Neuroimaging of cognitive brain function in paediatric obsessive compulsive disorder: a review of literature and preliminary meta-analysis

The Efficacy and Acceptability of Non-Invasive Brain Stimulation Interventions for Obsessive-Compulsive Disorder Management: A Network Meta-Analysis Based on 24 Stimulation Methods

INTRODUCTION

Despite the high lifetime prevalence and elevated disability rates, treatments for obsessive-compulsive disorder (OCD) have limited efficacy. Considering the abnormal connectivity in the cortical-striatal-thalamic-cortical loop circuits in OCD, several randomized controlled trials (RCTs) have addressed the efficacy of different non-invasive brain stimulation (NIBS) modalities for the management of OCD. However, these RCTs yielded inconclusive results.

METHODS

This network meta-analysis (NMA) included RCTs of NIBS interventions, such as transcranial direct current stimulation (tDCS) and various repetitive transcranial magnetic stimulation (rTMS), in OCD patients. The primary outcomes were changes in the overall severity of OCD and acceptability (i.e., dropout rates).

RESULTS

This NMA of 34 eligible RCTs (1089 participants) and 24 different NIBS interventions revealed that three NIBS interventions significantly improved overall OCD severity compared with sham controls, which were high-frequency rTMS over the dorsolateral prefrontal cortex (DLPFC) [mean difference (MD) = -10.81, 95% confidence intervals (95% CIs) = -20.80 to -0.82], high-frequency deep TMS over the dorsal medial prefrontal cortex/anterior cingulate cortex (dmPFC/ACC) (MD = -9.74, 95% CIs = -16.42 to -3.06), and low-frequency rTMS over the right DLPFC (MD = -4.70, 95% CIs = -8.84 to -0.57).

CONCLUSIONS

This study highlighted that excitatory stimulation over the dmPFC/ACC and bilateral DLPFC, or inhibitory stimulation over the right DLPFC, was associated with significant improvements in overall OCD severity. Further large-scale RCTs with longer follow-up periods are needed to investigate the true impact of NIBS-based intervention to manage OCD.

TRIAL REGISTRATION

PROSPERO: CRD42023394953.

Elucidating distinct and common fMRI-complexity patterns in pre-adolescent children with Attention-Deficit/Hyperactivity Disorder, Oppositional Defiant Disorder, and Obsessive-Compulsive Disorder diagnoses

Importance

The pathophysiology of ADHD is complicated by high rates of psychiatric comorbidities, thus delineating unique versus shared functional brain perturbations is critical in elucidating illness pathophysiology.

Objective

To investigate resting-state fMRI (rsfMRI)-complexity alterations among children with ADHD, oppositional defiant disorder (ODD), and obsessive-compulsive disorder (OCD), respectively, and comorbid ADHD, ODD, and OCD, within the cool and hot executive function (EF) networks.

Design

We leveraged baseline data (wave 0) from the Adolescent Brain and Cognitive Development (ABCD) Study.

Setting

The data was collected between September 2016 and September 2019 from 21 sites in the USA.

Participants

Children who singularly met all DSM-5 behavioral criteria for ADHD (N = 61), ODD (N = 38), and OCD (N = 48), respectively, were extracted, alongside children with comorbid ADHD, ODD, OCD, and/or other psychiatric diagnoses (N = 833). A control sample of age-, sex-, and developmentally-matched children was also extracted (N = 269).

Main Outcomes and Measures

Voxel-wise sample entropy (SampEn) was computed using the LOFT Complexity Toolbox. Mean SampEn within all regions of the EF networks was calculated for each participant and hierarchical models with Generalized Estimating Equations compared SampEn of comorbid-free and comorbid ADHD, ODD, and OCD within the EF networks.

Results

SampEn was reduced in comorbid-free ADHD and ODD in overlapping regions of both EF networks, including the bilateral superior frontal gyrus, anterior/posterior cingulate gyrus, and bilateral caudate (Wald statistic = 5.682 to 10.798, p < 0.05 & BH corrected), with ADHD additionally affected in the right inferior/middle frontal gyrus and bilateral frontal orbital cortex (Wald statistic = 7.231 to 9.420, p < 0.05 & BH corrected). Among comorbid presentations, the additional presence of ADHD symptomatology was associated with significantly lower SampEn in every region of interest (z = -3.973 to -2.235, p < 0.05 & BH corrected).

Conclusions and Relevance

ADHD and ODD shared common impairments underlying the EF networks in the comorbid-free presentations, with ADHD showing more widespread complexity reduction. When ADHD co-occurred with other psychiatric disorders, the reduction in SampEn extended beyond the regions affected in comorbid-free ADHD, indicating that comorbidities amplify neural complexity deficits.

Will Transcranial Magnetic Stimulation Improve the Treatment of Obsessive-Compulsive Disorder? A Systematic Review and Meta-Analysis of Current Targets and Clinical Evidence

BACKGROUND

Although in 2017 a repetitive transcranial magnetic stimulation (rTMS) protocol received Food and Drug Administration approval for the first time for the treatment of obsessive-compulsive disorder (OCD), which neural target and which protocol should be used for OCD are still debated. The aim of the present study was to perform a systematic review and meta-analysis of the available open and sham-controlled trials.

METHODS

The primary analysis included a pairwise meta-analysis (over 31 trials), and then subgroup analyses were performed for each targeted brain area. Meta-regression analyses explored the possible moderators of effect size.

RESULTS

The pairwise meta-analysis showed a significant reduction in OCD symptoms following active rTMS (g = -0.45 [95%CI: -0.62, -0.29]) with moderate heterogeneity (I² = 34.9%). Subgroup analyses showed a significant effect of rTMS over the bilateral pre-SMA (supplementary motor area), the DLPFC (dorsolateral prefrontal cortex), the ACC/mPFC (anterior cingulate cortex and medial prefrontal cortex), and the OFC (orbitofrontal cortex). No moderators of the effect size emerged.

CONCLUSIONS

TMS of several brain targets represents a safe and effective treatment option for OCD patients. Further studies are needed to help clinicians to individualize TMS protocols and targets for each patient.

Case report: Co-occurring autism spectrum disorder (Level One) and obsessive-compulsive disorder in a gender-diverse adolescent

This fictionalized case report captures the common themes and considerations during the diagnostic assessment and behavioral treatment of adolescents demonstrating symptoms of autism spectrum disorder (ASD), obsessive-compulsive disorder (OCD), and attention-deficit/hyperactivity disorder (ADHD), as well as gender-diversity concerns. Our patient was a white, non-Hispanic 17-year-old individual who identified as gender-neutral but had been assigned female at birth. Symptoms presented were social withdrawal, rigid rule-following behavior, unusual repetitive behavior, impairments in social communication skills, sensory sensitivity, body dissatisfaction, self-injury, and anxiety related to contamination, perfectionism, and social interactions. These symptoms contributed to functional impairment with school attendance, school achievement, family relationships, and the activities of daily living. This case report summarizes instruments employed for differential diagnosis concerning cognitive functioning, ASD, OCD, ADHD, depression, anxiety, and commonly co-occurring repetitive behavior. This patient was ultimately diagnosed with ASD, level one for both social communication and restricted, repetitive behaviors, without accompanying intellectual or language impairment; OCD with panic attacks; gender dysphoria; major depressive disorder (single episode and moderate); and ADHD. The subsequent 40-session course of cognitive-behavioral therapy with exposure and response prevention (CBT/ERP) to treat OCD tailored to an individual with ASD and gender diversity concerns is described in detail. Components of family involvement are highlighted. As a result, significant improvements in school attendance, OCD symptoms, depression, social relationships, and adaptive functioning were measured. Lastly, recommendations for clinicians are summarized.

Correlations between single nucleotide polymorphisms in obsessive-compulsive disorder with the clinical features or response to therapy

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder, in which the patient endures intrusive thoughts or is compelled to perform repetitive or ritualized actions. Many cases of OCD are considered to be familial or heritable in nature. It has been shown that a variety of internal and external risk factors are involved in the pathogenesis of OCD. Among the internal factors, genetic modifications play a critical role in the pathophysiological process. Despite many investigations performed to determine the candidate genes, the precise genetic factors involved in the disease remain largely undetermined. The present review summarizes the single nucleotide polymorphisms that have been proposed to be associated with OCD symptoms, early onset disease, neuroimaging results, and response to therapy. This information could help us to draw connections between genetics and OCD symptoms, better characterize OCD in individual patients, understand OCD prognosis, and design more targeted personalized treatment approaches.

Preliminary Observations of Resting-State Magnetoencephalography in Nonmedicated Children with Obsessive-Compulsive Disorder

Background: Cortico-striato-thalamo-cortical (CSTC) network alterations are hypothesized to contribute to symptoms of obsessive-compulsive disorder (OCD). To date, very few studies have examined whether CSTC network alterations are present in children with OCD, who are medication naive. Medication-naive pediatric imaging samples may be optimal to study neural correlates of illness and identify brain-based markers, given the proximity to illness onset. Methods: Magnetoencephalography (MEG) data were analyzed at rest, in 18 medication-naive children with OCD (M = 12.1 years ±2.0 standard deviation [SD]; 10 M/8 F) and 13 typically developing children (M = 12.3 years ±2.2 SD; 6 M/7 F). Whole-brain MEG-derived resting-state functional connectivity (rs-fc), for alpha- and gamma-band frequencies were compared between OCD and typically developing (control) groups. Results: Increased MEG-derived rs-fc across alpha- and gamma-band frequencies was found in the OCD group compared to the control group. Increased MEG-derived rs-fc at alpha-band frequencies was evident across a number of regions within the CSTC circuitry and beyond, including the cerebellum and limbic regions. Increased MEG-derived rs-fc at gamma-band frequencies was restricted to the frontal and temporal cortices. Conclusions: This MEG study provides preliminary evidence of altered alpha and gamma networks, at rest, in medication-naive children with OCD. These results support prior findings pointing to the relevance of CSTC circuitry in pediatric OCD and further support accumulating evidence of altered connectivity between regions that extend beyond this network, including the cerebellum and limbic regions. Given the substantial portion of children and youth whose OCD symptoms do not respond to conventional treatments, our findings have implications for future treatment innovation research aiming to target and track whether brain patterns associated with having OCD may change with treatment and/or predict treatment response.

Inhibitory control in obsessive compulsive disorder: A systematic review and activation likelihood estimation meta-analysis of functional magnetic resonance imaging studies

BACKGROUND

Patients with obsessive compulsive disorder (OCD) often show deficits in inhibitory control, which may underlie poor control over obsessions and compulsions. Several functional magnetic resonance imaging (fMRI) experiments utilizing a variety of tasks have investigated the neural correlates of inhibitory control in OCD. Evidence from existing meta-analyses suggests aberrant activation of regions in fronto-striatal circuits during inhibitory control. However, new fMRI articles have since been published, and a more rigorous methodology for neuroimaging meta-analyses is now available.

OBJECTIVES

First, to reevaluate the evidence for abnormal brain activation during performance of inhibitory control tasks in OCD while adhering to current best practices for meta-analyses, and second, to extend previous findings by separately assessing different subprocesses of inhibitory control.

METHOD

We systematically searched Web of Knowledge, ScienceDirect, Scopus, PubMed and the functional BrainMap database for fMRI articles that compared activation during performance of inhibitory control tasks in patients with OCD and healthy control (HC) subjects. Thirty-five experiments from 21 articles met our criteria for inclusion. We first performed activation-likelihood-estimation meta-analyses to elucidate brain areas in which case-control activation differences converged across articles and tasks. We then aimed to extend previous work by separately evaluating experiments requiring inhibition of a prepotent response without execution of an alternative response (i.e., response inhibition) and experiments requiring inhibition of a prepotent response and execution of an alternative response (i.e., cognitive inhibition).

RESULTS

The 35 experiments included a total of 394 patients and 410 controls. We did not find evidence of abnormal brain activation in OCD during inhibitory control when pooling data from all experiments. Analysis restricted to cognitive inhibition experiments showed abnormal activation of the dorsal anterior cingulate cortex (dACC; P = .04, cluster-level familywise error-corrected, cluster volume of 824 mm³). We did not have sufficient data to evaluate response inhibition experiments separately.

CONCLUSION

Findings of abnormal brain activation in OCD from different inhibitory control tasks do not appear to converge on the same brain regions, but the dACC may be implicated in abnormal cognitive inhibition. Our findings highlight a need for experiments that specifically target subprocesses of inhibitory control to achieve a more differentiated understanding of the neural correlates for impaired inhibitory control in OCD.

Detailed measurements and simulations of electric field distribution of two TMS coils cleared for obsessive compulsive disorder in the brain and in specific regions associated with OCD

The FDA cleared deep transcranial magnetic stimulation (Deep TMS) with the H7 coil for obsessive-compulsive disorder (OCD) treatment, following a double-blinded placebo-controlled multicenter trial. Two years later the FDA cleared TMS with the D-B80 coil on the basis of substantial equivalence. In order to investigate the induced electric field characteristics of the two coils, these were placed at the treatment position for OCD over the prefrontal cortex of a head phantom, and the field distribution was measured. Additionally, numerical simulations were performed in eight Population Head Model repository models with two sets of conductivity values and three Virtual Population anatomical head models and their homogeneous versions. The H7 was found to induce significantly higher maximal electric fields (p<0.0001, t = 11.08) and to stimulate two to five times larger volumes in the brain (p<0.0001, t = 6.71). The rate of decay of electric field with distance is significantly slower for the H7 coil (p < 0.0001, Wilcoxon matched-pairs test). The field at the scalp is 306% of the field at a 3 cm depth with the D-B80, and 155% with the H7 coil. The H7 induces significantly higher intensities in broader volumes within the brain and in specific brain regions known to be implicated in OCD (dorsal anterior cingulate cortex (dACC), dorsolateral prefrontal cortex (dlPFC), inferior frontal gyrus (IFG), orbitofrontal cortex (OFC) and pre-supplementary motor area (pre-SMA)) compared to the D-B80. Significant field ≥ 80 V/m is induced by the H7 (D-B80) in 15% (1%) of the dACC, 78% (29%) of the pre-SMA, 50% (20%) of the dlPFC, 30% (12%) of the OFC and 15% (1%) of the IFG. Considering the substantial differences between the two coils, the clinical efficacy in OCD should be tested and verified separately for each coil.

The metacontrol hypothesis as diagnostic framework of OCD and ADHD: A dimensional approach based on shared neurobiological vulnerability

Obsessive-compulsive disorder (OCD) and attention-deficit hyperactivity disorder (ADHD) are multi-faceted neuropsychiatric conditions that in many aspects appear to be each other's antipodes. We suggest a dimensional approach, according to which these partially opposing disorders fall onto a continuum that reflects variability regarding alterations of cortico-striato-thalamo-cortical (CSTC) circuits and of the processing of neural noise during cognition. By using theoretical accounts of human cognitive metacontrol, we develop a framework according to which OCD can be characterized by a chronic bias towards exaggerated cognitive persistence, equivalent to a high signal-to-noise ratio (SNR)-which facilitates perseverative behaviour but impairs mental flexibility. In contrast, ADHD is characterized by a chronic bias towards inflated cognitive flexibility, equivalent to a low SNR-which increases behavioural variability but impairs the focusing on one goal and on relevant information. We argue that, when pharmacology is not feasible, novel treatments of these disorders may involve methods to manipulate the signal-to-noise ratio via non-invasive brain stimulation techniques, in order to normalize the situational imbalance between cognitive persistence and cognitive flexibility.

Efficacy and Safety of Deep Transcranial Magnetic Stimulation for Obsessive-Compulsive Disorder: A Prospective Multicenter Randomized Double-Blind Placebo-Controlled Trial

(Appeared originally in American Journal of Psychiatry 2019; 176:931-938) Reprinted with permission from American Psychiatric Association Publishing.

Deep TMS H7 Coil: Features, Applications & Future

INTRODUCTION

Transcranial magnetic stimulation (TMS) uses magnetic pulses to induce electrical current in the underlying neuronal tissue. A variety of TMS coils exist on the market, differing primarily in configuration, orientation, and flexibility of the wire windings of the coil. Deep TMS^TM utilizes H-Coils, flexible coils with different configurations for stimulating different brain regions implicated in different neuropsychiatric disorders. The H7 Coil, designed to target primarily the medial prefrontal cortex and the anterior cingulate cortex, is FDA-cleared for obsessive-compulsive disorder (OCD). It was chosen as the focus of this review since it recently showed promise in various neuropsychiatric populations in addition to growing understanding of its mechanism of action (MOA).

AREAS COVERED

Here we assembled all peer-reviewed publications on the H7 Coil to showcase its efficacy in: (a) various OCD patient populations (e.g., different degrees of symptom severity, treatment resistance, comorbidities) (b) other neuropsychiatric populations (e.g., addiction, major depressive disorder and autism spectrum disorder).

EXPERT OPINION

While substantial evidence pertaining to the H7 Coil's efficacy as well as its MOA has accumulated, much work remains. In the final section of this review, we highlight areas of ongoing and future research that will further elucidate the coil's MOA as well as its full efficacy potential.

A Diagnostic Strategy via Multiresolution Synchrosqueezing Transform on Obsessive Compulsive Disorder

This research presents a new method for detecting obsessive-compulsive disorder (OCD) based on time-frequency analysis of multi-channel electroencephalogram (EEG) signals using the multi-variate synchrosqueezing transform (MSST). With the evolution of multi-channel sensor implementations, the employment of multi-channel techniques for the extraction of features arising from multi-channel dependency and mono-channel characteristics has become common. MSST has recently been proposed as a method for modeling the combined oscillatory mechanisms of multi-channel signals. It makes use of the concepts of instantaneous frequency (IF) and bandwidth. Electrophysiological data, like other nonstationary signals, necessitates both joint time-frequency analysis and independent time and frequency domain studies. The usefulness and effectiveness of a multi-variate, wavelet-based synchrosqueezing algorithm paired with a band extraction method are tested using electroencephalography data obtained from OCD patients and control groups in this research. The proposed methodology yields substantial results when analyzing differences between patient and control groups.

Moderators and predictors of response to deep transcranial magnetic stimulation for obsessive-compulsive disorder

Deep transcranial magnetic stimulation (dTMS) has emerged as a treatment option for adults with obsessive-compulsive disorder (OCD) who continue to exhibit impairing symptoms following an adequate response to first line interventions. Currently, little is known about the predictors or moderators of dTMS outcome for OCD. This paper examined if several theoretically relevant variables may predict and moderate treatment effects including OCD symptom severity, functional impairment, co-occurring depressive symptoms, age, gender, age of OCD onset, and family history of OCD. As part of a previously reported study, 100 patients received 29 dTMS or sham stimulation treatments over 6 weeks. dTMS was administered using a Magstim Rapid2 TMS (The Magstim Co. Ltd., Whitland, Carmarthenshire, United Kingdom) stimulator equipped with a H shaped coil design, which was specifically designed to stimulate the dorsal mPFC-ACC bilaterally. Findings suggest older participants and those with lower OCD severity and disability respond faster to both dTMS and sham stimulation. dTMS of the dorsal mPFC/ACC appeared to have larger benefits for individuals with greater OCD severity, whereas the difference between treatment arms was minimal in those with lower severity. Implications of these findings for treatment of OCD are discussed.

Obsessive-Compulsive Symptoms Among Children in the Adolescent Brain and Cognitive Development Study: Clinical, Cognitive, and Brain Connectivity Correlates

BACKGROUND

Childhood obsessive-compulsive symptoms (OCSs) are common and can be an early risk marker for obsessive-compulsive disorder. The Adolescent Brain and Cognitive Development (ABCD) Study provides a unique opportunity to characterize OCSs in a large normative sample of school-age children and to explore corticostriatal and task-control circuits implicated in pediatric obsessive-compulsive disorder.

METHODS

The ABCD Study acquired data from 9- and 10-year-olds (N = 11,876). Linear mixed-effects models probed associations between OCSs (Child Behavior Checklist) and cognition (NIH Toolbox), brain structure (subcortical volume, cortical thickness), white matter (diffusion tensor imaging), and resting-state functional connectivity.

RESULTS

OCS scores showed good psychometric properties and high prevalence, and they were related to familial/parental factors, including family conflict. Higher OCS scores related to better cognitive performance (β = .06, t9966.60 = 6.28, p < .001, ηp2= .01), particularly verbal, when controlling for attention-deficit/hyperactivity disorder, which related to worse performance. OCSs did not significantly relate to brain structure but did relate to lower superior corticostriatal tract fractional anisotropy (β = -.03, t = -3.07, p = .002, ηp2= .02). Higher OCS scores were related to altered functional connectivity, including weaker connectivity within the dorsal attention network (β = -.04, t7262.87 = -3.71, p < .001, ηp2= .002) and weaker dorsal attention-default mode anticorrelation (β = .04, t7251.95 = 3.94, p < .001, ηp2 = .002). Dorsal attention-default mode connectivity predicted OCS scores at 1 year (β = -.04, t2407.61 = -2.23, p = .03, ηp2 = .03).

CONCLUSIONS

OCSs are common and may persist throughout childhood. Corticostriatal connectivity and attention network connectivity are likely mechanisms in the subclinical-to-clinical spectrum of OCSs. Understanding correlates and mechanisms of OCSs may elucidate their role in childhood psychiatric risk and suggest potential utility of neuroimaging, e.g., dorsal attention-default mode connectivity, for identifying children at increased risk for obsessive-compulsive disorder.

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.

Visuomotor Activation of Inhibition-Processing in Pediatric Obsessive Compulsive Disorder: A Magnetoencephalography Study

Background: Response inhibition engages the cortico-striato-thalamo-cortical (CSTC) circuit, which has been implicated in children, and youth with obsessive compulsive disorder (OCD). This study explored whether CSTC engagement during response inhibition, measured using magnetoencephalography (MEG), differed in a sample of medication-naïve youth with OCD, compared to typically developing controls (TDC). Methods: Data was analyzed in 17 medication-naïve children and youth with OCD (11.7 ± 2.2 SD years) and 13 TDC (12.6 ± 2.2 SD years). MEG was used to localize and characterize neural activity during a Go/No-Go task. Task performance on Go/No-Go conditions and regional differences in amplitude of activity during Go and No-Go condition between OCD vs. TDC were examined using two-sample t-tests. Post-hoc analysis with Bayesian t-tests was used to estimate the certainty of outcomes. Results: No differences in Go/No-Go performance were found between OCD and TDC groups. In response to the visual cue presented during the Go condition, participants with OCD showed significantly increased amplitude of activity in the primary motor (MI) cortex compared to TDC. In addition, significantly reduced amplitude of PCu was found following successful stopping to No-Go cues in OCD vs. TDC during No-Go task performance. Bayesian t-tests indicated high probability and large effect sizes for the differences in MI and PCu amplitude found between groups. Conclusion: Our preliminary study in a small medication-naïve sample extends previous work indicating intact response inhibition in pediatric OCD. While altered neural response in the current study was found during response inhibition performance in OCD, differences localized to regions outside of the CSTC. Our findings suggest that additional imaging research in medication-naïve samples is needed to clarify regional differences associated with OCD vs. influenced by medication effects, and suggest that MEG may be sensitive to detecting such differences.

On the Development of OCD

OCD most often arises before adulthood with adolescence being a particularly vulnerable period. This is also a time when both brain and cognition undergo fundamental developmental change and reorganisation. However, the neurocognitive mechanisms that drive the emergence of OCD during development are still largely unknown. In this chapter, I review the relatively sparse literature on the developmental aspects of OCD and I discuss the symptomatic, cognitive and neural patterns in OCD and the developing mind. I highlight how we need to understand the emergence of cognitive impairments and neural alteration in a developmental context if we want to understand more about the mechanisms that give rise to OCD. Moreover, I outline how we best approach this challenge to overcome the current limitations in research.

Serotonin system gene variants and regional brain volume differences in pediatric OCD

Obsessive-compulsive disorder (OCD) is phenotypically heterogeneous and genetically complex. This study aimed to reduce heterogeneity using structural brain imaging to study putative intermediate phenotypes for OCD. We hypothesized that select serotonin gene variants would differ in their relationship with brain volume in specific regions of the cortico-striato-thalamo-cortical (CSTC) circuits between OCD patients and controls. In a total of 200 pediatric subjects, we genotyped candidate serotonin genes (SLC6A4, HTR2A, HTR1B, and HTR2C) and conducted structural magnetic resonance imaging (sMRI) to measure regional brain volumes within CSTC circuits. In males and females separately, we first tested the association between serotonin gene variants and OCD and the effect of serotonin gene variants on brain volume irrespective of diagnosis. We then carried out a series of analyses to assess the effect of genotype-diagnosis interaction on brain volume. In females, but not in males, we identified a statistically significant genotype-diagnosis interaction for two single nucleotide polymorphisms (SNPs) in HTR2C, rs12860460 (interaction term estimate of 5.45 cc and interaction P value of 9.70e-8) and rs12854485 (interaction term estimate of 4.28 cc and interaction P value of 2.07e-6). The tested allele in each SNP was associated with decreased anterior cingulate cortex (ACC) volume in controls and with increased ACC volume in OCD patients. Our findings suggest that, in females, sequence variation in HTR2C influences ACC volume in pediatric OCD. The variants may contribute to differences in ACC volume and to OCD in a sex-specific manner when acting together with other genetic, biological, and/or environmental factors.

Towards a computational psychiatry of juvenile obsessive-compulsive disorder

Obsessive-Compulsive Disorder (OCD) most often emerges during adolescence, but we know little about the aberrant neural and cognitive developmental mechanisms that underlie its emergence during this critical developmental period. To move towards a computational psychiatry of juvenile OCD, we review studies on the computational, neuropsychological and neural alterations in juvenile OCD and link these findings to the adult OCD and cognitive neuroscience literature. We find consistent difficulties in tasks entailing complex decision making and set shifting, but limited evidence in other areas that are altered in adult OCD, such as habit and confidence formation. Based on these findings, we establish a neurocomputational framework that illustrates how cognition can go awry and lead to symptoms of juvenile OCD. We link these possible aberrant neural processes to neuroimaging findings in juvenile OCD and show that juvenile OCD is mainly characterised by disruptions of complex reasoning systems.

Intrinsic Synchronization Analysis of Brain Activity in Obsessive-compulsive Disorders

Obsessive-compulsive disorder (OCD) is one of the neuropsychiatric disorders qualified by intrusive and iterative annoying thoughts and mental attitudes that are activated by these thoughts. In recent studies, advanced signal processing techniques have been favored to diagnose OCD. This research suggests four different measurements; intrinsic phase-locked value, intrinsic coherence, intrinsic synchronization likelihood, and intrinsic visibility graph similarity that quantifies the synchronization level and complexity in electroencephalography (EEG) signals. This intrinsic synchronization is achieved by utilizing Multivariate Empirical Mode Decomposition (MEMD), a data-driven method that resolves nonlinear and nonstationary data into their intrinsic mode functions. Our intrinsic technique in this study demonstrates that MEMD-based synchronization analysis gives us much more detailed knowledge rather than utilizing the synchronization method alone. Furthermore, the nonlinear synchronization method presents more consistent results considering OCD heterogeneity. Statistical evaluation using sample [Formula: see text]-test and [Formula: see text]-test has shown the significance of such new methodology.

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.

Are candidate neurocognitive endophenotypes of OCD present in paediatric patients? A systematic review

To-date it has been difficult to ascertain the exact cognitive profile of childhood OCD as studies report variable results. Adult OCD research lately utilises the endophenotype approach; studying cognitive traits that are present in both patients and their unaffected first-degree relatives, and are thought to lie closer to the genotype than the full-blown disorder. By observing whether candidate endopenotypes of adult OCD are present in child patients, we can determine whether the two subtypes show cognitive overlap. We conducted a systematic review of the paediatric OCD literature focussing on proposed neurocognitive endophenotypes of OCD: cognitive flexibility, response inhibition, memory, planning, decision-making, action monitoring, and reversal learning. We found that paediatric patients present robust increases in brain error related negativity associated with abnormal action monitoring, impaired decision-making under uncertainty, planning, and visual working memory, but there is less evidence for deficits in other cognitive domains. This implies that children with OCD show some cognitive similarities with adult patients, but other dysfunctions may only manifest later in the disorder trajectory.

Efficacy and Safety of Deep Transcranial Magnetic Stimulation for Obsessive-Compulsive Disorder: A Prospective Multicenter Randomized Double-Blind Placebo-Controlled Trial

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a chronic and disabling condition that often responds unsatisfactorily to pharmacological and psychological treatments. Converging evidence suggests a dysfunction of the cortical-striatal-thalamic-cortical circuit in OCD, and a previous feasibility study indicated beneficial effects of deep transcranial magnetic stimulation (dTMS) targeting the medial prefrontal cortex and the anterior cingulate cortex. The authors examined the therapeutic effect of dTMS in a multicenter double-blind sham-controlled study.

METHODS

At 11 centers, 99 OCD patients were randomly allocated to treatment with either high-frequency (20 Hz) or sham dTMS and received daily treatments following individualized symptom provocation, for 6 weeks. Clinical response to treatment was determined using the Yale-Brown Obsessive Compulsive Scale (YBOCS), and the primary efficacy endpoint was the change in score from baseline to posttreatment assessment. Additional measures were response rates (defined as a reduction of ≥30% in YBOCS score) at the posttreatment assessment and after another month of follow-up.

RESULTS

Eighty-nine percent of the active treatment group and 96% of the sham treatment group completed the study. The reduction in YBOCS score among patients who received active dTMS treatment was significantly greater than among patients who received sham treatment (reductions of 6.0 points and 3.3 points, respectively), with response rates of 38.1% and 11.1%, respectively. At the 1-month follow-up, the response rates were 45.2% in the active treatment group and 17.8% in the sham treatment group. Significant differences between the groups were maintained at follow-up.

CONCLUSIONS

High-frequency dTMS over the medial prefrontal cortex and anterior cingulate cortex significantly improved OCD symptoms and may be considered as a potential intervention for patients who do not respond adequately to pharmacological and psychological interventions.

Neural correlates of symptom provocation in pediatric obsessive-compulsive disorder

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Largest controlled pediatric OCD symptom provocation study.

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Novel standardized symptom provocation picture set for pediatric OCD.

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Behavioral group differences strongest for ‘Just Right’ factor.

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Temporal pole recruited by OCD group.

Obsessive-compulsive disorder

(OCD)-affected adults and children exhibit three to four symptom dimensions with distinct but overlapping neural correlates. No symptom provocation behavioural or imaging study has examined all symptom dimensions in a pediatric OCD sample.

Method

Clinically diagnosed pediatric OCD-affected participants (n = 25) as well as age, gender and Tanner pubertal stage-matched healthy controls (HCs; n = 24) (total sample: mean age = 14.77 ± 2.93 years; age range = 9–18 years; 35% male) viewed alternating blocks of OCD symptom provocation (Contamination, Bad Thoughts, and Just Right symptom dimensions), Fear, Neutral and Rest (i.e. fixation) conditions during functional magnetic resonance imaging. A region-of-interest analysis used seeds based upon results of an adult OCD meta-analysis

Results

OCD participants found OCD symptom-related stimuli bothersome, particularly when compared to controls in the “Just Right” symptom dimension. Pediatric OCD patients exhibited greater recruitment of the left superior temporal gyrus (STG) than healthy controls during combined symptom provocation versus neutral conditions.

Conclusion

Findings suggest involvement of the temporal poles rather than in classic cortico-striatal-thalamico-cortical circuits in pediatric OCD during symptom provocation.

From self-induced to perceived errors - A generalized over-monitoring activity in obsessive-compulsive disorder

Well-functioning error monitoring of the inner and outer environments is essential for adaptively altering behavior, while malfunction characterizes conditions such as obsessive-compulsive disorder (OCD). The underlying brain processing is manifested as Error-Related Negativity (ERN) signal elicited following error comission, and Perceived Error Related Theta Activity (PERTA) signal elicited following detection of discrepancy in the environment. Yet, while enhanced ERN was repeatedly demonstrated in OCD patients and was found to be potentiated among their unaffected first degree relatives, no comparable observations were reported with regard to PERTA. We recorded EEG activity while OCD patients, OCD patients' siblings (Family), and healthy controls (HC) performed computerized tasks. For the examination of ERN we used the Stroop task and for the examination of PERTA we presented correct and incorrect mathematical equations. Increased ERN (0-120 ms post response) was observed in both the OCD and Family groups, but only the OCD patients' signal significantly differed from that of HC's. Similarly, modified PERTA activity was observed in both the OCD and Family groups in the N1 peak (65-125 ms post perceived error), but only for the OCD group this activity significantly differed from that of HC. Both ERN and PERTA's N1 are fast occurring peaks, which suggests that OCD is associate with a constantly over-activated detection system that monitors the inner and outer environment and reacts promptly following detection of a mistake. Furthermore, the modified but non-significantly different activity of the Family group suggests that the pathological condition evolves in vulnerable individuals with neuronal predisposition.

Pediatric OCD in the era of RDoC

The NIMH Research Domain Criteria (RDoC) initiative was established with the goal of developing an alternative research classification to further research efforts in mental health. While RDoC acknowledges that constructs should be considered within a developmental framework, developmental considerations have not yet been well integrated within the existing RDoC matrix. In this paper, we consider RDoC in relation to pediatric OCD, a paradigmatic example of a neuropsychiatric disorder that often has onset in childhood but is also present across the lifespan. We discuss three RDoC subdomains with relevance to OCD as exemplars, providing for each construct a brief review of normative developmental changes, the state of construct-relevant research in pediatric OCD, and challenges and limitations related to developmental considerations within each subdomain. Finally, we conclude with a brief discussion of how RDoC may continue to evolve with regard to developmental considerations in order to further research in pediatric OCD.

Early intervention for obsessive compulsive disorder: An expert consensus statement

Obsessive-compulsive disorder (OCD) is common, emerges early in life and tends to run a chronic, impairing course. Despite the availability of effective treatments, the duration of untreated illness (DUI) is high (up to around 10 years in adults) and is associated with considerable suffering for the individual and their families. This consensus statement represents the views of an international group of expert clinicians, including child and adult psychiatrists, psychologists and neuroscientists, working both in high and low and middle income countries, as well as those with the experience of living with OCD. The statement draws together evidence from epidemiological, clinical, health economic and brain imaging studies documenting the negative impact associated with treatment delay on clinical outcomes, and supporting the importance of early clinical intervention. It draws parallels between OCD and other disorders for which early intervention is recognized as beneficial, such as psychotic disorders and impulsive-compulsive disorders associated with problematic usage of the Internet, for which early intervention may prevent the development of later addictive disorders. It also generates new heuristics for exploring the brain-based mechanisms moderating the 'toxic' effect of an extended DUI in OCD. The statement concludes that there is a global unmet need for early intervention services for OC related disorders to reduce the unnecessary suffering and costly disability associated with under-treatment. New clinical staging models for OCD that may be used to facilitate primary, secondary and tertiary prevention within this context are proposed.

Functional and Structural Neural Changes in Obsessive-compulsive Disorder after Pharmacotherapy

Obsessive-compulsive disorder (OCD) is an important disorder which is disturbing the quality of life and is characterized by repetitive thoughts and behaviors, now in a different category in the Diagnostic and Statistical Manual for Mental Disorders Fifth Edition (DSM 5). Neuroimaging investigations are very useful to reveal a neurobiological model of the OCD. Studies conducted in the last quarter century have shown clear results and revealed that specific cortico-subcortical circuits could be involved in the occurrence of OCD symptomatology. These neuroimaging studies pointed out some important findings for OCD patients. Our present information implicates some problems in some cortico-subcortical in the pathophysiology of OCD. In the present paper, final information on the neuroanatomy and neurochemistry of OCD was reviewed, revising the effects of anti-obsessional drugs on the structural and functional neuroimaging studies. As can be seen in the review, drug treatments can generally affect the brain structurally and functionally, suggesting that brain of OCD tends to neuroplasticity. However, it is not clear that these effects of pharmacotherapy are related to anti-obsessional drugs per se or impact on the improvement of the disorder.

The Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation at Orbitofrontal Cortex in the Treatment of Patients With Medication-Refractory Obsessive-Compulsive Disorder: A Retrospective Open Study

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a chronic debilitating psychiatric disorder, with significant proportion of patients failing to respond with current first-line treatments. The present study assesses the safety and effectiveness of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) over left-orbitofrontal cortex (Lt-OFC) as a potential augmentation strategy in treatment of patients with medication-refractory OCD in real-world clinical setting. The present report also aims to examine the factors affecting response to rTMS and the durability of effects produced by rTMS over 1 month of follow-up period.

METHODS

Retrospective review and analysis of clinical case files of 25 patients with medication-refractory OCD, all of whom had received 20 sessions of LF-rTMS over Lt-OFC as part of routine clinical care. A reduction of 25% and 35% in Yale-Brown Obsessive Compulsive Scale scores was used to determine the proportion of partial and complete responders, respectively.

RESULTS

There was a significant decrease in mean Yale-Brown Obsessive Compulsive Scale score at the end of 20 sessions of rTMS compared with baseline (7.04 ± 5.07; P < 0.001), with no further significant change during the subsequent 1-month follow-up period (0.20 ± 1.38; P = 0.47). Thirteen patients (52%) met criteria for partial response, of which 11 patients (44%) showed complete response. Furthermore, higher number of failed medication trials was found to be significantly associated with greater chances of nonresponse to rTMS treatment.

CONCLUSIONS

There is a role of applying LF-rTMS over Lt-OFC as an augmentation strategy in ameliorating clinical symptoms among patients with medication-refractory OCD.

Cool and Hot Aspects of Executive Function in Childhood Obsessive-Compulsive Disorder

Aspects of executive functioning (EF) have been put forward as endophenotypes in obsessive- compulsive disorder (OCD) and meta-analyses support EF underperformance in adult samples. Childhood-onset OCD has been suggested to constitute a separate neurodevelopmental subtype of the disorder but studies on neuropsychological functioning in childhood OCD are limited. The aim of the present study was to investigate performance-based EF in pediatric OCD using observed and latent variable analyses. A case-control design was applied including 50 unmedicated children and adolescents with OCD aged 7-17 years of which 70% were female, 50 pairwise age and gender matched non-psychiatric controls (NP) and 38 children and adolescents with mixed anxiety disorders (MA). Participants underwent structured diagnostic interviews and assessment with a battery encompassing cool EF tasks of working memory, set shifting, inhibition, and planning, and hot EF tasks of decision making and dot probe paradigm affective interference. First, groups were compared on observed variables with multilevel mixed-effects linear regression and analysis of variance. Then the latent structure of cool EF was tested with confirmatory factor analysis (CFA) and groups were compared on the CFA scores. No significant differences between groups appeared on individual cool EF tasks. On the hot EF tasks the OCD group displayed significant interference effects on the dot probe paradigm OCD-specific stimuli relative to NP, but not compared to MA and no group differences emerged for decision making. In the CFA a one-factor solution showed best fit, but the groups did not differ significantly on the resulting latent variable. The present study does not support cool or hot EF impairments in childhood OCD.

Multivariate resting-state functional connectivity predicts response to cognitive behavioral therapy in obsessive-compulsive disorder

Cognitive behavioral therapy (CBT) is an effective treatment for many with obsessive-compulsive disorder (OCD). However, response varies considerably among individuals. Attaining a means to predict an individual's potential response would permit clinicians to more prudently allocate resources for this often stressful and time-consuming treatment. We collected resting-state functional magnetic resonance imaging from adults with OCD before and after 4 weeks of intensive daily CBT. We leveraged machine learning with cross-validation to assess the power of functional connectivity (FC) patterns to predict individual posttreatment OCD symptom severity. Pretreatment FC patterns within the default mode network and visual network significantly predicted posttreatment OCD severity, explaining up to 67% of the variance. These networks were stronger predictors than pretreatment clinical scores. Results have clinical implications for developing personalized medicine approaches to identifying individual OCD patients who will maximally benefit from intensive CBT.

Increased decision thresholds trigger extended information gathering across the compulsivity spectrum

Indecisiveness and doubt are cognitive phenotypes of compulsive disorders, including obsessive-compulsive disorder. Little is known regarding the cognitive mechanisms that drive these behaviours across a compulsivity spectrum. Here, we used a sequential information gathering task to study indecisiveness in subjects with high and low obsessive-compulsive scores. These subjects were selected from a large population-representative database, and matched for intellectual and psychiatric factors. We show that high compulsive subjects sampled more information and performed better when sampling was cost-free. When sampling was costly, both groups adapted flexibly to reduce their information gathering. Computational modelling revealed that increased information gathering behaviour could be explained by higher decision thresholds that, in turn, were driven by a delayed emergence of impatience or urgency. Our findings show that indecisiveness generalises to a compulsivity spectrum beyond frank clinical disorder, and this behaviour can be explained within a decision-theoretic framework as arising from an augmented decision threshold associated with an attenuated urgency signal.

Shared and Disorder-Specific Neurocomputational Mechanisms of Decision-Making in Autism Spectrum Disorder and Obsessive-Compulsive Disorder

Autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD) often share phenotypes of repetitive behaviors, possibly underpinned by abnormal decision-making. To compare neural correlates underlying decision-making between these disorders, brain activation of boys with ASD (N = 24), OCD (N = 20) and typically developing controls (N = 20) during gambling was compared, and computational modeling compared performance. Patients were unimpaired on number of risky decisions, but modeling showed that both patient groups had lower choice consistency and relied less on reinforcement learning compared to controls. ASD individuals had disorder-specific choice perseverance abnormalities compared to OCD individuals. Neurofunctionally, ASD and OCD boys shared dorsolateral/inferior frontal underactivation compared to controls during decision-making. During outcome anticipation, patients shared underactivation compared to controls in lateral inferior/orbitofrontal cortex and ventral striatum. During reward receipt, ASD boys had disorder-specific enhanced activation in inferior frontal/insular regions relative to OCD boys and controls. Results showed that ASD and OCD individuals shared decision-making strategies that differed from controls to achieve comparable performance to controls. Patients showed shared abnormalities in lateral-(orbito)fronto-striatal reward circuitry, but ASD boys had disorder-specific lateral inferior frontal/insular overactivation, suggesting that shared and disorder-specific mechanisms underpin decision-making in these disorders. Findings provide evidence for shared neurobiological substrates that could serve as possible future biomarkers.

Comparison of neural substrates of temporal discounting between youth with autism spectrum disorder and with obsessive-compulsive disorder

BACKGROUND

Autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD) share abnormalities in hot executive functions such as reward-based decision-making, as measured in the temporal discounting task (TD). No studies, however, have directly compared these disorders to investigate common/distinct neural profiles underlying such abnormalities. We wanted to test whether reward-based decision-making is a shared transdiagnostic feature of both disorders with similar neurofunctional substrates or whether it is a shared phenotype with disorder-differential neurofunctional underpinnings.

METHODS

Age and IQ-matched boys with ASD (N = 20), with OCD (N = 20) and 20 healthy controls, performed an individually-adjusted functional magnetic resonance imaging (fMRI) TD task. Brain activation and performance were compared between groups.

RESULTS

Boys with ASD showed greater choice-impulsivity than OCD and control boys. Whole-brain between-group comparison revealed shared reductions in ASD and OCD relative to control boys for delayed-immediate choices in right ventromedial/lateral orbitofrontal cortex extending into medial/inferior prefrontal cortex, and in cerebellum, posterior cingulate and precuneus. For immediate-delayed choices, patients relative to controls showed reduced activation in anterior cingulate/ventromedial prefrontal cortex reaching into left caudate, which, at a trend level, was more decreased in ASD than OCD patients, and in bilateral temporal and inferior parietal regions.

CONCLUSIONS

This first fMRI comparison between youth with ASD and with OCD, using a reward-based decision-making task, shows predominantly shared neurofunctional abnormalities during TD in key ventromedial, orbital- and inferior fronto-striatal, temporo-parietal and cerebellar regions of temporal foresight and reward processing, suggesting trans-diagnostic neurofunctional deficits.

1H magnetic resonance spectroscopy evidence for occipital involvement in treatment-naive paediatric obsessive-compulsive disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a chronic psychiatric disorder leading to considerable distress and disability. Therapies are effective in a majority of paediatric patients, however, many only get partial response. It is therefore important to study the underlying pathophysiology of the disorder.

METHODS

1H magnetic resonance spectroscopy (MRS) was used to study the concentration of brain metabolites in four different locations (cingulate gyrus and sulcus, occipital cortex, thalamus and right caudate nucleus). Treatment-naive children and adolescents with OCD (13 subjects) were compared with a group of healthy age- and gender-matched subjects (11 subjects). Multivariate analyses were performed on the concentration values.

RESULTS

No separation between controls and patients was found. However, a correlation between metabolite concentrations and symptom severity as measured with the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) was found. Strongest was the correlation with the CY-BOCS obsession subscore and aspartate and choline in the caudate nucleus (positively correlated with obsessions), lipids at 2 and 0.9 ppm in thalamus, and occipital glutamate+glutamine, N-acetylaspartate and myo-inosytol (negatively correlated with obsessions).

CONCLUSIONS

The observed correlations between 1H MRS and CY-BOCS in treatment-naive patients further supports an occipital involvement in OCD. The results are consistent with our previous study on adult OCD patients. The 1H MRS data were not supportive of a separation between the patient and control groups.

Increased fronto-striatal reward prediction errors moderate decision making in obsessive-compulsive disorder

BACKGROUND

Obsessive-compulsive disorder (OCD) has been linked to functional abnormalities in fronto-striatal networks as well as impairments in decision making and learning. Little is known about the neurocognitive mechanisms causing these decision-making and learning deficits in OCD, and how they relate to dysfunction in fronto-striatal networks.

METHOD

We investigated neural mechanisms of decision making in OCD patients, including early and late onset of disorder, in terms of reward prediction errors (RPEs) using functional magnetic resonance imaging. RPEs index a mismatch between expected and received outcomes, encoded by the dopaminergic system, and are known to drive learning and decision making in humans and animals. We used reinforcement learning models and RPE signals to infer the learning mechanisms and to compare behavioural parameters and neural RPE responses of the OCD patients with those of healthy matched controls.

RESULTS

Patients with OCD showed significantly increased RPE responses in the anterior cingulate cortex (ACC) and the putamen compared with controls. OCD patients also had a significantly lower perseveration parameter than controls.

CONCLUSIONS

Enhanced RPE signals in the ACC and putamen extend previous findings of fronto-striatal deficits in OCD. These abnormally strong RPEs suggest a hyper-responsive learning network in patients with OCD, which might explain their indecisiveness and intolerance of uncertainty.

Increased decision thresholds enhance information gathering performance in juvenile Obsessive-Compulsive Disorder (OCD)

Patients with obsessive-compulsive disorder (OCD) can be described as cautious and hesitant, manifesting an excessive indecisiveness that hinders efficient decision making. However, excess caution in decision making may also lead to better performance in specific situations where the cost of extended deliberation is small. We compared 16 juvenile OCD patients with 16 matched healthy controls whilst they performed a sequential information gathering task under different external cost conditions. We found that patients with OCD outperformed healthy controls, winning significantly more points. The groups also differed in the number of draws required prior to committing to a decision, but not in decision accuracy. A novel Bayesian computational model revealed that subjective sampling costs arose as a non-linear function of sampling, closely resembling an escalating urgency signal. Group difference in performance was best explained by a later emergence of these subjective costs in the OCD group, also evident in an increased decision threshold. Our findings present a novel computational model and suggest that enhanced information gathering in OCD can be accounted for by a higher decision threshold arising out of an altered perception of costs that, in some specific contexts, may be advantageous.

Biological markers for anxiety disorders, OCD and PTSD - a consensus statement. Part I: Neuroimaging and genetics

OBJECTIVES

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part I) summarises findings on potential biomarkers in neuroimaging studies, including structural brain morphology, functional magnetic resonance imaging and techniques for measuring metabolic changes, including positron emission tomography and others. Furthermore, this review reports on the clinical and molecular genetic findings of family, twin, linkage, association and genome-wide association studies. Part II of the review focuses on neurochemistry, neurophysiology and neurocognition.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high-quality research has accumulated that will improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Developmental Neuroimaging in Pediatric Obsessive-Compulsive Disorder

Purpose of review

This review examines emerging neuroimaging research in pediatric obsessive compulsive disorder (OCD) and explores the possibility that developmentally sensitive mechanisms may underlie OCD across the lifespan.

Recent findings

Diffusion tensor imaging (DTI) studies of pediatric OCD reveal abnormal structural connectivity within frontal-striato-thalamic circuity (FSTC). Resting-state functional magnetic resonance imaging (fMRI) studies further support atypical FSTC connectivity in young patients, but also suggest altered connectivity within cortical networks for task-control. Task-based fMRI studies show that hyper- and hypo-activation of task control networks may depend on task difficulty in pediatric patients similar to recent findings in adults.

Summary

This review suggests that atypical neurodevelopmental trajectories may underlie the emergence and early course of OCD. Abnormalities of structural and functional connectivity may vary with age, while functional engagement during task may vary with age and task complexity. Future research should combine DTI, resting-state fMRI and task-based fMRI methods and incorporate longitudinal designs to reveal developmentally sensitive targets for intervention.

Neural correlates associated with symptom provocation in pediatric obsessive compulsive disorder after a single session of sham-controlled repetitive transcranial magnetic stimulation

Treatments for pediatric obsessive-compulsive disorder (OCD) could be enhanced if the physiological changes engendered by treatment were known. This study examined neural correlates of a provocation task in youth with OCD, before and after sham-controlled repetitive transcranial magnetic stimulation (rTMS). We hypothesized that rTMS to the right dorsolateral prefrontal cortex would inhibit activity in cortico-striato-thalamic (CST) circuits associated with OCD to a greater extent than sham rTMS. After baseline (Time 1) functional magnetic resonance imaging (fMRI) during a provocation task, subjects received one session of either fMRI-guided sham (SG; n=8) or active (AG; n=10) 1-Hz rTMS over the rDLPFC for 30min. During rTMS, subjects were presented with personalized images that evoked OCD-related anxiety. Following stimulation, fMRI and the provocation task were repeated (Time 2). Contrary to our prediction for the provocation task, the AG was associated with no changes in BOLD response from Times 1 to 2. In contrast, the SG had a significant increase at Time 2 in BOLD response in the right inferior frontal gyrus and right putamen, which persisted after adjusting for age, gender, and time to scanner as covariates. This study provides an initial framework for TMS interrogation of the CST circuit in pediatric OCD.

White matter structural alterations in pediatric obsessive-compulsive disorder: relation to symptom dimensions

The aims of this study were to identify gray matter (GM) and white matter (WM) volume abnormalities in pediatric obsessive-compulsive patients, to examine their relationship between these abnormalities and the severity of disorder, and to explore whether they could be explained by the different symptom dimensions.

METHODS

62 child and adolescent OCD patients (11-18years old) and 46 healthy subjects of the same gender and similar age and estimated intellectual quotient were assessed by means of psychopathological scales and magnetic resonance imaging (MRI). Axial three-dimensional T1-weighted images were obtained in a 3T scanner and analyzed using optimized voxel-based morphometry (VBM).

RESULTS

Compared with healthy controls, OCD patients showed lower white matter (WM) volume in the left dorsolateral and cingulate regions involving the superior and middle frontal gyri and anterior cingulate gyrus (t=4.35, p=0.049 FWE (family wise error)-corrected). There was no significant correlation between WM and the severity of obsessive-compulsive symptomatology. There were no regions with lower gray matter (GM) volume in OCD patients than in controls. Compared with healthy controls, only the "harm/checking" OCD dimension showed a cluster with a near significant decrease in WM volume in the right superior temporal gyrus extending into the insula (t=5.61, p=.056 FWE-corrected).

CONCLUSION

The evidence suggests that abnormalities in the dorsolateral prefrontal cortex, anterior cingulate cortex, temporal and limbic regions play a central role in the pathophysiology of OCD. Moreover, regional brain volumes in OCD may vary depending on specific OCD symptom dimensions, indicating the clinical heterogeneity of the condition.

Management of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a common, often debilitating disorder characterized by the presence of obsessions and compulsions. Obsessions are repetitive thoughts or images which are experienced as intrusive and unwanted; they cause marked anxiety and distress. Compulsions (also known as rituals) are repetitive behaviors or mental acts that individuals with OCD perform in an attempt to decrease their anxiety. Patients tend to hide their symptoms due to shame; the amount of time between onset of symptoms and appropriate treatment is often many years. The disorder likely results from several etiological variables; functional imaging studies have consistently shown hyperactivity in the orbitofrontal cortex, anterior cingulate, thalamus, and striatum. The mainstays of treatment include cognitive-behavioral therapy in the form of exposure and response prevention (ERP) and serotonin reuptake inhibiting medications. Several pharmacological augmentation strategies exist for treatment-resistant OCD, with addition of antipsychotics being most commonly employed. Radio and neurosurgical procedures, including gamma knife radiation and deep brain stimulation, are reserved for severe, treatment-refractory disease that has not responded to multiple treatments, and some patients may benefit from transcranial magnetic stimulation.

Imaging genetics in obsessive-compulsive disorder: linking genetic variations to alterations in neuroimaging

Obsessive-compulsive disorder (OCD) occurs in ∼1-3% of the general population, and its often rather early onset causes major disabilities in the everyday lives of patients. Although the heritability of OCD is between 35 and 65%, many linkage, association, and genome-wide association studies have failed to identify single genes that exhibit high effect sizes. Several neuroimaging studies have revealed structural and functional alterations mainly in cortico-striato-thalamic loops. However, there is also marked heterogeneity across studies. These inconsistencies in genetic and neuroimaging studies may be due to the heterogeneous and complex phenotypes of OCD. Under the consideration that genetic variants may also influence neuroimaging in OCD, researchers have started to combine both domains in the field of imaging genetics. Here, we conducted a systematic search of PubMed and Google Scholar literature for articles that address genetic imaging in OCD and related disorders (published through March 2014). We selected 8 publications that describe the combination of imaging genetics with OCD, and extended it with 43 publications of comorbid psychiatric disorders. The most promising findings of this systematic review point to the involvement of variants in genes involved in the serotonergic (5-HTTLPR, HTR2A), dopaminergic (COMT, DAT), and glutamatergic (SLC1A1, SAPAP) systems. However, the field of imaging genetics must be further explored, best through investigations that combine multimodal imaging techniques with genetic profiling, particularly profiling techniques that employ polygenetic approaches, with much larger sample sizes than have been used up to now.

The neurobiological link between OCD and ADHD

Obsessive compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) are two of the most common neuropsychiatric diseases in paediatric populations. The high comorbidity of ADHD and OCD with each other, especially of ADHD in paediatric OCD, is well described. OCD and ADHD often follow a chronic course with persistent rates of at least 40–50 %. Family studies showed high heritability in ADHD and OCD, and some genetic findings showed similar variants for both disorders of the same pathogenetic mechanisms, whereas other genetic findings may differentiate between ADHD and OCD. Neuropsychological and neuroimaging studies suggest that partly similar executive functions are affected in both disorders. The deficits in the corresponding brain networks may be responsible for the perseverative, compulsive symptoms in OCD but also for the disinhibited and impulsive symptoms characterizing ADHD. This article reviews the current literature of neuroimaging, neurochemical circuitry, neuropsychological and genetic findings considering similarities as well as differences between OCD and ADHD.