The Relationship of Rumination, Worry and OCD Symptoms During Technology Supported Mindfulness Therapy for OCD.

BACKGROUND: In this study, we re-examined data from a previous randomized controlled trial investigating 'technology supported mindfulness' (TSM)-an 8-week treatment intervention for individuals experiencing OCD. The current analysis involves an examination of the longitudinal relationships between rumination, worry and OCD symptom changes during mindfulness treatment, in comparison to a waitlist control. METHODS: Participants experiencing OCD (n = 71) were randomly assigned to 8 weeks of (1) TSM or (2) waitlist control. We tested the extent to which rumination (using the Ruminative Response Scale) and worry (using the Penn State Worry Questionnaire) are associated with OCD symptom changes during the acute phase of treatment, concurrently (i.e., within the same longitudinal model). RESULTS: Generalized linear model (GLM) results indicated a significant time (week 1 vs. week 8) by condition interaction involving decreased rumination in the TSM condition: F(1, 61) = 13.37, p = 0.001, partial η2 = 0.18 and observed power = 0.94. A second GLM demonstrated decreased worry in the TSM condition: F(1, 69) = 37.34, p = 0.001, partial η2 = 0.35 and observed power = 0.83. Longitudinal 'latent difference' structural equation analyses demonstrated a cross-lagged association between worry (but not rumination) and OCD symptom changes. CONCLUSIONS: Individuals in the TSM condition experienced greater reductions in rumination and worry during 8 weeks of TSM treatment compared to the waitlist control, and reduced worry predicted subsequent OCD symptom reduction.

Genetic and polygenic investigation of heart rate variability to identify biomarkers associated with Anxiety disorders.

Given that anxiety disorders (AD) are associated with reduced vagally-mediated heart rate variability (HRV), genetic variants related to HRV may provide insight into anxiety etiology. This study used polygenic risk scores (PRS) to explore the genetic overlap between AD and HRV, and investigated whether HRV-related polymorphisms influence anxiety risk. Resting vagally-mediated HRV was measured using a wearable device in 188 European individuals (AD=101, healthy controls=87). AD PRS was tested for association with resting HRV, and HRV PRS for association with AD. We also investigated 15 significant hits from an HRV genome-wide association study (GWAS) for association with resting HRV and AD and if this association is mediated through resting HRV. The AD PRS and HRV PRS showed nominally significant associations with resting HRV and anxiety disorders, respectively. HRV GWAS variants associated with resting HRV were rs12980262 (NDUFA11), rs2680344 (HCN4), rs4262 and rs180238 (GNG11), and rs10842383 (LINC00477). Mediation analyses revealed that NDUFA11 rs12980262 A-carriers and GNG11 rs180238 and rs4262 C-carriers had higher anxiety risk through lower HRV. This study supports an anxiety-HRV genetic relationship, with HRV-related genetic variants translating to AD. This study encourages exploration of HRV genetics to understand mechanisms and identify novel treatment targets for anxiety.

Investigating the association of anxiety disorders with heart rate variability measured using a wearable device.

BACKGROUND: Reduced vagally-mediated heart rate variability (HRV) has been associated with anxiety disorders (AD). The aim of this study was to use a wearable device and remote study design to re-evaluate the association of HRV with ADs, anxiety-related traits, and confounders. METHODS: 240 individuals (AD = 120, healthy controls = 120) completed an at-home assessment of their short-term resting vagally-mediated HRV using a wristband, monitored over videoconference. Following quality control, analyses were performed investigating differences in HRV between individuals with AD (n = 119) and healthy controls (n = 116), associations of HRV with anxiety-related traits and confounders, and antidepressants effects on HRV in patients, including analyses stratified by ancestry (i.e., European, East Asian, African). RESULTS: Among the confounders investigated, only age had a significant association with HRV. Patients with an AD had significantly lower vagally-mediated HRV than healthy controls in the European subsample, with a trend of significance in the whole sample. HRV was significantly associated with the Hamilton Anxiety Rating Scale (HAM-A) but not with antidepressant use in the European subsample. LIMITATIONS: The study measures occurred in a non-standardized at-home setting, and the three ancestry group sample sizes were unequal. CONCLUSIONS: This study demonstrates reduced vagally-mediated HRV among patients with ADs compared to healthy controls. Results also point to low HRV being related to more physical anxiety symptoms (measured via HAM-A), suggesting a possible anxiety subtype. Overall, this study highlights the feasibility of using wearables for patients and encourages exploration of the biological and clinical utility of HRV as a risk factor for ADs.

Online versus in-person delivery of cognitive behaviour therapy for obsessive compulsive disorder: An examination of effectiveness.

Cognitive behavioural therapy (CBT) including exposure and response prevention is the first-line psychological treatment for obsessive compulsive disorder (OCD). Given changes in the clinical landscape, there are increasing efforts to evaluate its effectiveness in online contexts. Mirroring the traditional in-person delivery, few studies have assessed the role of therapist-guided, manual-based CBT for OCD delivered in real-time via videoconferencing methods. The present study sought to fill this gap by comparing in-person and online delivery of group-based CBT for the treatment of OCD. A convenience sample of participants with moderate to severe OCD (n = 144) were recruited from a naturalistic database from two large OCD specialty assessment and treatment centres. Patients received group-based CBT that was provided in-person (pre-COVID-19 pandemic; March 2018 to March 2020) or online via videoconferencing (during the COVID-19 pandemic; March 2020 to April 2021). In both delivery methods, treatment consisted of 2-h weekly sessions led by trained clinicians. Analyses revealed that, regardless of treatment modality, both in-person and online groups demonstrated significant, reliable, and statistically equivalent improvements in OCD symptoms post-treatment. Videoconferenced, clinician-led CBT may be a promising alternative to in-person delivery for those with moderate to severe OCD symptoms.

The effect of aerobic exercise alone and in combination with cognitive behavioural therapy on obsessive compulsive disorder: A randomized control study.

PURPOSE: Cognitive behavioural therapy (CBT) has been found to be an effective treatment for OCD, but there remains a significant proportion of individuals who fail to show a treatment response. Aerobic exercise has previously been associated with decreases in anxiety and depression, as well as improvements in OCD symptoms in small-scale studies. The purpose of the present research was to use a randomized control trial design to examine the effects of exercise alone and in combination with CBT, on OCD symptoms and secondary symptoms. METHOD: 125 participants were randomly assigned to one of four treatment groups: waitlist control, exercise, CBT, and CBT with exercise. OCD symptom severity was measured at four points over the course of treatment, secondary outcome measures were gathered at three points over treatment. RESULTS: CBT alone and combined with exercise was associated with significantly greater OCD symptom reduction than exercise alone or the control groups. Total exercise frequency predicted OCD symptom reduction in the groups in which exercise was measured. Group membership did not significantly predict reductions in secondary outcome measures. CONCLUSION: Exercise frequency, rather than the presence or absence of exercise, appears to predict OCD symptom reduction, as did participation in CBT.

White matter volume and myelin oligodendrocyte glycoprotein (MOG) microsatellites in pediatric obsessive-compulsive disorder.

The myelin oligodendrocyte glycoprotein ( MOG ) gene plays an important role in myelination and has been implicated in the genetics of white matter changes in obsessive-compulsive disorder (OCD). We examined the association between variations of two microsatellite markers across MOG for association and total white matter volume as measured using volumetric MRI in 37 pediatric OCD patients 7-18 years. We compared white matter volumes between microsatellite allele groups using analysis of covariance with covariates of age, gender, and total intracranial volume. After controlling for multiple comparisons, a significant relationship was detected between MOG (TAAA)n and increased total white matter volume ( P  = 0.018-0.028). Although preliminary, our findings provide further support for the involvement of MOG in OCD.

Mapping the future of interventional psychiatry for the obsessive-compulsive related disorders: A scoping review.

Body dysmorphic disorder (BDD), hoarding disorder (HD), skin-picking disorder (SPD), and hair-pulling disorder (HPD) are characterized by compulsive behaviours leading to distress and impairment. Current treatments attain only partial or non-response. Interventional psychiatric approaches may target specific regions of the brain for treatment. This scoping review maps the current literature and synthesizes key findings. Databases were searched up to June 27, 2022 for studies examining interventional psychiatric treatments for BDD, HD, SPD, and HPD, producing 910 results. Twenty were included; 16 were case reports, two were case series, and two were randomized controlled trials. Studies reported on electroconvulsive therapy (ECT) (n=7), deep brain stimulation (DBS) (n=1), and intermittent theta-burst stimulation repetitive transcranial magnetic stimulation (rTMS) (n=1) for BDD; rTMS (n=1) and transcranial direct current stimulation (n=1) for HD; gamma knife capsulotomy (n=1) and rTMS (n=1) for SPD; and rTMS (n=2) and ECT (n=1) for HPD. Four studies reported on DBS for other indications complicated by SPD or HPD. The current literature consists mainly of case reports. Future studies should be randomized, controlled, adequately powered and blinded, examining rTMS localized to the anatomical targets for each disorder. Presently, the mainstay of treatment remains disorder-specific psychotherapy with limited evidence for medications.

Systematic Review and Meta-Analysis of the Placebo Effect and its Correlates in Obsessive Compulsive Disorder.

BACKGROUND: Obsessive-compulsive disorder (OCD) is a major mental health condition with a lifetime prevalence rate of 1.3% among adults. While placebo effects are well described for conditions such as depressive and anxiety disorders, they have not been systematically characterized in OCD. OBJECTIVES: We aimed to determine the impact of placebos in improving different symptom domains in patients with OCD. METHODS: We systematically searched PubMed, EMBASE, Scopus, Web of Science, Ovid, the Cochrane Library, and Google Scholar databases/search engine from inception to January 2021 for randomized controlled trials of treatments for OCD with a placebo arm. A modified Cohen's effect size (ES) was calculated using change in baseline to endpoint scores for different measurement scales within placebo arms to estimate placebo effects and to investigate their correlates by random-effects model meta-analyses. RESULTS: Forty-nine clinical trials (placebo group n = 1993), reporting 80 OCD specific (153 measures in general) were included in the analysis. Overall placebo ES (95% confidence interval [CI]) was 0.32 (0.22-0.41) on OCD symptoms, with substantial heterogeneity (I-square = 96.1%). Among secondary outcomes, general scales, ES: 0.27 (95%CI: 0.14-0.41), demonstrated higher ES than anxiety and depression scales, ES: 0.14 (95%CI: -0.4 to 0.32) and 0.05 (95%CI: -0.05 to 0.14), respectively. Clinician-rated scales, ES: 0.27(95%CI: 0.20-0.34), had a higher ES than self-reported scales, ES: 0.07 (95%CI: -0.08 to 0.22). More recent publication year, larger placebo group sample size, shorter follow-up duration, and younger age of participants were all associated with larger placebo ES. Egger's test reflected possible small-study effect publication bias (P = 0.029). CONCLUSION: Placebo effects are modest in OCD trials and are larger in clinician ratings, for younger patients, and early in the treatment course. These findings underscore the need for clinicians and scientists to be mindful of placebo effects when formulating treatments or research trials for OCD. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42019125979.

Characterizing the content, messaging, and tone of trichotillomania on YouTube: A content analysis.

BACKGROUND: Trichotillomania is associated with secrecy and reluctance to seek help due to shame and lack of knowledge. Social media can connect people with similar lived experience. However, there is no literature regarding online communities related to trichotillomania. This study is a content analysis of depictions of trichotillomania on YouTube to identify the potential role of social media in this disorder. METHODS: We used a cross-sectional observational study to examine the 100 most-viewed YouTube videos for trichotillomania content until June 2018. Up to 96 variables were abstracted from each video including demographics, characteristics of the videos, and depictions of trichotillomania. RESULTS: View counts ranged from 9,186 to 15,597,149. Uploaders had a mean age of 20.1 years, were mostly female (85%) and appearing Caucasian (63%). Nearly half of the videos were self-filmed stories (48%). Most had a neutral message (44%), provided strategies to stop hair-pulling (31%), or focused on stimulating discussion (17%). Approximately half had a factual tone (51%) and many were hopeful (44%). Videos accurately described hair-pulling and associated characteristics. LIMITATIONS: This study was limited to an analysis of video content. Future research should examine the comments on the videos as well as other social media platforms. It may also be important to assess the socioeconomic status of video uploaders and ensure the broader accessibility of positive messages on trichotillomania. CONCLUSIONS: People with trichotillomania may find positive messages, information, and helpful recommendations on YouTube. This may represent an under-leveraged venue to improve clinical outcomes for people with trichotillomania.

Technology supported mindfulness for obsessive compulsive disorder: The role of obsessive beliefs.

The current study examined the association of OCD symptoms and OCD belief domains, for individuals engaged in Technology Supported Mindfulness training (TSM) using an EEG-based biofeedback device (called "Muse") that permits individuals to engage in home based mindfulness meditation practices. In this randomized controlled study, treatment-seeking participants with a principal DSM-5 diagnosis of OCD (N = 71) were randomly assigned to eight weeks of: 1) a meditation program involving daily use of the "Muse" device, or 2) wait list control. At weeks 1, 4, and 8, participants completed self-report measures of OCD symptoms (YBOCS: Yale-Brown Obsessive Compulsive Scale) and OCD beliefs (OBQ; OCCWG, 2005). Latent Difference Score (LDS) models indicated that there was no significant longitudinal relationship between OBQ "Responsibility/Threat" (OBQ R/T) scores and OCD symptoms. The analysis of OBQ "Perfectionism/Certainty" (OBQ P/C) and OCD symptoms demonstrated a significant reciprocal relationship between these two variables, in which OCD symptoms predicted subsequent increases in OBQ P/C and vice versa. The analysis of OBQ "Importance/Control of Thoughts" (OBQ I/C) and OCD symptoms demonstrated a significant reciprocal relationship between these two variables, in which OCD symptoms predicted subsequent increases in OBQ I/C and vice versa. The analysis of OBQ domains and EEG derived attentional changes demonstrated a significant association between OBQ P/C and Alpha band frequencies. These results clarify the association of OBQ belief domains, OCD symptom change and EEG derived indicators of attention during TSM.

A narrative review of exercise and obsessive-compulsive disorder.

OBJECTIVE: Individuals with obsessive-compulsive disorder (OCD) suffer significant distress due to their condition; however, there can be multiple barriers to treatment. Even following OCD-tailored treatment, symptoms often remain. Exercise may be an effective and available approach to managing OCD, and yet, there are no specifically dedicated reviews, limiting integration into clinical practice. This study aimed to provide an overview of the literature on exercise and OCD. METHOD: Four databases, the Cochrane Central Register of Controlled Trials, MEDLINE, PsycINFO, and EMBASE, were systematically searched. 1534 records were screened and the reference lists of eligible articles were examined. For this review, 11 extracted studies were narratively explored. RESULTS: Two observational and nine interventional studies were included, of which one article focused on youth and ten studies focused on adults. Physical activity likely reduces the risk of metabolic syndrome or general health conditions. Several pre-post studies demonstrated exercise's benefits for OCD symptoms, while the only randomized controlled trial showed negative findings for its efficacy in reducing obsessions and compulsions. CONCLUSIONS: The evidence for aerobic exercise's long-term benefits for the symptoms of OCD is mixed, but remains promising. Potential mechanisms of exercise's effects and future directions for research are explored.

An association of Myelin Oligodendrocyte Glycoprotein (MOG) gene variants with white matter volume in pediatric obsessive-compulsive disorder.

An increasing number of neuroimaging studies have implicated alterations of white matter in obsessive-compulsive disorder (OCD). The myelin oligodendrocyte glycoprotein (MOG) gene plays a major role in myelination, and has previously demonstrated significant association with this disorder, thus variations in this gene may contribute to observed white matter alterations. The purpose of this study is to examine the relationship between white matter volume in OCD and genetic variations in the MOG gene. Two polymorphisms in the MOG gene, MOG(C1334T) and MOG(C10991T), were investigated for association with total white matter volume as measured using volumetric magnetic resonance imaging in 37 pediatric OCD patients. We compared white matter volumes between allele and genotype groups for each polymorphism using ANCOVA. A significant relationship was detected between genotype C/C of MOG(C10991T) and decreased total white matter volume (P = 0.016). Our results showed an association between a MOG genetic variant and white matter volume. This finding is intriguing in light of the posited role of white matter alteration in the etiology of at least some cases of childhood-onset OCD. Further investigation with larger samples and sub-regional white matter volume phenotypes is warranted.

Technology supported mindfulness for obsessive compulsive disorder: Self-reported mindfulness and EEG correlates of mind wandering.

Cognitive Behavior Therapy (CBT) incorporating Exposure with Response Prevention (ERP) is the most efficacious treatment intervention for Obsessive Compulsive Disorder (OCD); however, there is a growing literature indicating that mindfulness based approaches can be beneficial in terms of managing OCD symptoms. The current study examined the potential benefits of using a consumer grade EEG-based biofeedback device (called "Muse") that permits individuals to engage in mindfulness meditation practices while at home. In this randomized controlled study, participants with a principal DSM-5 diagnosis of OCD (N = 71) were randomly assigned to eight weeks of: 1) a meditation program involving daily use of the "Muse" device, or 2) waitlist control. At weeks 1, 4, and 8, participants completed a five minute "open monitoring" practice while EEG data was recorded, and they completed self-report measures of mindfulness (FFMQ: Five Factor Mindfulness Questionnaire) and OCD symptoms (YBOCS: Yale-Brown Obsessive Compulsive Scale). Latent Difference Score (LDS) models demonstrated that the FFMQ "Non-Reactivity" facet and EEG-derived correlates of "Mind Wandering" (i.e., alpha, beta, but not delta or theta band power) were temporally associated with subsequent changes in YBOCS symptom scores. Participants in the Muse group (in comparison to the control group) experienced increased FFMQ "Non-Reactivity" and decreased mind wandering (increased alpha and beta band power), and in each case, these variables were associated with subsequent OCD symptom improvement. These results suggest that technology supported mindfulness training for OCD is associated with improvements in OCD symptoms, mindfulness and decreased mind wandering.

Filling the Gap for Obsessive-Compulsive Disorder Services in Canada: Implementing an Intensive Care Program.

Obsessive-compulsive disorder (OCD) is a significant psychiatric illness that can impact an individual in terms of their quality of life, functional abilities, and interpersonal relationships. Until recently, services for individuals with severe symptoms of OCD were limited within Canada. The Frederick W. Thompson Anxiety Disorders Centre at Sunnybrook Health Sciences Centre in Toronto, Canada, recently launched an intensive services program for individuals with severe symptoms of OCD. This article provides an overview of the steps that were taken to develop this program. Methods involved incorporation of information gathered from both service users and service providers of these models of treatment within North America and beyond. This article provides a potential treatment model for residential psychiatric treatment that can be applied to OCD and possibly other severe treatment refractory psychiatric illnesses in terms of methods used and generalizable key ingredients.

De Novo Damaging DNA Coding Mutations Are Associated With Obsessive-Compulsive Disorder and Overlap With Tourette's Disorder and Autism.

BACKGROUND: Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder with a genetic risk component, yet identification of high-confidence risk genes has been challenging. In recent years, risk gene discovery in other complex psychiatric disorders has been achieved by studying rare de novo (DN) coding variants. METHODS: We performed whole-exome sequencing in 222 OCD parent-child trios (184 trios after quality control), comparing DN variant frequencies with 777 previously sequenced unaffected trios. We estimated the contribution of DN mutations to OCD risk and the number of genes involved. Finally, we looked for gene enrichment in other datasets and canonical pathways. RESULTS: DN likely gene disrupting and predicted damaging missense variants are enriched in OCD probands (rate ratio, 1.52; p = .0005) and contribute to risk. We identified 2 high-confidence risk genes, each containing 2 DN damaging variants in unrelated probands: CHD8 and SCUBE1. We estimate that 34% of DN damaging variants in OCD contribute to risk and that DN damaging variants in approximately 335 genes contribute to risk in 22% of OCD cases. Furthermore, genes harboring DN damaging variants in OCD are enriched for those reported in neurodevelopmental disorders, particularly Tourette's disorder and autism spectrum disorder. An exploratory network analysis reveals significant functional connectivity and enrichment in canonical pathways, biological processes, and disease networks. CONCLUSIONS: Our findings show a pathway toward systematic gene discovery in OCD via identification of DN damaging variants. Sequencing larger cohorts of OCD parent-child trios will reveal more OCD risk genes and will provide needed insights into underlying disease biology.

Effectiveness of intensive treatment services for obsessive compulsive disorder: outcomes from the first Canadian residential treatment program.

Background: Obsessive-Compulsive Disorder (OCD) is a psychiatric illness that can result in debilitating symptoms and functional impairment. Until recently, individuals with severe OCD symptoms have not received appropriate services within the Canadian healthcare system. The Frederick W. Thompson Anxiety Disorders Centre launched an Intensive Services Residential treatment programme for OCD in July 2017 to meet the needs of the Canadian population. This paper sets out to demonstrate the effectiveness of this programme.Methods: This study incorporated quantitative and qualitative data collection. Quantitative data were analysed using paired sample t-tests while qualitative data was transcribed and coded for emerging themes.Results: Beneficial changes in symptomatology were found. Client narrative emphasised the importance of exposure response prevention (ERP), creation of an OCD community as well as enhanced functionality in clients' lives. Clients also commented on why they believed the treatment worked and points of potential improvement for discharge planning and programme organisation.Conclusions: This study adds to the growing body of evidence regarding the importance of intensive services for individuals experiencing severe symptoms of OCD. Enhancing accessibility to services and ensuring ongoing maintenance of gains will be important next steps in ensuring long-term recovery for individuals with severe symptoms of OCD.Key pointsIntensive services treatment for OCD has been found to be beneficial for clients and this paper demonstrates the first time this has been seen within a Canadian programme.Treatment provided decreased OCD severity and increased functionality and quality of life.Clients cited exposure and response prevention work as a key ingredient in their recovery.Our programme is always in an ongoing state of quality improvement, ensuring client engagement and satisfaction.

Towards precision medicine in generalized anxiety disorder: Review of genetics and pharmaco(epi)genetics.

Generalized anxiety disorder (GAD) is a prevalent and chronic mental disorder that elicits widespread functional impairment. Given the high degree of non-response/partial response among patients with GAD to available pharmacological treatments, there is a strong need for novel approaches that can optimize outcomes, and lead to medications that are safer and more effective. Although investigations have identified interesting targets predicting treatment response through pharmacogenetics (PGx), pharmaco-epigenetics, and neuroimaging methods, these studies are often solitary, not replicated, and carry several limitations. This review provides an overview of the current status of GAD genetics and PGx and presents potential strategies to improve treatment response by combining better phenotyping with PGx and improved analytical methods. These strategies carry the dual benefit of delivering data on biomarkers of treatment response as well as pointing to disease mechanisms through the biology of the markers associated with response. Overall, these efforts can serve to identify clinical, genetic, and epigenetic factors that can be incorporated into a pharmaco(epi)genetic test that may ultimately improve treatment response and reduce the socioeconomic burden of GAD.

Does the addition of cognitive therapy to exposure and response prevention for obsessive compulsive disorder enhance clinical efficacy? A randomized controlled trial in a community setting.

OBJECTIVES: Exposure and response prevention (ERP) remains the most empirically supported psychological treatment for obsessive compulsive disorder (OCD). Clinical guidelines recommend the addition of cognitive approaches to ERP although the presumed additive benefits have not been directly tested. The aim of this was to compare a treatment that integrated cognitive therapy with ERP (ERP + CT) to traditional, manualized ERP to test the additive benefits. DESIGN: A longitudinal, randomized control trial design was used. METHODS: Participants (N = 127) with OCD were randomly assigned to receive individual outpatient ERP or ERP + CT. Obsessive-compulsive symptom severity measures were completed pre- and post-treatment and at 6-month follow-up. RESULTS: While both conditions led to significant symptom and obsessive belief reduction, ERP + CT led to significantly greater symptom and belief reduction as compared to ERP across all main symptom presentations of OCD. Based on a priori definitions of effectiveness, more patients in ERP + CT compared to the ERP group were also deemed treatment responders. CONCLUSIONS: The results of this study suggest that cognitive therapy can be readily integrated with ERP to improve clinical outcomes beyond ERP alone. PRACTITIONER POINTS: Both ERP and ERP + CT were effective, however a course of ERP + CT was significantly more effective at reducing symptoms of OCD than the ERP treatment condition. Significantly more participants who received ERP + CT experienced clinically significant change in OCD symptoms compared to those who received ERP. OCD symptom dimension did not significantly impact response to either ERP or ERP + CT treatments.

Pharmacogenetic evaluation of a DISP1 gene variant in antidepressant treatment of obsessive-compulsive disorder.

OBJECTIVES: A recent genome-wide association study (GWAS) in obsessive-compulsive disorder (OCD) reported a significant marker in the dispatched homolog 1 (Drosophila) gene (DISP1 gene) associated with serotonin reuptake inhibitor (SRI) antidepressant response (Qin et al., ). DISP1 has never been examined before in terms of association with SRI response until this GWAS. We attempt to replicate the GWAS finding by investigating the association of the DISP1 rs17162912 polymorphism with SRI response in our sample of 112 European Caucasian OCD patients. METHODS: Patients were previously treated naturalistically with up to 6 different SRIs sequentially, including 5 selective SRIs (fluoxetine, fluvoxamine, sertraline, paroxetine, and citalopram) and 1 SRI (clomipramine). Each medication trial was evaluated retrospectively for response and was rated categorically as either responder or nonresponder using the Clinical Global Impression-Improvement scale. Fisher's exact test was used to investigate the relationship between the DISP1 rs17162912 genotype distribution and SRI response. RESULTS: We did not observe a significant association between rs17162912 and SRI response (p = .32). CONCLUSION: This replication study did not support the role of DISP1 in predicting SRI response in OCD; however, methodological differences between the original GWAS and our study, as well as limited power and low minor allele frequency, may have hindered replication.