONCLUSIONS

On the basis of co-morbidity and familiality, OCD appears related both to anxiety disorders and to some conditions currently classified in other sections of DSM-IV.

Comprehensive family-based association study of the glutamate transporter gene SLC1A1 in obsessive-compulsive disorder

SLC1A1 encodes a neuronal glutamate transporter and is a promising candidate gene for obsessive-compulsive disorder (OCD). Several independent research groups have reported significant associations between OCD and single nucleotide polymorphisms (SNPs) in this gene. Previously, we evaluated 13 SNPs in, or near, SLC1A1 and reported a strong association signal with rs301443, a SNP 7.5 kb downstream of the gene [Shugart et al. (2009); Am J Med Genet Part B 150B:886–892]. The aims of the current study were first, to further investigate this finding by saturating the region around rs301443; and second, to explore the entire gene more thoroughly with a dense panel of SNP markers. We genotyped an additional 111 SNPs in or near SLC1A1, covering from 9 kb upstream to 84 kb downstream of the gene at average spacing of 1.7 kb per SNP, and conducted family-based association analyses in 1,576 participants in 377 families.We found that none of the surrounding markers were in linkage disequilibrium with rs301443, nor were any associated with OCD. We also found that SNP rs4740788, located about 8.8 kb upstream of the gene, was associated with OCD in all families (P = 0.003) and in families with male affecteds (P = 0.002). A three-SNP haplotype (rs4740788–rs10491734–rs10491733) was associated with OCD in the total sample (P = 0.00015) and in families with male affecteds (P = 0.0007). Although of nominal statistical significance considering the number of comparisons, these findings provide further support for the involvement of SLC1A1 in the pathogenesis of OCD.

Sexual orientation obsessions in obsessive-compulsive disorder: prevalence and correlates

Sexual obsessions are a common symptom of obsessive-compulsive disorder (OCD) that may be particularly troubling to patients. However, little research has examined concerns surrounding sexual orientation, which includes obsessive doubt about one's sexual orientation, fears of becoming homosexual, or fears that others might think one is homosexual. The present study reports rates and related characteristics of individuals with sexual orientation obsessions in a clinical sample. Participants from the DSM-IV Field Trial (n=409; Foa et al., 1995) were assessed with the Yale-Brown Obsessive Compulsive Symptom Checklist and Severity Scale (YBOCS). We found that 8% (n=33) reported current sexual orientation obsessions and 11.9% (n=49) endorsed lifetime symptoms. Patents with a history of sexual orientation obsessions were twice as likely to be male than female, with moderate OCD severity. Time, interference, and distress items from the YBOCS obsessions subscale were significantly and positively correlated with a history of obsessions about sexual orientation. Avoidance was positively correlated at a trend level (p=0.055). Obsessions about sexual orientation may be associated with increased distress, interference, and avoidance, which may have unique clinical implications. Considerations for diagnosis and treatment are discussed.

Annual Research Review: Transgenic mouse models of childhood-onset psychiatric disorders

Childhood-onset psychiatric disorders, such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), mood disorders, obsessive compulsive spectrum disorders (OCSD), and schizophrenia (SZ), affect many school-age children, leading to a lower quality of life, including difficulties in school and personal relationships that persist into adulthood. Currently, the causes of these psychiatric disorders are poorly understood, resulting in difficulty diagnosing affected children, and insufficient treatment options. Family and twin studies implicate a genetic contribution for ADHD, ASD, mood disorders, OCSD, and SZ. Identification of candidate genes and chromosomal regions associated with a particular disorder provide targets for directed research, and understanding how these genes influence the disease state will provide valuable insights for improving the diagnosis and treatment of children with psychiatric disorders. Transgenic mouse models are one important approach in the study of human diseases, allowing for the use of a variety of experimental approaches to dissect the contribution of a specific chromosomal or genetic abnormality in human disorders. While it is impossible to model an entire psychiatric disorder in a single mouse model, these models can be extremely valuable in dissecting out the specific role of a gene, pathway, neuron subtype, or brain region in a particular abnormal behavior. In this review we discuss existing transgenic mouse models for childhood-onset psychiatric disorders. We compare the strength and weakness of various transgenic mouse models proposed for each of the common childhood-onset psychiatric disorders, and discuss future directions for the study of these disorders using cutting-edge genetic tools.

Pediatric autoimmune neuropsychiatric disorders associated with Streptococcus in identical siblings

Termed pediatric autoimmune neuropsychiatric disorders associated with Streptococcus (PANDAS), these cases of childhood-onset obsessive compulsive disorder and tic disorders resemble the presentation of Sydenham chorea, in that they have an acute onset following a group A beta-hemolytic streptococcal infection (group A Streptococcus), with accompanying neurological signs, and an episodic or sawtooth course. Familial associations of this subgroup of patients remain understudied. This report provides phenotypic descriptions of three youth with PANDAS as well as their genetically identical siblings (in two cases of twins and one case of triplets). These cases highlight the potential for environmental influences for discordant presentations in genetically identical siblings. Despite identical genetics, presentations showed marked variation across siblings (from a full PANDAS presentation to asymptomatic). Further research into environmentally driven influences such as postinfectious molecular mimicry and epigenetic factors that may influence the manifestation of these pediatric neuropsychiatric disorders will promote our understanding of their prevention and treatment.

Separation anxiety disorder in OCD

BACKGROUND

A history of separation anxiety disorder (SAD) is frequently reported by patients with obsessive-compulsive disorder (OCD). The purpose of this study was to determine if there are clinical differences between OCD-affected individuals with, versus without, a history of SAD.

METHODS

Using data collected during the OCD Collaborative Genetic Study, we studied 470 adult OCD participants; 80 had a history of SAD, whereas 390 did not. These two groups were compared as to onset and severity of OCD, lifetime prevalence of Axis I disorders, and number of personality disorder traits.

RESULTS

OCD participants with a history of SAD were significantly younger than the non-SAD group (mean, 34.2 versus 42.2 years; P<.001). They had an earlier age of onset of OCD symptoms (mean, 8.0 versus 10.5 years; P<.003) and more severe OCD, as measured by the Yale-Brown Obsessive Compulsive Scale (mean, 27.5 versus 25.0; P<.005). In addition, those with a history of SAD had a significantly greater lifetime prevalence of agoraphobia (odds ratio (OR) = 2.52, 95% confidence interval (CI) = 1.4-4.6, P<.003), panic disorder (OR = 1.84, CI = 1.03-3.3 P<.04), social phobia (OR = 1.69, CI 1.01-2.8, P<.048), after adjusting for age at interview, age at onset of OCD, and OCD severity in logistic regression models. There was a strong relationship between the number of dependent personality disorder traits and SAD (adjusted OR = 1.42, CI = 1.2-1.6, P<.001).

CONCLUSIONS

A history of SAD is associated with anxiety disorders and dependent personality disorder traits in individuals with OCD.

Association of SLC6A4 variants with obsessive-compulsive disorder in a large multicenter US family study

Genetic association studies of SLC6A4 (SERT) and obsessive-compulsive disorder (OCD) have been equivocal. We genotyped 1241 individuals in 278 pedigrees from the OCD Collaborative Genetics Study for 13 single-nucleotide polymorphisms, for the linked polymorphic region (LPR) indel with molecular haplotypes at rs25531, for VNTR polymorphisms in introns 2 and 7 and for a 381-bp deletion 3' to the LPR. We analyzed using the Family-Based Association Test (FBAT) under additive, dominant, recessive and genotypic models, using both OCD and sex-stratified OCD as phenotypes. Two-point FBAT analysis detected association between Int2 (P = 0.0089) and Int7 (P = 0.0187) (genotypic model). Sex-stratified two-point analysis showed strong association in females with Int2 (P<0.0002), significant after correction for linkage disequilibrium, and multiple marker and model testing (P(Adj) = 0.0069). The SLC6A4 gene is composed of two haplotype blocks (our data and the HapMap); FBAT whole-marker analysis conducted using this structure was not significant. Several noteworthy nonsignificant results have emerged. Unlike Hu et al., we found no evidence for overtransmission of the LPR L(A) allele (genotype relative risk = 1.11, 95% confidence interval: 0.77-1.60); however, rare individual haplotypes containing L(A) with P<0.05 were observed. Similarly, three individuals (two with OCD/OCPD) carried the rare I425V SLC6A4 variant, but none of them passed it on to their six OCD-affected offspring, suggesting that it is unlikely to be solely responsible for the 'OCD plus syndrome', as reported by Ozaki et al. In conclusion, we found evidence of genetic association at the SLC6A4 locus with OCD. A noteworthy lack of association at the LPR, LPR-rs25531 and rare 425V variants suggests that hypotheses about OCD risk need revision to accommodate these new findings, including a possible gender effect.

Diagnosis and treatment of a patient with both psychotic and obsessive-compulsive symptoms

When a patient presents with both psychotic and obsessive-compulsive symptoms, the clinician is faced with a differential diagnosis that includes comorbid schizophrenia and obsessive-compulsive disorder (OCD), OCD with poor insight, and schizophrenia with antipsychotic-induced obsessive-compulsive symptoms. If the psychotic symptoms are subthresh-old or attenuated in form, the individual may have OCD and putative prodromal schizophrenia. The authors present a case to outline a strategy for differentiating among these possible diagnoses and for optimizing treatment.

Tic disorders: some key issues for DSM-V

This study provides a focused review of issues that are relevant to the nosology of the tic disorders and presents preliminary recommendations to be considered for DSM-V. The recommended changes are designed to clarify and simplify the diagnostic criteria, reduce the use of the residual category, tic disorder not otherwise specified, and are not intended to alter substantially clinical practice or the continuity of past and future research. Specific recommendations include: (1) a more precise definition of motor and vocal tics; (2) simplification of the duration criterion for the tic disorders; (3) revising the term "transient tic disorder" for those with tic symptoms of less than 12-month duration; (4) establishing new tic disorder categories for those with substance induced tic disorder and tic disorder due to a general medical condition; and (5) including a motor tic only and vocal tic only specifier for the chronic motor or vocal tic disorder category.

A screen of SLC1A1 for OCD-related alleles

SLC1A1, which encodes the neuronal and epithelial glutamate transporter, is a promising candidate gene for obsessive-compulsive disorder (OCD). In this study, we conducted capillary electrophoresis single-strand conformation polymorphism (CE-SSCP) screen for all 12 identified exons, including all coding regions and approximately 50 bp of flanking introns of the human SLC1A1 in 378 OCD-affected individuals. Full sequencing was completed on samples that showed an aberrant SSCP tracing for identification of the underlying sequence variants. Our aim was to determine if there are differences in the frequencies of relatively common alleles, or rare functional alleles, in 378 OCD cases and 281 ethnically matched controls. We identified one nonsynonymous coding SNP (c.490A > G, T164A) and three synonymous coding SNP (c.81G > C, A27A; c.414A > G, T138T; c.1110T > C, T370T) in case samples. We found no statistical differences in genotype and allele frequencies of common cSNPs in SLC1A1 between the OCD cases and controls. The rare variant T164A was found only in one family. Further investigation of this variant is necessary to determine whether and how it is related to OCD. There was no other evidence of significant accumulation of deleterious coding mutations in SLC1A1 in the OCD cases.

Basal ganglia MR relaxometry in obsessive-compulsive disorder: T2 depends upon age of symptom onset

Dysfunction in circuits linking frontal cortex and basal ganglia (BG) is strongly implicated in obsessive-compulsive disorder (OCD). On MRI studies, neuropsychiatric disorders with known BG pathology have abnormally short T2 relaxation values (a putative biomarker of elevated iron) in this region. We asked if BG T2 values are abnormal in OCD. We measured volume and T2 and T1 relaxation rates in BG of 32 adults with OCD and 33 matched controls. There were no group differences in volume or T1 values in caudate, putamen, or globus pallidus (GP). The OCD group had lower T2 values (suggesting higher iron content) in the right GP, with a trend in the same direction for the left GP. This effect was driven by patients whose OCD symptoms began from around adolescence to early adulthood. The results suggest a possible relationship between age of OCD onset and iron deposition in the basal ganglia.

A family-based association study of the glutamate transporter gene SLC1A1 in obsessive-compulsive disorder in 378 families

SLC1A encodes the neuronal and epithelial glutamate transporter and was previously tested as a candidate for obsessive-compulsive disorder (OCD) by several research groups. Recently, three independent research groups reported significant association findings between OCD and several genetic variants in SLC1A1. This study reports the results from a family-based association study, which examined the association between 13 single nucleotide polymorphisms (SNPs) within or in proximity to the SLC1A1 gene. Although we did not replicate association findings for those significant SNPs reported by previous studies, our study indicated a strong association signal with the SNP RS301443 (P-value = 0.000067; Bonferroni corrected P-value = 0.0167) under a dominant model, with an estimated odds ratio of 3.5 (confidence interval: 2.66-4.50). Further, we conducted single SNP analysis after stratifying the full data set by the gender status of affected in each family. The P-value for RS301443 in families with the male affected was 0.00027, and the P-value in families with female affected was 0.076. The fact that we identified a signal which was not previously reported by the other research groups may be due to differences in study designs and sample ascertainment. However, it is also possible that this significant SNP may be part of a regulator for SLC1A1, given that it is roughly 7.5 kb away from the boundary of the SLC1A1 gene. However, this potential finding needs to be validated biologically. Further functional studies in this region are planned by this research group.

Obsessive-compulsive disorder: subclassification based on co-morbidity

BACKGROUND

Obsessive-compulsive disorder (OCD) is probably an etiologically heterogeneous condition. Many patients manifest other psychiatric syndromes. This study investigated the relationship between OCD and co-morbid conditions to identify subtypes.

METHOD

Seven hundred and six individuals with OCD were assessed in the OCD Collaborative Genetics Study (OCGS). Multi-level latent class analysis was conducted based on the presence of eight co-morbid psychiatric conditions [generalized anxiety disorder (GAD), major depression, panic disorder (PD), separation anxiety disorder (SAD), tics, mania, somatization disorders (Som) and grooming disorders (GrD)]. The relationship of the derived classes to specific clinical characteristics was investigated.

RESULTS

Two and three classes of OCD syndromes emerge from the analyses. The two-class solution describes lesser and greater co-morbidity classes and the more descriptive three-class solution is characterized by: (1) an OCD simplex class, in which major depressive disorder (MDD) is the most frequent additional disorder; (2) an OCD co-morbid tic-related class, in which tics are prominent and affective syndromes are considerably rarer; and (3) an OCD co-morbid affective-related class in which PD and affective syndromes are highly represented. The OCD co-morbid tic-related class is predominantly male and characterized by high conscientiousness. The OCD co-morbid affective-related class is predominantly female, has a young age at onset, obsessive-compulsive personality disorder (OCPD) features, high scores on the 'taboo' factor of OCD symptoms, and low conscientiousness.

CONCLUSIONS

OCD can be classified into three classes based on co-morbidity. Membership within a class is differentially associated with other clinical characteristics. These classes, if replicated, should have important implications for research and clinical endeavors.

Recent advances in the genetics of obsessive-compulsive disorder

This article reviews recent developments in understanding the genetic etiology of obsessive-compulsive disorder (OCD). Family studies provide further support for the familial aggregation of OCD. Genome-wide linkage studies indicate that specific chromosomal regions are linked to OCD. Moreover, results from recent molecular genetic studies suggest that several candidate genes are associated with OCD. However, specific genes causing OCD have not been conclusively identified, and the molecular pathogenesis of the disorder has not been elucidated. The search for genes is complicated by the clinical and etiologic heterogeneity of OCD, as well as the possibility of gene-gene and gene-environment interactions. Despite this complexity, further refinement of the phenotype and developments in molecular and statistical genetics hold promise for further deepening our genetic understanding of OCD in the future.

Sapap3 and pathological grooming in humans: Results from the OCD collaborative genetics study

SAP90/PSD95-associated protein (SAPAP) family proteins are post-synaptic density (PSD) components that interact with other proteins to form a key scaffolding complex at excitatory (glutamatergic) synapses. A recent study found that mice with a deletion of the Sapap3 gene groomed themselves excessively, exhibited increased anxiety-like behaviors, and had cortico-striatal synaptic defects, all of which were preventable with lentiviral-mediated expression of Sapap3 in the striatum; the behavioral abnormalities were also reversible with fluoxetine. In the current study, we sought to determine whether variation within the human Sapap3 gene was associated with grooming disorders (GDs: pathologic nail biting, pathologic skin picking, and/or trichotillomania) and/or obsessive-compulsive disorder (OCD) in 383 families thoroughly phenotyped for OCD genetic studies. We conducted family-based association analyses using the FBAT and GenAssoc statistical packages. Thirty-two percent of the 1,618 participants met criteria for a GD, and 65% met criteria for OCD. Four of six SNPs were nominally associated (P < 0.05) with at least one GD (genotypic relative risks: 1.6-3.3), and all three haplotypes were nominally associated with at least one GD (permuted P < 0.05). None of the SNPs or haplotypes were significantly associated with OCD itself. We conclude that Sapap3 is a promising functional candidate gene for human GDs, though further work is necessary to confirm this preliminary evidence of association.

Obsessions and compulsions in the community: prevalence, interference, help-seeking, developmental stability, and co-occurring psychiatric conditions

OBJECTIVE

It is unclear how many people in the community have obsessions and compulsions and associated levels of interference. It is also unknown what variables predict help-seeking for these symptoms, whether they are developmentally stable, and whether they increase the risk of mental disorders.

METHOD

The authors analyzed data from the prospective longitudinal Dunedin study of an unselected birth cohort. The presence of obsessions and compulsions and mental disorders was assessed using the Diagnostic Interview Schedule (DIS) at ages 11, 26, and 32. Data on interference and help-seeking were obtained at ages 26 and 32.

RESULTS

Obsessions and compulsions were frequent in individuals with mental disorders other than obsessive-compulsive disorder (OCD) and among people without mental disorders. Even in the latter group, these symptoms caused significant interference. The presence of anxiety/depression and of obsessions (particularly aggressive and shameful thoughts), but not compulsions, was associated with help-seeking. Harm/checking was the most prevalent symptom dimension. Symptom dimensions were temporally stable and associated with increased comorbidity. Obsessive-compulsive symptoms at age 11 predicted a high risk of an adult OCD diagnosis as well as elevated adult symptom dimensions.

CONCLUSIONS

Obsessions and compulsions are common in the adult population, have their roots in childhood, and are associated with interference, risk for disorders, and help-seeking. Subclinical obsessions and compulsions should be taken into account in research, intervention, and DSM-V.

Gender differences in genetic linkage and association on 11p15 in obsessive-compulsive disorder families

Several clinical and genetic studies have reported gender differences in obsessive-compulsive disorder (OCD). Previously, we conducted a linkage genome scan using multipoint allele-sharing methods to test for linkage in 219 families participating in the OCD Collaborative Genetics Study. When these families were stratified by proband's gender, suggestive linkage to chromosome 11p15 at marker D11S2362 (KAC(all) = 2.92, P = 0.00012) was detected in families with male probands, but not in the ones with female probands. We have since conducted fine mapping with a denser microsatellite marker panel in the region of 11p15, and detected a significant linkage signal at D11S4146 (KAC(all) = 5.08, P < 0.00001) in the families of male probands. Subsequently, 632 SNPs were genotyped spanning a 4.0 Mb region of the 1 LOD unit interval surrounding the linkage peak in the original families and an additional 165 families. Six SNPs were associated with OCD (P < 0.001): two SNPs were identified when all the families were included, and four SNPs only in male proband families. No SNP showed significant association with the OCD phenotype only in the families with a female proband. The results suggest a possible gender effect in the etiology of OCD.

The association between parental bonding and obsessive compulsive disorder in offspring at high familial risk

BACKGROUND

The aim of the current study is to estimate the association between parenting factors derived from the Parental Bonding Instrument (PBI) and a lifetime DSM-IV diagnosis of OCD.

METHOD

Data were from approximately 1200 adults from 465 families assessed as part of a large family and genetic study of OCD. The association of three parenting factors, for fathers and mothers, with offspring OCD status were examined; analyses were stratified by parental OCD status and family loading for OCD (multiplex versus sporadic).

RESULTS

Three factors were derived by principal components factor analysis of the PBI (maternal and paternal care, overprotection and control). Maternal overprotection was associated with OCD in offspring with familial OCD (familial cases) but only if neither parent was affected with OCD, which suggests independent but additive environmental and genetic risk (OR = 5.9, 95% CI 1.2, 29.9, p = 0.031). Paternal care was a protective factor in those not at high genetic risk (sporadic cases) (OR = 0.2, 95% CI 0.0, 0.8, p = 0.027). Maternal overprotection was also associated with offspring OCD in sporadic families (OR = 2.9, 95% CI 1.3, 6.6, p = 0.012). The finding that parental overprotection and care were not associated with offspring OCD when at least one parent had OCD addressed directly the hypothesis of maternal or paternal OCD adversely impacting parenting.

CONCLUSIONS

This study provides evidence that aspects of parenting may contribute to the development of OCD among offspring. Prospective studies of children at risk for OCD are needed to explore the direction of causality.

Evidence for potential relationship between SLC1A1 and a putative genetic linkage region on chromosome 14q to obsessive-compulsive disorder with compulsive hoarding

Obsessive-compulsive disorder (OCD) is likely a disorder involving complex genetic transmission. This suggests that multiple genetic and environmental factors are involved in its etiology. This is complicated further by the probability of genetic heterogeneity for this phenotype. In this report, we describe a preliminary approach to deal with both complexities. SLC1A1, a glutamate transporter gene on chromosome 9p, was originally proposed to be related to OCD based on two linkage studies, and subsequently association of OCD to the gene has been replicated. Additionally, genetic linkage to a subtype of OCD, compulsive hoarding, has been reported on chromosome 14q. We hypothesized that both genomic regions contribute to OCD in some instances. Using the analytic program GENEFINDER we found that conditioning linkage on chromosome 14q to a marker adjacent to SLC1A1, reduced the size of the linkage region on chromosome 14q and provided evidence for interaction between the regions on chromosomes 9p and 14q.

Further development of YBOCS dimensions in the OCD Collaborative Genetics study: symptoms vs. categories

Despite progress in identifying homogeneous subphenotypes of obsessive-compulsive disorder (OCD) through factor analysis of the Yale Brown Obsessive-Compulsive Scale Symptom Checklist (YBOCS-SC), prior solutions have been limited by a reliance on presupposed symptom categories rather than discrete symptoms. Furthermore, there have been few attempts to evaluate the familiality of OCD symptom dimensions. The purpose of this study was to extend prior work by this collaborative group in category-based dimensions by conducting the first-ever exploratory dichotomous factor analysis using individual OCD symptoms, comparing these results to a refined category-level solution, and testing the familiality of derived factors. Participants were 485 adults in the six-site OCD Collaborative Genetics Study, diagnosed with lifetime OCD using semi-structured interviews. YBOCS-SC data were factor analyzed at both the individual item and symptom category levels. Factor score intraclass correlations were calculated using a subsample of 145 independent affected sib pairs. The item- and category-level factor analyses yielded nearly identical 5-factor solutions. While significant sib-sib associations were found for four of the five factors, Hoarding and Taboo Thoughts were the most robustly familial (r ICC>or=0.2). This report presents considerable converging evidence for a five-factor structural model of OCD symptoms, including separate factor analyses employing individual symptoms and symptom categories, as well as sibling concordance. The results support investigation of this multidimensional model in OCD genetic linkage studies.

Sex-specific clinical correlates of hoarding in obsessive-compulsive disorder

Little is known about whether the clinical correlates of hoarding behavior are different in men and women with obsessive-compulsive disorder (OCD). In the current study, we evaluated the association of hoarding with categories of obsessions and compulsions, psychiatric disorders, personality dimensions, and other clinical characteristics separately in 151 men and 358 women with OCD who were examined during the OCD Collaborative Genetics Study. We found that, among men but not women, hoarding was associated with aggressive, sexual, and religious obsessions and checking compulsions. In men, hoarding was associated with generalized anxiety disorder and tics whereas, among women, hoarding was associated with social phobia, post-traumatic stress disorder, body dysmorphic disorder, nail biting, and skin picking. In women but not men, hoarding was associated with schizotypal and dependent personality disorder dimensions, and with low conscientiousness. These findings indicate that specific clinical correlates of hoarding in OCD are different in men and women and may reflect sex-specific differences in the course, expression, and/or etiology of hoarding behavior in OCD.

Genetic and environmental influences on obsessive-compulsive disorder

It is important to understand how genetic and environmental factors interact in the development of obsessive-compulsive disorder (OCD) in order to provide a cohesive model of the underlying pathogenic mechanisms. In this article, we provide an overview of the current knowledge of possible genetic and environmental contributions to the development of OCD. We consider the significant challenges for identifying risk factors for OCD as well as promising avenues for overcoming these obstacles in future research. In particular, we discuss the value of focusing on certain phenotypes, applying a dimensional approach, and investigating possible endophenotypes. We also describe innovative study designs that may be used in future research to explore the interaction between genetic vulnerability and environmental risk factors for OCD.

Clinical characteristics and medical complications of pathologic skin picking

OBJECTIVE

This study sought to detail the phenomenology and medical consequences of pathologic skin picking (PSP).

METHOD

Sixty subjects (11.7% males) with PSP (mean+/-S.D.=33.7+/-11.6 years) were assessed. Subjects seen in a pharmacological study as well as those from an ongoing outpatient longitudinal study comprised this sample. Subjects were assessed for current and lifetime psychiatric comorbidity (using the Structured Clinical Interview for DSM-IV Axis I Disorders), clinical severity (using the Clinical Global Impression - Severity scale) and psychosocial interference due to picking (using the Sheehan Disability Scale). Clinical characteristic data, including time spent picking per day, sites picked and medical complications directly resulting from skin picking behavior, as well as family history, were also obtained.

RESULTS

The mean age (+/-S.D.) of onset for PSP was 12.3+/-9.6 years. The face was the most common area picked. Subjects reported picking a mean of 107.6 min each day. Scarring, ulcerations and infections were common. Few had ever sought psychiatric treatment for their behavior. Current comorbid Axis I psychiatric conditions were found in 38.3% of the sample. Trichotillomania (36.7%), compulsive nail biting (26.7%), depressive disorder (16.7%) and obsessive-compulsive disorder (15%) were the most common current comorbid conditions.

CONCLUSION

PSP appears to be time consuming and frequently associated with medical complications. Research is needed to optimize patient care for individuals with this behavior.

A large case-control study of common functional SLC6A4 and BDNF variants in obsessive-compulsive disorder

Both serotonin transporter (SLC6A4) and brain-derived neurotrophic factor (BDNF) genes have shown positive associations with obsessive-compulsive disorder (OCD) and some other psychiatric disorders, but these results have not been consistently replicated. To explore the hypothesis that this variability might result from the effects of differing combinations of overlooked variants within SLC6A4 together with small OCD and control sample sizes, we studied three common functional polymorphisms (5-HTTLPR, STin2, and the newly discovered SNP, rs25531) in the largest sample size of OCD patients (N=347) and controls (N=749) ever investigated. During methods development, we found evidence for potential SLC6A4 genotyping problems with earlier methodology, a third possible contributor to variability in earlier studies. A fourth possible explanation might be SLC6A4 x BDNF interactions, which prompted us to investigate combined genotypes of BDNF V66M with the three SLC6A4 loci. Except for a nominal association with rs25531 alone, which did not survive correction for multiple comparisons, we found no evidence for any of these other variants being associated alone or together with OCD, and we therefore also examined clinical OCD subtypes within the sample to evaluate clinical heterogeneity. Subgroups based on the age of OCD onset, gender, familiality, factor analysis-derived symptom dimensions, or comorbidity with other psychiatric disorders failed to identify SLC6A4- or BDNF-associated phenotypes, with one exception of overall number of comorbid anxiety disorders being significantly associated with 5-HTTLPR/rs25531. We conclude that despite their attractiveness as candidate genes in OCD, our data provide no support for association in this large OCD patient sample and point toward the need to examine other genes as candidates for risk determinants in OCD.