Increases in functional connectivity between the default mode network and sensorimotor network correlate with symptomatic improvement after transcranial direct current stimulation for obsessive-compulsive disorder

BACKGROUND

Non-invasive neuromodulation is a promising intervention for obsessive-compulsive disorder (OCD), although its neurobiological mechanisms of action are still poorly understood. Recent evidence suggests that abnormalities in the connectivity of the default mode network (DMN) and the supplementary motor area (SMA) with other brain regions and networks are involved in OCD pathophysiology. We examined if transcranial direct current stimulation (tDCS) alters these connectivity patterns and if they correlate with symptom improvement in treatment-resistant OCD.

METHODS

In 23 patients from a larger clinical trial (comparing active tDCS to sham) who underwent pre- and post-treatment MRI scans, we assessed resting-state functional MRI (rs-fMRI) data. The treatment involved 30-minute daily tDCS sessions for four weeks (weekdays only), with the cathode over the SMA and the anode over the left deltoid. We conducted whole-brain connectivity analysis comparing active tDCS-treated to sham-treated patients.

RESULTS

We found that active tDCS, but not sham, led to connectivity increasing between the DMN and the bilateral pre/postcentral gyri (p = 0.004, FDR corrected) and temporal-auditory areas plus the SMA (p = 0.028, FDR corrected). Also, symptom improvement was directly associated with connectivity increasing between the left lateral sensorimotor network and the left precuneus (r = 0.589, p = 0.034).

LIMITATIONS

Limited sample size (23 participants with resting-state neuroimaging), inability to analyze specific OCD symptom dimensions (e.g., harm, sexual/religious, symmetry/checking, cleaning/contamination).

CONCLUSIONS

These data offer novel information concerning functional connectivity changes associated with non-invasive neuromodulation interventions in OCD and can guide new brain stimulation interventions in the framework of personalized interventions.

Latin American Trans-ancestry INitiative for OCD genomics (LATINO): Study protocol

Obsessive-compulsive disorder (OCD) is a debilitating psychiatric disorder. Worldwide, its prevalence is ~2% and its etiology is mostly unknown. Identifying biological factors contributing to OCD will elucidate underlying mechanisms and might contribute to improved treatment outcomes. Genomic studies of OCD are beginning to reveal long-sought risk loci, but >95% of the cases currently in analysis are of homogenous European ancestry. If not addressed, this Eurocentric bias will result in OCD genomic findings being more accurate for individuals of European ancestry than other ancestries, thereby contributing to health disparities in potential future applications of genomics. In this study protocol paper, we describe the Latin American Trans-ancestry INitiative for OCD genomics (LATINO, https://www.latinostudy.org). LATINO is a new network of investigators from across Latin America, the United States, and Canada who have begun to collect DNA and clinical data from 5000 richly phenotyped OCD cases of Latin American ancestry in a culturally sensitive and ethical manner. In this project, we will utilize trans-ancestry genomic analyses to accelerate the identification of OCD risk loci, fine-map putative causal variants, and improve the performance of polygenic risk scores in diverse populations. We will also capitalize on rich clinical data to examine the genetics of treatment response, biologically plausible OCD subtypes, and symptom dimensions. Additionally, LATINO will help elucidate the diversity of the clinical presentations of OCD across cultures through various trainings developed and offered in collaboration with Latin American investigators. We believe this study will advance the important goal of global mental health discovery and equity.

An evaluation of treatment response and remission definitions in adult obsessive-compulsive disorder: A systematic review and individual-patient data meta-analysis

INTRODUCTION

Expert consensus operationalized treatment response and remission in obsessive-compulsive disorder (OCD) as a Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) reduction ≥35% and score ≤12 with ≤2 on Clinical Global Impressions Improvement (CGI-I) and Severity (CGI-S) scales, respectively. However, there has been scant empirical evidence supporting these definitions.

METHODS

We conducted a systematic review and an individual participant data meta-analysis of randomized-controlled trials (RCTs) in adults with OCD to determine optimal Y-BOCS thresholds for response and remission. We estimated pooled sensitivity/specificity for each percent reduction threshold (response) or posttreatment score (remission) to determine response and remission defined by a CGI-I and CGI-S ≤ 2, respectively.

RESULTS

Individual participant data from 25 of 94 eligible RCTs (1235 participants) were included. The optimal threshold for response was ≥30% Y-BOCS reduction and for remission was ≤15 posttreatment Y-BOCS. However, differences in sensitivity and specificity between the optimal and nearby thresholds for response and remission were small with some uncertainty demonstrated by the confidence ellipses.

CONCLUSION

While the empirically derived Y-BOCS thresholds in our meta-analysis differ from expert consensus, given the predominance of data from more recent trials of OCD, which involved more refractory participants and novel treatment modalities as opposed to first-line therapies, we recommend the continued use of the consensus definitions.

White matter diffusion estimates in obsessive-compulsive disorder across 1653 individuals: machine learning findings from the ENIGMA OCD Working Group

White matter pathways, typically studied with diffusion tensor imaging (DTI), have been implicated in the neurobiology of obsessive-compulsive disorder (OCD). However, due to limited sample sizes and the predominance of single-site studies, the generalizability of OCD classification based on diffusion white matter estimates remains unclear. Here, we tested classification accuracy using the largest OCD DTI dataset to date, involving 1336 adult participants (690 OCD patients and 646 healthy controls) and 317 pediatric participants (175 OCD patients and 142 healthy controls) from 18 international sites within the ENIGMA OCD Working Group. We used an automatic machine learning pipeline (with feature engineering and selection, and model optimization) and examined the cross-site generalizability of the OCD classification models using leave-one-site-out cross-validation. Our models showed low-to-moderate accuracy in classifying (1) "OCD vs. healthy controls" (Adults, receiver operator characteristic-area under the curve = 57.19 ± 3.47 in the replication set; Children, 59.8 ± 7.39), (2) "unmedicated OCD vs. healthy controls" (Adults, 62.67 ± 3.84; Children, 48.51 ± 10.14), and (3) "medicated OCD vs. unmedicated OCD" (Adults, 76.72 ± 3.97; Children, 72.45 ± 8.87). There was significant site variability in model performance (cross-validated ROC AUC ranges 51.6-79.1 in adults; 35.9-63.2 in children). Machine learning interpretation showed that diffusivity measures of the corpus callosum, internal capsule, and posterior thalamic radiation contributed to the classification of OCD from HC. The classification performance appeared greater than the model trained on grey matter morphometry in the prior ENIGMA OCD study (our study includes subsamples from the morphometry study). Taken together, this study points to the meaningful multivariate patterns of white matter features relevant to the neurobiology of OCD, but with low-to-moderate classification accuracy. The OCD classification performance may be constrained by site variability and medication effects on the white matter integrity, indicating room for improvement for future research.

Age of onset of obsessive-compulsive disorder differentially affects white matter microstructure

Previous diffusion MRI studies have reported mixed findings on white matter microstructure alterations in obsessive-compulsive disorder (OCD), likely due to variation in demographic and clinical characteristics, scanning methods, and underpowered samples. The OCD global study was created across five international sites to overcome these challenges by harmonizing data collection to identify consistent brain signatures of OCD that are reproducible and generalizable. Single-shell diffusion measures (e.g., fractional anisotropy), multi-shell Neurite Orientation Dispersion and Density Imaging (NODDI) and fixel-based measures, were extracted from skeletonized white matter tracts in 260 medication-free adults with OCD and 252 healthy controls. We additionally performed structural connectome analysis. We compared cases with controls and cases with early (<18) versus late (18+) OCD onset using mixed-model and Bayesian multilevel analysis. Compared with healthy controls, adult OCD individuals showed higher fiber density in the sagittal stratum (B[SE] = 0.10[0.05], P = 0.04) and credible evidence for higher fiber density in several other tracts. When comparing early (n = 145) and late-onset (n = 114) cases, converging evidence showed lower integrity of the posterior thalamic radiation -particularly radial diffusivity (B[SE] = 0.28[0.12], P = 0.03)-and lower global efficiency of the structural connectome (B[SE] = 15.3[6.6], P = 0.03) in late-onset cases. Post-hoc analyses indicated divergent direction of effects of the two OCD groups compared to healthy controls. Age of OCD onset differentially affects the integrity of thalamo-parietal/occipital tracts and the efficiency of the structural brain network. These results lend further support for the role of the thalamus and its afferent fibers and visual attentional processes in the pathophysiology of OCD.

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

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

Right Prefrontal Cortical Thickness Is Associated With Response to Cognitive-Behavioral Therapy in Children With Obsessive-Compulsive Disorder

OBJECTIVE

Cognitive-behavioral therapy (CBT) is considered a first-line treatment for obsessive-compulsive disorder (OCD) in pediatric and adult populations. Nevertheless, some patients show partial or null response. The identification of predictors of CBT response may improve clinical management of patients with OCD. Here, we aimed to identify structural magnetic resonance imaging (MRI) predictors of CBT response in 2 large series of children and adults with OCD from the worldwide ENIGMA-OCD consortium.

METHOD

Data from 16 datasets from 13 international sites were included in the study. We assessed which variations in baseline cortical thickness, cortical surface area, and subcortical volume predicted response to CBT (percentage of baseline to post-treatment symptom reduction) in 2 samples totaling 168 children and adolescents (age range 5-17.5 years) and 318 adult patients (age range 18-63 years) with OCD. Mixed linear models with random intercept were used to account for potential cross-site differences in imaging values.

RESULTS

Significant results were observed exclusively in the pediatric sample. Right prefrontal cortex thickness was positively associated with the percentage of CBT response. In a post hoc analysis, we observed that the specific changes accounting for this relationship were a higher thickness of the frontal pole and the rostral middle frontal gyrus. We observed no significant effects of age, sex, or medication on our findings.

CONCLUSION

Higher cortical thickness in specific right prefrontal cortex regions may be important for CBT response in children with OCD. Our findings suggest that the right prefrontal cortex plays a relevant role in the mechanisms of action of CBT in children.

Measurement fidelity of clinical assessment methods in a global study on identifying reproducible brain signatures of obsessive-compulsive disorder

OBJECTIVE

To describe the steps of ensuring measurement fidelity of core clinical measures in a five-country study on brain signatures of obsessive-compulsive disorder (OCD).

METHOD

We collected data using standardized instruments, which included the Yale-Brown Obsessive-Compulsive Scale (YBOCS), the Dimensional YBOCS (DYBOCS), the Brown Assessment of Beliefs Scale (BABS), the 17-item Hamilton Depression Scale (HAM-D), the Hamilton Anxiety Scale (HAM-A), and the Structured Clinical Interview for DSM-5 (SCID). Steps to ensure measurement fidelity included translating instruments, developing a clinical decision manual, and continuing reliability training with 11-13 transcripts of each instrument by 13 independent evaluators across sites over 4 years. We use multigroup confirmatory factor analysis (MGCFA) to report interrater reliability (IRR) among the evaluators and factor structure for each scale in 206 participants with OCD.

RESULTS

The overall IRR for most scales was high (ICC > 0.94) and remained good to excellent throughout the study. Consistent factor structures (configural invariance) were found for all instruments across the sites, while similarity in the factor loadings for the items (metric invariance) could be established only for the DYBOCS and the BABS.

CONCLUSIONS

It is feasible to achieve measurement fidelity of clinical measures in multisite, multilinguistic global studies, despite the challenges inherent to such endeavors. Future studies should not only report IRR but also consider reporting methods of standardization of data collection and measurement invariance to identify factor structures of core clinical measures. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Global multi-center and multi-modal magnetic resonance imaging study of obsessive-compulsive disorder: Harmonization and monitoring of protocols in healthy volunteers and phantoms

OBJECTIVES

We describe the harmonized MRI acquisition and quality assessment of an ongoing global OCD study, with the aim to translate representative, well-powered neuroimaging findings in neuropsychiatric research to worldwide populations.

METHODS

We report on T1-weighted structural MRI, resting-state functional MRI, and multi-shell diffusion-weighted imaging of 140 healthy participants (28 per site), two traveling controls, and regular phantom scans.

RESULTS

Human image quality measures (IQMs) and outcome measures showed smaller within-site variation than between-site variation. Outcome measures were less variable than IQMs, especially for the traveling controls. Phantom IQMs were stable regarding geometry, SNR, and mean diffusivity, while fMRI fluctuation was more variable between sites.

CONCLUSIONS

Variation in IQMs persists, even for an a priori harmonized data acquisition protocol, but after pre-processing they have less of an impact on the outcome measures. Continuous monitoring IQMs per site is valuable to detect potential artifacts and outliers. The inclusion of both cases and healthy participants at each site remains mandatory.

Latin American Trans-ancestry INitiative for OCD genomics (LATINO): Study Protocol

Obsessive-compulsive disorder (OCD) is a debilitating psychiatric disorder. Worldwide, its prevalence is ~2% and its etiology is mostly unknown. Identifying biological factors contributing to OCD will elucidate underlying mechanisms and might contribute to improved treatment outcomes. Genomic studies of OCD are beginning to reveal long-sought risk loci, but >95% of the cases currently in analysis are of homogenous European ancestry. If not addressed, this Eurocentric bias will result in OCD genomic findings being more accurate for individuals of European ancestry than other ancestries, thereby contributing to health disparities in potential future applications of genomics. In this study protocol paper, we describe the Latin American Trans-ancestry INitiative for OCD genomics (LATINO, www.latinostudy.org). LATINO is a new network of investigators from across Latin America, the United States, and Canada who have begun to collect DNA and clinical data from 5,000 richly-phenotyped OCD cases of Latin American ancestry in a culturally sensitive and ethical manner. In this project, we will utilize trans-ancestry genomic analyses to accelerate the identification of OCD risk loci, fine-map putative causal variants, and improve the performance of polygenic risk scores in diverse populations. We will also capitalize on rich clinical data to examine the genetics of treatment response, biologically plausible OCD subtypes, and symptom dimensions. Additionally, LATINO will help elucidate the diversity of the clinical presentations of OCD across cultures through various trainings developed and offered in collaboration with Latin American investigators. We believe this study will advance the important goal of global mental health discovery and equity.

Systematic Review and Meta-analysis: An Empirical Approach to Defining Treatment Response and Remission in Pediatric Obsessive-Compulsive Disorder

OBJECTIVE

A lack of universal definitions for response and remission in pediatric obsessive-compulsive disorder (OCD) has hampered the comparability of results across trials. To address this problem, we conducted an individual participant data diagnostic test accuracy meta-analysis to evaluate the discriminative ability of the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) in determining response and remission. We also aimed to generate empirically derived cutoffs on the CY-BOCS for these outcomes.

METHOD

A systematic review of PubMed, PsycINFO, Embase and CENTRAL identified 5,401 references; 42 randomized controlled clinical trials were considered eligible, and 21 provided data for inclusion (N = 1,234). Scores of ≤2 in the Clinical Global Impressions Improvement and Severity scales were chosen to define response and remission, respectively. A 2-stage, random-effects meta-analysis model was established. The area under the curve (AUC) and the Youden Index were computed to indicate the discriminative ability of the CY-BOCS and to guide for the optimal cutoff, respectively.

RESULTS

The CY-BOCS had sufficient discriminative ability to determine response (AUC = 0.89) and remission (AUC = 0.92). The optimal cutoff for response was a ≥35% reduction from baseline to posttreatment (sensitivity = 83.9, 95% CI = 83.7-84.1; specificity = 81.7, 95% CI = 81.5-81.9). The optimal cutoff for remission was a posttreatment raw score of ≤12 (sensitivity = 82.0, 95% CI = 81.8-82.2; specificity = 84.6, 95% CI = 84.4-84.8).

CONCLUSION

Meta-analysis identified empirically optimal cutoffs on the CY-BOCS to determine response and remission in pediatric OCD randomized controlled clinical trials. Systematic adoption of standardized operational definitions for response and remission will improve comparability across trials for pediatric OCD.

Toward a neurocircuit-based taxonomy to guide treatment of obsessive-compulsive disorder

An important challenge in mental health research is to translate findings from cognitive neuroscience and neuroimaging research into effective treatments that target the neurobiological alterations involved in psychiatric symptoms. To address this challenge, in this review we propose a heuristic neurocircuit-based taxonomy to guide the treatment of obsessive-compulsive disorder (OCD). We do this by integrating information from several sources. First, we provide case vignettes in which patients with OCD describe their symptoms and discuss different clinical profiles in the phenotypic expression of the condition. Second, we link variations in these clinical profiles to underlying neurocircuit dysfunctions, drawing on findings from neuropsychological and neuroimaging studies in OCD. Third, we consider behavioral, pharmacological, and neuromodulatory treatments that could target those specific neurocircuit dysfunctions. Finally, we suggest methods of testing this neurocircuit-based taxonomy as well as important limitations to this approach that should be considered in future research.

Cellular and Extracellular White Matter Abnormalities in Obsessive-Compulsive Disorder: A Diffusion Magnetic Resonance Imaging Study

BACKGROUND

While previous studies have implicated white matter (WM) as a core pathology of obsessive-compulsive disorder (OCD), the underlying neurobiological processes remain elusive. This study used free-water (FW) imaging derived from diffusion magnetic resonance imaging to identify cellular and extracellular WM abnormalities in patients with OCD compared with control subjects. Next, we investigated the association between diffusion measures and clinical variables in patients.

METHODS

We collected diffusion-weighted magnetic resonance imaging and clinical data from 83 patients with OCD (56 women/27 men, age 37.7 ± 10.6 years) and 52 control subjects (27 women/25 men, age 32.8 ± 11.5 years). Fractional anisotropy (FA), FA of cellular tissue, and extracellular FW maps were extracted and compared between patients and control subjects using tract-based spatial statistics and voxelwise comparison in FSL Randomise. Next, we correlated these WM measures with clinical variables (age of onset and symptom severity) and compared them between patients with and without comorbidities and patients with and without psychiatric medication.

RESULTS

Patients with OCD demonstrated lower FA (43.4% of the WM skeleton), lower FA of cellular tissue (31% of the WM skeleton), and higher FW (22.5% of the WM skeleton) compared with control subjects. We did not observe significant correlations between diffusion measures and clinical variables. Comorbidities and medication status did not influence diffusion measures.

CONCLUSIONS

Our findings of widespread FA, FA of cellular tissue, and FW abnormalities suggest that OCD is associated with microstructural cellular and extracellular abnormalities beyond the corticostriatothalamocortical circuits. Future multimodal longitudinal studies are needed to understand better the influence of essential clinical variables across the illness trajectory.

Higher volumes of hippocampal subfields in pediatric obsessive-compulsive disorder

Differences in hippocampus volume have been identified in adult patients with obsessive-compulsive disorder (OCD). However, the role of this limbic structure in pediatric patients is unclear. This study aimed to investigate the hippocampus and its subregions in a sample of 29 children and adolescents with OCD compared to 28 healthy controls, matched for age, sex, education, and IQ. Volumetric segmentation was performed using the Freesurfer software to calculate the volumes of the subregions that reflect the hippocampal cytoarchitecture. The volumes of three anatomic subregions (tail, body, and head) were also calculated. ANCOVA was performed to investigate differences of these volumes between patients and controls, controlling for total gray matter volume. After Bonferroni correction for multiple comparisons (p-value < 0.00556 for the body and < 0.00625 for the head structures), patients presented statistically significant larger volumes of the following structures: left subiculum body; left CA4 body; left GC-DG body; left molecular layer body; right parasubiculum; left CA4 head; left molecular layer head; right subiculum head and right molecular layer head. These enlarged volumes resulted in larger left and right whole hippocampi in patients, as well as bilateral hippocampal heads and left hippocampal body (all p-values < 0.00625). There were no associations between OCD severity and hippocampal volumes. These findings diverge from previous reports on adults and may indicate that larger hippocampal volumes could reflect an early marker of OCD, not present in adults.

Symmetry Dimension in Obsessive-Compulsive Disorder: Prevalence, Severity and Clinical Correlates

Background: Obsessive–compulsive disorder (OCD) is a very heterogeneous condition that frequently includes symptoms of the “symmetry dimension” (i.e., obsessions and/or compulsions of symmetry, ordering, repetition, and counting), along with aggressive, sexual/religious, contamination/cleaning, and hoarding dimensions. Methods: This cross-sectional study aimed to investigate the prevalence, severity, and demographic and clinical correlates of the symmetry dimension among 1001 outpatients from the Brazilian Research Consortium on Obsessive–Compulsive Spectrum Disorders. The main assessment instruments used were the Dimensional Yale–Brown Obsessive–Compulsive Scale, the Yale–Brown Obsessive–Compulsive Scale, the USP-Sensory Phenomena Scale, the Beck Depression and Anxiety Inventories, the Brown Assessment of Beliefs Scale, and the Structured Clinical Interview for DSM-IV Axis I Disorders. Chi-square tests, Fisher’s exact tests, Student’s t-tests, and Mann–Whitney tests were used in the bivariate analyses to compare patients with and without symptoms of the symmetry dimension. Odds ratios (ORs) with confidence intervals and Cohen’s D were also calculated as effect size measures. Finally, a logistic regression was performed to control for confounders. Results: The symmetry dimension was highly prevalent (86.8%) in this large clinical sample and, in the logistic regression, it remained associated with earlier onset of obsessive–compulsive symptoms, insidious onset of compulsions, more severe depressive symptoms, and presence of sensory phenomena. Conclusions: A deeper knowledge about specific OCD dimensions is essential for a better understanding and management of this complex and multifaceted disorder.

Lower Ventromedial Prefrontal Cortex Glutamate Levels in Patients With Obsessive-Compulsive Disorder

Background: Recent studies using magnetic resonance spectroscopy (¹H-MRS) indicate that patients with obsessive-compulsive disorder (OCD) present abnormal levels of glutamate (Glu) and gamma aminobutyric acid (GABA) in the frontal and striatal regions of the brain. These abnormalities could be related to the hyperactivation observed in cortico-striatal circuits of patients with OCD. However, most of the previous ¹H-MRS studies were not capable of differentiating the signal from metabolites that overlap in the spectrum, such as Glu and glutamine (Gln), and referred to the detected signal as the composite measure-Glx (sum of Glu and Gln). In this study, we used a two-dimensional JPRESS ¹H-MRS sequence that allows the discrimination of overlapping metabolites by observing the differences in J-coupling, leading to higher accuracy in the quantification of all metabolites. Our objective was to identify possible alterations in the neurometabolism of OCD, focusing on Glu and GABA, which are key neurotransmitters in the brain that could provide insights into the underlying neurochemistry of a putative excitatory/inhibitory imbalance. Secondary analysis was performed including metabolites such as Gln, creatine (Cr), N-acetylaspartate, glutathione, choline, lactate, and myo-inositol. Methods: Fifty-nine patients with OCD and 42 healthy controls (HCs) underwent 3T ¹H-MRS in the ventromedial prefrontal cortex (vmPFC, 30 × 25 × 25 mm³). Metabolites were quantified using ProFit (version 2.0) and Cr as a reference. Furthermore, Glu/GABA and Glu/Gln ratios were calculated. Generalized linear models (GLMs) were conducted using each metabolite as a dependent variable and age, sex, and gray matter fraction (fGM) as confounding factors. GLM analysis was also used to test for associations between clinical symptoms and neurometabolites. Results: The GLM analysis indicated lower levels of Glu/Cr in patients with OCD (z = 2.540; p = 0.011). No other comparisons reached significant differences between groups for all the metabolites studied. No associations between metabolites and clinical symptoms were detected. Conclusions: The decreased Glu/Cr concentrations in the vmPFC of patients with OCD indicate a neurochemical imbalance in the excitatory neurotransmission that could be associated with the neurobiology of the disease and may be relevant for the pathophysiology of OCD.

Cutting-edge genetics in obsessive-compulsive disorder

This article reviews recent advances in the genetics of obsessive-compulsive disorder (OCD). We cover work on the following: genome-wide association studies, whole-exome sequencing studies, copy number variation studies, gene expression, polygenic risk scores, gene–environment interaction, experimental animal systems, human cell models, imaging genetics, pharmacogenetics, and studies of endophenotypes. Findings from this work underscore the notion that the genetic architecture of OCD is highly complex and shared with other neuropsychiatric disorders. Also, the latest evidence points to the participation of gene networks involved in synaptic transmission, neurodevelopment, and the immune and inflammatory systems in this disorder. We conclude by highlighting that further study of the genetic architecture of OCD, a great part of which remains to be elucidated, could benefit the development of diagnostic and therapeutic approaches based on the biological basis of the disorder. Studies to date revealed that OCD is not a simple homogeneous entity, but rather that the underlying biological pathways are variable and heterogenous. We can expect that translation from bench to bedside, through continuous effort and collaborative work, will ultimately transform our understanding of what causes OCD and thus how best to treat it.

Social losses predict a faster onset and greater severity of obsessive-compulsive disorder

BACKGROUND

While stressful life events increase the risk of developing a range of psychiatric disorders, including obsessive-compulsive disorder (OCD), their ability to precipitate specific obsessive-compulsive symptoms' dimensions is unknown. Here we aimed to evaluate the potential role of three different types of stressful life events, herein termed losses (death of a loved one, termination of a romantic relationship and severe illness) in predicting the speed of progression from subclinical to clinical OCD and the severity of specific OCD dimensions in a large multicentre OCD sample.

METHODS

Nine hundred and fifty-four OCD outpatients from the Brazilian OCD Research Consortium were included in this study. Several semi-structured and structured instruments were used, including the Structured Clinical Interview for DSM-IV Axis I Disorders, the Yale-Brown Obsessive-Compulsive Scale, the Dimensional Yale-Brown Obsessive-Compulsive Scale, the Brown Assessment of Beliefs Scale, the Beck Depression Inventory, the Beck Anxiety Inventory and the Yale OCD Natural History Questionnaire. Regression models investigated the interaction between types of loss and gender to predict speed of progression from subclinical obsessive-compulsive symptoms to OCD, and the severity of five symptom dimensions.

RESULTS

While termination of a relationship was associated with a faster speed of progression from subthreshold to clinical OCD, the death of a loved one was associated with increased severity of hoarding symptoms. There was also an interaction between gender and experiences of death, which predicted a faster speed of progression to OCD in males.

CONCLUSIONS

Stressful life events have the ability to accelerate the progression from subclinical to clinical OCD, as well as impact the severity of specific OCD dimensions. Gender also plays a role in both the progression and severity of symptoms. These findings suggest that stressful life events may represent a marker to identify individuals at risk of progressing to clinical OCD.

Is it time to change the gold standard of obsessive-compulsive disorder severity assessment? Factor structure of the Yale-Brown Obsessive-Compulsive Scale

OBJECTIVES

The Yale-Brown Obsessive-Compulsive Scale has been considered the gold standard scale to assess obsessive-compulsive disorder severity. Previous studies using exploratory factor analysis and confirmatory factor analysis with this scale showed mixed findings in terms of factor structure and fit of models. Therefore, we used confirmatory factor analysis to compare different Yale-Brown Obsessive-Compulsive Scale models in a large sample aiming to identify the best model fit.

METHODS

We assessed adult obsessive-compulsive disorder patients (n = 955) using three measures: Yale-Brown Obsessive-Compulsive Scale severity ratings, the Dimensional Yale-Brown Obsessive-Compulsive Scale and the clinical global impression scale. We tested all factor structures reported by previous studies to investigate which model best fitted the data: one-factor, two-factor, three-factor and their equivalent high-order solutions. We also investigated Yale-Brown Obsessive-Compulsive Scale items correlations with scores from the other measures of obsessive-compulsive disorder severity.

RESULTS

Confirmatory factor analysis models presented mediocre to fair goodness-of-fit indexes. Severity items related to resistance to obsessions and compulsions presented low factor loadings. The model with the best fit indexes was a high-order model without obsessive-compulsive disorder resistance items. These items also presented small correlations with other obsessive-compulsive disorder severity measures.

CONCLUSION

The obsessive-compulsive disorder field needs to discuss further improvements in the Yale-Brown Obsessive-Compulsive Scale and/or continue to search for better measures of obsessive-compulsive disorder severity.

A transdiagnostic perspective of constructs underlying obsessive-compulsive and related disorders: An international Delphi consensus study

BACKGROUND

The Research Domain Criteria seeks to bridge knowledge from neuroscience with clinical practice by promoting research into valid neurocognitive phenotypes and dimensions, irrespective of symptoms and diagnoses as currently conceptualized. While the Research Domain Criteria offers a vision of future research and practice, its 39 functional constructs need refinement to better target new phenotyping efforts. This study aimed to determine which Research Domain Criteria constructs are most relevant to understanding obsessive-compulsive and related disorders, based on a consensus between experts in the field of obsessive-compulsive and related disorders.

METHODS

Based on a modified Delphi method, 46 experts were recruited from Australia, Africa, Asia, Europe and the Americas. Over three rounds, experts had the opportunity to review their opinion in light of feedback from the previous round, which included how their response compared to other experts and a summary of comments given.

RESULTS

Thirty-four experts completed round one, of whom 28 (82%) completed round two and 24 (71%) completed round three. At the final round, four constructs were endorsed by ⩾75% of experts as 'primary constructs' and therefore central to understanding obsessive-compulsive and related disorders. Of these constructs, one came from the Positive Valence System (Habit), two from the Cognitive Control System (Response Selection/Inhibition and Performance Monitoring) and the final construct was an additional item suggested by experts (Compulsivity).

CONCLUSION

This study identified four Research Domain Criteria constructs that, according to experts, cut across different obsessive-compulsive and related disorders. These constructs represent key areas for future investigation, and may have potential implications for clinical practice in terms of diagnostic processes and therapeutic management of obsessive-compulsive and related disorders.

Clinical advances in obsessive-compulsive disorder: a position statement by the International College of Obsessive-Compulsive Spectrum Disorders

In this position statement, developed by The International College of Obsessive-Compulsive Spectrum Disorders, a group of international experts responds to recent developments in the evidence-based management of obsessive-compulsive disorder (OCD). The article presents those selected therapeutic advances judged to be of utmost relevance to the treatment of OCD, based on new and emerging evidence from clinical and translational science. Areas covered include refinement in the methods of clinical assessment, the importance of early intervention based on new staging models and the need to provide sustained well-being involving effective relapse prevention. The relative benefits of psychological, pharmacological and somatic treatments are reviewed and novel treatment strategies for difficult to treat OCD, including neurostimulation, as well as new areas for research such as problematic internet use, novel digital interventions, immunological therapies, pharmacogenetics and novel forms of psychotherapy are discussed.

The rates of co-occurring behavioural addictions in treatment-seeking individuals with obsessive-compulsive disorder: a preliminary report

Objectives: To assess the rates of co-occurring putative 'behavioural addictions' in patients with obsessive-compulsive disorder (OCD).Methods: Twenty-three international centres specialising in the treatment of OCD were invited to participate in a survey of the rates of behavioural addictions and other relevant comorbidity within their samples.Results: Sixteen of 23 (69.6%) invited centres from 13 countries had sufficient data to participate in the survey. The use of validated diagnostic tools was discrepant, with most centres relying on a 'clinical diagnosis' to diagnose behavioural addictions. The final sample comprised of 6916 patients with a primary diagnosis of OCD. The reported rates of behavioural addictions were as follows: 8.7% for problematic internet use, 6.8% for compulsive sexual behaviour disorder, 6.4% for compulsive buying, 4.1% for gambling disorder and 3.4% for internet gaming disorder.Conclusions: Behavioural addictions should be better assessed for patients with OCD. The absence of diagnostic scales developed specifically for behavioural addictions and overlapping obsessive-compulsive phenomena such as compulsive checking of information on the internet may explain the relatively high rate of problematic internet use in this sample. The study encourages better efforts to assess and to conceptualise the relatedness of behavioural addictions to obsessive-compulsive 'spectrum' disorders.

Bipolar disorder comorbidity in patients with obsessive-compulsive disorder: Prevalence and predictors

BACKGROUND

Patients with obsessive-compulsive disorder (OCD) often present with comorbidities, mainly anxiety and affective disorders, which may influence OCD course, help-seeking and treatment response. Some authors have studied bipolar disorder (BD) comorbidity in patients with OCD, but usually in small samples. The objective was to estimate the lifetime prevalence of BD in a large clinical sample of OCD patients, and to compare demographic and clinical features of patients with and without BD comorbidity.

METHOD

This cross-sectional study with 955 adult OCD patients from the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders (C-TOC) used several assessment instruments, including the Yale-Brown Obsessive-Compulsive Scale, the Dimensional Yale-Brown Obsessive-Compulsive Scale, the Beck Depression and Anxiety Inventories, and the Structured Clinical Interview for DSM-IV Axis I Disorders. Descriptive and bivariate analyses were followed by logistic regression.

RESULTS

The lifetime prevalence of BD was 7.75% (N = 74). The variables that were independently associated with BD comorbidity were: panic disorder with agoraphobia, impulse control disorders, and suicide attempts.

LIMITATIONS

The cross-sectional design does not permit causal inferences; the external validity may be limited, as the participants were from tertiary services. Despite the large sample size, some analyses may have been underpowered due to the relatively low prevalence of the outcome and of some explanatory variables.

CONCLUSIONS

Patients with OCD comorbid with BD have some clinical features indicative of greater severity, including higher suicide risk, and require a careful therapeutic approach for the appropriate treatment of both disorders.

Obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a highly prevalent and chronic condition that is associated with substantial global disability. OCD is the key example of the 'obsessive-compulsive and related disorders', a group of conditions which are now classified together in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, and the International Classification of Diseases, 11th Revision, and which are often underdiagnosed and undertreated. In addition, OCD is an important example of a neuropsychiatric disorder in which rigorous research on phenomenology, psychobiology, pharmacotherapy and psychotherapy has contributed to better recognition, assessment and outcomes. Although OCD is a relatively homogenous disorder with similar symptom dimensions globally, individualized assessment of symptoms, the degree of insight, and the extent of comorbidity is needed. Several neurobiological mechanisms underlying OCD have been identified, including specific brain circuits that underpin OCD. In addition, laboratory models have demonstrated how cellular and molecular dysfunction underpins repetitive stereotyped behaviours, and the genetic architecture of OCD is increasingly understood. Effective treatments for OCD include serotonin reuptake inhibitors and cognitive-behavioural therapy, and neurosurgery for those with intractable symptoms. Integration of global mental health and translational neuroscience approaches could further advance knowledge on OCD and improve clinical outcomes.

Evolution of gamma knife capsulotomy for intractable obsessive-compulsive disorder

For more than half a century, stereotactic neurosurgical procedures have been available to treat patients with severe, debilitating symptoms of obsessive-compulsive disorder (OCD) that have proven refractory to extensive, appropriate pharmacological, and psychological treatment. Although reliable predictors of outcome remain elusive, the establishment of narrower selection criteria for neurosurgical candidacy, together with a better understanding of the functional neuroanatomy implicated in OCD, has resulted in improved clinical efficacy for an array of ablative and non-ablative intervention techniques targeting the cingulum, internal capsule, and other limbic regions. It was against this backdrop that gamma knife capsulotomy (GKC) for OCD was developed. In this paper, we review the history of this stereotactic radiosurgical procedure, from its inception to recent advances. We perform a systematic review of the existing literature and also provide a narrative account of the evolution of the procedure, detailing how the procedure has changed over time, and has been shaped by forces of evidence and innovation. As the procedure has evolved and adverse events have decreased considerably, favorable response rates have remained attainable for approximately one-half to two-thirds of individuals treated at experienced centers. A reduction in obsessive-compulsive symptom severity may result not only from direct modulation of OCD neural pathways but also from enhanced efficacy of pharmacological and psychological therapies working in a synergistic fashion with GKC. Possible complications include frontal lobe edema and even the rare formation of delayed radionecrotic cysts. These adverse events have become much less common with new radiation dose and targeting strategies. Detailed neuropsychological assessments from recent studies suggest that cognitive function is not impaired, and in some domains may even improve following treatment. We conclude this review with discussions covering topics essential for further progress of this therapy, including suggestions for future trial design given the unique features of GKC therapy, considerations for optimizing stereotactic targeting and dose planning using biophysical models, and the use of advanced imaging techniques to understand circuitry and predict response. GKC, and in particular its modern variant, gamma ventral capsulotomy, continues to be a reliable treatment option for selected cases of otherwise highly refractory OCD.

Obsessive-Compulsive Personality Symptoms Predict Poorer Response to Gamma Ventral Capsulotomy for Intractable OCD

Gamma ventral capsulotomy (GVC) is a radiosurgical procedure which aims to create lesions in the ventral part of the anterior limb of the internal capsule (ALIC). It has been used as a treatment option for patients with intractable obsessive-compulsive disorder (OCD) who do not respond to several first-line treatments attempts. However, changes in personality disorder symptoms after GVC have not been investigated. The aims of this study are to investigate changes in personality disorder symptoms after GVC and to search for baseline personality disorder symptoms that may predict clinical response to GVC. Fourteen treatment-intractable OCD patients who underwent GVC completed the Structured Clinical Interview for DSM-IV Personality Disorders (SCID-II) at baseline and one year after the procedure. Wilcoxon signed-rank test was performed to investigate personality disorder symptom changes before and after surgery. Linear regression models were utilized to predict treatment response, using baseline personality disorder symptoms as independent variables. We did not observe any quantitative changes in personality disorder symptoms after GVC, compared with baseline. Higher severity of obsessive-compulsive personality disorder symptoms at baseline was correlated with worse treatment response after GVC for OCD (β = -0.085, t-value = -2.52, p-value = 0.027). These findings advocate for the safety of the GVC procedure in this specific population of intractable OCD patients, in terms of personality disorder symptom changes. They also highlight the importance of taking into account the severity of obsessive-compulsive personality disorder symptoms when GVC is indicated for intractable OCD patients.

Treatments used for obsessive-compulsive disorder-An international perspective

OBJECTIVE

The objective of this study was to characterise international trends in the use of psychotropic medication, psychological therapies, and novel therapies used to treat obsessive-compulsive disorder (OCD).

METHODS

Researchers in the field of OCD were invited to contribute summary statistics on the characteristics of their samples. Consistency of summary statistics across countries was evaluated.

RESULTS

The study surveyed 19 expert centres from 15 countries (Argentina, Australia, Brazil, China, Germany, Greece, India, Italy, Japan, Mexico, Portugal, South Africa, Spain, the United Kingdom, and the United States) providing a total sample of 7,340 participants. Fluoxetine (n = 972; 13.2%) and fluvoxamine (n = 913; 12.4%) were the most commonly used selective serotonin reuptake inhibitor medications. Risperidone (n = 428; 7.3%) and aripiprazole (n = 415; 7.1%) were the most commonly used antipsychotic agents. Neurostimulation techniques such as transcranial magnetic stimulation, deep brain stimulation, gamma knife surgery, and psychosurgery were used in less than 1% of the sample. There was significant variation in the use and accessibility of exposure and response prevention for OCD.

CONCLUSIONS

The variation between countries in treatments used for OCD needs further evaluation. Exposure and response prevention is not used as frequently as guidelines suggest and appears difficult to access in most countries. Updated treatment guidelines are recommended.

Kundalini Yoga Meditation Versus the Relaxation Response Meditation for Treating Adults With Obsessive-Compulsive Disorder: A Randomized Clinical Trial

Background: Obsessive-compulsive disorder (OCD) is often a life-long disorder with high psychosocial impairment. Serotonin reuptake inhibitors (SRIs) are the only FDA approved drugs, and approximately 50% of patients are non-responders when using a criterion of 25% to 35% improvement with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). About 30% are non-responders to combined first-line therapies (SRIs and exposure and response prevention). Previous research (one open, one randomized clinical trial) has demonstrated that Kundalini Yoga (KY) meditation can lead to an improvement in symptoms of obsessive-compulsive severity. We expand here with a larger trial. Design: This trial compared two parallel run groups [KY vs. Relaxation Response meditation (RR)]. Patients were randomly allocated based on gender and Y-BOCS scores. They were told two different (unnamed) types of meditation would be compared, and informed if one showed greater benefits, the groups would merge for 12 months using the more effective intervention. Raters were blind in Phase One (0-4.5 months) to patient assignments, but not in Phase Two. Main Outcome Measures: Primary outcome variable, clinician-administered Y-BOCS. Secondary scales: Dimensional Yale-Brown Obsessive Compulsive Scale (clinician-administered), Profile of Mood Scales, Beck Anxiety Inventory, Beck Depression Inventory, Clinical Global Impression, Short Form 36 Health Survey. Results: Phase One: Baseline Y-BOCS scores: KY mean = 26.46 (SD 5.124; N = 24), RR mean = 26.79 (SD = 4.578; N = 24). An intent-to-treat analysis with the last observation carried forward for dropouts showed statistically greater improvement with KY compared to RR on the Y-BOCS, and statistically greater improvement on five of six secondary measures. For completers, the Y-BOCS showed 40.4% improvement for KY (N = 16), 17.9% for RR (N = 11); 31.3% in KY were judged to be in remission compared to 9.1% in RR. KY completers showed greater improvement on five of six secondary measures. At the end of Phase Two (12 months), patients, drawn from the initial groups, who elected to receive KY continued to show improvement in their Y-BOCS scores. Conclusion: KY shows promise as an add-on option for OCD patients unresponsive to first line therapies. Future studies will establish KY's relative efficacy compared to Exposure and Response Prevention and/or medications, and the most effective treatment schedule. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT01833442.

No evidence of attentional bias toward angry faces in patients with obsessive-compulsive disorder

Objective:

Although attentional bias (AB) toward angry faces is well established in patients with anxiety disorders, it is still poorly studied in obsessive-compulsive disorder (OCD). We investigated whether OCD patients present AB toward angry faces, whether AB is related to symptom severity and whether AB scores are associated with specific OCD symptom dimensions.

Method:

Forty-eight OCD patients were assessed in clinical evaluations, intelligence testing and a dot-probe AB paradigm that used neutral and angry faces as stimuli. Analyses were performed with a one-sample t-test, Pearson correlations and linear regression.

Results:

No evidence of AB was observed in OCD patients, nor was there any association between AB and symptom severity or dimension. Psychiatric comorbidity did not affect our results.

Conclusion:

In accordance with previous studies, we were unable to detect AB in OCD patients. To investigate whether OCD patients have different brain activation patterns from anxiety disorder patients, future studies using a transdiagnostic approach should evaluate AB in OCD and anxiety disorder patients as they perform AB tasks under functional neuroimaging protocols.

Assessment of Safety and Outcome of Lateral Hypothalamic Deep Brain Stimulation for Obesity in a Small Series of Patients With Prader-Willi Syndrome

IMPORTANCE

Deep brain stimulation (DBS) has been investigated for treatment of morbid obesity with variable results. Patients with Prader-Willi syndrome (PWS) present with obesity that is often difficult to treat.

OBJECTIVE

To test the safety and study the outcome of DBS in patients with PWS.

DESIGN, SETTING, AND PARTICIPANTS

This case series was conducted in the Hospital das Clínicas, University of São Paulo, Brazil. Four patients with genetically confirmed PWS presenting with severe obesity were included.

EXPOSURE

Deep brain stimulation electrodes were bilaterally implanted in the lateral hypothalamic area. After DBS implantation, the treatment included the following phases: titration (1-2 months), stimulation off (2 months), low-frequency DBS (40 Hz; 1 month), washout (15 days), high-frequency DBS (130 Hz; 1 month), and long-term follow-up (6 months).

MAIN OUTCOMES AND MEASURES

Primary outcome measures were adverse events recorded during stimulation and long-term DBS treatment. Secondary outcomes consisted of changes in anthropometric measures (weight, body mass index [calculated as weight in kilograms divided by height in meters squared], and abdominal and neck circumference), bioimpedanciometry, and calorimetry after 6 months of treatment compared with baseline. The following evaluations and measurements were conducted before and after DBS: clinical, neurological, psychiatric, neuropsychological, anthropometry, calorimetry, blood workup, hormonal levels, and sleep studies. Adverse effects were monitored during all follow-up visits.

RESULTS

Four patients with PWS were included (2 male and 2 female; ages 18-28 years). Baseline mean (SD) body mass index was 39.6 (11.1). Two patients had previous bariatric surgery, and all presented with psychiatric comorbidity, which was well controlled with the use of medications. At 6 months after long-term DBS, patients had a mean 9.6% increase in weight, 5.8% increase in body mass index, 8.4% increase in abdominal circumference, 4.2% increase in neck circumference, 5.3% increase in the percentage of body fat, and 0% change in calorimetry compared with baseline. Also unchanged were hormonal levels and results of blood workup, sleep studies, and neuropsychological evaluations. Two patients developed stimulation-induced manic symptoms. Discontinuation of DBS controlled this symptom in 1 patient. The other required adjustments in medication dosage. Two infections were documented, 1 associated with skin picking.

CONCLUSIONS AND RELEVANCE

Safety of lateral hypothalamic area stimulation was in the range of that demonstrated in patients with similar psychiatric conditions receiving DBS. In the small cohort of patients with PWS treated in our study, DBS was largely ineffective.

Adaptive treatment strategies for children and adolescents with Obsessive-Compulsive Disorder: A sequential multiple assignment randomized trial

OBJECTIVE

This sequential multiple assignment randomized trial (SMART) tested the effect of beginning treatment of childhood OCD with fluoxetine (FLX) or group cognitive-behavioral therapy (GCBT) accounting for treatment failures over time.

METHODS

A two-stage, 28-week SMART was conducted with 83 children and adolescents with OCD. Participants were randomly allocated to GCBT or FLX for 14 weeks. Responders to the initial treatment remained in the same regimen for additional 14 weeks. Non-responders, defined by less than 50% reduction in baseline Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores, were re-randomized to either switch to or add the other treatment. Assessments were performed at baseline, 7, 14, 21, and 28 weeks.

RESULTS

Among the 43 children randomized to FLX who completed the first stage, 15 (41.7%) responded to treatment and 21 non-responders were randomized to switch to (N = 9) or add GCBT (N = 12). Among the 40 children randomized to GCBT who completed the first stage, 18 (51.4%) responded to treatment and 17 non-responders were randomized to switch to (N = 9) or add FLX (N = 8). Primary analysis showed that significant improvement occurred in children initially treated with either FLX or GCBT. Each time point was statistically significant, showing a linear trend of symptom reduction. Effect sizes were large within (0.76-0.78) and small between (-0.05) groups.

CONCLUSIONS

Fluoxetine and GCBT are similarly effective initial treatments for childhood OCD considering treatment failures over time. Consequently, provision of treatment for childhood OCD could be tailored according to the availability of local resources.

Personality measures after gamma ventral capsulotomy in intractable OCD

BACKGROUND

Neurosurgeries such as gamma ventral capsulotomy (GVC) are an option for otherwise intractable obsessive-compulsive disorder (OCD) patients. In general, clinical and neuropsychological status both improve after GVC. However, its consequences on personality traits are not well-studied. The objective of this study was to investigate personality changes after one year of GVC in intractable OCD patients.

METHODS

The personality assessment was conducted using the Revised NEO Personality Inventory (NEO PI-R) and Cloninger's Temperament and Character Inventory (TCI) in 14 intractable OCD patients before and one year after GVC. Comparisons of personality features between treatment responders (n=5) and non-responders (n=9) were performed. Multiple linear regression was also used for predicting changes in clinical and global functioning variables.

RESULTS

Overall, no deleterious effect was found in personality after GVC. Responders had a reduction in neuroticism (p=0.043) and an increase in extraversion (p=0.043). No significant changes were observed in non-responders. Increases in novelty seeking and self-directedness, and decreases in persistence and cooperativiness predicted OCD symptom improvement. Similary, improvement in functioning was also predicted by hgher novelty seeking and self-directedness after GVC, whereas better functioning was also associated with lower reward dependence and cooperativeness after surgery.

CONCLUSIONS

The pattern of changes in personality traits after GVC was generally towards that observed in nonclinical population, and does not raise safety concerns.

Quantifying dimensional severity of obsessive-compulsive disorder for neurobiological research

Current research to explore genetic susceptibility factors in obsessive-compulsive disorder (OCD) has resulted in the tentative identification of a small number of genes. However, findings have not been readily replicated. It is now broadly accepted that a major limitation to this work is the heterogeneous nature of this disorder, and that an approach incorporating OCD symptom dimensions in a quantitative manner may be more successful in identifying both common as well as dimension-specific vulnerability genetic factors. As most existing genetic datasets did not collect specific dimensional severity ratings, a specific method to reliably extract dimensional ratings from the most widely used severity rating scale, the Yale-Brown Obsessive Compulsive Scale (YBOCS), for OCD is needed. This project aims to develop and validate a novel algorithm to extrapolate specific dimensional symptom severity ratings in OCD from the existing YBOCS for use in genetics and other neurobiological research. To accomplish this goal, we used a large data set comprising adult subjects from three independent sites: the Brazilian OCD Consortium, the Sunnybrook Health Sciences Centre in Toronto, Canada and the Hospital of Bellvitge, in Barcelona, Spain. A multinomial logistic regression was proposed to model and predict the quantitative phenotype [i.e., the severity of each of the five homogeneous symptom dimensions of the Dimensional YBOCS (DYBOCS)] in subjects who have only YBOCS (categorical) data. YBOCS and DYBOCS data obtained from 1183 subjects were used to build the model, which was tested with the leave-one-out cross-validation method. The model's goodness of fit, accepting a deviation of up to three points in the predicted DYBOCS score, varied from 78% (symmetry/order) to 84% (cleaning/contamination and hoarding dimensions). These results suggest that this algorithm may be a valuable tool for extracting dimensional phenotypic data for neurobiological studies in OCD.

Dissecting the Yale-Brown Obsessive-Compulsive Scale severity scale to understand the routes for symptomatic improvement in obsessive-compulsive disorder

We aimed to investigate which items of the Yale-Brown Obsessive-Compulsive Severity Scale best discriminate the reduction in total scores in obsessive-compulsive disorder patients after 4 and 12 weeks of pharmacological treatment. Data from 112 obsessive-compulsive disorder patients who received fluoxetine (⩽80 mg/day) for 12 weeks were included. Improvement indices were built for each Yale-Brown Obsessive-Compulsive Severity Scale item at two timeframes: from baseline to week 4 and from baseline to week 12. Indices for each item were correlated with the total scores for obsessions and compulsions and then ranked by correlation coefficient. A correlation coefficient ⩾0.7 was used to identify items that contributed significantly to reducing obsessive-compulsive disorder severity. At week 4, the distress items reached the threshold of 0.7 for improvement on the obsession and compulsion subscales although, contrary to our expectations, there was greater improvement in the control items than in the distress items. At week 12, there was greater improvement in the time, interference, and control items than in the distress items. The use of fluoxetine led first to reductions in distress and increases in control over symptoms before affecting the time spent on, and interference from, obsessions and compulsions. Resistance did not correlate with overall improvement. Understanding the pathway of improvement with pharmacological treatment in obsessive-compulsive disorder may provide clues about how to optimize the effects of medication.

Comorbidity, age of onset and suicidality in obsessive-compulsive disorder (OCD): An international collaboration

OBJECTIVES

To collate data from multiple obsessive-compulsive disorder (OCD) treatment centers across seven countries and five continents, and to report findings in relation to OCD comorbidity, age of onset of OCD and comorbid disorders, and suicidality, in a large clinical and ethnically diverse sample, with the aim of investigating cultural variation and the utility of the psychiatric diagnostic classification of obsessive-compulsive and related disorders.

METHODS

Researchers in the field of OCD were invited to contribute summary statistics on current and lifetime psychiatric comorbidity, age of onset of OCD and comorbid disorders and suicidality in their patients with OCD.

RESULTS

Data from 3711 adult patients with primary OCD came from Brazil (n=955), India (n=802), Italy (n=750), South Africa (n=565), Japan (n=322), Australia (n=219), and Spain (n=98). The most common current comorbid disorders were major depressive disorder (28.4%; n=1055), obsessive-compulsive personality disorder (24.5%, n=478), generalized anxiety disorder (19.3%, n=716), specific phobia (19.2%, n=714) and social phobia (18.5%, n=686). Major depression was also the most commonly co-occurring lifetime diagnosis, with a rate of 50.5% (n=1874). OCD generally had an age of onset in late adolescence (mean=17.9years, SD=1.9). Social phobia, specific phobia and body dysmorphic disorder also had an early age of onset. Co-occurring major depressive disorder, generalized anxiety disorder and psychotic disorders tended to have a later age of onset than OCD. Suicidal ideation within the last month was reported by 6.4% (n=200) of patients with OCD and 9.0% (n=314) reported a lifetime history of suicide attempt.

CONCLUSIONS

In this large cross-continental study, comorbidity in OCD was common. The high rates of comorbid major depression and anxiety disorders emphasize the need for clinicians to assess and monitor for these disorders. Earlier ages of onset of OCD, specific phobia and social phobia may indicate some relatedness between these disorders, but this requires further study. Although there do not appear to be significant cultural variations in rates or patterns of comorbidity and suicidality, further research using similar recruitment strategies and controlling for demographic and clinical variables may help to determine whether any sociocultural factors protect against suicidal ideation or psychiatric comorbidity in patients with OCD.

Randomized, Double-Blind, Placebo-Controlled Trial of N-Acetylcysteine Augmentation for Treatment-Resistant Obsessive-Compulsive Disorder

OBJECTIVE

To evaluate the efficacy of serotonin reuptake inhibitor (SRI) augmentation with N-acetylcysteine (NAC), a glutamate modulator and antioxidant medication, for treatment-resistant obsessive-compulsive disorder (OCD).

METHODS

We conducted a randomized, double-blind, placebo-controlled, 16-week trial of NAC (3,000 mg daily) in adults (aged 18-65 years) with treatment-resistant OCD, established according to DSM-IV criteria. Forty subjects were recruited at an OCD-specialized outpatient clinic at a tertiary hospital (May 2012-October 2014). The primary outcome measure was the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores. To evaluate the variables group, time, and interaction effects for Y-BOCS scores at all time points, we used nonparametric analysis of variance with repeated measures. Secondary outcomes were the severity scores for anxiety, depression, specific OCD symptom dimensions, and insight.

RESULTS

Both groups showed a significant reduction of baseline Y-BOCS scores at week 16: the NAC group had a reduction of 4.3 points (25.6 to 21.3), compared with 3.0 points (24.8 to 21.8) for the placebo group. However, there were no significant differences between groups (P = .92). Adding NAC was superior to placebo in reducing anxiety symptoms (P = .02), but not depression severity or specific OCD symptom dimensions. In general, NAC was well tolerated, despite abdominal pain being more frequently reported in the NAC group (n [%]: NAC = 9 [60.0], placebo = 2 [13.3]; P < .01).

CONCLUSIONS

Our trial did not demonstrate a significant benefit of NAC in reducing OCD severity in treatment-resistant OCD adults. Secondary analysis suggested that NAC might have some benefit in reducing anxiety symptoms in treatment-resistant OCD patients.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01555970.

The Child Behavior Checklist-Obsessive-Compulsive Subscale Detects Severe Psychopathology and Behavioral Problems Among School-Aged Children

OBJECTIVE

The aims of this study were (1) to assess obsessive-compulsive symptoms (OCS) dimensionally in a school-aged community sample and to correlate them with clinical and demographical variables; (2) to determine a subgroup with significant OCS ("at-risk for OCD") using the Child Behavior Checklist (CBCL-OCS) and (3) to compare it with the rest of the sample; (4) To review the CBCL-OCS subscale properties as a screening tool for pediatric OCD.

METHODS

Data from the Brazilian High Risk Cohort were analyzed. The presence and severity of OCS were assessed through the CBCL-OCS subscale. DSM-IV psychiatric diagnoses were obtained by the Developmental and Well-Being Assessment. Behavioral problems were assessed using the Strengths and Difficulties Questionnaire, the Youth Strengths Inventory, and the CBCL internalizing and externalizing behavior subscales.

RESULTS

A total of 2512 (mean age: 8.86 ± 1.84 years; 55.0% male) children were included. Moderate correlations were found between OCS severity and functional impairment (r = 0.36, p < 0.001). Children with higher levels of OCS had higher rates of psychiatric comorbidity and behavioral problems (p < 0.001). A score of 5 or higher in the CBCL-OCS scale determined an "at-risk for OCD" subgroup, comprising 9.7% of the sample (n = 244), with behavioral patterns and psychiatric comorbidities (e.g., tics [odds ratios, OR = 6.41, p < 0.001]), anxiety disorders grouped [OR = 3.68, p < 0.001] and depressive disorders [OR = 3.0, p < 0.001] very similar to those described in OCD. Sensitivity, specificity, positive predictive value, and negative predictive value of the CBCL-OCS for OCD diagnosis were, respectively, 48%, 91.5%; 15.1%, and 98.2%.

CONCLUSIONS

The dimensional approach suggests that the presence of OCS in children is associated with higher rates of comorbidity, behavioral problems, and impairment. The "at-risk for OCD" group defined by the CBCL revealed a group of patients phenotypically similar to full blown OCD.

International prescribing practices in obsessive-compulsive disorder (OCD)

OBJECTIVES

To assess rates of psychotropic medication use in patients with obsessive-compulsive disorder (OCD) in seven different countries on five continents and to compare these with international treatment guidelines.

METHODS

Researchers in the field of OCD were invited to contribute summary statistics on the characteristics of their patients with OCD and on their incidence of psychotropic use. Consistency of summary statistics across countries was evaluated.

RESULTS

The data came from Brazil (n = 955), Italy (n = 750), South Africa (n = 555), Japan (n = 382), Australia (n = 213), India (n = 202) and Spain (n = 82). The majority (77.9%; n = 2445) of the total sample of 3139 participants received a psychotropic medication. Consistent with international guidelines, selective serotonin reuptake inhibitors (SSRIs) were most commonly used (73.5%, n = 1796), but their use ranged from 59% in Australia to 96% in Japan. Clomipramine use varied from 5% in Japan and South Africa to 26% in India and Italy. Atypical antipsychotic use ranged from 12% in South Africa to 50% in Japan.

CONCLUSIONS

Pharmacotherapy for OCD varied significantly across sites. Prospective studies are required to determine the cultural, pharmacoeconomic and pharmacogenomic factors that may play a role in the variation in prescribing practices internationally and whether these variations influence treatment outcomes. Copyright © 2016 John Wiley & Sons, Ltd.

Prevalence and correlates of electroconvulsive therapy delivery in 1001 obsessive-compulsive disorder outpatients

Individuals with obsessive-compulsive disorder (OCD) who sought treatment in seven different specialized centers (n=1001) were evaluated with a structured assessment battery. Thirteen OCD patients (1.3% of the sample) reported having been treated with electroconvulsive therapy (ECT) in the past. They were older and exhibited higher global severity of OCD symptoms, but were less likely to display symmetry/ordering and contamination/washing symptoms. They also had greater suicidality and increased rates of psychosis. Finally, OCD patients exposed to ECT were more frequently treated with antipsychotics, although they did not differ in terms of responses to adequate trials with serotonin reuptake inhibitors.

Obsessive-compulsive symptoms are associated with psychiatric comorbidities, behavioral and clinical problems: a population-based study of Brazilian school children

Pediatric-onset obsessive-compulsive disorder (OCD) is underdiagnosed, and many affected children are untreated. The present study seeks to evaluate the presence and the clinical impact of OCD and obsessive-compulsive symptoms (OCS) in a large sample of school-age children. In Phase I, we performed an initial screening using the Family History Screen (FHS). In Phase II, we identified an "at-risk" sample, as well as a randomly selected group of children. A total of 2,512 children (6-12 years old) were assessed using the FHS, the Development and Well-Being Assessment (DAWBA), the Strengths and Difficulties Questionnaire (SDQ), and the Child Behavior Checklist (CBCL). Data analyses included descriptive and multivariate analytical techniques. 2,512 children (mean age: 8.86 ± 1.84 years; 55.0% male) were categorized into one of the three diagnostic groups: OCD (n = 77), OCS (n = 488), and unaffected controls (n = 1,947). There were no significant socio-demographic differences (age, gender, socioeconomic status) across groups. The OCS group resembled the OCD on overall impairment, including school problems and delinquent behaviors. However, the OCD group did have significantly higher rates of several comorbid psychiatric disorders, including separation anxiety, generalized anxiety, and major depressive disorder, than OCS or unaffected controls. Moreover, the OCD group also scored higher than the SDQ, as well as on each of CBCL items rated by the parent. Our findings suggest that there is a psychopathological continuum between OCS and OCD in school-aged children. The presence of OCS is associated with functional impairment, which needs further investigation in longitudinal studies.

ORBITOFRONTAL THICKNESS AS A MEASURE FOR TREATMENT RESPONSE PREDICTION IN OBSESSIVE-COMPULSIVE DISORDER

BACKGROUND

Early prediction of treatment response could reduce exposure to ineffective treatments and optimize the use of medical resources. Neuroimaging techniques have been used to identify biomarkers that are predictive of outcomes. The aims of this study were to investigate orbitofrontal cortex (OFC) thickness as a potential morphometric biomarker to discriminate outcomes in obsessive-compulsive disorder (OCD) and then to reexamine this biomarker in an independent cohort

METHODS

Using a logistic regression model based on the mean baseline thickness of subregions of the OFC, we estimated the probability of treatment response in 29 treatment-naïve OCD patients who participated in a clinical trial. That algorithm was then tested in an independent cohort of 12 patients with a confirmed diagnosis of refractory OCD RESULTS: Among the treatment-naïve OCD patients, measures of OFC thickness statistically significantly differentiated responders (n = 13) and nonresponders (n = 16), with an overall classification accuracy of ≈80%, a sensitivity of 77% (10/13), and a specificity of 81% (13/16). Of the refractory OCD patients in the second independent cohort, 67% were correctly classified as nonresponders. The most discriminative measures in the initial cohort of treatment-naïve patients were the thicknesses of the left and right medial OFC (P = .009 and P = .028, respectively)

CONCLUSIONS

We found OFC thickness to be a strong predictor of treatment response in treatment-naïve OCD patients. Although there are not yet any brain imaging biomarkers with clinical utility, our results highlight the potential of these measures as tools for predicting treatment outcomes in OCD.

Defining clinical severity in adults with obsessive-compulsive disorder

OBJECTIVE

The Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) is the most commonly used instrument to assess the clinical severity of obsessive-compulsive symptoms. Treatment determinations are often based on Y-BOCS score thresholds. However, these benchmarks are not empirically based, which may result in non-evidence based treatment decisions. Accordingly, the present study sought to derive empirically-based benchmarks for defining obsessive-compulsive symptom severity.

METHOD

Nine hundred fifty-four adult patients with obsessive-compulsive disorder (OCD), recruited through the Brazilian Research Consortium on Obsessive-Compulsive Spectrum Disorders, were evaluated by experienced clinicians using a structured clinical interview, the Y-BOCS, and the Clinical Global Impressions-Severity scale (CGI-Severity).

RESULTS

Similar to results in treatment-seeking children with OCD, our findings demonstrated convergence between the Y-BOCS and global OCD severity assessed by the CGI-Severity (Nagelkerke R(2)=.48). Y-BOCS scores of 0-13 corresponded with 'mild symptoms' (CGI-Severity=0-2), 14-25 with 'moderate symptoms' (CGI-Severity=3), 26-34 with 'moderate-severe symptoms' (CGI-Severity=4) and 35-40 with 'severe symptoms' (CGI-Severity=5-6). Neither age nor ethnicity was associated with Y-BOCS scores, but females demonstrated more severe obsessive-compulsive symptoms than males (d=.34). Time spent on obsessions/compulsions, interference, distress, resistance, and control were significantly related to global OCD severity although the symptom resistance item pairing demonstrated a less robust relationship relative to other components of the Y-BOCS.

CONCLUSIONS

These data provide empirically-based benchmarks on the Y-BOCS for defining the clinical severity of treatment seeking adults with OCD, which can be used for normative comparisons in the clinic and for future research.

Visuospatial Memory Improvement after Gamma Ventral Capsulotomy in Treatment Refractory Obsessive-Compulsive Disorder Patients

Gamma ventral capsulotomy (GVC) radiosurgery is intended to minimize side effects while maintaining the efficacy of traditional thermocoagulation techniques for the treatment of refractory obsessive-compulsive disorder (OCD). Neuropsychological outcomes are not clear based on previous studies and, therefore, we investigated the effects of GVC on cognitive and motor performance. A double-blind, randomized controlled trial (RCT) was conducted with 16 refractory OCD patients allocated to active treatment (n=8) and sham (n=8) groups. A comprehensive neuropsychological evaluation including intellectual functioning, attention, verbal and visuospatial learning and memory, visuospatial perception, inhibitory control, cognitive flexibility, and motor functioning was applied at baseline and one year after the procedure. Secondary analysis included all operated patients: eight from the active group, four from the sham group who were submitted to surgery after blind was broken, and five patients from a previous open pilot study (n=5), totaling 17 patients. In the RCT, visuospatial memory (VSM) performance significantly improved in the active group after GVC (p=0.008), and remained stable in the sham group. Considering all patients operated, there was no decline in cognitive or motor functioning after one year of follow-up. Our initial results after 1 year of follow-up suggests that GVC not only is a safe procedure in terms of neuropsychological functioning but in fact may actually improve certain neuropsychological domains, particularly VSM performance, in treatment refractory OCD patients.

Brain structural correlates of sensory phenomena in patients with obsessive-compulsive disorder

BACKGROUND

Sensory phenomena (SP) are uncomfortable feelings, including bodily sensations, sense of inner tension, "just-right" perceptions, feelings of incompleteness, or "urge-only" phenomena, which have been described to precede, trigger or accompany repetitive behaviours in individuals with obsessive-compulsive disorder (OCD). Sensory phenomena are also observed in individuals with tic disorders, and previous research suggests that sensorimotor cortex abnormalities underpin the presence of SP in such patients. However, to our knowledge, no studies have assessed the neural correlates of SP in patients with OCD.

METHODS

We assessed the presence of SP using the University of São Paulo Sensory Phenomena Scale in patients with OCD and healthy controls from specialized units in São Paulo, Brazil, and Barcelona, Spain. All participants underwent a structural magnetic resonance examination, and brain images were examined using DARTEL voxel-based morphometry. We evaluated grey matter volume differences between patients with and without SP and healthy controls within the sensorimotor and premotor cortices.

RESULTS

We included 106 patients with OCD and 87 controls in our study. Patients with SP (67% of the sample) showed grey matter volume increases in the left sensorimotor cortex in comparison to patients without SP and bilateral sensorimotor cortex grey matter volume increases in comparison to controls. No differences were observed between patients without SP and controls.

LIMITATIONS

Most patients were medicated. Participant recruitment and image acquisition were performed in 2 different centres.

CONCLUSION

We have identified a structural correlate of SP in patients with OCD involving grey matter volume increases within the sensorimotor cortex; this finding is in agreement with those of tic disorder studies showing that abnormal activity and volume increases within this region are associated with the urges preceding tic onset.

Transcranial direct current stimulation in obsessive-compulsive disorder: emerging clinical evidence and considerations for optimal montage of electrodes

BACKGROUND

Neuromodulation techniques for obsessive-compulsive disorder (OCD) treatment have expanded with greater understanding of the brain circuits involved. Transcranial direct current stimulation (tDCS) might be a potential new treatment for OCD, although the optimal montage is unclear.

OBJECTIVE

To perform a systematic review on meta-analyses of repetitive transcranianal magnetic stimulation (rTMS) and deep brain stimulation (DBS) trials for OCD, aiming to identify brain stimulation targets for future tDCS trials and to support the empirical evidence with computer head modeling analysis.

METHODS

Systematic reviews of rTMS and DBS trials on OCD in Pubmed/MEDLINE were searched. For the tDCS computational analysis, we employed head models with the goal of optimally targeting current delivery to structures of interest.

RESULTS

Only three references matched our eligibility criteria. We simulated four different electrodes montages and analyzed current direction and intensity.

CONCLUSION

Although DBS, rTMS and tDCS are not directly comparable and our theoretical model, based on DBS and rTMS targets, needs empirical validation, we found that the tDCS montage with the cathode over the pre-supplementary motor area and extra-cephalic anode seems to activate most of the areas related to OCD.