Neurobiological model of obsessive-compulsive disorder: evidence from recent neuropsychological and neuroimaging findings

Brain activation alterations with adjunctive deep transcranial magnetic stimulation in obsessive-compulsive disorder: an fMRI study

BACKGROUND

Obsessive-compulsive disorder (OCD) is one of the most common neuropsychiatric disorders with lifetime prevalence higher than that of schizophrenia and bipolar disorders. Inadequate response to available pharmacological and psychotherapeutic interventions is common in OCD. Adjunctive brain stimulation methods to address the inadequate treatment response in OCD have found a special interest in research. This study aimed to examine the efficacy of adjunctive deep transcranial magnetic stimulation (dTMS) in ameliorating the symptoms of OCD and the effect of dTMS on activation of brain regions while performing the Stroop task using functional magnetic resonance imaging (fMRI).

METHODS

A total of 41 patients were assessed for the study out of which 15 OCD patients received 10 sessions of high-frequency dTMS using the H7 coil to target the anterior cingulate cortex and the medial prefrontal cortex over a period of 2 weeks. The Yale-Brown Obsessive-Compulsive Scale, the Hamilton Anxiety Rating Scale, and the Hamilton Depression Rating Scale were used for the pre- and post-stimulation clinical assessment. fMRI was used to measure the activation of brain regions while performing the Stroop task.

RESULTS

There was a significant improvement in the obsessive-compulsive, anxiety, and depressive symptoms after the 2 weeks of the dTMS treatment. A significant decrease in the activation of left caudate nucleus and adjacent white matter was noted while performing the Stroop task after the dTMS treatment.

CONCLUSION

The study provides preliminary evidence for functional correlates of effectiveness of dTMS as an adjunctive treatment modality for OCD.

Cognitive, Graphomotor, and Psychosocial Challenges in Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections (PANDAS)

OBJECTIVES

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS) is characterized by the sudden onset of obsessive-compulsive disorder (OCD) and other neurobehavioral symptoms following group A streptococcal infection. The cardinal neuropsychiatric symptoms are believed to reflect an aberrant autoimmune or inflammatory response that may selectively disrupt basal ganglia function. The investigators examined whether neuropsychological skills associated with frontostriatal networks (executive functions and motor skills) are affected in patients with PANDAS following resolution of acute symptoms and the degree to which there are persistent social, emotional, and academic difficulties.

METHODS

Twenty-seven patients ages 6-14 years (mean age=9.63 years [SD=1.78]; male, N=22) completed neuropsychological testing as part of routine clinical care. Performances on measures of intellectual ability, executive function, motor skills, and academic skills are reported, as well as parent-reported emotional, behavioral, and social skills.

RESULTS

On neuropsychological measures, patients exhibited average intellectual functioning with relative and mild difficulties in skills supporting cognitive efficiency, including attentional regulation, inhibitory control, and processing speed. Dexterity was normal but graphomotor skills were reduced. Core reading, math, and writing skills were within expectations, but reading and math fluency were reduced, and the majority of patients received special education services or accommodations. Parents reported high levels of concern about anxiety, depression, inattention, hyperactivity, and social skills.

CONCLUSIONS

These findings indicated relative difficulties with aspects of executive and motor functions. Although evaluations were performed following the resolution of acute symptoms, ongoing and significant academic difficulties and emotional, behavioral, and social concerns were targets for clinical intervention and support.

Aggressiveness, ADHD-like behaviour, and environment influence repetitive behaviour in dogs

Repetitive behaviour ranges from variants of normal repetitive behaviours to abnormal repetitive behaviours. The domestic dog spontaneously performs different repetitive behaviours, which can be severe and impair the quality of life and the dog-owner relationship. We collected comprehensive behavioural questionnaire data from almost 4500 Finnish pet dogs and studied the effect of several demographic, environmental, and behavioural factors on canine repetitive behaviour with logistic regression. We replicated findings from previous studies by revealing comorbidity between repetitive behaviour and behavioural factors aggressiveness, hyperactivity/impulsivity, and inattention. We also found a novel association between repetitive behaviour and the owner’s dog experience. In addition, we showed that repetitive behaviour is more common in dogs that live without conspecifics, dogs that were given a low amount of exercise, dogs that lived in larger families, young dogs and elderly dogs, and neutered dogs. Finally, we identified breed differences in repetitive behaviour, suggesting that some breeds are more vulnerable to repetitive behaviour and indicate a genetic susceptibility. As abnormal repetitive behaviour can considerably worsen the well-being of dogs and impair the dog-owner relationship, a better understanding of the environmental, lifestyle, and molecular factors affecting canine repetitive behaviour can benefit both dogs and humans.

Resting state functional brain imaging in obsessive-compulsive disorder across genders

OBJECTIVES

Epidemiological and clinical gender differences in obsessive-compulsive disorder (OCD) have been reported; however, gender differences in brain functional connectivity and the relationship between resting brain functional imaging and clinical symptoms has not been studied in OCD.

METHODS

A total of 62 drug-naive patients with OCD (31 males, 31 females) and 60 healthy controls (HCs) (30 males, 30 females) matched for age, sex, and education underwent magnetic resonance imaging. Amplitude of low-frequency fluctuations (ALFF) over the whole brain and seed-based connectivity analyses were evaluated to examine the intrinsic cerebral activity of the subjects. Additionally, associations between functional connectivity and clinical features were analysed.

RESULTS

Compared to male OCD (mOCD) patients, female OCD (fOCD) patients showed higher ALFF values in the right parahippocampal gyrus. Compared to HCs, fOCD patients showed significantly decreased functional connectivity between the right parahippocampal gyrus and whole brain to the right posterior central gyrus/precentral gyrus/superior temporal gyrus/barycentric lobule and left anterior cuneus. Abnormal functional connectivity was negatively correlated with the Yale-Brown Obsessive-Compulsive Scale, Beck Depression Inventory-II, and Beck Anxiety Inventory total scores.

CONCLUSIONS

Our results suggest that the right parahippocampal gyrus, which is related to executive control and emotional regulation, may show gender differences in OCD.

Olfactory identification impairment in early-and late-onset obsessive-compulsive disorder

BACKGROUND

Early-onset obsessive-compulsive disorder (EOCD) is a comparatively severe subtype of obsessive-compulsive disorder (OCD). Olfactory dysfunction is a common symptom of OCD, but all previous studies have focused on late-onset OCD (LOCD).

METHODS

The current study compared olfactory identification ability in EOCD patients and age-matched and sex-matched LOCD patients and healthy controls. Thirty patients with EOCD, 30 patients with LOCD and 30 healthy controls were included in the study. Olfactory function was measured using the University of Pennsylvania Smell Identification Test. The Logical Memory and Visual Reproduction components of the Revised Wechsler Memory Scale were used to evaluate verbal and visual memory.

RESULTS

There were significant differences in olfactory identification ability between the three groups. EOCD patients were comparable to LOCD patients, while both patients' group showing worse olfactory identification ability than controls. Olfactory identification ability was not significantly correlated with verbal and visual memory or clinical symptoms in the EOCD group or the LOCD group.

CONCLUSIONS

The results of the present study suggest that olfactory identification ability may be a relatively stable indicator of OCD, independent of age, duration of illness, verbal and visual memory, and severity of clinical symptoms.

P300 and delay-discounting in obsessive-compulsive disorder

Previous research showed that dysfunctions of fronto-striatal neural networks are implicated in the pathophysiology of obsessive-compulsive disorder (OCD). Accordingly, patients with OCD showed altered performances during decision-making tasks. As P300, evoked by oddball paradigms, is suggested to be related to attentional and cognitive processes and generated in the medial temporal lobe and orbitofrontal and cingulate cortices, it is of special interest in OCD research. Therefore, this study aimed to investigate P300 in OCD and its associations with brain activity during decision-making: P300, evoked by an auditory oddball paradigm, was analysed in 19 OCD patients and 19 healthy controls regarding peak latency, amplitude and source density power in parietal cortex areas by sLORETA. Afterwards, using a fMRI paradigm, Blood-oxygen-level-dependent (BOLD) contrast imaging was conducted during a delay-discounting paradigm. We hypothesised differences between groups regarding P300 characteristics and associations with frontal activity during delay-discounting. The P300 did not differ between groups, however, the P300 latency over the P4 electrode correlated negatively with the NEO-FFI score openness to experience in patients with OCD. In healthy controls, P300 source density power correlated with activity in frontal regions when processing rewards, a finding which was absent in OCD patients. To conclude, associations of P300 with frontal brain activation during delay-discounting were found, suggesting a contribution of attentional or context updating processes. Since this association was absent in patients with OCD, the findings could be interpreted as being indeed related to dysfunctions of fronto-striatal neural networks in patients with OCD.

Could the Thyroid Gland Dominate the Brain in Obsessive-Compulsive Disorder?

Thyroid hormones have an essential role in brain maturation and neuronal functioning. The comorbidity of thyroid disorders and several mental disturbances is frequently reported. We aimed to evaluate the literature on the potential relationship between thyroid disorders and obsessive-compulsive disorder (OCD) and obsessive-compulsive symptoms (OCS). We searched the literature using PUBMED, ProQuest, Google Scholar, and PsycInfo electronic databases for original studies (cross-sectional, case series, case report) on the association between thyroid dysfunctions and OCD and OCS between 1977 and 2021. Eleven studies met the inclusion criteria. Despite some methodological limitations, the OCD rates in patients with autoimmune thyroid disorders were found to be higher than the normal population in two studies. The findings on thyroid dysfunction in OCD patients were inconclusive. In the light of available data, it could be proposed that there might be a possible association between thyroid disorders and OCD. Some shared immunological mechanisms could play a role in the pathophysiology of both thyroid diseases and OCD. New research is needed to confirm this association and elucidate the underlying common mechanisms between these disorders.

Obsessive Thought, Compulsive Behavior, and Their Associations With Suicide Ideation and Attempts and Major Depressive Disorder: A Nationwide Community Sample of Korean Adults

ABSTRACT

In this study, we defined obsessive thoughts (OT) as bothersome, unpleasant thoughts about oneself that keep entering the mind against one's will, and compulsive behavior (CB) as behavior that a person repeats against his or her wishes. The study included 12,532 adults selected randomly through a one-person-per-household method. Each subject selected underwent a face-to-face interview using the Korean version of the Composite International Diagnostic Interview with a questionnaire that examines lifetime suicide attempts (LSAs). Among the participants, 341 (2.74%) had OT and 639 (5.14%) had CB. The highest LSA rate was in subjects with both OT and CB, followed by those with either OT or CB; subjects with neither OT nor CB had the lowest LSA rate. In a multivariate logistic regression analysis of OT and CB, OT, ordering, and rituals of repeating words were significantly associated with LSAs. In subjects with OT and CB, those with MDD had a significantly higher risk of LSAs compared with those without, and MDD with both OT and CB showed odds of approximately 27-fold (adjusted odds ratio, 27.24; 13.29-55.82; p < 0.0001) compared with those without MDD, OT, or CB. OT and CB were associated with increased risk of LSAs, and comorbid MDD further increased LSAs.

Canine hyperactivity, impulsivity, and inattention share similar demographic risk factors and behavioural comorbidities with human ADHD

Attention-deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder impairing the quality of life of the affected individuals. The domestic dog can spontaneously manifest high hyperactivity/impulsivity and inattention which are components of human ADHD. Therefore, a better understanding of demographic, environmental and behavioural factors influencing canine hyperactivity/impulsivity and inattention could benefit both humans and dogs. We collected comprehensive behavioural survey data from over 11,000 Finnish pet dogs and quantified their level of hyperactivity/impulsivity and inattention. We performed generalised linear model analyses to identify factors associated with these behavioural traits. Our results indicated that high levels of hyperactivity/impulsivity and inattention were more common in dogs that are young, male and spend more time alone at home. Additionally, we showed several breed differences suggesting a substantial genetic basis for these traits. Furthermore, hyperactivity/impulsivity and inattention had strong comorbidities with compulsive behaviour, aggressiveness and fearfulness. Multiple of these associations have also been identified in humans, strengthening the role of the dog as an animal model for ADHD.

Diagnosis of obsessive-compulsive disorder via spatial similarity-aware learning and fused deep polynomial network

Obsessive-compulsive disorder (OCD) is a type of hereditary mental illness, which seriously affect the normal life of the patients. Sparse learning has been widely used in detecting brain diseases objectively by removing redundant information and retaining monitor valuable biological characteristics from the brain functional connectivity network (BFCN). However, most existing methods ignore the relationship between brain regions in each subject. To solve this problem, this paper proposes a spatial similarity-aware learning (SSL) model to build BFCNs. Specifically, we embrace the spatial relationship between adjacent or bilaterally symmetric brain regions via a smoothing regularization term in the model. We develop a novel fused deep polynomial network (FDPN) model to further learn the powerful information and attempt to solve the problem of curse of dimensionality using BFCN features. In the FDPN model, we stack a multi-layer deep polynomial network (DPN) and integrate the features from multiple output layers via the weighting mechanism. In this way, the FDPN method not only can identify the high-level informative features of BFCN but also can solve the problem of curse of dimensionality. A novel framework is proposed to detect OCD and unaffected first-degree relatives (UFDRs), which combines deep learning and traditional machine learning methods. We validate our algorithm in the resting-state functional magnetic resonance imaging (rs-fMRI) dataset collected by the local hospital and achieve promising performance.

Potential scalp stimulation targets for mental disorders: evidence from neuroimaging studies

Mental disorders widely contribute to the modern global disease burden, creating a significant need for improvement of treatments. Scalp stimulation methods (such as scalp acupuncture and transcranial electrical stimulation) have shown promising results in relieving psychiatric symptoms. However, neuroimaging findings haven’t been well-integrated into scalp stimulation treatments. Identifying surface brain regions associated with mental disorders would expand target selection and the potential for these interventions as treatments for mental disorders. In this study, we performed large-scale meta-analyses separately on eight common mental disorders: attention deficit hyperactivity disorder, anxiety disorder, autism spectrum disorder, bipolar disorder, compulsive disorder, major depression, post-traumatic stress disorder and schizophrenia; utilizing modern neuroimaging literature to summarize disorder-associated surface brain regions, and proposed neuroimaging-based target protocols. We found that the medial frontal gyrus, the supplementary motor area, and the dorsal lateral prefrontal cortex are commonly involved in the pathophysiology of mental disorders. The target protocols we proposed may provide new brain targets for scalp stimulation in the treatment of mental disorders, and facilitate its clinical application.

Disrupted pathways from frontal-parietal cortex to basal ganglia and cerebellum in patients with unmedicated obsessive compulsive disorder as observed by whole-brain resting-state effective connectivity analysis - a small sample pilot study

OBJECTIVE

To date, a systematic characterization of abnormalities in resting-state effective connectivity (rsEC) in obsessive-compulsive disorder (OCD) is lacking. The present study aimed to systematically characterize whole-brain rsEC in OCD patients as compared to healthy controls.

METHODS

Using resting-state fMRI data of 50 unmedicated patients with OCD and 50 healthy participants, we constructed whole-brain rsEC networks using Granger causality analysis followed by univariate and multivariate comparisons between patients and controls. Similar analyses were performed for resting-state functional connectivity (rsFC) networks to examine how rsFC and rsEC differentially capture abnormal brain connectivity in OCD.

RESULTS

Univariate comparisons identified 10 rsEC networks that were significantly disrupted in patients, and which were mainly associated with frontal-parietal cortex, basal ganglia, and cerebellum. Conversely, abnormal rsFC networks were widely distributed throughout the whole brain. Multivariate pattern analysis revealed a classification accuracy as high as 80.5% for distinguishing patients from controls using combined whole-brain rsEC and rsFC.

CONCLUSIONS

The results of the present study suggest disrupted communication of information from frontal-parietal cortex to basal ganglia and cerebellum in OCD patients. Using combined whole-brain rsEC and rsFC, multivariate pattern analysis revealed a classification accuracy as high as 80.5% for distinguishing patients from controls. The alterations observed in OCD patients could aid in identifying treatment mechanisms for OCD.

Therapeutic Neurostimulation in Obsessive-Compulsive and Related Disorders: A Systematic Review

Invasive and noninvasive neurostimulation therapies for obsessive-compulsive and related disorders (OCRD) were systematically reviewed with the aim of assessing clinical characteristics, methodologies, neuroanatomical substrates, and varied stimulation parameters. Previous reviews have focused on a narrow scope, statistical rather than clinical significance, grouped together heterogenous protocols, and proposed inconclusive outcomes and directions. Herein, a comprehensive and transdiagnostic evaluation of all clinically relevant determinants is presented with translational clinical recommendations and novel response rates. Electroconvulsive therapy (ECT) studies were limited in number and quality but demonstrated greater efficacy than previously identified. Targeting the pre-SMA/SMA is recommended for transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS). TMS yielded superior outcomes, although polarity findings were conflicting, and refinement of frontal/cognitive control protocols may optimize outcomes. For both techniques, standardization of polarity, more treatment sessions (>20), and targeting multiple structures are encouraged. A deep brain stimulation (DBS) 'sweet spot' of the striatum for OCD was proposed, and CBT is strongly encouraged. Tourette's patients showed less variance and reliance on treatment optimization. Several DBS targets achieved consistent, rapid, and sustained clinical response. Analysis of fiber connectivity, as opposed to precise neural regions, should be implemented for target selection. Standardization of protocols is necessary to achieve translational outcomes.

Functional connectivity within an anxiety network and associations with anxiety symptom severity in middle-aged adults with and without autism

Anxiety is highly prevalent in autism spectrum disorders (ASDs). However, few functional magnetic resonance imaging (fMRI) studies of ASDs have focused on anxiety (and fewer still on anxiety in middle-aged adults). Thus, relationships between atypical connectivity and anxiety in this population are poorly understood. The current study contrasted functional connectivity within anxiety network regions across adults (40-64 years) with and without autism, and tested for group by functional connectivity interactions on anxiety. Twenty-two adults with ASDs (16 males) and 26 typical control (TC) adults (22 males) completed the Beck Anxiety Inventory and a resting-state fMRI scan. An anxiety network consisting of 12 regions of interest was defined, based on a meta-analysis in TC individuals and two studies on anxiety in ASDs. We tested for main effects of group and group by anxiety interactions on connectivity within this anxiety network, controlling for head motion using ANCOVA. Results are reported at an FDR adjusted threshold of q < 0.1 (corrected) and p < 0.05 (uncorrected). Adults with ASDs showed higher anxiety and underconnectivity within the anxiety network, mostly involving bilateral insula. Connectivity within the anxiety network in the ASD group showed distinct relationships with anxiety symptoms that did not relate to ASD symptom severity. Functional connectivity involving the bilateral posterior insula was positively correlated with anxiety in the ASD (but not the TC) group. Increased anxiety in middle-aged adults with ASD is associated with atypical functional connectivity, predominantly involving bilateral insula. Results were not related to ASD symptom severity suggesting independence of anxiety-related effects. LAY SUMMARY: Anxiety is very common in adults with autism but the brain basis of this difference is not well understood. We compared functional connectivity between anxiety-related brain regions in middle-aged adults with and without autism. Adults with autism were more anxious and showed weaker functional connections between these regions. Some relationships between functional connectivity and higher anxiety were specific to the autism group. Results suggest that anxiety functions differently in autism.

Carga cognitiva y control atencional en puertorriqueños con trastorno obsesivocompulsivo

Trasfondo:El control ejecutivo de la atención media la resolución de problemas y la acción voluntaria y está implicado en la regulación de las emociones. Se ha reportado que el control atencional está afectado en personas con trastorno obsesivo-compulsivo (TOC). Sin embargo, no se ha considerado la influencia de la carga cognitiva y la distracción en la ejecución de tareas, lo que pudiera tener un impacto en el control atencional. En este estudio evaluamos si la carga cognitiva alta y baja influyen en el control atencional de personas con TOC, en comparación con un grupo control. Método:Quince adultos puertorriqueños con TOC (M=31.60, DE=10.70) y 26 saludables (M=28.42, DE=10.73) participaron en el estudio. Se administró el Attention Network Test y una tarea de carga cognitiva para evaluar el control atencional. Resultados:No se observaron diferencias significativas en las puntuaciones de alerta, orientación y control atencional entre los grupos en ambas condiciones de carga cognitiva (p>0.05). Solo se observó una diferencia significativa en el control atencional de los participantes con TOC (z=1.99, p=0.047) y del grupo control (z=-2.83, p=0.005) durante tareas con carga cognitiva baja y alta. Conclusiones:Ambos grupos experimentaron menor interferencia de distractores bajo alta carga cognitiva, lo que sugiere un mayor control de la atención durante esta condición. Es posible que el aumento de carga cognitiva pueda reducir la distracción en puertorriqueños saludables y aquellos con TOC. Tomar en cuenta la carga cognitiva puede facilitar el entrenamiento cognitivo para el control atencional y aumentar la flexibilidad cognitiva, mejorando la respuesta al tratamiento.  

Causal investigations into orbitofrontal control of human decision making

Although it is widely accepted that the orbitofrontal cortex (OFC) is important for decision making, its precise contribution to behavior remains a topic of debate. While many loss of function experiments have been conducted in animals, causal studies of human OFC function are relatively scarce. This review discusses recent causal investigations into the human OFC, with an emphasis on advances in network-based brain stimulation approaches to indirectly perturb OFC function. Findings show that disruption of human OFC impairs decisions that require mental simulation of outcomes. Taken together, these results support the idea that human OFC contributes to decision making by representing a cognitive map of the task environment, facilitating inference of outcomes not yet experienced. Future work may utilize similar non-invasive approaches in clinical settings to mitigate decision making deficits in neuropsychiatric disorders.

To be specific: The role of orbitofrontal cortex in signaling reward identity

The orbitofrontal cortex (OFC) plays a prominent role in signaling reward expectations. Two important features of rewards are their value (how good they are) and their specific identity (what they are). Whereas research on OFC has traditionally focused on reward value, recent findings point toward a pivotal role of reward identity in understanding OFC signaling and its contribution to behavior. Here, we review work in rodents, nonhuman primates, and humans on how the OFC represents expectations about the identity of rewards, and how these signals contribute to outcome-guided behavior. Moreover, we summarize recent findings suggesting that specific reward expectations in OFC are learned and updated by means of identity errors in the dopaminergic midbrain. We conclude by discussing how OFC encoding of specific rewards complements recent proposals that this region represents a cognitive map of relevant task states, which forms the basis for model-based behavior. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Complexity of information processing in obsessive-compulsive disorder based on fractal analysis of EEG signal

The human brain is considered as a self-organizing system with self-similarities at various temporal and spatial scales called "fractals". In this scale-free system, it is possible to decode the complexity of information processing using fractal behavior. For instance, the complexity of information processing in the brain can be evaluated by fractal dimensions (FDs). However, it is unclear how over-elaboration of information processing impacts the dimensionality of its fractal behavior. In this study, we hypothesized that FDs of electroencephalogram (EEG) in obsessive-compulsive disorder (OCD) should be higher than healthy controls (HCs) because of exaggeration of information processing mainly in the frontal regions. Therefore, a group of 39 OCDs (age: 34.76±8.22, 25 female, 3 left-handed) and 19 HCs (age: 31.94±8.22, 11 female, 1 left-handed) were recruited and their brain activities were recorded using a 19-channel EEG recorder in the eyes-open resting-state condition. Subsequently, fractal dimensions of the cleaned EEG data were calculated using Katz's method in a frequency band-specific manner. After the test of normality, significant changes in the OCDs as compared to the HCs were calculated using a two-sample t-test. OCDs showed higher FDs in the frontal regions in all frequency bands as compared to HCs. Although, significant increases were only observed in the beta and lower gamma bands, mainly at the high beta. Interestingly, neurophysiological findings also show association with severity of obsessive behaviors. The results demonstrate that complexity of information processing in the brain follows an intimate nature of structural and functional impairments of the brain in OCD.

Neural correlates of cognitive behavioral therapy response in youth with negative valence disorders: A systematic review of the literature

BACKGROUND

Cognitive-behavioral therapy (CBT) is the gold-standard psychotherapeutic treatment for pediatric negative valence disorders. However, some youths do not respond optimally to treatment, which may be due to variations in neural functioning.

METHODS

We systematically reviewed functional magnetic resonance imaging studies in youths with negative valence disorders to identify pre- and post-treatment neural correlates of CBT response.

RESULTS

A total of 21 studies were identified, of overall weak to moderate quality. The most consistent findings across negative valence disorders consisted of associations of treatment response with pre- and post-treatment task-based activation and/or functional connectivity within and between the prefrontal cortex, the medial temporal lobe, and other limbic regions. Associations of CBT response with baseline and/or post-treatment activity in the striatum, precentral and postcentral gyri, medial and posterior cingulate cortices, and parietal cortex, connectivity within and between the default-mode, cognitive control, salience, and frontoparietal networks, and metrics of large-scale brain network organization, were also reported, although less consistently.

LIMITATIONS

The poor quality and limited number of studies and the important heterogeneity of study designs and results considerably limit the conclusions that can be drawn from this literature.

CONCLUSIONS

Despite these limitations, these findings provide preliminary evidence suggesting youths presenting certain patterns of brain function may respond better to CBT, whereas others may benefit from alternative or augmented forms of treatment.

Neuropsychological outcome in refractory obsessive-compulsive disorder treated with anterior capsulotomy including repeated surgery

AIM

Anterior capsulotomy (AC) is one of the last therapeutic options for obsessive-compulsive disorder (OCD) refractory to conservative treatments. Several forms of cognitive dysfunction have been identified after assessment of neuropsychological outcomes in OCD patients; however, few studies focused on cognitive changes in OCD patients after surgery. In the present study, we evaluated the effects of AC on cognitive performance and mood status in patients with refractory OCD.

METHODS

A total of 12 patients underwent bilateral AC between 2012 and 2019 at our institution. The patients (n = 12, female : male 5:7; mean age 39.7 years; duration ≥5 years) were assessed before and 6 months after intervention. The diagnosis of treatment-refractory OCD was based on recommended criteria for surgical treatment. Patients were assessed using a neuropsychological battery and questionnaires focused on anxiety-depressive symptomatology. The Yale-Brown Obsessive Compulsive Scale was administered as a measure of severity of OCD symptoms.

RESULTS

We detected a significant decrease of OCD, and anxiety and depressive symptomatology assessed by Yale-Brown Obsessive Compulsive Scale, Beck Depression Inventory, and Beck Anxiety Inventory (P < 0.05) 6 months after AC in eight patients, and a partial decrease in four patients. Four patients underwent repeated AC with more pronounced improvement achieved after the first procedure. We did not detect decline in cognitive performance in any patients, but did find better visual memory performance (P < 0.05).

CONCLUSION

AC reduced OCD and anxiety-depressive symptoms, and did not appear to influence cognitive performance, even after repeated surgery.

Altered phospholipid and high-energy phosphate metabolism in the basal ganglia and thalamus of severe obsessive compulsive patients with treatment resistance: A phosphorus 31 nuclear magnetic resonance spectroscopy study

INTRODUCTION

Cerebral metabolism in obsessive-compulsive-disorder(OCD) has been the subject of numerous studies using proton magnetic resonance spectroscopy(MRS). Despite heterogeneous results, some studies have unraveled membrane turnover and energy metabolism abnormalities in different brain regions, suggesting that alterations in these processes may contribute to the pathophysiology. So far, no authors have explored phospholipids and high-energy phosphate metabolism using ³¹P-MRS, which allows in vivo quantification of phosphorus metabolites that are considered to be related to membrane turnover and energy metabolism.

MATERIALS AND METHODS

The aim of our study was to describe and compare brain metabolic changes using ³¹P-MRS in the striatum and the thalamus, between 23 severe OCD patients and 22 healthy controls. All subject underwent a clinical examination and a same ³¹P-MRS protocol.

RESULTS

Significantly, increased concentrations of PC, PDE,PME,GPC,PME/PCr,PDE/PCr were found in patients compared to controls in the striatum and the thalamus. PCr and tATP were decreased in the striatum. Finally, significant correlations were found in the striatum and the thalamus between illness duration and some specific measured parameters.

CONCLUSION

Our results showed significant modifications of the membrane and energy metabolism in the basal ganglia of severe OCD patients and suggests a link between energetic buffer and serotonin metabolism disorder.

Individual-fMRI-approaches reveal cerebellum and visual communities to be functionally connected in obsessive compulsive disorder

There is significant interest in understanding the pathophysiology of Obsessive-Compulsive Disorder (OCD) using resting-state fMRI (rsfMRI). Previous studies acknowledge abnormalities within and beyond the fronto-striato-limbic circuit in OCD that require further clarifications. However, limited information could be inferred from the conventional way of investigating the functional connectivity differences between OCD and healthy controls. Here, we identified altered brain organization in patients with OCD by applying individual-based approaches to maximize the identification of underlying network-based features specific to the OCD group. rsfMRI of 20 patients with OCD and 22 controls were preprocessed, and individual-fMRI-subspace was derived for each subject within each group. We evaluated group differences in functional connectivity using individual-fMRI-subspace and established its advantage over conventional-fMRI methodology. We applied prediction-based approaches to highlight the group differences by evaluating the differences in functional connections that predicted the clinical scores (namely, the Obsessive-Compulsive Inventory-Revised (OCI-R) and Hamilton Anxiety Rating Scale). Then, we explored the brain network organization of both groups by estimating the subject-specific communities within each group. Lastly, we evaluated associations between the inter-individual variation of nodes in the communities to clinical measures using linear regression. Functional connectivity analysis using individual-fMRI-subspace detected 83 connections that were different between OCD and control groups, compared to none found using conventional-fMRI methodology. Connectome-based prediction analysis did not show significant overlap between the two groups in the functional connections that predicted the clinical scores. This suggests that the functional architecture in patients with OCD may be different compared to controls. Seven communities were found in both groups. Interestingly, within the OCD group but not controls, we observed functional connectivity between cerebellar and visual regions, and lack of connectivity between striato-limbic and frontal areas. Inter-individual variations in the community-size of these two communities were also associated with the OCI-R score (p < .005). Due to our small sample size, we further validated our results by (i) accounting for head motion, (ii) applying global signal regression (GSR) in data processing, and (iii) using an alternate atlas for parcellation. While the main results were consistently observed with accounting for head motion and using another atlas, the key findings were not reproduced with GSR application. The study demonstrated the existence of disconnectedness in fronto-striato-limbic community and connectedness between cerebellar and visual areas in OCD patients, which was also related to the clinical symptomatology of OCD.

Brain Activation of Patients With Obsessive-Compulsive Disorder During a Mental Rotation Task: A Functional MRI Study

Functional neuroimaging studies have implicated alterations in frontostriatal and frontoparietal circuits in obsessive-compulsive disorder (OCD) during various tasks. To date, however, brain activation for visuospatial function in conjunction with symptoms in OCD has not been comprehensively evaluated. To elucidate the relationship between neural activity, cognitive function, and obsessive-compulsive symptoms, we investigated regional brain activation during the performance of a visuospatial task in patients with OCD using functional magnetic resonance imaging (fMRI). Seventeen medication-free patients with OCD and 21 age-, sex-, and IQ-matched healthy controls participated in this study. Functional magnetic resonance imaging data were obtained while the subjects performed a mental rotation (MR) task. Brain activation during the task was compared between the two groups using a two-sample t-test. Voxel-wise whole-brain multiple regression analyses were also performed to examine the relationship between obsessive-compulsive symptom severity and neural activity during the task. The two groups did not differ in MR task performance. Both groups also showed similar task-related activation patterns in frontoparietal regions with no significant differences. Activation in the right dorsolateral prefrontal cortex in patients with OCD during the MR task was positively associated with their total Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores. This study identified the specific brain areas associated with the interaction between symptom severity and visuospatial cognitive function during an MR task in medication-free patients with OCD. These findings may serve as potential neuromodulation targets for OCD treatment.

Evidências Neurobiológicas de Viés Atencional no Transtorno Obsessivo-Compulsivo: Revisão Sistemática

Resumo O viés atencional corresponde à alocação de recursos de atenção a materiais irrelevantes à tarefa. Supõe-se que pacientes com transtorno obsessivo-compulsivo (TOC) apresentem viés atencional voltado à ameaça. Com o objetivo de descrever os achados neurobiológicos do viés atencional voltado à ameaça no TOC, foi realizada uma busca sistemática por estudos experimentais com investigação neurobiológica nas bases de dados: MEDLINE, Web of Science, Scopus e LILACS. Quatro estudos com grupo controle são descritos nos resultados, todos indicam diferenças estatisticamente significativas na atividade encefálica associada a atenção em pacientes. Os achados neurobiológicos dos estudos incluídos na revisão sugerem a alocação de recursos da atenção a estímulos irrelevantes, independente da valência emocional no TOC.

Structural neuroimaging of somatoform disorders: A systematic review

Although there has been an increment in neuroimaging research in somatoform disorders (SD), to date little is known about the neural correlates of these diseases. Therefore, in this systematic, review we aimed at summarizing the existing evidence of structural brain alterations in SD as per DSM-IV and DSM-5 criteria. Three electronic databases (Scopus, PubMed and Web of Science) were searched. Only case-control studies using structural neuroimaging were included. Forty-five out of 369 articles fulfilled inclusion criteria and were reviewed. Compared to controls, subjects with SD showed morphological alterations encompassing motor, limbic and somatosensory circuits. Although far from being conclusive, the results suggested that SD are characterized by selective alterations of large-scale brain networks implicated in cognitive control, emotion regulation and processing, stress and somatic-visceral perception. This review highlights the need for further multimodal neuroimaging studies with longitudinal designs, in larger and better-characterized samples, to elucidate the temporal and causal relationship between neuroanatomical changes and SD, which is paramount for informing tailored treatments.

Hippocampal functional network: The mediating role between obsession and anxiety in adult patients with obsessive-compulsive disorder

OBJECTIVES

Anxiety is a very common symptom and closely related to obsessive-compulsive symptoms in obsessive-compulsive disorder (OCD). However, the association between anxiety and obsessive-compulsive symptoms at the hippocampus network level remains unclear.

METHODS

This study enrolled 42 patients with OCD and 42 healthy controls (HCs), who underwent resting-state functional magnetic resonance imaging (fMRI) and clinical evaluation. Multiple linear regression analysis was performed to investigate the behavioural significance and interactive effects of obsessive-compulsive and anxiety symptoms on the hippocampus functional connectivity (HFC). The mediation analysis model was used to explore whether the hippocampus functional connectivity (FC) network indirectly mediated the relationship between obsessive-compulsive symptoms and anxiety.

RESULTS

Results showed that the FCs with the cerebellum, middle temporal gyrus (MTG) and anterior cingulate gyrus (ACG) were increased in the hippocampus FC network in patients with OCD compared with those in HCs. The regions of interactive effects between anxiety and obsession, which are mainly located in the prefrontal cortex and MTG, were positively correlated. The mediation effect is 0.018 between obsession and anxiety on the HFC networks in patients with OCD.

CONCLUSIONS

The FC between the hippocampus and MTG plays a key role in the relationship between anxiety and obsession.

Disrupted pathways from the frontal-parietal cortices to basal nuclei and the cerebellum are a feature of the obsessive-compulsive disorder spectrum and can be used to aid in early differential diagnosis

A marker for distinguishing patients with obsessive-compulsive disorder (OCD) spectrum has not yet been identified. Whole-brain resting-state effective and functional connectivity (rsEC and rsFC, respectively) networks were constructed for 50 unmedicated OCD (U-OCD) patients, 45 OCD patients in clinical remission (COCD), 47 treatment-resistant OCD (T-OCD) patients, 42 chronic schizophrenia patients who exhibit OCD symptoms (SCHOCD), and 50 healthy controls (HCs). Multivariate pattern analysis (MVPA) was performed to investigate the accuracy of using connectivity alterations to distinguished among the aforementioned groups. Compared to HCs, rsEC connections were significantly disrupted in the U-OCD (n = 15), COCD (n = 8), and T-OCD (n = 19) groups. Additionally, 21 rsEC connections were significantly disrupted in the T-OCD group compared to the SCHOCD group. The disrupted rsEC networks were associated mainly with the frontal-parietal cortex, basal ganglia, limbic regions, and the cerebellum. Classification accuracies for distinguishing OCD patients from HCs and SCHOCD patients ranged from 66.6% to 98.0%. In conclusion, disrupted communication from the frontal-parietal cortices to subcortical basal nuclei and the cerebellum may represent a functional pathological feature of the OCD spectrum. MVPA based on both abnormal rsEC and rsFC patterns may aid in early differential diagnosis of OCD.

Deactivation of anterior cingulate cortex during virtual social interaction in obsessive-compulsive disorder

Studies about social functioning in obsessive-compulsive disorder (OCD) are lacking, even though neuroimaging studies and metacognition evaluation results suggest abnormal neural responses during social interactions. This study examined neural responses of OCD patients during handshakes with a virtual avatar. Because of the nature of the handshaking task, we expected that OCD patients with predominantly contamination/washing symptoms (CON) would show different neural responses compared to healthy controls (HCs) and to disease-controlled (NCON) patients. Thirteen CON, 13 NCON, and 18 HC participants performed handshake tasks with clean or dirty virtual avatars while undergoing functional magnetic resonance imaging. During handshakes with a clean avatar, deactivation in the left anterior cingulate cortex was found in CON patients compared to NCON and HC subjects. This cortical deactivation also occurred with dirty-avatar handshakes, but the difference was significant only between the two OCD groups and HC patients. Deactivation in the left anterior cingulate cortex was correlated with both OCD symptom severity and social anxiety traits. This cortical deactivation in OCD, especially in CON patients, suggests that social dysfunction in OCD may be due to interactions between OCD symptoms and impairment in social cognition, including emotional processing.

Do Individuals With Obsessive-Compulsive Disorder and Obsessive-Compulsive Personality Disorder Share Similar Neural Mechanisms of Decision-Making Under Ambiguous Circumstances?

Impaired decision-making is well documented in obsessive-compulsive disorder (OCD) and a range of electrophysiological and functional neuroimaging measures have begun to reveal the pathological mechanisms that underlie the decision-making process. Obsessive-compulsive personality disorder (OCPD) has core symptoms that often overlap with OCD, but similarities between these disorders at the behavioral and neurological levels are often unclear, including whether OCPD exhibits similar decision-making deficits and shared neurological dysfunction. To address these issues, we examined 24 cases of OCD, 19 cases of OCPD, and 26 matched normal control (NC) subjects during the revised Iowa Gambling Task (IGT) using event-related potentials (ERPs). The net IGT scores were lower for OCD subjects than for OCPD or NC subjects, thus indicating that OCD subjects chose more disadvantageous options and were "short-sighted" with regards to information. The feedback-related negativity (FRN) waveform (lose-win) was larger in both OCD and OCPD subjects, which suggested that obstacles exist in the feedback process. Consequently, these subjects might share similar neural mechanisms under ambiguous decision-making circumstances. Furthermore, IGT net scores were significantly and negatively correlated with Hamilton Anxiety Rating Scale (HAMA) and Hamilton Depression Rating Scale (HAMD) scales. This implies that more severe obsessive-compulsive symptoms inspired more negative emotions that led to worse decision-making ability. Therefore, although similar neural mechanisms might exist, this led to different behaviors in which OCPD is associated with better behavioral performance compared to OCD patients.

The Psychopharmacology of Obsessive-Compulsive Disorder: A Preclinical Roadmap

This review evaluates current knowledge about obsessive-compulsive disorder (OCD), with the goal of providing a roadmap for future directions in research on the psychopharmacology of the disorder. It first addresses issues in the description and diagnosis of OCD, including the structure, measurement, and appropriate description of the disorder and issues of differential diagnosis. Current pharmacotherapies for OCD are then reviewed, including monotherapy with serotonin reuptake inhibitors and augmentation with antipsychotic medication and with psychologic treatment. Neuromodulatory therapies for OCD are also described, including psychosurgery, deep brain stimulation, and noninvasive brain stimulation. Psychotherapies for OCD are then reviewed, focusing on behavior therapy, including exposure and response prevention and cognitive therapy, and the efficacy of these interventions is discussed, touching on issues such as the timing of sessions, the adjunctive role of pharmacotherapy, and the underlying mechanisms. Next, current research on the neurobiology of OCD is examined, including work probing the role of various neurotransmitters and other endogenous processes and etiology as clues to the neurobiological fault that may underlie OCD. A new perspective on preclinical research is advanced, using the Research Domain Criteria to propose an adaptationist viewpoint that regards OCD as the dysfunction of a normal motivational system. A systems-design approach introduces the security motivation system (SMS) theory of OCD as a framework for research. Finally, a new perspective on psychopharmacological research for OCD is advanced, exploring three approaches: boosting infrastructure facilities of the brain, facilitating psychotherapeutic relearning, and targeting specific pathways of the SMS network to fix deficient SMS shut-down processes. SIGNIFICANCE STATEMENT: A significant proportion of patients with obsessive-compulsive disorder (OCD) do not achieve remission with current treatments, indicating the need for innovations in psychopharmacology for the disorder. OCD may be conceptualized as the dysfunction of a normal, special motivation system that evolved to manage the prospect of potential danger. This perspective, together with a wide-ranging review of the literature, suggests novel directions for psychopharmacological research, including boosting support systems of the brain, facilitating relearning that occurs in psychotherapy, and targeting specific pathways in the brain that provide deficient stopping processes in OCD.

Pharmacological management of comorbid obsessive–compulsive disorder and chronic non-affective psychosis

The comorbidity of obsessive–compulsive symptoms (OCS) in the context of schizophrenia is often not recognised by clinicians, and patients may not report these symptoms until they become severe. However, there is a reported prevalence of 10–24% for obsessive–compulsive disorder (OCD) in schizophrenia and related disorders. The onset of OCS/OCD has been noted to occur both before and after the diagnosis of schizophrenia or schizoaffective disorder. It has also been known to occur following commencement of treatment with antipsychotic medications, especially clozapine. Current literature provides limited guidance for treatment. Review of the current evidence supports: addition of selective serotonin reuptake inhibitors (SSRIs) to antipsychotics; addition of aripiprazole, amisulpride or lamotrigine; or reduction in the dosage of clozapine. There is also evidence supporting the addition of cognitive–behavioural therapy and electroconvulsive therapy (ECT). The SSRIs that are evidenced to be useful are fluvoxamine, escitalopram, sertraline and paroxetine. More studies are needed to expand the evidence base. Early targeted interventions are recommended.

Deep transcranial magnetic stimulation for obsessive compulsive disorder

INTRODUCTION

Obsessive-compulsive disorder (OCD) is a common psychiatric disorder that can be chronic and debilitating if not properly treated. Current first-line treatments for OCD include cognitive-behavioral therapy with exposure and response prevention and serotonin uptake inhibitor medications; however, these therapies are not effective for all individuals.

AREAS COVERED

Deep transcranial magnetic stimulation (dTMS) has been hypothesized to be an effective alternative for individuals with treatment-resistant OCD. dTMS has thought to be favorable due to its low side effect profile and its minimally invasive nature.

EXPERT OPINION

This review evaluates the current research on effectiveness of dTMS therapy for individuals with treatment-resistant OCD. This review also investigates shortcomings in current dTMS research and the hypothesized future of dTMS therapy.

Cognitive performance in children and adolescents at high-risk for obsessive-compulsive disorder

BACKGROUND

Cognitive performance has been studied in adults with obsessive-compulsive symptoms (OCS) and in adult relatives of patients with obsessive-compulsive disorder (OCD) Meanwhile, few studies have been conducted with children under the same conditions. This study compared the neurocognitive domains previously associated with dysfunction in OCD, especially visuoconstructive ability, visuospatial memory, executive functions, and intelligence, in children and adolescents at high risk (HR) for OCD (n = 18) and non-OCD controls (NOC) (n = 31).

METHODS

For the HR group, we considered the first-degree relatives of patients with OCD that present OCS, but do not meet diagnostic criteria for OCD. Psychiatric diagnosis was assessed by experienced clinicians using the Structured Clinical Interview for DSM-IV and OCS severity was measured by the Yale-Brown Obsessive-Compulsive Scale. Neurocognitive assessment was performed with a comprehensive neuropsychological battery. Performance on the cognitive domains was compared between groups using Multivariate Analysis of Variance, whereas performance on the neuropsychological variables was compared between groups using independent t-tests in a cognitive subdomain analysis.

RESULTS

The cognitive domain analysis revealed a trend towards significance for impairments in the motor and processing speed domain (p = 0.019; F = 3.12) in the HR group. Moreover, the cognitive subdomain analysis identified a statistically significant underperformance in spatial working memory in the HR group when compared to the NOC group (p = 0.005; t = - 2.94), and a trend towards significance for impairments in non-verbal memory and visuoconstructive tasks in the HR group.

CONCLUSIONS

Our results suggest impairments in spatial working memory and motor and processing speed in a non-clinical sample of HR participants. Considering the preliminary nature of our findings, further studies investigating these neurocognitive domains as potential predictors of pediatric OCD are warranted.

Treating refractory obsessive-compulsive disorder with transcranial direct current stimulation: An open label study

BACKGROUND

Obsessive-compulsive disorder (OCD) is a complex disorder with 40%-60% of patients' refractory to treatment. Transcranial direct current stimulation (tDCS) has been shown to induce potent and long-lasting effects on cortical excitability. The aim of the present clinical trial was to evaluate the therapeutic efficacy and tolerability of cathodal tDCS over the supplementary motor area (SMA) in treatment-resistant OCD patients.

METHODS

Twenty-one treatment-resistant OCD outpatients received 10 sessions of tDCS. Each treatment session consisted of 2 mA stimuli for 30 min. The cathode was positioned over the bilateral SMA and the anode over the right supraorbital area. Patients were evaluated at baseline, end of treatment, one-month follow-up, and three-month follow-up. Response to treatment was defined as at least a decrease of 35% on the Yale-Brown Obsessive-Compulsive Scale (YBOCS) and a score of 2 or less on the Clinical Global Impressions-Improvement (CGI-I) between baseline and 1-month follow-up.

RESULTS

There was a significant decrease of YBOCS scores between baseline and one-month assessment. At one month, five patients (24%) were considered as responders and 3 (15%) at 3 months. We also observed concomitant changes in depressive symptoms, and insight. The treatment was well tolerated. Short-lasting side effects were reported as localized tingling sensation and skin redness.

CONCLUSION

Our results suggest that the use of cathodal tDCS over the SMA and anodal tDCS over the right supraorbital area in OCD treatment-refractory patients is safe and promising to improve obsessive and compulsive symptoms. Large randomized controlled trials are needed to confirm this positive result.

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.

A potential role for psilocybin in the treatment of obsessive-compulsive disorder

The recent revivification of interest in the therapeutic use of psychedelics has had a particular focus on mood disorders and addiction, although there is reason to think these drugs may be effective more widely. After outlining pertinent aspects of psilocybin and obsessive-compulsive disorder (OCD), the current review summarizes the evidence indicating that there may be a role for psilocybin in the treatment of OCD, as well as highlighting a range of potential therapeutic mechanisms that reflect the action of psilocybin on brain function. Although the current evidence is limited, that multiple signals point in directions consistent with treatment potential, alongside the psychological and physiological safety of clinically administered psilocybin, support the expansion of research, both in animal models and in further randomized controlled trials, to properly investigate this potential.

Functional connectivity in obsessive-compulsive disorder and its subtypes

BACKGROUND

Obsessive-compulsive disorder (OCD) is an anxiety disorder with significant morbidity whose pathophysiology is not fully understood. Neuroimaging studies have characterized OCD in terms of elevated striatal and prefrontal reactivity to emotion provocation. This neural model may be informed by investigation of functional connectivity in OCD, identifying alterations in how sensory information is integrated into frontostriatal regions.

METHODS

The current study employed functional magnetic resonance imaging (fMRI) to compare neural activity and connectivity in 31 OCD patients (12 washing and 19 checking subtypes) and 17 healthy volunteers in an emotion provocation paradigm using visual stimuli.

RESULTS

OCD status was associated with hyper-activation of the posterior cingulate (PCg) in response to emotion provocation. Additionally, OCD patients demonstrated elevated PCg functional connectivity with the visual cortices and frontostriatal regions. Exploratory analyses suggested that stimulus-provoked activity and connectivity was elevated for checking subtypes in motor cortices, and elevated in washing subtypes in the anterior insula and orbitofrontal cortex.

CONCLUSIONS

The PCg's role in moderating connectivity between the visual cortex and frontolimbic regions is muted in OCD, consistent with the PCg's suggested role in regulating attention towards emotional stimuli. Exploratory analyses suggest distinct PCg connectivity profiles in OCD subtypes, with checking linked to motor activation, but washing linked to a network supporting emotional salience. The study was not powered to fully investigate the effects of medication, patients often endorsed secondary symptom subtypes that muddied washing/checking distinctions, and the emotion provocation paradigm was of limited intensity compared to life stressors.

The anterior limb of the internal capsule: Anatomy, function, and dysfunction

The last two decades have seen a re-emergence of neurosurgery for severe, refractory psychiatric diseases, largely due to the advent of more precise and safe operative techniques. Nevertheless, the optimal targets for these surgeries remain a matter of debate, and are often grandfathered from experiences in the late 20th century. To better explore the rationale for one target in particular - the anterior limb of the internal capsule (ALIC) - we comprehensively reviewed all available literature on its role in the pathophysiology and treatment of mental illness. We first provide an overview of its functional anatomy, followed by a discussion on its role in several prevalent psychiatric diseases. Given its structural integration into the limbic system and involvement in a number of cognitive and emotional processes, the ALIC is a robust target for surgical treatment of refractory psychiatric diseases. The advent of novel neuroimaging techniques, coupled with image-guided therapeutics and neuromodulatory treatments, will continue to enable study on the ALIC in mental illness.

Obsessive-Compulsive and Perseverative Behaviors in Huntington's Disease

Background:

Neuropsychiatric symptoms are highly prevalent in Huntington’s disease (HD). However, little is known of the prevalence and course of obsessive-compulsive behaviors (OCBs) and perseverative behaviors (PBs) during the progression of the disease.

Objective:

This review provides a summary of the literature on OCBs and PBs in HD gene expansion carriers (HDGECs).

Methods:

Pubmed database was searched for articles on OCBs and PBs in HD up to 2017. We used search terms, all synonyms for HD, and various terms for OCBs and PBs.

Results:

We found 5 case series and 11 original articles that describe a prevalence range of 5 to 52% for OCBs and up to 75% for PBs depending on disease stage and measurement scale used. Premanifest HDGECs report more OCBs compared to controls, and manifest HDGECs report a higher rate of OCBs compared to premanifest HDGECs. OCBs and PBs are associated with a longer disease duration and disease severity in manifest HDGECs, but decrease in the most advanced stages. When HDGECs come closer to estimated motor onset, the companion ratings on OCBs appear to be higher than the self-ratings of HDGECs.

Conclusions:

Both OCBs and PBs are characteristic neuropsychiatric features of HD. Perseveration is probably best distinguished from OCBs as it occurs without the individual’s full awareness or insight into their presence (and the behavior may not be distressing). Although these behaviors are seldom distinguished, we conclude that differentiating OCBs from PBs in HD is beneficial for the management and treatment of these symptoms in HDGECs.

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.

Inhibition-Related Cortical Hypoconnectivity as a Candidate Vulnerability Marker for Obsessive-Compulsive Disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) is a prevalent neuropsychiatric condition, with biological models implicating disruption of cortically mediated inhibitory control pathways, ordinarily serving to regulate our environmental responses and habits. The aim of this study was to evaluate inhibition-related cortical dysconnectivity as a novel candidate vulnerability marker of OCD.

METHODS

In total, 20 patients with OCD, 18 clinically asymptomatic first-degree relatives of patients with OCD, and 20 control participants took part in a neuroimaging study comprising a functional magnetic resonance imaging stop signal task. Brain activations during the contrasts of interest were cluster thresholded, and a three-dimensional watershed algorithm was used to decompose activation maps into discrete clusters. Functional connections between these key neural nodes were examined using a generalized psychophysiological interaction model.

RESULTS

The three groups did not differ in terms of age, education level, gender, IQ, or behavioral task parameters. Patients with OCD exhibited hyperactivation of the bilateral occipital cortex during the task versus the other groups. Compared with control participants, patients with OCD and their relatives exhibited significantly reduced connectivity between neural nodes, including frontal cortical, middle occipital cortical, and cerebellar regions, during the stop signal task.

CONCLUSIONS

These findings indicate that hypoconnectivity between anterior and posterior cortical regions during inhibitory control represents a candidate vulnerability marker for OCD. Such vulnerability markers, if found to generalize, may be valuable to shed light on etiological processes contributing not only to OCD but also obsessive-compulsive-related disorders more widely.

Targeted Stimulation of Human Orbitofrontal Networks Disrupts Outcome-Guided Behavior

Outcome-guided behavior requires knowledge about the current value of expected outcomes. Such behavior can be isolated in the reinforcer devaluation task, which assesses the ability to infer the current value of specific rewards after devaluation. Animal lesion studies demonstrate that orbitofrontal cortex (OFC) is necessary for normal behavior in this task, but a causal role for human OFC in outcome-guided behavior has not been established. Here, we used sham-controlled, non-invasive, continuous theta-burst stimulation (cTBS) to temporarily disrupt human OFC network activity by stimulating a site in the lateral prefrontal cortex that is strongly connected to OFC prior to devaluation of food odor rewards. Subjects in the sham group appropriately avoided Pavlovian cues associated with devalued food odors. However, subjects in the stimulation group persistently chose those cues, even though devaluation of food odors themselves was unaffected by cTBS. This behavioral impairment was mirrored in changes in resting-state functional magnetic resonance imaging (rs-fMRI) activity such that subjects in the stimulation group exhibited reduced OFC network connectivity after cTBS, and the magnitude of this reduction was correlated with choices after devaluation. These findings demonstrate the feasibility of indirectly targeting the human OFC with non-invasive cTBS and indicate that OFC is specifically required for inferring the value of expected outcomes.

Effect of Escitalopram on Serum GDNF and BDNF Levels and 5-HT Level of Brain Tissue of Obsessive-Compulsive Disorder Rats

The present study aims to discuss the effect of escitalopram in glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF) levels, and 5-Hydroxytryptamine (5-HT) in obsessive-compulsive disorder rats. A total of 42 rats were divided into three groups randomly: control group (n = 14), model group (n = 14) (obsessive-compulsive disorder group), and escitalopram group (n = 14) (model + obsessive-compulsive disorder group + escitalopram treatment). The open-field method was used to test the rat behavior, enzyme-linked immunosorbent assay (ELISA) was used to determine the serum GDNF and BDNF levels. In addition, Western blot was used to determine the brain tissue protein levels of GDNF and BDNF and high-performance liquid chromatography + electrochemistry method to determine the 5-HT level of brain tissue. Visiting place was changed, rotational frequency and fixed duration enhanced in escitalopram group compared to model group (P < 0.05). Besides, GDNF and BDNF levels of serum and brain tissue were decreased in model group and escitalopram group compared to control group (P < 0.05), while GDNF and BDNF levels of serum and brain tissue were increased in escitalopram group compared to model group (P < 0.05). Moreover, the 5-HT level of brain tissue in escitalopram group was higher than that in model group (P < 0.05). Escitalopram could increase GDNF and BDNF levels and 5-HT content in serum and brain tissue in obsessive-compulsive disorder rats, which contributes to a function on the treatment of obsessive-compulsive disorder.

"Fake it till You Make it"! Contaminating Rubber Hands ("Multisensory Stimulation Therapy") to Treat Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is a deeply enigmatic psychiatric condition associated with immense suffering worldwide. Efficacious therapies for OCD, like exposure and response prevention (ERP), are sometimes poorly tolerated by patients. As many as 25% of patients refuse to initiate ERP mainly because they are too anxious to follow exposure procedures. Accordingly, we proposed a simple and tolerable (immersive yet indirect) low-cost technique for treating OCD that we call “multisensory stimulation therapy.” This method involves contaminating a rubber hand during the so-called “rubber hand illusion” (RHI) in which tactile sensations may be perceived as arising from a fake hand. Notably, Jalal et al. (2015) showed that such fake hand contamination during the RHI provokes powerful disgust reactions in healthy volunteers. In the current study, we explored the therapeutic potential of this novel approach. OCD patients (n = 29) watched as their hidden real hand was being stroked together with a visible fake hand; either synchronously (inducing the RHI; i.e., the experimental condition; n = 16) or asynchronously (i.e., the control condition; n = 13). After 5 min of tactile stimulation, the rubber hand was contaminated with fake feces, simulating conventional exposure therapy. Intriguingly, results suggested sensory assimilation of contamination sensations into the body image via the RHI: patients undergoing synchronous stimulation did not report greater contamination sensations when the fake hand was initially contaminated relative to asynchronous stroking. But contrary to expectations, they did so after the rubber hand had been contaminated for 5 min, as assessed via disgust facial expressions (a secondary outcome) and in vivo exposure (upon discontinuing the illusion). Further, to our surprise, synchronous and asynchronous stroking induced an equally vivid and fast-emerging illusion, which helps explain why both conditions initially (5 min after initiating tactile stimulation) provoked contamination reactions of equal magnitude. This study is the first to suggest heightened malleability of body image in OCD. Importantly, it may pave the way for a tolerable technique for the treatment of OCD—highly suitable for poorly resourced and emergency settings, including low-income and developing countries with minimal access to high-tech solutions like virtual reality.

How obsessive-compulsive and bipolar disorders meet each other? An integrative gene-based enrichment approach

BACKGROUND

The novel approaches to psychiatric classification assume that disorders, contrary to what was previously thought, are not completely separate phenomena. In this regard, in addition to symptom-based criteria, disturbances are also considered on the basis of lower level components. With this viewpoint, identifying common biochemical markers would be beneficial in adopting a comprehensive strategy for prevention, diagnosis and treatment.

MAIN BODY

One of the problematic areas in clinical settings is the coexistence of both obsessive-compulsive disorder (OCD) and bipolar disorder (BD) that is challenging and difficult to manage. In this study, using a system biologic approach we aimed to assess the interconnectedness of OCD and BD at different levels. Gene Set Enrichment Analysis (GSEA) method was used to identify the shared biological network between the two disorders. The results of the analysis revealed 34 common genes between the two disorders, the most important of which were CACNA1C, GRIA1, DRD2, NOS1, SLC18A1, HTR2A and DRD1. Dopaminergic synapse and cAMP signaling pathway as the pathways, dopamine binding and dopamine neurotransmitter receptor activity as the molecular functions, dendrite and axon part as the cellular component and cortex and striatum as the brain regions were the most significant commonalities.

SHORT CONCLUSION

The results of this study highlight the role of multiple systems, especially the dopaminergic system in linking OCD and BD. The results can be used to estimate the disease course, prognosis, and treatment choice, particularly in the cases of comorbidity. Such perspectives, going beyond symptomatic level, help to identify common endophenotypes between the disorders and provide diagnostic and therapeutic approaches based on biological in addition to the symptomatic level.

Social Cognition and Obsessive-Compulsive Disorder: A Review of Subdomains of Social Functioning

Disturbances in social cognitive processes such as the ability to infer others' mental states importantly contribute to social and functional impairments in psychiatric disorders. Yet, despite established social, emotional, and cognitive problems, the role of social cognition in obsessive-compulsive disorder is largely overlooked. The current review provides a first comprehensive overview of social (neuro)cognitive disturbances in adult patients with obsessive-compulsive disorder. Results of our review indicate various social cognitive alterations. Patients with obsessive-compulsive disorder show deficits in the recognition of affective social cues, specifically facial expressions of disgust, and more general deficits in theory of mind/mentalizing. Additionally, patients show heightened affective reactions and altered neural responding to emotions of self and others, as well as poor emotion regulation skills, which may contribute to poor social functioning of patients. However, the discrepancies in findings and scarcity of studies make it difficult to draw firm conclusions with regard to the specificity of social cognitive disturbances. The review offers directions for future research and highlights the need to investigate obsessive-compulsive disorder from an interactive social neurocognitive perspective in addition to the prevalent passive spectator perspective to advance our understanding of this intricate and burdensome disorder.