Genome-wide association study identifies 30 obsessive-compulsive disorder associated loci

Obsessive-compulsive disorder (OCD) affects ~1% of the population and exhibits a high SNP-heritability, yet previous genome-wide association studies (GWAS) have provided limited information on the genetic etiology and underlying biological mechanisms of the disorder. We conducted a GWAS meta-analysis combining 53,660 OCD cases and 2,044,417 controls from 28 European-ancestry cohorts revealing 30 independent genome-wide significant SNPs and a SNP-based heritability of 6.7%. Separate GWAS for clinical, biobank, comorbid, and self-report sub-groups found no evidence of sample ascertainment impacting our results. Functional and positional QTL gene-based approaches identified 249 significant candidate risk genes for OCD, of which 25 were identified as putatively causal, highlighting WDR6, DALRD3, CTNND1 and genes in the MHC region. Tissue and single-cell enrichment analyses highlighted hippocampal and cortical excitatory neurons, along with D1- and D2-type dopamine receptor-containing medium spiny neurons, as playing a role in OCD risk. OCD displayed significant genetic correlations with 65 out of 112 examined phenotypes. Notably, it showed positive genetic correlations with all included psychiatric phenotypes, in particular anxiety, depression, anorexia nervosa, and Tourette syndrome, and negative correlations with a subset of the included autoimmune disorders, educational attainment, and body mass index.. This study marks a significant step toward unraveling its genetic landscape and advances understanding of OCD genetics, providing a foundation for future interventions to address this debilitating disorder.

Clinical predictors of quality of life in a large sample of adult obsessive-compulsive disorder outpatients

BACKGROUND

OCD causes impairment in different areas of the patients' quality of life (QoL), such as sociability, family relationships, and occupational performance. The literature has emphasized the relevance of assessing QoL as a critical outcome in mental health studies.

AIMS

The aim of this study was to investigate sociodemographic and clinical predictors of QoL, including treatment response, in a large sample of OCD subjects.

PROCEDURES

575 adult OCD outpatients were interviewed as part of the Brazilian OCD Consortium (CTOC). A smaller number of subjects (N = 143) participated on a clinical trial conducted by one of the CTOC sites.

RESULTS

OCD patients were more impaired in their QoL when compared to the Brazilian normative data. Obsessive-compulsive symptoms (OCS) severity had significant correlations with all Medical Outcome Short-Form questionnaire (SF-36) domains. Different OCS dimensions had specific correlations with each SF-36 domain. OCS, depression and anxiety severity significantly increased the impairment risk for the SF-36 domains. Suicidality increased the relative risks for impairment in the Role-Functioning and the Vitality domains by 51% and 17%, respectively. There was a significant improvement in some SF-36 dimensions after treatment.

CONCLUSIONS

QoL domains are highly compromised in OCD patients. Each SF-36 domain had distinct associations with sociodemographic and clinical variables, including OCS dimensions, suicidality and treatment response. These findings emphasize the OCD heterogeneity and the need for including QoL assessment in clinical practice and research studies.

Cross-disorder genome-wide analyses suggest a complex genetic relationship between Tourette's syndrome and OCD

OBJECTIVE

Obsessive-compulsive disorder (OCD) and Tourette's syndrome are highly heritable neurodevelopmental disorders that are thought to share genetic risk factors. However, the identification of definitive susceptibility genes for these etiologically complex disorders remains elusive. The authors report a combined genome-wide association study (GWAS) of Tourette's syndrome and OCD.

METHOD

The authors conducted a GWAS in 2,723 cases (1,310 with OCD, 834 with Tourette's syndrome, 579 with OCD plus Tourette's syndrome/chronic tics), 5,667 ancestry-matched controls, and 290 OCD parent-child trios. GWAS summary statistics were examined for enrichment of functional variants associated with gene expression levels in brain regions. Polygenic score analyses were conducted to investigate the genetic architecture within and across the two disorders.

RESULTS

Although no individual single-nucleotide polymorphisms (SNPs) achieved genome-wide significance, the GWAS signals were enriched for SNPs strongly associated with variations in brain gene expression levels (expression quantitative loci, or eQTLs), suggesting the presence of true functional variants that contribute to risk of these disorders. Polygenic score analyses identified a significant polygenic component for OCD (p=2×10(-4)), predicting 3.2% of the phenotypic variance in an independent data set. In contrast, Tourette's syndrome had a smaller, nonsignificant polygenic component, predicting only 0.6% of the phenotypic variance (p=0.06). No significant polygenic signal was detected across the two disorders, although the sample is likely underpowered to detect a modest shared signal. Furthermore, the OCD polygenic signal was significantly attenuated when cases with both OCD and co-occurring Tourette's syndrome/chronic tics were included in the analysis (p=0.01).

CONCLUSIONS

Previous work has shown that Tourette's syndrome and OCD have some degree of shared genetic variation. However, the data from this study suggest that there are also distinct components to the genetic architectures of these two disorders. Furthermore, OCD with co-occurring Tourette's syndrome/chronic tics may have different underlying genetic susceptibility compared with OCD alone.

Copy number variation in obsessive-compulsive disorder and tourette syndrome: a cross-disorder study

OBJECTIVE

Obsessive-compulsive disorder (OCD) and Tourette syndrome (TS) are heritable neurodevelopmental disorders with a partially shared genetic etiology. This study represents the first genome-wide investigation of large (>500 kb), rare (<1%) copy number variants (CNVs) in OCD and the largest genome-wide CNV analysis in TS to date.

METHOD

The primary analyses used a cross-disorder design for 2,699 case patients (1,613 ascertained for OCD, 1,086 ascertained for TS) and 1,789 controls. Parental data facilitated a de novo analysis in 348 OCD trios.

RESULTS

Although no global CNV burden was detected in the cross-disorder analysis or in secondary, disease-specific analyses, there was a 3.3-fold increased burden of large deletions previously associated with other neurodevelopmental disorders (p = .09). Half of these neurodevelopmental deletions were located in a single locus, 16p13.11 (5 case patient deletions: 0 control deletions, p = .08 in the current study, p = .025 compared to published controls). Three 16p13.11 deletions were confirmed de novo, providing further support for the etiological significance of this region. The overall OCD de novo rate was 1.4%, which is intermediate between published rates in controls (0.7%) and in individuals with autism or schizophrenia (2-4%).

CONCLUSION

Several converging lines of evidence implicate 16p13.11 deletions in OCD, with weaker evidence for a role in TS. The trend toward increased overall neurodevelopmental CNV burden in TS and OCD suggests that deletions previously associated with other neurodevelopmental disorders may also contribute to these phenotypes.

Partitioning the heritability of Tourette syndrome and obsessive compulsive disorder reveals differences in genetic architecture

The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained by all SNPs for two phenotypically-related neurobehavioral disorders, obsessive-compulsive disorder (OCD) and Tourette Syndrome (TS), using GCTA. Our analysis yielded a heritability point estimate of 0.58 (se = 0.09, p = 5.64e-12) for TS, and 0.37 (se = 0.07, p = 1.5e-07) for OCD. In addition, we conducted multiple genomic partitioning analyses to identify genomic elements that concentrate this heritability. We examined genomic architectures of TS and OCD by chromosome, MAF bin, and functional annotations. In addition, we assessed heritability for early onset and adult onset OCD. Among other notable results, we found that SNPs with a minor allele frequency of less than 5% accounted for 21% of the TS heritability and 0% of the OCD heritability. Additionally, we identified a significant contribution to TS and OCD heritability by variants significantly associated with gene expression in two regions of the brain (parietal cortex and cerebellum) for which we had available expression quantitative trait loci (eQTLs). Finally we analyzed the genetic correlation between TS and OCD, revealing a genetic correlation of 0.41 (se = 0.15, p = 0.002). These results are very close to previous heritability estimates for TS and OCD based on twin and family studies, suggesting that very little, if any, heritability is truly missing (i.e., unassayed) from TS and OCD GWAS studies of common variation. The results also indicate that there is some genetic overlap between these two phenotypically-related neuropsychiatric disorders, but suggest that the two disorders have distinct genetic architectures.

Genome-wide association study of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a common, debilitating neuropsychiatric illness with complex genetic etiology. The International OCD Foundation Genetics Collaborative (IOCDF-GC) is a multi-national collaboration established to discover the genetic variation predisposing to OCD. A set of individuals affected with DSM-IV OCD, a subset of their parents, and unselected controls, were genotyped with several different Illumina SNP microarrays. After extensive data cleaning, 1465 cases, 5557 ancestry-matched controls and 400 complete trios remained, with a common set of 469,410 autosomal and 9657 X-chromosome single nucleotide polymorphisms (SNPs). Ancestry-stratified case-control association analyses were conducted for three genetically-defined subpopulations and combined in two meta-analyses, with and without the trio-based analysis. In the case-control analysis, the lowest two P-values were located within DLGAP1 (P=2.49 × 10(-6) and P=3.44 × 10(-6)), a member of the neuronal postsynaptic density complex. In the trio analysis, rs6131295, near BTBD3, exceeded the genome-wide significance threshold with a P-value=3.84 × 10(-8). However, when trios were meta-analyzed with the case-control samples, the P-value for this variant was 3.62 × 10(-5), losing genome-wide significance. Although no SNPs were identified to be associated with OCD at a genome-wide significant level in the combined trio-case-control sample, a significant enrichment of methylation QTLs (P<0.001) and frontal lobe expression quantitative trait loci (eQTLs) (P=0.001) was observed within the top-ranked SNPs (P<0.01) from the trio-case-control analysis, suggesting these top signals may have a broad role in gene expression in the brain, and possibly in the etiology of OCD.

Trajectory in obsessive-compulsive disorder comorbidities

The main goal of this study is to contribute to the understanding of the trajectory of comorbid disorders associated with obsessive-compulsive disorder (OCD) according to the first manifested psychiatric disorder and its impact in the clinical course of OCD and subsequent psychiatric comorbidities. One thousand and one OCD patients were evaluated at a single time point. Standardized instruments were used to determine the current and lifetime psychiatric diagnoses (Structured Clinical Interview for DSM-IV Axis I and for impulse-control disorders) as well as to establish current obsessive-compulsive, depressive and anxiety symptom severity (Yale-Brown Obsessive-Compulsive Scale; Dimensional Yale-Brown Obsessive-Compulsive Scale, Beck Depression and Anxiety Inventories and the OCD Natural History Questionnaire). To analyze the distribution of comorbidities according to age at onset Bayesian approach was used. Five hundred eight patients had the first OC symptom onset till the age of 10 years old. The first comorbidity to appear in the majority of the sample was separation anxiety disorder (17.5%, n=175), followed by ADHD (5.0%, n=50) and tic disorders (4.4%, n=44). OCD patients that presented with separation anxiety disorder as first diagnosis had higher lifetime frequency of post-traumatic stress disorder (p=0.003), higher scores in the Sexual/Religious dimension (p=0.04), Beck Anxiety (p<0.001) and Depression (p=0.005) Inventories. OCD patients that initially presented with ADHD had higher lifetime frequencies of substance abuse and dependence (p<0.001) and worsening OCD course (p=0.03). OCD patients that presented with tic disorders as first diagnosis had higher lifetime frequencies of OC spectrum disorders (p=0.03). OCD is a heterogeneous disorder and that the presence of specific comorbid diagnoses that predate the onset of OCD may influence its clinical presentation and course over the lifetime.

Eating disorders in patients with obsessive-compulsive disorder: prevalence and clinical correlates

OBJECTIVE

The objective is to evaluate the prevalence and associated clinical characteristics of eating disorders (ED) in patients with obsessive-compulsive disorder (OCD).

METHOD

This is a cross-sectional study comparing 815 patients with OCD. Participants were assessed with structured interviews and scales: SCID-I, Y-BOCS, Dimensional Y-BOCS, BABS, Beck Depression and Anxiety Inventories.

RESULTS

Ninety-two patients (11.3%) presented the following EDs: binge-eating disorders [= 59 (7.2%)], bulimia nervosa [= 16 (2.0%)], or anorexia nervosa [= 17 (2.1%)]. Compared to OCD patients without ED (OCD-Non-ED), OCD-ED patients were more likely to be women with previous psychiatric treatment. Mean total scores in Y-BOCS, Dimensional Y-BOCS, and BABS were similar within groups. However, OCD-ED patients showed higher lifetime prevalence of comorbid conditions, higher anxiety and depression scores, and higher frequency of suicide attempts than did the OCD-Non-ED group. Primarily diagnosed OCD patients with comorbid ED may be associated with higher clinical severity.

DISCUSSION

Future longitudinal studies should investigate dimensional correlations between OCD and ED.

Quetiapine versus clomipramine in the augmentation of selective serotonin reuptake inhibitors for the treatment of obsessive-compulsive disorder: a randomized, open-label trial

After 12 weeks of selective serotonin reuptake inhibitor (SSRI) monotherapy with inadequate response, 10 patients received clomipramine and 11 received quetiapine as augmentation agents of the SSRI. The primary outcome measure was the difference between initial and final scores of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), rated in a blinded fashion, and the score of clinical global improvement (CGI-I). Statistical analyses were performed using nonparametric tests to evaluate treatment efficacy and the difference between treatment groups. Percentile plots were constructed with YBOCS scores from the clomipramine and quetiapine groups. Considering response a >or=35% reduction in the initial Y-BOCS score plus a rating of 'much improved' or 'very much improved' on CGI-I, four of eleven quetiapine patients and one out of ten clomipramine patients were classified as responders. The mean final Y-BOCS score was significantly lower than baseline in the quetiapine augmentation group (P = 0.023), but not in the clomipramine augmentation group (P = 0.503). The difference between groups showed a trend towards significance only at week 4, the mean Y-BOCS score being lower for those receiving quetiapine (P = 0.052). A difference between groups was also observed at week 4 according to percentile plots. These results corroborate previous findings of quetiapine augmentation efficacy in obsessive-compulsive disorder (OCD). Clomipramine augmentation did not produce a significant reduction in Y-BOCS scores. Higher target maximum dosages might have yielded different results.

Obsessive-compulsive symptoms and disorder in patients with schizophrenia treated with clozapine or haloperidol

We conducted a cross-sectional study to compare the prevalence and severity of obsessive-compulsive symptoms (OCSs) and obsessive-compulsive disorder (OCD) in patients with schizophrenia treated with clozapine or haloperidol. Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I disorders-patient edition was used to diagnose schizophrenia and OCD. Sixty subjects, 40 of them using clozapine and 20 using haloperidol, completed the Yale-Brown Obsessive-Compulsive Scale, the Positive and Negative Syndrome Scale (PANSS), and the Clinical Global Impression. The prevalence of OCD in patients taking clozapine was 20%, whereas the prevalence of patients taking haloperidol was 10%, although this difference was not statistically significant (P = .540). However, patients using clozapine showed higher severity of OCSs than patients using haloperidol (P = .027) did. When schizophrenia patients were divided according to the presence or absence of OCD or OCSs, patients with schizophrenia and OCD or OCSs showed higher severity of schizophrenia symptoms when compared to those with schizophrenia without OCD and OCSs (P = .002). A PANSS total score higher than 70 and the use of antidepressants were predictors of the presence of OCSs or OCD. Schizophrenia patients taking clozapine had higher severity scores both in obsessive-compulsive and schizophrenia rating scales. These results may support an association between the exacerbation of obsessive-compulsive phenomena and the use of clozapine.

Perfectionism and sensory phenomena: phenotypic components of obsessive-compulsive disorder

BACKGROUND

The aim of the study was to investigate how perfectionism and sensory phenomena (SP) interact as possible phenotypic components of obsessive-compulsive disorder (OCD).

METHODS

Forty-seven adult outpatients, meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for OCD, and a control group of 41 community subjects were assessed using the Frost Multidimensional Perfectionism Scale (FMPS), the University of São Paulo-Sensory Phenomena Scale, and other standard measures of OCD severity.

RESULTS

Three of the FMPS subscales ("concern over mistakes," "doubts about action," and "parental criticism") were significantly different between OCD patients and control subjects. All subtypes of SP were significantly more frequent and more severe in OCD than in control subjects. The "incompleteness" subtype of SP was associated with high scores on all dimensions of the FMPS, whereas the "just-right" subtype of SP was only associated with "doubts about action," "personal standards," and "organization" subscales of the FMPS.

CONCLUSIONS

Presence and severity of SP and specific elements of perfectionism clearly distinguish OCD patients from healthy control subjects. Some SP subtypes are associated with specific FPMS subscale scores, whereas others are not. These results emphasize the relevance of assessing different subtypes of perfectionism and SP in OCD patients as important subcomponents of the OCD phenotype.

Higher prevalence of obsessive-compulsive spectrum disorders in rheumatic fever

OBJECTIVE

This study aims to compare the prevalence of obsessive-compulsive spectrum disorders (OCSD) in psychiatric outpatients with and without a history of rheumatic fever (RF).

METHODS

An analytical cross-sectional study assessing a large sample of consecutive psychiatric outpatients at a Brazilian private practice was conducted during a 10-year period. Psychiatric diagnoses were made by a senior psychiatrist based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Best-estimate diagnosis procedure was also performed.

RESULTS

The total sample comprised 678 subjects, 13 of whom (1.92%) presented with a previous history of RF. This group showed a higher prevalence of subclinical obsessive-compulsive disorder (P=.025) and OCSD (P=.007) when compared to individuals with no such history.

CONCLUSIONS

A previous history of RF was associated with OCSD. These results suggest that clinicians should be encouraged to actively investigate obsessive-compulsive symptoms and related disorders in patients with a positive history of RF.

Distonia primária e transtorno obsessivo-compulsivo

OBJETIVO: Uma maior freqüência de transtorno obsessivo-compulsivo (TOC) em pacientes com distonia primária vem sendo relatada na literatura. O objetivo deste trabalho é revisar os estudos que investigaram a associação entre TOC e distonia primária. MÉTODOS: Artigos que correlacionaram ambas as condições, incluindo estudos caso-controle, descritivos, relatos e série de casos, foram selecionados. As bases de dados avaliadas foram Medline e Lilacs. RESULTADOS: Foram encontrados 12 artigos, sendo 8 estudos caso-controle e 4 séries ou relatos de casos. Metade dos estudos caso-controle observou mais sintomas obsessivo-compulsivos nos pacientes com distonia em relação a controles, enquanto a outra metade não. CONCLUSÃO: Os resultados são conflitantes, não sendo possível estabelecer uma conclusão definitiva acerca da associação entre distonia e TOC.

Association of polymorphisms within the promoter region of the tumor necrosis factor-alpha with clinical outcomes of rheumatic fever

Rheumatic fever (RF)/rheumatic heart disease (RHD) is an inflammatory disease with a complex etiology in which Group A streptococci within a genetically susceptible host untreated for strep-throat may deviate the innate and adaptive arms of the immune system towards recognition of autoantigens. The TNFA gene has been associated with a number of autoimmune diseases, including RF. We investigated whether the G-308A and G-238A polymorphisms of the TNFA gene are associated with clinical outcomes of RF in a cohort of 318 patients and 281 healthy controls (HC). Both polymorphisms showed borderline associations with RF (TNFA -308G/A, OR=1.4 [1-2.2], P=0.026; TNFA -238G/A, OR=1.9 [1-3.3], P=0.015). The presence of either one of the minor alleles (-308A and -238A) was more common among patients with RF/RHD than controls (P=0.0006). Stratification of patients according to clinical phenotype also showed significant associations between presence of either one of the minor alleles and RHD (Pc=0.0006) when compared with controls. This association was stronger with the development of aortic valve lesions. In contrast, there was no association between genotype and Sydenham's chorea or RF patients with mild carditis. In conclusion, we show that the TNFA is a susceptibility locus for RF. The ability to predict which RF patients will develop valve lesion may have therapeutic, economic and social implications.

Obsessive-compulsive symptoms in heart disease patients with and without history of rheumatic fever

By comparing 51 heart disease patients with history of rheumatic fever and 46 heart disease patients with no rheumatic fever history, the authors found a higher prevalence of obsessive-compulsive symptoms in rheumatic fever subjects. This suggests that rheumatic fever activity is not a necessary condition for the expression of neuropsychiatric symptoms.

Clinical features associated with treatment response in obsessive-compulsive disorder

OBJECTIVE

This study aims to investigate the effect of sociodemographic and clinical features on the short-term response to pharmacological treatment in obsessive-compulsive disorder (OCD). We focused especially on investigating factors previously associated with poorer prognosis, such as comorbidity with tic disorders, early onset of symptoms, and sensory phenomena preceding compulsions, which have been described as common in both tic-related and early-onset OCD.

METHOD

The study involved 41 consecutive adult patients with OCD diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria and was conducted at the OCD Spectrum Disorders Clinic of the University of Sao Paulo School of Medicine in São Paulo, Brazil, between January of 2000 and December of 2001. All patients were treated exclusively with oral clomipramine for 14 weeks. Treatment response, measured for Yale-Brown Obsessive-Compulsive Scale score decrease from baseline, was assessed by an investigator blinded as to the variables of interest present.

RESULTS

Linear regression analysis showed that having a partner and sensory phenomena preceding compulsions were associated with better response to clomipramine treatment (P = .04 and P = .002, respectively). Tic comorbidity and early onset of symptoms were not associated with poorer response.

CONCLUSIONS

In OCD, having a partner and sensory phenomena preceding compulsions seem to be associated with a favorable response to pharmacological treatment.

Obsessive-compulsive spectrum disorders in rheumatic fever patients

Based on five cases of obsessive-compulsive spectrum disorders in rheumatic fever patients, the authors discuss the range of psychiatric disorders associated with poststreptococcal autoimmune reactions and its implications for immunology/CNS interaction.

Obsessive-compulsive disorder phenotypes: implications for genetic studies

Obsessive-compulsive disorder (OCD) clinical presentation is remarkably diverse, and can vary both within and across patients over time. This variability in the phenotypic expression has led to the hypothesis that OCD is a heterogeneous disorder and that this heterogeneity obscures the findings of clinical, natural history and treatment response studies and complicates the search for vulnerability genes. A complete understanding of what comprises OCD and the underlying etiological mechanisms will require a dramatic change in how the disorder is conceptualized. In this review, several different approaches that may represent the first steps in this reconceptualization are discussed. These approaches include (1) narrowing the phenotype to identify categorically defined more homogeneous and mutually exclusive subtypes of OCD, (2) considering OC symptom dimensions as quantitative components of the more complex OCD phenotype and (3) broadening the phenotype to include other etiologically related conditions. A combined dimensional approach within distinctive subgroups is proposed as probably the most effective in helping to identify the heritable components of OCD. By identifying heritable components of OCD, it should be possible to find genes for these separate components. The review continues with the illustration of the possible role of some epigenetic risk and protective factors in the OCD presentation and the relevance of examining associated traits and/or endophenotypes to enhance our ability to understand the genetic basis of OCD. To conclude, we discuss the variability in treatment outcome and the significance of the development of specific pharmacological and/or behavioral based therapies tailored to each of these phenotypes.

Impact of age at onset and duration of illness on the expression of comorbidities in obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) patients usually experience comorbidities including tics, trichotillomania, body dysmorphic disorder, and mood and anxiety disorders. The present report verifies how age at onset of obsessive-compulsive symptoms and duration of illness are associated with comorbid diagnoses in OCD patients.

METHOD

Psychiatric comorbidity was assessed using a structured clinical interview in 161 consecutive outpatients referred for treatment between 1996 and 2001 who met DSM-IV criteria for OCD. Age at onset and duration of illness were retrospectively assessed by direct interviews.

RESULTS

An earlier age at onset of obsessive-compulsive symptoms was associated with tic disorders, while longer illness duration was associated with depressive disorder (major depressive disorder or dysthymia) and social phobia.

CONCLUSION

Age at onset and duration of OCD illness are meaningful variables affecting the expression of comorbidities in OCD. Tic disorders and OCD may share common etiologic pathways. Depressive disorders, in contrast, may be secondary complications of OCD.