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

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

Abnormalities in migration of neural precursor cells in familial bipolar disorder

Cellular migration is a ubiquitous feature that brings brain cells into appropriate spatial relationships over time; and it helps in the formation of a functional brain. We studied the migration patterns of induced pluripotent stem cell-derived neural precursor cells (NPCs) from individuals with familial bipolar disorder (BD) in comparison with healthy controls. The BD patients also had morphological brain abnormalities evident on magnetic resonance imaging. Time-lapse analysis of migrating cells was performed, through which we were able to identify several parameters that were abnormal in cellular migration, including the speed and directionality of NPCs. We also performed transcriptomic analysis to probe the mechanisms behind the aberrant cellular phenotype identified. Our analysis showed the downregulation of a network of genes, centering on EGF/ERBB proteins. The present findings indicate that collective, systemic dysregulation may produce the aberrant cellular phenotype, which could contribute to the functional and structural changes in the brain reported for bipolar disorder.

This article has an associated First Person interview with the first author of the paper.

Impact of the COVID-19 Pandemic on the Short-Term Course of Obsessive-Compulsive Disorder

ABSTRACT

There is an understandable concern that obsessive-compulsive disorder (OCD) may worsen during the COVID-19 pandemic, but there are little empirical data. We report the impact of COVID-19 pandemic on the short-term course of OCD. A cohort of patients with a primary diagnosis of OCD (n = 240) who were on regular follow-up at a tertiary care specialty OCD clinic in India were assessed telephonically, about 2 months after the declaration of the pandemic ("pandemic" cohort). Data from the medical records of an independent set of patients with OCD (n = 207) who were followed up during the same period, 1 year prior, was used for comparison (historical controls). The pandemic group and historical controls did not differ in the trajectories of the Yale-Brown Obsessive-Compulsive Scale scores (chi-square likelihood ratio test of the group × time interaction = 2.73, p = 0.255) and relapse rate (21% vs. 20%; adjusted odds ratio, 0.81; 95% confidence interval, 0.41-1.59; p = 0.535). Preexisting contamination symptoms and COVID-19-related health anxiety measured by the COVID-Threat Scale did not predict relapse. Only a small proportion of patients (6%) reported COVID-19-themed obsessive-compulsive symptoms. The COVID-19 pandemic, at least in the short run, did not influence the course of illness.

The rates of co-occurring behavioural addictions in treatment-seeking individuals with obsessive-compulsive disorder: a preliminary report

Objectives: To assess the rates of co-occurring putative 'behavioural addictions' in patients with obsessive-compulsive disorder (OCD).Methods: Twenty-three international centres specialising in the treatment of OCD were invited to participate in a survey of the rates of behavioural addictions and other relevant comorbidity within their samples.Results: Sixteen of 23 (69.6%) invited centres from 13 countries had sufficient data to participate in the survey. The use of validated diagnostic tools was discrepant, with most centres relying on a 'clinical diagnosis' to diagnose behavioural addictions. The final sample comprised of 6916 patients with a primary diagnosis of OCD. The reported rates of behavioural addictions were as follows: 8.7% for problematic internet use, 6.8% for compulsive sexual behaviour disorder, 6.4% for compulsive buying, 4.1% for gambling disorder and 3.4% for internet gaming disorder.Conclusions: Behavioural addictions should be better assessed for patients with OCD. The absence of diagnostic scales developed specifically for behavioural addictions and overlapping obsessive-compulsive phenomena such as compulsive checking of information on the internet may explain the relatively high rate of problematic internet use in this sample. The study encourages better efforts to assess and to conceptualise the relatedness of behavioural addictions to obsessive-compulsive 'spectrum' disorders.

Treatments used for obsessive-compulsive disorder-An international perspective

OBJECTIVE

The objective of this study was to characterise international trends in the use of psychotropic medication, psychological therapies, and novel therapies used to treat obsessive-compulsive disorder (OCD).

METHODS

Researchers in the field of OCD were invited to contribute summary statistics on the characteristics of their samples. Consistency of summary statistics across countries was evaluated.

RESULTS

The study surveyed 19 expert centres from 15 countries (Argentina, Australia, Brazil, China, Germany, Greece, India, Italy, Japan, Mexico, Portugal, South Africa, Spain, the United Kingdom, and the United States) providing a total sample of 7,340 participants. Fluoxetine (n = 972; 13.2%) and fluvoxamine (n = 913; 12.4%) were the most commonly used selective serotonin reuptake inhibitor medications. Risperidone (n = 428; 7.3%) and aripiprazole (n = 415; 7.1%) were the most commonly used antipsychotic agents. Neurostimulation techniques such as transcranial magnetic stimulation, deep brain stimulation, gamma knife surgery, and psychosurgery were used in less than 1% of the sample. There was significant variation in the use and accessibility of exposure and response prevention for OCD.

CONCLUSIONS

The variation between countries in treatments used for OCD needs further evaluation. Exposure and response prevention is not used as frequently as guidelines suggest and appears difficult to access in most countries. Updated treatment guidelines are recommended.

Discovery biology of neuropsychiatric syndromes (DBNS): a center for integrating clinical medicine and basic science

BACKGROUND

There is emerging evidence that there are shared genetic, environmental and developmental risk factors in psychiatry, that cut across traditional diagnostic boundaries. With this background, the Discovery biology of neuropsychiatric syndromes (DBNS) proposes to recruit patients from five different syndromes (schizophrenia, bipolar disorder, obsessive compulsive disorder, Alzheimer's dementia and substance use disorders), identify those with multiple affected relatives, and invite these families to participate in this study. The families will be assessed: 1) To compare neuro-endophenotype measures between patients, first degree relatives (FDR) and healthy controls., 2) To identify cellular phenotypes which differentiate the groups., 3) To examine the longitudinal course of neuro-endophenotype measures., 4) To identify measures which correlate with outcome, and 5) To create a unified digital database and biorepository.

METHODS

The identification of the index participants will occur at well-established specialty clinics. The selected individuals will have a strong family history (with at least another affected FDR) of mental illness. We will also recruit healthy controls without family history of such illness. All recruited individuals (N = 4500) will undergo brief clinical assessments and a blood sample will be drawn for isolation of DNA and peripheral blood mononuclear cells (PBMCs). From among this set, a subset of 1500 individuals (300 families and 300 controls) will be assessed on several additional assessments [detailed clinical assessments, endophenotype measures (neuroimaging- structural and functional, neuropsychology, psychophysics-electroencephalography, functional near infrared spectroscopy, eye movement tracking)], with the intention of conducting repeated measurements every alternate year. PBMCs from this set will be used to generate lymphoblastoid cell lines, and a subset of these would be converted to induced pluripotent stem cell lines and also undergo whole exome sequencing.

DISCUSSION

We hope to identify unique and overlapping brain endophenotypes for major psychiatric syndromes. In a proportion of subjects, we expect these neuro-endophenotypes to progress over time and to predict treatment outcome. Similarly, cellular assays could differentiate cell lines derived from such groups. The repository of biomaterials as well as digital datasets of clinical parameters, will serve as a valuable resource for the broader scientific community who wish to address research questions in the area.

Non-motor features in essential tremor

INTRODUCTION

Essential tremor (ET) is increasingly recognized to have several non-motor manifestations. The aim of this study was to determine the prevalence of non-motor manifestations in ET and its impact on the quality of life (QOL).

METHODS

This was a cross-sectional case-control questionnaire-based study. The subjects were 50 patients with ET and 50 matched healthy controls. All subjects were assessed by Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Parkinson Fatigue Scale, Brief Pain Inventory, Hamilton Anxiety Rating Scale, and Hamilton Depression Rating Scale. In addition, QOL in Essential Tremor questionnaire was administered to patients with ET.

RESULTS

Patients with ET, when compared with controls, had significantly higher prevalence and higher mean scores of sleep disturbances (46% vs 8%, P < 0.001; 5.9 ± 4.6 vs 2.6 ± 2.3, P < 0.001), fatigue (30% vs 8%, P = 0.009; 5.8 ± 0.8 vs 2.5 ± 0.4, P < 0.001), anxiety (66% vs 18%, P = 0.009; 7.4 ± 9.0 vs 0.7 ± 2.6, P < 0.001), depression (44% vs 8%, P = 0.009; 7.8 ± 7.9 vs 1.7 ± 3.3, P < 0.001) as well as higher mean score of pain severity (1.9 ± 2.3 vs 0.6 ± 1.2, P = 0.001) and interference owing to pain (2.0 ± 2.9 vs 0.5 ± 1.2, P = 0.001). Following hierarchical regression analysis, depression was the only non-motor feature that affected the QOL.

CONCLUSION

There was a significantly higher prevalence and greater severity of sleep disturbances, fatigue, pain, anxiety, and depression in patients with ET and depression significantly affected the QOL.