Inflammation in the Neurocircuitry of Obsessive-Compulsive Disorder

Neural dynamics in co-morbid schizophrenia and OCD: A computational approach

The co-morbidity of obsessive-compulsive disorder (OCD) and schizophrenia is higher than what would be expected by chance and the common underlying neuropathophysiology is not well understood. Repetitive stereotypes and routines can be caused by perseverative thoughts and motor sequences in both of these disorders. We extended a previously published computational model to investigate cortico-striatal network dynamics. Given the considerable overlap in symptom phenomenology and the high degree of co-morbidity between OCD and schizophrenia, we examined the dynamical consequences of functional connectivity variations in the overlapping network. This was achieved by focusing on the emergence of network oscillatory activity and examining parameter sensitivity. Opposing activity levels are present in orbitofrontal cortex (OFC) and anterior cingulate cortex (ACC) in schizophrenia and OCD. We found that with over-compensation of the primary pathology, emergence of the other disorder can occur. The oscillatory behavior is delicately modulated by connections between the OFC/ACC to the ventral and dorsal striatum and by the coupling between the ACC and dorsolateral prefrontal cortex (DLPFC). Modulation on cortical self-inhibition (e.g. serotonin reuptake inhibitor treatment) together with dopaminergic input to the striatum (e.g. anti-dopaminergic medication) has non-trivial complex effects on the network oscillatory behavior, with an optimal modulatory window. Additionally, there are several disruption mechanisms and compensatory processes in the cortico-striato-thalamic network which may contribute to the underlying neuropathophysiology and clinical heterogeneity in schizo-obsessive spectrum disorders. Our mechanistic model predicts that dynamic over-compensation of the primarily occuring neuropathophysiology can lead to the secondary co-morbid disease.

Immunoglobulin A Dysgammaglobulinemia Is Associated with Pediatric-Onset Obsessive-Compulsive Disorder

Background: Inflammation and immune dysregulation have been implicated in the pathogenesis of pediatric-onset obsessive-compulsive disorder (OCD) and tic disorders such as Tourette syndrome (TS). Though few replicated studies have identified markers of immune dysfunction in this population, preliminary studies suggest that serum immunoglobulin A (IgA) concentrations may be abnormal in these children with these disorders. Methods: This observational retrospective cohort study, conducted using electronic health records (EHRs), identified 206 children with pediatric-onset OCD and 1024 adults diagnosed with OCD who also had testing for serum levels of IgA. IgA deficiency and serum IgA levels in pediatric OCD were compared with IgA levels from children diagnosed with autism spectrum disorders (ASD; n = 524), tic disorders (n = 157), attention-deficit/hyperactivity disorder (ADHD; n = 534), anxiety disorders (n = 1206), and celiac disease, a condition associated with IgA deficiency (n = 624). Results: Compared with ASD and anxiety disorder cohorts, the pediatric OCD cohort displayed a significantly higher likelihood of IgA deficiency (OR = 1.93; 95% CI = 1.18-3.16, and OR = 1.98; 95% CI = 1.28-3.06, respectively), though no difference was observed between pediatric OCD and TS cohorts. Furthermore, the pediatric OCD cohort displayed similar rates of IgA deficiency and serum IgA levels when compared with the celiac disease cohort. The pediatric OCD cohort also displayed the highest percentage of IgA deficiency (15%,) when compared with TS (14%), celiac disease (14%), ADHD (13%), ASD (8%), and anxiety disorder (8%) cohorts. When segregated by sex, boys with OCD displayed a significantly higher likelihood of IgA deficiency when compared with all comparison cohorts except for celiac disease and tic disorders; no significant difference in IgA deficiency was observed between female cohorts. Pediatric OCD subjects also displayed significantly lower adjusted serum IgA levels than the ASD and anxiety disorder cohorts. Adults with OCD were also significantly less likely than children with OCD to display IgA deficiency (OR = 2.71; 95% CI = 1.71-4.28). When compared with children with celiac disease, no significant difference in IgA levels or rates of IgA deficiency were observed in the pediatric OCD cohort. Conclusions: We provide further evidence of IgA abnormalities in pediatric-onset OCD. These results require further investigation to determine if these abnormalities impact the clinical course of OCD in children.

Obsessive-Compulsive Disorder: Puzzles and Prospects

Obsessive-compulsive disorder is a severe and disabling psychiatric disorder that presents several challenges for neuroscience. Recent advances in its genetic and developmental causation, as well as its neuropsychological basis, are reviewed. Hypotheses concerning an imbalance between goal-directed and habitual behavior together with neural correlates in cortico-striatal circuitry are evaluated and contrasted with metacognitive theories. Treatments for obsessive-compulsive disorder (OCD) tend to be of mixed efficacy but include psychological, pharmacological, and surgical approaches, the underlying mechanisms of which are still under debate. Overall, the prospects for new animal models and an integrated understanding of the pathophysiology of OCD are considered in the context of dimensional psychiatry.

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.

Initial findings of striatum tripartite model in OCD brain samples based on transcriptome analysis

Obsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by obsessions and/or compulsions. Different striatal subregions belonging to the cortico-striato-thalamic circuitry (CSTC) play an important role in the pathophysiology of OCD. The transcriptomes of 3 separate striatal areas (putamen (PT), caudate nucleus (CN) and accumbens nucleus (NAC)) from postmortem brain tissue were compared between 6 OCD and 8 control cases. In addition to network connectivity deregulation, different biological processes are specific to each striatum region according to the tripartite model of the striatum and contribute in various ways to OCD pathophysiology. Specifically, regulation of neurotransmitter levels and presynaptic processes involved in chemical synaptic transmission were shared between NAC and PT. The Gene Ontology terms cellular response to chemical stimulus, response to external stimulus, response to organic substance, regulation of synaptic plasticity, and modulation of synaptic transmission were shared between CN and PT. Most genes harboring common and/or rare variants previously associated with OCD that were differentially expressed or part of a least preserved coexpression module in our study also suggest striatum subregion specificity. At the transcriptional level, our study supports differences in the 3 circuit CSTC model associated with OCD.

Challenges in the diagnosis and treatment of pediatric obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) affects 1%-3% of children worldwide and has a profound impact on quality of life for patients and families. Although our understanding of the underlying etiology remains limited, data from neuroimaging and genetic studies as well as the efficacy of serotonergic medications suggest the disorder is associated with the fundamental alterations in the function of cortico-striato-thalamocortical circuits. Significant delays to diagnosis are common, ultimately leading to more severe functional impairment with long-term developmental consequences. The clinical assessment requires a detailed history of specific OCD symptoms as well as psychiatric and medical comorbidities. Standardized assessment tools may aid in evaluating and tracking symptom severity and both individual and family functioning. In the majority of children, an interdisciplinary approach that combines cognitive behavioral therapy with a serotonin reuptake inhibitor leads to meaningful symptom improvement, although some patients experience a chronic, episodic course. There are limited data to guide the management of treatment-refractory illness in children, although atypical antipsychotics and glutamate-modulating agents may be used cautiously as augmenting agents. This review outlines a clinical approach to the diagnosis and management of OCD, highlighting associated challenges, and limitations to our current knowledge.

Diagnostic Issues in Early-Onset Obsessive-Compulsive Disorder and their Treatment Implications

BACKGROUND

The lifespan approach and recent shift in the conceptualization of Obsessive- Compulsive Disorder (OCD) promoted by the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM5) along with novel insights into the pathogenesis of this heterogeneous disorder are driving the development of new outcome measures and new treatments for a disease that, on the other hand, is characterized by high rates of refractoriness.

OBJECTIVE AND METHODS

The aim of this review is to provide a discussion of the translational evidence about Early Onset OCD (EO) in compliance with a neurodevelopmental and RdoC perspective.

RESULTS AND CONCLUSION

EO might be considered the neurodevelopmental subtype of OCD. Indeed there is evidence that different clusters of symptoms and dimensions at an early stage predict different trajectories in phenotype and that distinct neurocircuit pathways underpin the progression of the disorder. Despite the development of high refractoriness in the course of the disorder, evidence suggests that EO may be particularly treatment responsive in the early stages, thus showing the need for early recognition and additional recovery oriented studies in this subgroup. Consistent with the neurodevelopmental perspective, immunity and glutamate neurotransmission are emerging as novel pathways for parsing out the neurobiology of OCD, the EO form, in particular, supporting the implementation of new multisystemic models of the OCD phenotype. Brain connectivity patterns, immune and microbiome profiles are standing out as promising areas for biomarkers with the potential for targeted personalized therapies in EO.

Immune Aberrations in Obsessive-Compulsive Disorder: a Systematic Review and Meta-analysis

Some lines of evidence have indicated that immune dysregulation could play a role in the pathophysiology of obsessive-compulsive disorder (OCD). However, results have been inconsistent across studies. Thus, a systematic review and meta-analysis of studies measuring immune mediators in participants with OCD compared to healthy controls (HC) was conducted. The PubMed/MEDLINE, PsycINFO, and EMBASE electronic databases were systematically searched from inception through June 21, 2018. Sixteen studies met inclusion criteria comprising data from 1001 participants (538 with OCD and 463 were HCs). Levels of TNF-α, IL-6, IL-1β, IL-4, IL-10, and interferon-γ did not significantly differ between participants with OCD and healthy controls. In addition, the ex vivo production of TNF-α and IL-6 by isolated macrophages did not significantly differ between participants with OCD and HCs. Nevertheless, included studies have varied in methodological quality with the enrollment of samples that differed regarding medication status, the proper matching of OCD participants and HCs, age groups, and the presence of psychiatric comorbidities. In conclusion, an association between immune dysregulation and OCD remains unproven. Future studies should consider enrolling larger and more homogeneous samples with OCD.

Current and up-and-coming pharmacotherapy for obsessive-compulsive disorder in adults

INTRODUCTION

Only 40-60% of obsessive-compulsive patients respond to first line treatments, such as selective serotonin reuptake inhibitors (SSRIs) and cognitive-behavioral therapy. Several second-line treatments have been investigated in the last two decades, and most of them seem to work, at least in a subset of patients. However, since there is still a lack of treatment predictors, the treatment of obsessive-compulsive disorder (OCD) is still empirical and non-evidence based.

AREAS COVERED

In this paper, we review current and up-and-coming pharmacotherapy for OCD in adults, focusing on two emerging fields of research, inflammation and glutamate systems, since they have attracted the greatest attention in recent years in OCD pharmacological research.

EXPERT OPINION

Most of the investigated second-line agents seem to work at least in a subset of patients with OCD. These results raise an open question: what works for who? In our opinion, this question should be answered in a precision medicine perspective or, in other words, individualizing diagnostic processes and treatment approaches. In a precision medicine approach, OCD treatment should be sub-type specific, phase specific, multimodal and sequential, and, more importantly, dimensional.

Serum Proteomic Study of Women With Obsessive-Compulsive Disorder, Washing Subtype

Introduction

Many genetic studies are conducted on Obsessive-Compulsive Disorder (OCD). however, a high-throughput examination of proteome profile of this severe disease has not been performed yet.

Methods

Here, the proteomic study of OCD patients' serum samples was conducted by the application of Two-Dimensional Electrophoresis (2DE) followed by Mass Spectrometry (MALDI-TOF-TOF).

Results

A total of 240 protein spots were detected and among them, five significant differentially expressed protein spots with the fold change of ≥1.5 were considered for further evaluations. These proteins include IGKC, GC, HPX, and two isoforms of HP. While IGKC and HP show down-regulation, GC and HPX indicate up-regulation. Moreover, a validation study of overall HP levels in patients' serum via nephelometric quantification confirmed the lower levels of this protein in the serum of OCD patients. Additionally, enrichment analysis and validation test revealed that inflammation is one of most dominant processes in OCD.

Conclusion

It is suggested that these candidate proteins and their underlying processes (especially, inflammation) may be linked to OCD pathophysiology and can promise a clinical use after extensive validation studies.

Individualized Immunological Data for Precise Classification of OCD Patients

Obsessive⁻compulsive disorder (OCD) affects about 2% of the general population, for which several etiological factors were identified. Important among these is immunological dysfunction. This review aims to show how immunology can inform specific etiological factors, and how distinguishing between these etiologies is important from a personalized treatment perspective. We found discrepancies concerning cytokines, raising the hypothesis of specific immunological etiological factors. Antibody studies support the existence of a potential autoimmune etiological factor. Infections may also provoke OCD symptoms, and therefore, could be considered as specific etiological factors with specific immunological impairments. Finally, we underline the importance of distinguishing between different etiological factors since some specific treatments already exist in the context of immunological factors for the improvement of classic treatments.

Salivary Inflammatory Markers in Trichotillomania: A Pilot Study

BACKGROUND

Immune dysregulation has been hypothesized to be important in the development and pathophysiology of compulsive disorders such as obsessive compulsive disorder (OCD), which has a high comorbid overlap with trichotillomania (both are OC-related disorders). The role of inflammation in the pathophysiology of trichotillomania has garnered little research to date.

METHODS

Individuals with trichotillomania provided saliva sample for analysis of inflammatory cytokines. Additionally, these participants were examined on a variety of demographic variables (including body mass index [BMI], previously found to relate to inflammation) along with clinical measures (symptom severity, functioning, and comorbidity).

RESULTS

Thirty-one participants, mean age of 24.7 (±10.2) years, 27 (87.1%) females were -included. The mean score on the Massachusetts General Hospital Hair Pulling Scale was 15.7 (±4.2), reflective of moderate symptom severity. Compared to normative data, the mean inflammatory marker levels in the trichotillomania sample had the following Z scores: interleukin-1β (IL-1β) Z = -0.26, IL-6 Z = -0.39, IL-8 Z = -0.32, and tumor necrosis factor-α Z = -0.83. Levels of inflammatory markers did not correlate significantly with BMI, depressive mood, symptom severity, or disability.

CONCLUSIONS

The relatively low level of inflammatory saliva cytokines observed in the current study (negative z scores versus normative data with medium effect sizes) indicates that evaluation of blood inflammatory levels in trichotillomania versus matched controls would be valuable in future work. If a hypoinflammatory state is confirmed -using blood samples, this would differentiate trichotillomania from other mental disorders (such as OCD, schizophrenia, and depression), which have typically been linked with high inflammatory measures in the literature, at least in some cases.

Tourette syndrome research highlights from 2017

This is the fourth yearly article in the Tourette Syndrome Research Highlights series, summarizing research from 2017 relevant to Tourette syndrome and other tic disorders. The authors briefly summarize reports they consider most important or interesting. The  highlights from 2018 article is being drafted on the Authorea online authoring platform, and readers are encouraged to add references or give feedback on our selections using the comments feature on that page. After the calendar year ends, the article is submitted as the annual update for the Tics collection on F1000Research.

From Feline Idiopathic Ulcerative Dermatitis to Feline Behavioral Ulcerative Dermatitis: Grooming Repetitive Behaviors Indicators of Poor Welfare in Cats

Feline idiopathic head-and-neck dermatitis—also named feline idiopathic ulcerative dermatitis (IUD)—is considered as a rare skin disease of unknown origin. It is usually associated with a crusted, non-healing, self-induced ulcer occurring most commonly on the dorsal or lateral neck or between the scapula where self-grooming by scratching occurs. Usually, IUD is diagnosed after exclusion of other causes of pruritus. In feline medicine, self-induced alopecia is recognized as a behavioral disorder (abnormal repetitive behavior) due to excessive licking, which is an amplification of a normal maintenance behavior. Such repetitive behaviors, like self-induced alopecia or self-induced wounds, are named stereotypies and considered as indicators of poor welfare. The objectives of our study were to determine, first, if the repetitive behavior associated with self-induced wounds was related to a poor welfare, and, second, if improving the welfare in the cat’s environment would lead to healing, thanks to environmental enrichment. We recruited 13 cats diagnosed with IUD by a dermatologist. These cats were referred to a behaviorist for welfare evaluation. A welfare score was attributed using a new 21-point welfare scale. The median score of the 13 IUD cats was 16, while the median score of 35 healthy cats was 7 (significant difference, p < 0.001). Major modifications of the cat’s environment and the human–cat relationship were then recommended for IUD cats. Within 15 days after environment modifications, ulcerative lesions were healed and welfare scores improved significantly (median score of 6, significantly different from the score before environmental modifications), being similar to healthy cats (no significant differences). Only one cat was treated with a psychotropic drug, owners being reluctant to improve environmental modifications. These results suggest that feline IUD is a behavioral disorder indicative of poor welfare and that it requires management by behavior specialists, proposing environmental modifications. We hence propose to rename this affection to “behavioral ulcerative dermatitis,” given that welfare scores were significantly different from healthy cats, and that environmental modifications modified welfare scores and lead to successful healing in all cases.

Association of translocator protein total distribution volume with duration of untreated major depressive disorder: a cross-sectional study

BACKGROUND

People with major depressive disorder frequently exhibit increasing persistence of major depressive episodes. However, evidence for neuroprogression (ie, increasing brain pathology with longer duration of illness) is scarce. Microglial activation, which is an important component of neuroinflammation, is implicated in neuroprogression. We examined the relationship of translocator protein (TSPO) total distribution volume (V_T), a marker of microglial activation, with duration of untreated major depressive disorder, and with total illness duration and antidepressant exposure.

METHODS

In this cross-sectional study, we recruited participants aged 18-75 years from the Toronto area and the Centre for Addiction and Mental Health (Toronto, ON, Canada). Participants either had major depressive episodes secondary to major depressive disorder or were healthy, as confirmed with a structured clinical interview and consultation with a study psychiatrist. To be enrolled, participants with major depressive episodes had to score a minimum of 17 on the 17-item Hamilton Depression Rating Scale, and had to be medication free or taking a stable dose of medication for at least 4 weeks before PET scanning. Eligible participants were non-smokers; had no history of or concurrent alcohol or substance dependence, neurological illness, autoimmune disorder, or severe medical problems; and were free from acute medical illnesses for the previous 2 weeks before PET scanning. Participants were excluded if they had used brain stimulation treatments within the 6 months before scanning, had used anti-inflammatory drugs lasting at least 1 week within the past month, were taking hormone replacement therapy, had psychotic symptoms, had bipolar disorder (type I or II) or borderline antisocial personality disorder, or were pregnant or breastfeeding. We scanned three primary grey-matter regions of interest (prefrontal cortex, anterior cingulate cortex, and insula) and 12 additional regions and subregions using ¹⁸F-FEPPA PET to measure TSPO V_T. We investigated the duration of untreated major depressive disorder, and the combination of total duration of disease and duration of antidepressant treatment, as predictor variables of TSPO V_T, assessing their significance.

FINDINGS

Between Sept 1, 2009, and July 6, 2017, we screened 134 participants for eligibility, of whom 81 were included in the study (current major depressive episode n=51, healthy n=30). We excluded one participant with a major depressive episode from the analysis because of unreliable information about previous medication use. Duration of untreated major depressive disorder was a strong predictor of TSPO V_T (p<0·0001), as were total illness duration (p=0·0021) and duration of antidepressant exposure (p=0·037). The combination of these predictors accounted for about 50% of variance in TSPO V_T in the prefrontal cortex, anterior cingulate cortex, and insula. In participants who had untreated major depressive disorder for 10 years or longer, TSPO V_T was 29-33% greater in the prefrontal cortex, anterior cingulate cortex, and insula than in participants who were untreated for 9 years or less. TSPO V_T was also 31-39% greater in the three primary grey-matter regions of participants with long duration of untreated major depressive disorder compared with healthy participants (p=0·00047).

INTERPRETATION

Microglial activation, as shown by TSPO V_T, is greater in patients with chronologically advanced major depressive disorder with long periods of no antidepressant treatment than in patients with major depressive disorder with short periods of no antidepressant treatment, which is strongly suggestive of a different illness phase. Consistent with this, the yearly increase in microglial activation is no longer evident when antidepressant treatment is given.

FUNDING

Canadian Institutes of Health Research and Neuroscience Catalyst Fund.