Functional neural mechanisms of sensory phenomena in obsessive-compulsive disorder

Identifying subgroups of urge suppression in Obsessive-Compulsive Disorder using machine learning

Obsessive-compulsive disorder (OCD) is phenomenologically heterogeneous. While predominant models suggest fear and harm prevention drive compulsions, many patients also experience uncomfortable sensory-based urges ("sensory phenomena") that may be associated with heightened interoceptive sensitivity. Using an urge-to-blink eyeblink suppression paradigm to model sensory-based urges, we previously found that OCD patients as a group had more eyeblink suppression failures and greater activation of sensorimotor-interoceptive regions than controls. However, conventional approaches assuming OCD homogeneity may obscure important within-group variability, impeding precision treatment development. This study investigated the heterogeneity of urge suppression failure in OCD and examined relationships with clinical characteristics and neural activation. Eighty-two patients with OCD and 38 controls underwent an fMRI task presenting 60-s blocks of eyeblink suppression alternating with free-blinking blocks. Latent profile analysis identified OCD subgroups based on number of erroneous blinks during suppression. Subgroups were compared on behavior, clinical characteristics, and brain activation during task. Three patient subgroups were identified. Despite similar overall OCD severity, the subgroup with the most erroneous eyeblinks had the highest sensory phenomena severity, interoceptive sensitivity, and subjective urge intensity. Compared to other subgroups, this subgroup exhibited more neural activity in somatosensory and interoceptive regions during the early phase (first 30 s) of blink suppression and reduced activity in the middle frontal gyrus during the late phase (second 30 s) as the suppression period elapsed. Heterogeneity of urge suppression in OCD was associated with clinical characteristics and brain function. Our results reveal potential treatment targets that could inform personalized medicine.

Lower synaptic density and its association with cognitive dysfunction in patients with obsessive-compulsive disorder

Background

Understanding synaptic alteration in obsessive-compulsive disorder (OCD) is crucial for elucidating its pathological mechanisms, but in vivo research on this topic remains limited.

Aims

This study aimed to identify the synaptic density indicators in OCD and explore the relationship between cognitive dysfunction and synaptic density changes in OCD.

Methods

This study enrolled 28 drug-naive adults with OCD aged 18-40 years and 16 healthy controls (HCs). Three-dimensional T1-weighted structural magnetic resonance imaging and 18F-SynVesT-1 positron emission tomography were conducted. Cognitive function was assessed using the Wisconsin Cart Sorting Test (WCST) in patients with OCD and HCs. Correlative analysis was performed to examine the association between synaptic density reduction and cognitive dysfunction.

Results

Compared with HCs, patients with OCD showed reduced synaptic density in regions of the cortico-striato-thalamo-cortical circuit such as the bilateral putamen, left caudate, left parahippocampal gyrus, left insula, left parahippocampal gyrus and left middle occipital lobe (voxel p<0.001, uncorrected, with cluster level above 50 contiguous voxels). The per cent conceptual-level responses of WCST were positively associated with the synaptic density reduction in the left middle occipital gyrus (R2=0.1690, p=0.030), left parahippocampal gyrus (R2=0.1464, p=0.045) and left putamen (R2=0.1967, p=0.018) in patients with OCD.

Conclusions

Adults with OCD demonstrated lower 18F-labelled difluoro analogue of 18F-SynVesT-1 compared with HCs, indicating potentially lower synaptic density. This is the first study to explore the synaptic density in patients with OCD and provides insights into potential biological targets for cognitive dysfunctions in OCD.

Sensory over-responsivity and orbitofrontal cortex connectivity in obsessive-compulsive disorder

BACKGROUND

Sensory over-responsivity (SOR) in obsessive-compulsive disorder (OCD) is associated with illness severity and functional impairment. However, the neural substrates of SOR in OCD have not yet been directly probed.

METHODS

We examined resting-state global functional connectivity markers of SOR in 119 adults with OCD utilizing the CONN-fMRI Functional Connectivity Toolbox for SPM (v21a). We quantified SOR with the sensory sensitivity and sensory avoiding subscales of the Adult and Adolescent Sensory Profile (AASP). We also measured: OCD severity, with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and Obsessive-Compulsive Inventory-Revised (OCI-R); sensory phenomena with the Sensory Phenomena Scale (SPS); general anxiety, with the Beck Anxiety Inventory (BAI); and depressive symptomatology, with Quick Inventory of Depressive Symptoms, Self-Report (QIDS-SR).

RESULTS

There was a significant positive relationship of SOR with global connectivity in anterior and medial OFC (Brodmanns area 11, k = 154, x = 14, y = 62, z = -18, whole-brain corrected at FWE p < 0.05).

LIMITATIONS

Future investigations should explore neural responses to sensory stimulation tasks in OCD and compare findings with those obtained in other conditions also characterized by high SOR, such as autism spectrum disorder.

CONCLUSIONS

This study implicates OFC functional connectivity as a neurobiological mechanism of SOR in OCD and suggests that the substrates of SOR in OCD may be dissociable from both that of other symptoms in OCD, and SOR in other disorders. With replication and extension, the finding may be leveraged to develop and refine treatments for OCD and investigate the pathophysiology of SOR in other conditions.

Poor Insight in Obsessive-Compulsive Disorder as a Multifaceted Phenomenon: Evidence From Brain Activation During Symptom Provocation

BACKGROUND

Poor insight in obsessive-compulsive disorder (OCD) is associated with higher symptom severity, more comorbidities, and worse response to treatment. This study aimed to elucidate underlying mechanisms of poor insight in OCD by exploring its neurobiological correlates.

METHODS

Using a symptom provocation task during functional magnetic resonance imaging, we compared brain activation of patients with poor insight (n = 19; 14 female, 5 male), good/fair insight (n = 63; 31 female, 32 male), and healthy control participants (n = 42; 22 female, 20 male) using a Bayesian region-of-interest and a general linear model whole-brain approach. Insight was assessed using the Overvalued Ideas Scale.

RESULTS

Compared with patients with good/fair insight and healthy control participants, patients with OCD and poor insight showed widespread lower task-related activation in frontal areas (subgenual anterior cingulate cortex, ventromedial prefrontal cortex, dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, supplementary motor area, precentral gyrus), parietal areas (posterior parietal cortex, precuneus), and the middle temporal gyrus and insula. Results were not driven by interindividual differences in OCD symptom severity, medication usage, age of disorder onset, or state distress levels.

CONCLUSIONS

During symptom provocation, patients with OCD and poor insight show altered activation in brain circuits that are involved in emotional processing, sensory processing, and cognitive control. Future research should focus on longitudinal correlates of insight and/or use tasks that probe emotional and sensory processing and cognitive control.

The functional connectome in obsessive-compulsive disorder: resting-state mega-analysis and machine learning classification for the ENIGMA-OCD consortium

Current knowledge about functional connectivity in obsessive-compulsive disorder (OCD) is based on small-scale studies, limiting the generalizability of results. Moreover, the majority of studies have focused only on predefined regions or functional networks rather than connectivity throughout the entire brain. Here, we investigated differences in resting-state functional connectivity between OCD patients and healthy controls (HC) using mega-analysis of data from 1024 OCD patients and 1028 HC from 28 independent samples of the ENIGMA-OCD consortium. We assessed group differences in whole-brain functional connectivity at both the regional and network level, and investigated whether functional connectivity could serve as biomarker to identify patient status at the individual level using machine learning analysis. The mega-analyses revealed widespread abnormalities in functional connectivity in OCD, with global hypo-connectivity (Cohen's d: -0.27 to -0.13) and few hyper-connections, mainly with the thalamus (Cohen's d: 0.19 to 0.22). Most hypo-connections were located within the sensorimotor network and no fronto-striatal abnormalities were found. Overall, classification performances were poor, with area-under-the-receiver-operating-characteristic curve (AUC) scores ranging between 0.567 and 0.673, with better classification for medicated (AUC = 0.702) than unmedicated (AUC = 0.608) patients versus healthy controls. These findings provide partial support for existing pathophysiological models of OCD and highlight the important role of the sensorimotor network in OCD. However, resting-state connectivity does not so far provide an accurate biomarker for identifying patients at the individual level.

Associations Between Suicidality and Interoception in Obsessive-Compulsive Disorder

Background

Individuals with obsessive-compulsive disorder (OCD) are at increased risk for suicide. One potential risk factor is interoceptive sensibility (IS), which is one's subjective experience of bodily sensations. The current study examined the relationship between IS and current suicidal ideation and lifetime history of suicide attempt, controlling for relevant covariates.

Methods

Participants (N = 145) were a clinical sample of individuals with OCD from the New York City area. A clinical rater administered a diagnostic interview and an OCD severity assessment, and participants completed questionnaires about demographics, IS, and suicidality.

Results

Current suicidal ideation was associated with reduced trusting of the body, and lifetime history of suicide attempt was related to greater general awareness of sensation. These associations remained significant after controlling for covariates.

Conclusions

These results suggest that specific facets of IS may be associated with specific domains of suicidality. Decreased body trusting may represent a feeling of disconnection from the body that facilitates desire for death. Increased noticing of bodily sensations may lead to greater mental pain, which could interact with deficits in emotion regulation to increase risk for suicide attempt. Further research on the relationships between IS and suicidality in OCD is warranted.

A comparison of 'not just right experiences' in obsessive-compulsive disorder, anxiety and depressive disorders and non-clinical controls in China

OBJECTIVE

The aim of this study is to investigate the characteristics of 'not just right experiences' (NJREs) in patients with obsessive-compulsive disorder (OCD), anxiety disorders (ADs) or major depressive disorder (MDD), compared with those of healthy controls (HCs).

METHOD

One hundred adults with OCD, 86 adults with ADs, 57 adults with MDD and 60 HCs were enrolled in the study. The Not Just Right Experiences Questionnaire Revised (NJRE-QR), Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) were used to evaluate clinical symptoms in patients with OCD, ADs or MDD. The Obsessive Belief Questionnaire-44 (OBQ-44) was used to evaluate OC beliefs in the OCD patients. The HCs only received assessment using the NJRE-QR. Analysis of variance (ANOVA) and covariance (ANCOVA) were performed to compare the NJREs scores across the groups, while Pearson correlation and partial correlation analyses were used to examine the association between NJREs and other clinical features. The contribution of NJREs to predict OC symptoms was determined by multiple stratified linear regression.

RESULTS

Individuals with OCD had significantly higher scores for the number of NJREs than ADs, but not MDD. The severity of NJREs was also significantly higher in patients with OCD than those with MDD or ADs (F = 5.23 and F = 19.79, respectively, P < 0.01). All the clinical scores in the NJRE-QR were significantly higher than those in the HC group. The number and severity of NJREs correlated significantly with the Y-BOCS total score (r = 0.29 and r = 0.39, respectively, P < 0.01). NJREs showed an independent contribution to OC symptoms, which alone explained 8% of the variation (F = 16.49, ΔR2  = 0.08; P < 0.01).

CONCLUSION

NJREs are related closely to OC symptoms, with their severity discriminating between OCD patients and those with ADs or MDD. NJREs were more specific for OCD in the Chinese population and are therefore worthy of further study in the future.

Failures of Urge Suppression in Obsessive-Compulsive Disorder: Behavioral Modeling Using a Blink Suppression Task

Many individuals with obsessive-compulsive disorder (OCD) report sensory-based urges (e.g. 'not-just-right experiences') in addition to, or instead of, concrete fear-based obsessions. These sensations may be comparable to normative "urges-for-action" (UFA), such as the urge to blink. While research has identified altered functioning of brain regions related to UFA in OCD, little is known about behavioral patterns of urge suppression in the disorder. Using an urge-to-blink task as a model for sensory-based urges, this study compared failures of urge suppression between OCD patients and controls by measuring eyeblinks during 60-second blocks of instructed blink suppression. Cox shared frailty models estimated the hazard of first blinks during each 60-second block and recurrent blinks following each initial erroneous blink. OCD patients demonstrated a higher hazard of first and recurrent blinks compared to controls, suggesting greater difficulty resisting repetitive sensory-based urges. Within OCD, relationships between task outcomes and symptom severity were inconsistent. Findings provide support for a deficit in delaying initial urge-induced actions and terminating subsequent actions in OCD, which is not clearly related to clinical heterogeneity. Elucidating the nature of behavioral resistance to urges is relevant for informing conceptualizations of obsessive-compulsive psychopathology and optimizing treatment outcomes.

Obsessive-Compulsive Disorder from an Embodied Cognition Perspective

Obsessive Compulsive Disorder (OCD) is characterized by problems of control over behavior and cognition. Although almost all of the studies on pathogenesis of OCD point out fronto-striatal dysfunction, it is still not possible to reveal mechanisms to explain the entire clinical course of OCD through these circuits. A more holistic explanation can be given through the Embodied Cognition (EC) perspective, which suggests that the alteration/dysfunction of low-level sensory-motor process may appear as a multifarious extent of dysfunction of high-level cognitive processes. Fronto-striatal circuits play fundamental role in behavioral control. These circuits also have a central role for the feed-forward motor control (FFMC). In FFMC, the internal model of movement is driven by efference copies as templates for motor behavior, without being adjusted by sensory information. If impairment of low-level sensory-motor processing is crucial to occurrence of compulsions, one possible hypothesis about this impairment is the problem which emerges from occurrence of efference copy in FFMC. On the other hand, the efference copy has also pivotal role for subject's feeling of the agency of an action. Therefore, there may be role of failure in successfully reproduction of the efference copy in the background of subjects' experience of losing control on compulsive behaviors. In this paper, we will discuss how the embodied cognition (EC) perspective which can be one of the biological bases of computationalism, which brings neuroscientific explanations on the functioning of nervous system to a more symbolic perspective, may contribute to our understanding of etiopathogenesis of OCD. In this perspective, our method will be to integrate the theoretical basis provided by EC perspective to the current models for OCD, rather than falsifying them.

Abnormal resting-state functional connectivity of the insula in medication-free patients with obsessive-compulsive disorder

BACKGROUND

The function of the insula has been increasingly mentioned in neurocircuitry models of obsessive-compulsive disorder (OCD) for its role in affective processing and regulating anxiety and its wide interactions with the classic cortico-striato-thalamo-cortical circuit. However, the insular resting-state functional connectivity patterns in OCD remain unclear. Therefore, we aimed to investigate characteristic intrinsic connectivity alterations of the insula in OCD and their associations with clinical features.

METHODS

We obtained resting-state functional magnetic resonance imaging data from 85 drug-free OCD patients and 85 age- and sex-matched healthy controls (HCs). We performed a general linear model to compare the whole-brain intrinsic functional connectivity maps of the bilateral insula between the OCD and HC groups. In addition, we further explored the relationship between the intrinsic functional connectivity alterations of the insula and clinical features using Pearson or Spearman correlation analysis.

RESULTS

Compared with HCs, patients with OCD exhibited increased intrinsic connectivity between the bilateral insula and bilateral precuneus gyrus extending to the inferior parietal lobule and supplementary motor area. Decreased intrinsic connectivity was only found between the right insula and bilateral lingual gyrus in OCD patients relative to HC subjects, which was negatively correlated with the severity of depression symptoms in the OCD group.

CONCLUSION

In the current study, we identified impaired insular intrinsic connectivity in OCD patients and the dysconnectivity of the right insula and bilateral lingual gyrus associated with the depressive severity of OCD patients. These findings provide neuroimaging evidence for the involvement of the insula in OCD and suggest its potential role in the depressive symptoms of OCD.

Error-related activity of the sensorimotor network contributes to the prediction of response to cognitive-behavioral therapy in obsessive-compulsive disorder

BACKGROUND

Although cognitive behavioral therapy is a highly effective treatment for obsessive-compulsive disorder (OCD), yielding large symptom reductions on the group level, individual treatment response varies considerably. Identification of treatment response predictors may provide important information for maximizing individual treatment response and thus achieving efficient treatment resource allocation. Here, we investigated the predictive value of previously identified biomarkers of OCD, namely the error-related activity of the supplementary motor area (SMA) and the sensorimotor network (SMN, postcentral gyrus/precuneus).

METHODS

Seventy-two participants with a primary diagnosis of OCD underwent functional magnetic resonance imaging (fMRI) scanning while performing a flanker task prior to receiving routine-care CBT.

RESULTS

Error-related BOLD response of the SMN significantly contributed to the prediction of treatment response beyond the variance accounted for by clinical and sociodemographic variables. Stronger error-related SMN activity at baseline was associated with a higher likelihood of treatment response.

CONCLUSIONS

The present results illustrate that the inclusion of error-related SMN activity can significantly increase treatment response prediction quality in OCD. Stronger error-related activity of the SMN may reflect the ability to activate symptom-relevant processing networks and may thus facilitate response to exposure-based CBT interventions.

Going beyond the DSM in predicting, diagnosing, and treating autism spectrum disorder with covarying alexithymia and OCD: A structural equation model and process-based predictive coding account

Background

There is much overlap among the symptomology of autistic spectrum disorders (ASDs), obsessive compulsive disorders (OCDs), and alexithymia, which all typically involve impaired social interactions, repetitive impulsive behaviors, problems with communication, and mental health.

Aim

This study aimed to identify direct and indirect associations among alexithymia, OCD, cardiac interoception, psychological inflexibility, and self-as-context, with the DV ASD and depression, while controlling for vagal related aging.

Methodology

The data involved electrocardiogram (ECG) heart rate variability (HRV) and questionnaire data. In total, 1,089 participant's data of ECG recordings of healthy resting state HRV were recorded and grouped into age categories. In addition to this, another 224 participants completed an online survey that included the following questionnaires: Yale-Brown Obsessive Compulsive Scale (Y-BOCS); Toronto Alexithymia Scale 20 (TAS-20); Acceptance and Action Questionnaire (AAQII); Depression, Anxiety, and Stress Scale 21 (DAS21); Multi-dimensional Assessment of Interoceptive Awareness Scale (MAIA); and the Self-as-Context Scale (SAC).

Results

Heart rate variability was shown to decrease with age when controlling for BMI and gender. In the two SEMs produced, it was found that OCD and alexithymia were causally associated with autism and depression indirectly through psychological inflexibility, SAC, and ISen interoception.

Conclusion

The results are discussed in relation to the limitations of the DSM with its categorical focus of protocols for syndromes and provide support for more flexible ideographic approaches in diagnosing and treating mental health and autism within the Extended Evolutionary Meta-Model (EEMM). Graph theory approaches are discussed in their capacity to depict the processes of change potentially even at the level of the relational frame.

Aberrant cortico-striatal white matter connectivity and associated subregional microstructure of the striatum in obsessive-compulsive disorder

The striatum and its cortical circuits play central roles in the pathophysiology of obsessive-compulsive disorder (OCD). The striatum is subdivided by cortical connections and functions; however, the anatomical aberrations in different cortico-striatal connections and coexisting microstructural anomalies in striatal subregions of OCD patients are poorly understood. Thus, we aimed to elucidate the aberrations in cortico-striatal white matter (WM) connectivity and the associated subregional microstructure of the striatum in patients with OCD. From diffusion tensor/kurtosis imaging of 107 unmedicated OCD patients and 110 matched healthy controls (HCs), we calculated the cortico-striatal WM connectivity and segmented the striatum using probabilistic tractography. For the segmented striatal subregions, we measured average diffusion kurtosis values, which represent microstructural complexity. Connectivity and mean kurtosis values in each cortical target and associated striatal subregions were compared between groups. We identified significantly reduced orbitofrontal WM connectivity with its associated striatal subregion in patients with OCD compared to that in HCs. However, OCD patients exhibited significantly increased caudal-motor and parietal connectivity with the associated striatal subregions. The mean kurtosis values of the striatal subregions connected to the caudal-motor and parietal cortex were significantly decreased in OCD patients. Our results highlighted contrasting patterns of striatal WM connections with the orbitofrontal and caudal-motor/parietal cortices, thus supporting the cortico-striatal circuitry imbalance model of OCD. We suggest that aberrations in WM connections and the microstructure of their downstream regions in the caudal-motor-/parietal-striatal circuits may underlie OCD pathophysiology and further provide potential neuromodulation targets for the treatment of OCD.

Altered Intrinsic Brain Activity in Patients With Toothache Using the Percent Amplitude of a Fluctuation Method: A Resting-State fMRI Study

Objective

The percent amplitude of fluctuation (PerAF) technique was utilized to evaluate the neural functions of specific cerebrum areas in patients with toothache (TA).

Patients and Methods

An aggregation of 18 patients with TA (eight males and 10 females) were included in the study. We also recruited 18 healthy controls (HCs; eight men and 10 women) aligned for sex and age. Resting functional magnetic resonance imaging (rs-fMRI) scans were obtained. Then, we utilized the PerAF method and a support vector machine (SVM) to analyze the image data and measure neural abnormalities in related cerebrum areas. Receiver operating characteristic (ROC) curve analysis was utilized to appraise the two data sets.

Results

The PerAF signals in the right dorsolateral superior frontal gyrus (RDSFG) and the right posterior central gyrus (RPCG) of TA sufferers were lower than HC signals. These results may reveal neural dysfunctions in relevant cerebrum regions. The AUC values of PerAF in the two areas were 0.979 in the RDSFG and 0.979 in the RPCG. The SVM results suggested that PerAF could be utilized to distinguish the TA group from HCs with a sensitivity of 75.00%, a specificity of 66.67%, and an accuracy of 70.83%.

Conclusion

Patients with TA had marked differences in PerAF values in some regions of the cerebrum. Changes in PerAF values represented distinctions in blood oxygen level dependent semaphore intensity, which reflected the overactivity or inactivation of some cerebrum areas in those suffering from TA. At the same time, we analyzed the PerAF values of TAs with ROC curve, which can be helpful for the diagnosis of TA severity and subsequent treatment. Our results may help to elucidate the pathological mechanism of TA.

Randomized trial of the efficacy of trial-based cognitive therapy for obsessive-compulsive disorder: preliminary findings

INTRODUCTION

Obsessive-compulsive disorder (OCD) is the fourth most prevalent mental disorder and is a disabling condition. OCD is associated with anatomical and functional changes in the brain, in addition to dysfunctional cognitions. The treatments of choice are selective serotonin reuptake inhibitors, cognitive-behavioral therapy (CBT), and exposure and response prevention (ERP). Trial-based cognitive therapy (TBCT) is a recent and empirically validated psychotherapy with a focus on restructuring dysfunctional negative core beliefs (CBs). The objective of this study was to evaluate the efficacy of TBCT relative to ERP for treatment of OCD.

METHOD

A randomized, single-blind clinical trial was conducted, randomizing 26 patients for individual treatment with TBCT (n = 12) or ERP (n = 14). The groups were evaluated at baseline, at the end of 3 months (12 sessions), and at 3, 6, and 12-month follow-ups.

RESULTS

Both approaches reduced the severity of symptoms with large effect sizes. These results were maintained at the 12-month follow-up assessment.

CONCLUSION

TBCT may be a valid and promising treatment for this disorder.

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.

Interoception and Obsessive-Compulsive Disorder: A Review of Current Evidence and Future Directions

Disrupted interoceptive processes are present in a range of psychiatric conditions, and there is a small but growing body of research on the role of interoception in obsessive-compulsive disorder (OCD). In this review, we outline dimensions of interoception and review current literature on the processing of internal bodily sensations within OCD. Investigations in OCD utilizing objective measures of interoception are limited and results mixed, however, the subjective experience of internal bodily sensations appears to be atypical and relate to specific patterns of symptom dimensions. Further, neuroimaging investigations suggest that interoception is related to core features of OCD, particularly sensory phenomena and disgust. Interoception is discussed in the context of treatment by presenting an overview of existing interventions and suggesting how modifications aimed at better targeting interoceptive processes could serve to optimize outcomes. Interoception represents a promising direction for multi-method research in OCD, which we expect, will prove useful for improving current interventions and identifying new treatment targets.

Involvement of fear, incompleteness, and disgust during symptoms of pediatric obsessive-compulsive disorder

Fear has been assigned a central role in models of obsessive-compulsive disorder (OCD), but empirical investigations into the emotions that underpin OCD symptoms are few, especially in pediatric samples. Using validated, clinician-led structured interviews, 124 youth with OCD reported on the presence and severity of symptoms across the main symptom dimensions of OCD (aggressive, symmetry, contamination) and the degree to which fear, incompleteness, and disgust accompanied these symptoms. For comparison purposes, the degree of fear, incompleteness, and disgust during symptoms was obtained also from youth with social anxiety disorder (SAD; n = 27) and generalized anxiety disorder (GAD; n = 28). Participants with OCD reported that all three emotions were involved in their symptoms; however, fear was most strongly linked to aggressive symptoms, incompleteness to symmetry symptoms, and disgust to contamination symptoms. Incompleteness differentiated youth with OCD from those with SAD and GAD. No differences for these emotions were found for youth with OCD with versus without the tic-disorder subtype or comorbid autism. A positive association between incompleteness and self-reported hoarding emerged among youth with OCD. Further studies of the emotional architecture of pediatric OCD, and its relationship to etiology and treatment, are warranted.

Incompleteness and Disgust Predict Treatment Outcome in Pediatric Obsessive-Compulsive Disorder

Increasing evidence suggests that pediatric obsessive-compulsive disorder (OCD) is motivated not only by fear but also by feelings of incompleteness and disgust. However, it is currently unclear whether emotion involvement in OCD symptoms is associated with treatment response in youth with OCD. The present study examined whether treatment outcome for youth with OCD was predicted by the degree to which fear, disgust, and incompleteness were involved in baseline OCD symptoms. Children and adolescents with OCD entering treatment for this condition (N = 111) were administered standardized OCD symptom measures and an interview designed to assess the degree of fear, incompleteness, and disgust experienced during current OCD symptoms. Follow-up assessments occurred on average 13 months after baseline with each participant coded for outcome according to internationally acknowledged change criteria for pediatric OCD. Higher levels of incompleteness and disgust as part of baseline OCD symptoms predicted poorer outcome. The degree of fear during baseline OCD symptoms did not predict outcome. If replicated under controlled conditions, these results suggest that incompleteness and disgust may act as barriers to improvement in pediatric OCD and that treatment modifications that target these emotion-related motivators may improve outcome for a subset of youth.

Neuroimaging the emotional modulation of urge inhibition in Tourette Syndrome

Tourette Syndrome (TS) is a neuropsychiatric condition characterized by tics that are typically preceded by uncomfortable urges that build until the tic is performed. Both tics and their associated urges are commonly exacerbated during states of heightened emotion. However, the neural substrates that are responsible for the development of urges have not been fully elucidated, particularly with regards to the influence of emotion. In this study, we investigate the brain areas associated with the development of urges and their modulation by emotion in patients with TS. Moreover, we explore the influence of obsessive-compulsive symptoms (OCS) which are commonly comorbid in TS. Forty patients with TS and 20 healthy controls completed an emotional blink suppression paradigm while undergoing functional magnetic resonance imaging. For the paradigm, participants completed alternating blocks of blink inhibition and free blinking while viewing pictures of angry and neutral facial expressions. Compared to controls, patients exhibited greater activity in the superior temporal gyrus and midcingulate during the inhibition of urges. Within the patient group, tic severity was associated with activity in the superior frontal gyrus during the angry inhibition contrast as compared to neutral; greater premonitory urge severity was associated with greater activity in the hippocampus, middle temporal gyrus and in the subcortex; blink inhibition ability was negatively associated with activity in the thalamus and insula. There were no significant associations with OCS severity for the emotion-related contrasts. The observed activated regions may represent a network that produces urges in patients, or alternatively, could represent compensatory cortical activity needed to keep urges and tics under control during emotional situations. Additionally, our findings suggest that OCS in the context of TS is similar to traditional obsessive-compulsive disorder and is neurobiologically dissociable from tics.

Dimensions of interoception in obsessive-compulsive disorder

Interoceptive sensibility (IS) refers to the subjective experience of perceiving and being aware of one's internal body sensations, and is typically evaluated using self-report questionnaires or confidence ratings. Here we evaluated IS in 81 patients with OCD and 76 controls using the Multidimensional Scale of Interoceptive Awareness (MAIA), which contains 8 subscales assessing adaptive and maladaptive responses to sensation. Compared to controls, OCD patients showed hyperawareness of body sensations. Patients also demonstrated a more maladaptive profile of IS characterized by greater distraction from and worry about unpleasant sensations, and reduced tendency to experience the body as safe and trustworthy. These findings were independent of medication status and comorbidities in the patient group. Correlational analyses showed that subscales of the MAIA were differentially associated with OCD symptom dimensions. These findings indicate that patients with OCD show abnormality of IS that is independent of confounding factors related to medication and comorbidities and associated with different OCD symptom dimensions. Future work would benefit from examining neural correlates of these effects and evaluating whether dimensions of IS are impacted by treatments for the disorder.

Examining the functional activity of different obsessive-compulsive symptom dimensions in Tourette syndrome

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Patients with Tourette Syndrome completed an obsessive–compulsive provocation task.

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Patients reported higher anxiety for the provocation conditions than did controls.

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Group differences found in the insula, sensorimotor cortex and supramarginal gyri.

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Obsessive–compulsive severity associated with frontal and parietal lobe activity.

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Tic severity associated with anterior cingulate activity for the symmetry condition.

Objectives

Tourette syndrome (TS) is commonly comorbid with obsessive–compulsive disorder (OCD) and many phenomenological similarities exist between tics and obsessive–compulsive symptoms (OCS). Therefore, due to the clinical importance of comorbid OCD, the goal of this study was to investigate the neural substrates of OCS in TS using functional magnetic resonance imaging.

Methods

Forty patients with TS and 20 healthy controls underwent functional magnetic resonance imaging while viewing blocks of OCS-provoking pictures relating to washing, checking and symmetry symptoms, as well as generally disgusting and neutral scenes. Statistical comparisons were made between patients with moderate/severe OCS, absent/mild OCS and healthy controls. As well, within the entire TS patient group, significant associations with clinical measures were assessed for each of the provocation conditions.

Results

Group differences in the insula, sensorimotor cortex, supramarginal gyrus and visual processing regions were common among the checking, washing and disgust conditions. In the patient group, negative associations between OCS severity and activity in the supramarginal gyrus, inferior frontal gyrus, sensorimotor cortex, precuneus and visual processing regions were common among the provocation conditions. Tic severity was only associated with activity in the anterior cingulate cortex for the symmetry condition.

Conclusion

Our findings implicate areas previously reported to be involved in OCD, as well as areas not typically implicated in OCD, suggesting that the neurobiological profile of TS+OCD is intermediate to pure TS and pure OCD.

The buildup of an urge in obsessive-compulsive disorder: Behavioral and neuroimaging correlates

Obsessive-compulsive disorder (OCD) is highly heterogeneous. While obsessions often involve fear of harm, many patients report uncomfortable sensations and/or urges that drive repetitive behaviors in the absence of a specific fear. Prior work suggests that urges in OCD may be similar to everyday "urges-for-action" (UFA) such as the urge to blink, swallow, or scratch, but very little work has investigated the pathophysiology underlying urges in OCD. In the current study, we used an urge-to-blink approach to model sensory-based urges that could be experimentally elicited and compared across patients and controls using the same task stimuli. OCD patients and controls suppressed eye blinking over a period of 60 s, alternating with free blinking blocks, while brain activity was measured using functional magnetic resonance imaging. OCD patients showed significantly increased activation in several regions during the early phase of eyeblink suppression (first 30 s), including mid-cingulate, insula, striatum, parietal cortex, and occipital cortex, with lingering group differences in parietal and occipital regions during late eyeblink suppression (last 30 s). There were no differences in brain activation during free blinking blocks, and no conditions where OCD patients showed reduced activation compared to controls. In an exploratory analysis of blink counts performed in a subset of subjects, OCD patients were less successful than controls in suppressing blinks. These data indicate that OCD patients exhibit altered brain function and behavior when experiencing and suppressing the urge to blink, raising the possibility that the disorder is associated with a general abnormality in the UFA system that could ultimately be targeted by future treatments.

Sensory Hypersensitivity Severity and Association with Obsessive-Compulsive Symptoms in Adults with Tic Disorder

BACKGROUND

Sensory hypersensitivity, defined as heightened awareness of and reactivity to external stimuli, is a bothersome symptom that affects up to 80% of adults with Tourette syndrome (TS). Such widespread prevalence suggests sensory hypersensitivity is a core feature of the disorder, but its severity and association with other clinical features of TS remain largely unexplored. Complicating matters, sensory hypersensitivity has been observed in two neurodevelopmental disorders commonly comorbid with TS: obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD).

OBJECTIVE

We sought to measure sensory hypersensitivity in TS patients relative to healthy controls and to investigate the relationship of sensory hypersensitivity with OCD and ADHD symptoms in the context of TS.

METHODS

We recruited 34 adults with TS or chronic tic disorder to undergo evaluation with the Yale Global Tic Severity Scale (YGTSS) and a battery of validated self-report instruments assessing sensory hypersensitivity (Sensory Gating Inventory, SGI; Sensory Perception Quotient, SPQ), premonitory urge (Premonitory Urge to Tic Scale, PUTS), OCD (Dimensional Obsessive-Compulsive Scale, DOCS), and ADHD (Adult ADHD Self-Report Screening Scale for DSM-5, ASRS-V). Age- and sex-matched healthy controls were recruited to complete SGI and psychiatric measures.

RESULTS

SGI and SPQ scores strongly correlated (r _s = -0.73, p < 0.0001) within patients. SGI total score was significantly higher in patients versus controls (119.0 vs 67.6, U =-5.3, p < 0.0001), indicating greater sensory hypersensitivity in the tic disorder group. SGI score correlated modestly with PUTS, DOCS, and ASRS-V scores but not with YGTSS total tic score. Hierarchical linear regression analysis revealed that, of the tested variables, only DOCS score contributed significantly to mean SGI score, with β ranging from 1.03 (p = 0.044) to 1.41 (p = 0.001). A simple linear regression model with DOCS as the independent variable accounted for 31.9% of SGI score variance.

CONCLUSION

Sensory hypersensitivity is prominent in adults with tic disorder and is independently associated with obsessive-compulsive symptom severity.

Review: Exteroceptive Sensory Abnormalities in Childhood and Adolescent Anxiety and Obsessive-Compulsive Disorder: A Critical Review

OBJECTIVE

Childhood anxiety and obsessive-compulsive disorder (OCD) are defined by fear, worry, and uncertainty, but there is also evidence that affected children possess exteroceptive sensory abnormalities. These sensory features may often instigate symptoms and cause significant distress and functional impairment. In addition, a purported class of conditions known as "sensory processing disorders" may significantly overlap with childhood anxiety and OCD, which provides further support for a connection between abnormal sensation and fear-based psychopathology.

METHOD

The current review was conducted to synthesize and to critically evaluate the existing research on exteroceptive sensory abnormalities in childhood anxiety and OCD. Because of the paucity of research in this area, studies with adult populations were also briefly reviewed.

RESULTS

The review found significant support for the notion that sensory abnormalities are common in children with anxiety disorders and OCD, but there are significant limitations to research in this area that prevent firm conclusions.

CONCLUSION

Potential avenues for future research on sensory features of pediatric anxiety and OCD are discussed.

Social anxiety, posterior insula activation, and autonomic response during self-initiated action in a Cyberball game

BACKGROUND

An earlier study characterized the neural correlates of self-initiated actions in a Cyberball game in healthy individuals. It remains unclear how social anxiety may influence these neural processes.

METHODS

We examined regional activations to self-initiated actions in 25 adults with low and 25 with high social anxiety (LA and HA, respectively). Skin conductance was recorded concurrently with fMRI. We followed published routines in the analyses of imaging and skin conductance data.

RESULTS

We hypothesized that HA as compared to LA individuals would demonstrate increased cortical limbic activations during self-initiated actions (tossing or T > receiving or R trials, to control for motor activities) in social exclusion (EX) vs. fair game (FG) scenario. At a corrected threshold, HA as compared with LA group showed increases in bilateral posterior insula activation during T vs. R trials in EX as compared to FG. Further, HA as compared to LA showed higher skin conductance response to tossing trials during EX as compared to FG.

LIMITATIONS

With a limited sample size, we did not examine potential sex effects. Further, we cannot rule out the effects of depression on the findings.

CONCLUSIONS

Together, the results suggest that individuals with more severe social anxiety engaged the somatosensory insula to a greater extent and exhibited higher physiological arousal when initiating ball toss during social exclusion in the Cyberball game. Posterior insula response to self-initiated action may represent a biomarker of social anxiety. It remains to be investigated whether interventions to decrease physiological arousal may alleviate social anxiety.

Transcranial direct current stimulation in obsessive-compulsive disorder: an update in electric field modeling and investigations for optimal electrode montage

Introduction: Transcranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation intervention that has been investigated for several psychiatric disorders, including Obsessive-Compulsive Disorder (OCD). As there are several candidate brain regions for targeting OCD relevant networks, clinical studies using tDCS have considerably varied in terms of the electrode montages used. Computer modeling of electric field currents induced by tDCS can help guiding the research of relevant targets for OCD. In this review, the authors used this tool to investigate targeted brain areas from previous studies of tDCS in OCD. Areas covered: A literature search for articles with the keywords 'tDCS', 'Transcranial Direct Current Stimulation' and 'Obsessive Compulsive Disorder' was conducted to identify relevant publications. For comparing different electrode montages, electric field (EF) models were performed using high-resolution brain scan templates. Authors found 13 studies mostly showing an improvement in OCD symptoms. The electrode montages varied considerably between studies. Nonetheless, two main patterns of EFs could be identified: 'focal montages', with EFs concentrated in the prefrontal cortex, and 'diffuse montages', with widespread EFs over cortical areas. Expert opinion: Electric field simulation can guide future clinical trials in psychiatry, using personalized tDCS montages with distinct electrode positioning according to clusters of symptoms.