Abnormalities In Obsessive-compulsive Disorder Research Articles

Gray matter volume abnormalities in obsessive-compulsive disorder correlate with molecular and transcriptional profiles

Neuroimaging studies have consistently established altered brain structure in obsessive-compulsive disorder (OCD). However, the molecular and genetic mechanisms underlying structural brain abnormalities remain unclear. In this study, we aimed to investigate altered gray matter volume and its underlying molecular and genetic mechanisms in patients with OCD. Gray matter morphological abnormalities measured with voxel based morphometry analysis were identified in patients with OCD in comparison to sex- and age-matched healthy controls (HCs). Spatial correlations between gray matter morphological abnormalities and neurotransmitter maps were calculated to identify neurotransmitters relating to structural abnormalities. Structural abnormalities related genes were identified by conducting transcriptome-neuroimaging spatial correlations. Compared with HCs, patients with OCD demonstrated significant morphological abnormalities in distributed brain areas, including gray matter atrophy in the anterior cingulate and increased gray matter volume in the thalamus, caudate and precentral and postcentral gyrus. The morphological abnormalities were significantly associated with dopamine synthesis capacity and expression profiles of 1110 genes enriched for trans-synaptic signaling, regulation of membrane potential, modulation of chemical synaptic transmission, brain development, synapse organization and regulation of neurotransmitter levels. These results elucidate the molecular and transcriptional basis of altered gray matter morphology and build linking between molecular, transcriptional and neuroimaging information facilitating an integrative understanding of OCD.

Performance Monitoring: A Transdiagnostic Biomarker of Adaptive Behavior in Mental Disorders

Obsessive-compulsive disorder (OCD) is a severe and heterogeneous disorder with a considerable rate of treatment nonresponders. It is important to understand the neural underpinnings of the disorder so that they can inform and improve treatments. A well-established target candidate for the underlying psychopathology in OCD is the error-related negativity (ERN) as measured in performance monitoring ( 1 Endrass T. Ullsperger M. Specificity of performance monitoring changes in obsessive-compulsive disorder. Neurosci Biobehav Rev. 2014; 46: 124-138 Crossref PubMed Scopus (99) Google Scholar ). The ERN is important for the adaptation of behavior (e.g., affect/motivation) and subsequent actions. Many studies have observed an increased ERN and discussed this phenomenon as a potential biomarker or endophenotype for OCD. However, despite the need to identify qualified endophenotypes early in the course of the disorder—or even before a clinical threshold is reached, assuming it might be easier to treat at this early stage—evidence from pediatric samples and early-onset OCD is scarce. The study by Suzuki et al. ( 2 Suzuki T. Gu P. Grove T.B. Hammond T. Collins K.M. Pamidighantam P. et al. Abnormally enhanced midfrontal theta activity during response monitoring in youths with obsessive-compulsive disorder. Biol Psychiatry. 2023; 93: 1031-1040 Abstract Full Text Full Text PDF Google Scholar ) in the current issue of Biological Psychiatry provides evidence for an increased ERN and theta band power in a group of children and adolescents with early-onset OCD compared with an unaffected control group. Consistent with previous studies, the authors observed increased amplitudes and theta power in OCD not only following errors but also following correct responses. In addition, they analyzed intertrial phase coherence in the theta range—a measure for the synchronization of the phase of the signal between trials independent of amplitude ( 3 McLoughlin G. Gyurkovics M. Palmer J. Makeig S. Midfrontal theta activity in psychiatric illness: An index of cognitive vulnerabilities across disorders. Biol Psychiatry. 2022; 91: 173-182 Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar )—but group effects were not observed. Enhanced ERN and theta power have been suggested as biomarkers or endophenotypes for OCD. Although there is substantial evidence supporting the notion of performance monitoring abnormalities in OCD, we will discuss the following aspects: 1) the function of ERN and theta power for adaptive behavior and in mental disorders; 2) performance monitoring as a specific versus transdiagnostic biomarker; and 3) functional role and sensitivity to interventions. SEE CORRESPONDING ARTICLE ON PAGE 1031 SEE CORRESPONDING ARTICLE ON PAGE 1031 Abnormally Enhanced Midfrontal Theta Activity During Response Monitoring in Youths With Obsessive-Compulsive DisorderBiological PsychiatryVol. 93Issue 11PreviewResponse monitoring, as reflected in electroencephalogram recordings after commission of errors, has been consistently shown to be abnormally enhanced in individuals with obsessive-compulsive disorder (OCD). This has traditionally been quantified as error-related negativity (ERN) and may reflect abnormal neurophysiological mechanisms underlying OCD. However, the ERN reflects the increase in phase-locked activities, particularly in the theta-band (4–8 Hz), and does not reflect non–phase-locked activities. Full-Text PDF

A multimodal meta-analysis of regional functional and structural brain abnormalities in obsessive-compulsive disorder.

Numerous neuroimaging studies of resting-state functional imaging and voxel-based morphometry (VBM) have revealed abnormalities in specific brain regions in obsessive-compulsive disorder (OCD), but results have been inconsistent. We conducted a whole-brain voxel-wise meta-analysis on resting-state functional imaging and VBM studies that investigated differences of functional activity and gray matter volume (GMV) between patients with OCD and healthy controls (HCs) using seed-based d mapping (SDM) software. A total of 41 independent studies (51 datasets) for resting-state functional imaging and 42 studies (46 datasets) for VBM were included by a systematic literature search. Overall, patients with OCD displayed increased spontaneous functional activity in the bilateral inferior frontal gyrus (IFG) (extending to the bilateral insula) and bilateral medial prefrontal cortex/anterior cingulate cortex (mPFC/ACC), as well as decreased spontaneous functional activity in the bilateral paracentral lobule, bilateral cerebellum, left caudate nucleus, left inferior parietal gyri, and right precuneus cortex. For the VBM meta-analysis, patients with OCD displayed increased GMV in the bilateral thalamus (extending to the bilateral cerebellum), right striatum, and decreased GMV in the bilateral mPFC/ACC and left IFG (extending to the left insula). The conjunction analyses found that the bilateral mPFC/ACC, left IFG (extending to the left insula) showed decreased GMV with increased intrinsic function in OCD patients compared to HCs. This meta-analysis demonstrated that OCD exhibits abnormalities in both function and structure in the bilateral mPFC/ACC, insula, and IFG. A few regions exhibited only functional or only structural abnormalities in OCD, such as the default mode network, striatum, sensorimotor areas, and cerebellum. It may provide useful insights for understanding the underlying pathophysiology of OCD and developing more targeted and efficacious treatment and intervention strategies.

Analyzing Hereditary 5-HT Abnormalities in Obsessive-Compulsive Disorder (OCD)

Serotonin (5-HT) is one of the most essential and complicated neurotransmitters in humans, being an underlying cause of several neuropsychiatric disorders. Obsessive-Compulsive Disorder (OCD) is one of the disorders that is proved to be strongly correlated with 5-HT. This review focuses on how genetics of 5-HT influences the manifestation of OCD and suggests that further study needs to be done in order to find the genuine genetic cause of the disease and approach better treatments in the future. Smaller units, such as single nucleotide polymorphism (SNP), can bring an enormous change to the expression of gene and unveil the paradox of the findings from the past decades. Therefore, the unexplainable variety of findings might be answered if it is studied more thoroughly and utilizes new advanced technology. Keywords: Behavioral and social sciences; Neuroscience; Obsessive-Compulsive Disorder; Serotonin; Polymorphism

Association between gray/white matter contrast and white matter microstructural alterations in medication-naïve obsessive–compulsive disorder

Intracortical myelin is involved in speeding and synchronizing neural activity of the cerebral cortex and has been found to be disrupted in various psychiatric disorders. However, its role in obsessive–compulsive disorder (OCD) has remained unknown. In this study, we investigated the alterations in intracortical myelin and their association with white matter (WM) microstructural abnormalities in OCD. T1-weighted and diffusion-weighted brain images were obtained for 51 medication-naïve patients with OCD and 26 healthy controls (HCs). The grey/white matter contrast (GWC) was calculated from T1-weighted signal intensities to characterize the intracortical myelin profile in OCD. Diffusion parameters, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD), were extracted from diffusion-weighted images to examine the WM microstructure in OCD. Compared with HCs, patients with OCD showed increased GWC in the bilateral orbitofrontal, cuneus, lingual and fusiform gyrus, left anterior cingulate, left superior parietal, right inferior parietal, and right middle frontal cortices, suggesting reduced intracortical myelin. Patients with OCD also showed decreased FA in several WM regions, with a topology corresponding to the GWC alterations. In both groups, the mean GWC of the significant clusters in between-group GWC analysis was correlated negatively with the mean FA of the significant clusters in between-group FA analysis. In patients with OCD, the FA of a cluster in the right cerebellum correlated negatively with the Yale-Brown obsessive–compulsive scale scores. Our results suggest that abnormal intracortical and WM myelination could be the microstructural basis for the brain connectivity alterations and disrupted inhibitory control in OCD.

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

BackgroundWhile 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. MethodsWe 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. ResultsPatients 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. ConclusionsOur 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.

Magnetic Resonance Spectroscopy (MRS) and Positron Emission Tomography (PET) Imaging in Obsessive-Compulsive Disorder.

Obsessive-compulsive disorder (OCD) is characterised by structural and functional deficits in the cortico-striato-thalamic-cortical (CSTC) circuitry and abnormal neurochemical changes are thought to modulate these deficits. The hypothesis that an imbalanced concentration of the brain neurotransmitters, in particular glutamate (Glu) and gamma-amino-butyric acid (GABA), could impair the normal functioning of the CSTC, thus leading to OCD symptoms, has been tested in humans using magnetic resonance spectroscopy (MRS) and positron emission tomography (PET). This chapter summarises these neurochemical findings and represents an attempt to condense such scattered literature. We also discuss potential challenges in the field that may explain the inconsistent findings and suggest ways to overcome them. There is some convergent research from MRS pointing towards abnormalities in the brain concentration of neurometabolite markers of neuronal integrity, such as N-acetylaspartate (NAA) and choline (Cho). Lower NAA levels have been found in dorsal and rostral ACC of OCD patients (as compared to healthy volunteers), which increase after CBT and SSRI treatment, and higher Cho concentration has been reported in the thalamus of the OCD brain. However, findings for other neurometabolites are very inconsistent. Studies have reported abnormalities in the concentrations of creatine (Cr), GABA, glutamate (Glu), glutamine (Gln), Ins (myo-inositol), and serotonin (5-HT), but most of the results were not replicated. The question remains whether the NAA and Cho findings are genuinely the only neurochemical abnormalities in OCD or whether the lack of consistent findings for the other neurometabolites is caused by the lower magnetic field (1-3 Tesla (T)) used by the studies conducted so far, their small sample sizes or a lack of proper control for medication effects. To answer these questions and to further inform the biological underpinning of the symptoms and the cognitive problems at the basis of OCD we need better controlled studies using clear medicated vs unmedicated groups, larger sample sizes, stronger magnetic fields (e.g. at 7T), and more consistency in the definition of the regions of interest.

Harmonizing the Neurobiology and Treatment of Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a common, chronic, and oftentimes disabling disorder. The only established first-line treatments for OCD are exposure and response prevention, and serotonin reuptake inhibitor medications (SRIs). However, a subset of patients fails to respond to either modality, and few experience complete remission. Beyond SRI monotherapy, antipsychotic augmentation is the only medication approach for OCD with substantial empirical support. Our incomplete understanding of the neurobiology of OCD has hampered efforts to develop new treatments or enhance extant interventions. This review focuses on several promising areas of research that may help elucidate the pathophysiology of OCD and advance treatment. Multiple studies support a significant genetic contribution to OCD, but pinpointing the specific genetic determinants requires additional investigation. The preferential efficacy of SRIs in OCD has neither led to discovery of serotonergic abnormalities in OCD nor to development of new serotonergic medications for OCD. Several lines of preclinical and clinical evidence suggest dysfunction of the glutamatergic system in OCD, prompting testing of several promising glutamate modulating agents. Functional imaging studies in OCD show consistent evidence for increased activity in brain regions that form a cortico-striato-thalamo-cortical (CSTC) loop. Neuromodulation treatments with either noninvasive devices (e.g., transcranial magnetic stimulation) or invasive procedures (e.g., deep brain stimulation) provide further support for the CSTC model of OCD. A common substrate for various interventions (whether drug, behavioral, or device) may be modulation (at different nodes or connections) of the CSTC circuit that mediates the symptoms of OCD.

Microstructural white matter abnormalities in obsessive-compulsive disorder: A coordinate-based meta-analysis of diffusion tensor imaging studies.

There are no conclusive diffusion tensor imaging (DTI) findings on obsessive-compulsive disorder (OCD) for now. We conducted a comprehensive meta-analysis of DTI studies to identify white matter (WM) microarchitecture changes in OCD, and also to compare the results differences between the two most frequently used methods (voxel-based analysis, VBA versus tract-based spatial statistics, TBSS) for DTI data. A systematic search was performed on relevant studies that reported fractional anisotropy (FA) alterations between patients with OCD and healthy controls (HC). Seed-based d mapping (SDM) was applied to analyze microstructural WM abnormalities in OCD patients. Subgroup meta-analysis was subsequently performed to explore methodological differences between VBA and TBSS approaches. A total of 30 studies (with 31 datasets) that comprised 855 patients and 875 HC were identified. OCD patients exhibited significantly decreased FA in the right cerebellar hemispheric lobule, corpus callosum (CC), left superior frontal gyrus (orbital part), right gyrus rectus, left superior longitudinal fasciculus and right lenticular nucleus in the pooled meta-analysis. The VBA subgroup showed lower FA in several brain regions while the TBSS subgroup only exhibited significant FA reductions in the CC. According to the pooled meta-analysis, OCD patients presented microstructural abnormalities in distributed WM tracts. However, heterogeneous results were found between VBA and TBSS studies.

A voxel-based analysis of cerebral blood flow abnormalities in obsessive-compulsive disorder using pseudo-continuous arterial spin labeling MRI.

To identify abnormalities of regional cerebral blood flow (rCBF) in individuals with obsessive-compulsive disorder (OCD) by conducting a voxel-based analysis of pseudo-continuous arterial spin labeling (pCASL) perfusion images. This prospective study included 23 OCD patients (nine males, 14 females; age 21-62 years; mean ± SD 37.2 ± 10.7 years) diagnosed based on DSM-IV-TR criteria and 64 healthy controls (27 males, 37 females; age 20-64 years; mean ± SD 38.3 ± 12.8 years). Subjects were recruited from October 2011 to August 2017. Imaging was performed on a 3T scanner. Quantitative rCBF maps generated from pCASL images were co-registered and resliced with the three-dimensional T1-weighted images, and then spatially normalized to a brain template and smoothed. We used statistical nonparametric mapping to assess the differences in rCBF and gray matter volume between the OCD and control groups. The significance level was set at the p-value <0.05 with family-wise error rate correction for multiple comparisons. Compared to the control group, there were significant rCBF reductions in the right putamen, right frontal operculum, left midcingulate cortex, and right temporal pole in the OCD group. There were no significant between-group differences in the gray matter volume. The pCASL imaging noninvasively detected physiologically disrupted areas without structural abnormalities in OCD patients. The rCBF reductions observed in these regions in OCD patients could be associated with the pathophysiology of OCD.

White matter disruption in obsessive-compulsive disorder revealed by meta-analysis of tract-based spatial statistics.

Exploring white matter (WM) microstructural alterations is a momentous step for gaining insights about underlying mechanisms of obsessive-compulsive disorder (OCD) and improving the efficacy of therapies for this condition. Many tract-based spatial statistics (TBSS) studies have revealed abnormalities of fractional anisotropy (FA; an index of WM integrity) in OCD. However, research works have not drawn robust conclusions. Therefore, we integrated the findings of TBSS studies to identify the most consistent FA changes in OCD using meta-analytical approach. Online databases were systematically searched for all TBSS studies comparing FA between patients with OCD and controls. A coordinate-based meta-analysis was performed using anisotropic effect size version of the seed-based d mapping software. Meanwhile, meta-regression was used to explore the potential association of clinical characteristics with regional FA abnormalities. Our meta-analysis included 488 OCD patients and 519 controls across 17 datasets. FA reductions were identified in the genu of the corpus callosum and the left orbitofrontal WM in OCD patients relative to controls. Metaregression analyses showed that the FA in the left orbitofrontal WM was negatively and independently correlated with symptom severity and illness duration in patients withOCD. The current study provides a quantitative overview of TBSS findings in OCD and demonstrates the most prominent and replicable WM abnormalities in OCD are in the anterior part of the brain including interhemispheric connection and orbitofrontal region. Additionally, our findings suggest that FA reduction in the orbitofrontal WM might be a potential biomarker in predicting disease severity and progression in patients with OCD.

P.486 Common structural grey matter and functional activation abnormalities in obsessive-compulsive disorder: A meta-analytic investigation

Reports exist regarding a gradual approach to the care of patients with differences of sexual development. Each patient and family have different values and styles of learning that have to be taken into account. The goals of care should include education about the condition, counseling of the patient and family, and a complete outlining of treatment options. Motivated by a call from the 2010 Health Reform Law for the use of shared decision-making tools and the emphasis placed on these issues by the DSD Consensus Statement, we sought to develop and implement such tools for the DSD population.1–3 Thus, we developed an organized checklist for providers to share with a patients and families affected by CAIS, beginning with the initial visit. The development of the document enlisted input from physicians, clinical coordinator, advocacy groups and affected individuals. It allows providers to explain the process of care and develop a plan for delivery of that care over multiple visits spanning six months or more. The checklist is divided into five sections: 1) An overview addressing how much information is desired and in what manner the patient prefers to obtain information; 2) A preferred words list so that the patient can choose nomenclature that is most comfortable; 3) A list of topics to review over the course of multiple visits; 4) A list of questions to be answered by the providers or other resources over time, and; 5) A list of concerns to be addressed before surgical intervention is considered. An organized approach to long-term delivery of compassionate care and accurate information can be facilitated for patients with CAIS by the use of a shared decision-making checklist. Documentation of the care delivery process can stimulate referral to peer support and promote fully informed consent for treatment decisions. The use of the checklist should encourage trust in the provider, as well as aid in identifying and addressing stressors for the patient and family. The checklist will be updated and revised as new treatments and advanced technology emerges.

An MRI Study of the Metabolic and Structural Abnormalities in Obsessive-Compulsive Disorder.

Obsessive-compulsive disorder (OCD) is a neuropsychiatric illness characterized by obsessions and/or compulsions. Its pathophysiology is still not well understood but it is known that the cortico-striatal-thalamic-cortical (CSTC) circuitry plays an important role. Here, we used a multi-method MRI approach combining proton magnetic resonance spectroscopy (H1-MRS) and diffusion tensor imaging (DTI) techniques to investigate both the metabolic and the microstructural white matter (WM) changes of the anterior cingulate cortex (ACC) in OCD patients as compared to healthy controls. Twenty-three OCD patients and 21 age-, sex-, and education-matched healthy volunteers participated in the study. Our 1H-MRS findings show increased levels of Glx in ACC in OCD. Further, significantly lower fractional anisotropy (FA) values were observed in OCD patients’ left cingulate bundle (CB) as compared to healthy controls. Finally, there was a negative correlation between FA in the left CB and level of obsessions, as well as the duration of the illness. Our findings reinforce the involvement of CSTC bundles in pathophysiology of OCD, pointing to a specific role of glutamate (glutamine) and WM integrity.

Glutamatergic augmentation strategies in obsessive-compulsive disorder.

Proven treatment strategies for obsessive–compulsive disorder (OCD) include pharmacotherapy with serotonin reuptake inhibitors and cognitive behavior therapy (CBT). A significant proportion of patients (25%–30%) fail to respond to these treatment options, necessitating the need for additional treatment options to improve treatment outcomes and quality of life in patients with OCD. Augmentation strategies using various glutamatergic agents have been explored, with diverse outcomes. The aim of this review is to give an overview of the glutamatergic system in the brain with a focus on glutamatergic abnormalities in OCD and to review the existing evidence for various glutamatergic agents used for augmentation.

Metabolic and structural abnormalities in obsessive-compulsive disorder: A multimodal neuroimaging and clinical approach

Metabolic and structural abnormalities in obsessive-compulsive disorder: A multimodal neuroimaging and clinical approach

Blood levels of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha and cognitive functions in patients with obsessive compulsive disorder

BackgroundCognitive dysfunction and immune system disorders are two actual issues for the patients with Obsessive Compulsive Disorder (OCD). The cognitive dysfunctions have been considered to substantial part of clinical phenomenon of OCD but exploration of various etiopathogenesis of cognitive dysfunction is needed. Immune dysfuncion has been implicated to be important part of pathopysiology of OCD and different lines of evidence suggests immune abnormalities in OCD. But whether these immune changes are traits of disease or secondary to clinical burden of the disease such as cognitive dysfunctions has not been determined. Data regarding relation between the cognitive dysfunctions and immune system disorders in OCD is unsatisfied. In this study we aimed to investigate the relation of blood levels of interleukin 1-beta (IL-1ß), interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) with various neurocognitive functions in patients with OCD in comparison with its autogenous/reactive subtypes and healthy controls. Further exploration of the effects of various clinical variables on cognitive functioning in patients with OCD and additional investigation of whether the cognitive dysfunction associated with this disorder differs from or overlap with that in other anxiety disorders are needed. MethodsForty-two patient with OCD and 45 age, sex and educational level matched healthy control were enrolled in the study. The diagnosis of OCD was made with Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Yale- Brown Obsessive-Compulsive Scale, Beck Anxiety and Depression Inventory Scales were administered. Neuropsychological test battery including Wisconsin Card Sorting Test (WCST), Trail Making Test A and B (TMT-A, TMT-B) were used for evaluation of the patients and healthy control. The plasma of interleukin-1beta (IL-1ß), interleukin-6 (IL-6), Tumor Necrosis Factor-Alpha (TNF-α) of both groups were measured with ELISA kits. ResultsBlood levels of IL-1ß, IL-6 and TNF-α were significantly higher in patients with OCD than the healthy control. There was significant difference in IL-1ß, IL-6 but not in TNF-α between autogenous/reactive subtypes and healthy controls. TNF-α is positively correlated with TMT-A, TMT-B and Stroop Test Part 5, negatively correlated with immediate memory, verbal learning, interference effect, immediate recall, delayed recall and recognition in RAVLT. IL-1ß was positively correlated with TMT-A score. IL-6 was positively correlated with scores of TMT-A, TMT-B. IL-6 was negatively correlated with immediate memory, verbal learning, interference effect, immediate recall and delayed recall in RAVLT, positively correlated with number of perseverative error and negatively correlated with the number of categories completed in WCST. ConclusionThis is the first study that investigates the relation of IL- 1ß, IL-6 and TNF-α levels with cognitive functions in OCD. There may be a contribution to pathogenesis of OCD and subtypes then new choices for treatment might be developed. Moreover, uncovering the effect of cytokine blood levels on cognitive function of OCD, new data concerning etiopathogenesis and further treatment choices can be gained.

Cortical thickness and white matter integrity abnormalities in obsessive-compulsive disorder: A combined multimodal surface-based morphometry and tract-based spatial statistics study.

Cerebral morphological abnormalities may play a key role in pathogenesis of obsessive-compulsive disorder (OCD). However, few studies have used multimodal imaging strategies to investigate alterations of cortical morphometry and white matter (WM) integrity. This study aimed to evaluate cortical thickness, cortical and subcortical volume, and WM integrity characteristics in OCD patients comprehensively. We acquired magnetic resonance imaging (MRI) scans from 52 OCD patients and 46 well-matched healthy controls (HCs). Cortical thickness and cortical and subcortical volume were measured using the surface-based morphometry (SBM) approach. We also evaluated fractional anisotropy (FA) and mean diffusivity (MD) derived from diffusion tensor imaging (DTI) using tract-based spatial statistics (TBSS). The disease severity was evaluated by score of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). For those brain regions exhibiting altered structure, correlations between alterations and clinical symptoms severity were analyzed in all patients and medication-naïve patients, respectively. Compared with controls, OCD patients exhibited cortical thinning in right posterior cingulate cortex (PCC), as well as significantly decreased FA values in the genu and body of corpus callosum (CC). In medication-naïve patients group, the total Y-BOCS score and obsession score were significantly negative correlated with right PCC cortical thickness. OCD patients demonstrated symptom-related reduced cortical thickness structural alteration of the right PCC, and altered WM integrity in the genu and body of CC. Medication seems could alleviate the alteration of cortical thickness but not WM integrity. Combined multimodal neuroimaging methods may provide a more comprehensive perspective to clarify the pathological mechanism of OCD.

T30. Effect of Medication Status on the Gray Matter Volume Abnormalities in Obsessive Compulsive Disorder

T30. Effect of Medication Status on the Gray Matter Volume Abnormalities in Obsessive Compulsive Disorder

Morphometric and Connectivity White Matter Abnormalities in Obsessive Compulsive Disorder

Two psychological mechanisms seem to be associated with the obsessive-compulsive cycle: (1) an emotional mechanism characterized by intense emotional arousal associated with intrusive thoughts of impending danger; (2) a cognitive mechanism exemplified by difficulties with inhibitory control. More recently, several studies found more extensive cognitive deficits in Obsessive Compulsive Disorder (OCD) beyond problems of inhibitory control and emotional regulation, namely: visual-spatial processing and memory. Thus, there is now extensive research showing that alterations of these psychological mechanisms in OCD (i.e., inhibitory control, emotional regulation, working memory, and visual spatial processing) are associated with morphological gray matter alterations in widespread brain regions. More recently, researchers have started looking at white matter abnormalities in OCD. In this article we review the research looking at white matter morphometric and structural connectivity alterations in OCD. Altogether, while some contradictory findings are still present, there is now evidence for widespread white matter morphometric and connectivity abnormalities affecting major white matter tracts (superior longitudinal fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, cingulum bundle, semioval center, internal capsule, different regions of the corpus callosum, thalamic radiation, uncinate fasciculus and optic radiation) as well as white matter in regions adjacent to gray matter structures (superior frontal gyrus, dorsolateral prefrontal medial frontal cortex; inferior frontal gyrus, caudate, insulate cortex, parietal cortex, supramarginal and lingual gyri, and thalamus). These white matter alterations may help explaining the diversity of OCD psychological impairments in inhibitory control, emotional regulation, memory and visual spatial processing.

Abnormal regional spontaneous neuronal activity associated with symptom severity in treatment-naive patients with obsessive-compulsive disorder revealed by resting-state functional MRI

A large number of neuroimaging studies have revealed the dysfunction of brain activities in obsessive-compulsive disorder (OCD) during various tasks. However, regional spontaneous activity abnormalities in OCD are gradually being revealed. In this current study, we aimed to investigate cerebral regions with abnormal spontaneous activity using resting-state functional magnetic resonance imaging (fMRI) and further explored the relationship between the spontaneous neuronal activity and symptom severity of patients with OCD. Thirty-one patients with OCD and 32 age-and sex-matched normal controls received the fMRI scans and fractional amplitude of low-frequency fluctuation (fALFF) approach was applied to identify the abnormal brain activity. We found that patients with OCD showed decreased fALFF not only in the cortical-striato-thalamo-cortical (CSTC) circuits like the thalamus, but also in other cerebral systems like the cerebellum, the parietal cortex and the temporal cortex. Additionally, OCD patients demonstrated significant associations between decreased fALFF and obsessive-compulsive symptom severity in the thalamus, the paracentral lobule and the cerebellum. Our results provide evidence for abnormal spontaneous neuronal activity in distributed cerebral areas and support the notion that brain areas outside the CSTC circuits may also play an important role in the pathophysiology of OCD.