scholarly journals GENETICS OF OBSESSIVE-COMPULSIVE DISORDER

2021 ◽  
pp. 270-280
Author(s):  
V. Pomohaibo ◽  
O. Berezan ◽  
O. Petrushov

Obsessive-compulsive disorder (OCD) is characterized by recurrent episodes of obsessive thoughts, fears, and actions, which, in the opinion of the patient, can defuse frightening events. A patient himself is aware of his condition, but cannot prevent it by a simple effort of will. The prevalence of OCD in the general population varies between 0.7% and 3.0%. Patients with OCD often can have a lifetime diagnosis of other psychopathology – an anxiety disorder, depressive disorder, tic disorder and others. In addition, the OCD symptoms often accompany other mental disorders, such as schizophrenia, bipolar disorder, eating disorder and others. Family studies in OCD showed that the disorder risk of first-degree relatives of individuals with OCD were approximately 15%, that more likely to develop OCD than its prevalence in the general population. This indicates the presence of a genetic component in the OCD development, that is also confirmed by the significant reliable value of the heritability of OCD (42-53%). Males have an earlier age at onset of OCD than females. Moreover, males more likely to have symptoms in the forbidden thoughts and symmetry dimensions and females more likely to have symptoms in the cleaning dimension. In addition, geographical and cultural factors may shape the content of obsessions and compulsions. There are four publications that have shown OCD genetic linkage with defined regions of three chromosomes: 9p24, 3q27-28 and 14q23-32. It was also found that the region of chromosome 3q27-28 contains three genes of serotonin receptor subunits – HTR3C (5HT3C), HTR3D (5HT3D) and HTR3E (5HT3E). These genes can be candidate genes for OCD. In addition, the HTR3C gene (3q27.1) is expressed in the brain cells, where it produces the serotonin receptor 3 subunit, which is a very important neurotransmitter. All three genes involved in the pathogenesis of not only OCD, but also of schizophrenia. Now, according to scientific reviews and «MalaCard: The Human Disease Database» above 40 OCD candidate genes were offered by various researchers. But almost all these studies were conducted on statistically insignificant samples (mostly from several dozens to several hundred individuals), which gave discrepant findings. In addition, not fully used methodological possibilities, for example, case-control samples were used, but family studies were not used. For this reason, the Canadian researcher S. Taylor (2013) conducted a meta-analysis of the findings of 113 studies and obtained high reliable confirmation of an assumption that variants of several genes are involved in the risk of OCD. Two of these genes associated with metabolism of serotonin (SLC6A4 and HTR2A) and two genes, in males only, are involved in catecholamine modulation (COMT and MAOA). Some more three genes have moderate reliability, two of which are associated with the dopamine system (DRD3 and DAT1) and one is associated with the glutamate system (SLC1A1). In addition, in S. Taylor’s opinion, 13 candidate genes attract an attention and merit further investigation. The results of genetic studies showed that OCD has a polygenic nature, because it is associated with multiple genes, everyone of them makes small contributions to a risk for the disorder. To reveal of these small effects, further studies of fairly large samples are needed. In addition, environmental factors may be involved in the OCD etiology that further exploration of gene–gene and gene–environment interactions is needed. To identify reliable OCD candidate genes all comorbidities must take into account. The OCD picture is extremely various not only in a lifetime of one patient, but between patients within the same family that indicates genetic heterogeneity of the disorder, which complicates the study in addition. These problems induce to study the genetic nature and environmental risk factors of OCD to ensure an earliest and most accurate diagnosis of OCD with due regard for environmental factors.

CNS Spectrums ◽  
2000 ◽  
Vol 5 (S4) ◽  
pp. 40-46 ◽  
Author(s):  
Donald W. Black

AbstractThis manuscript summarizes presentations by an international panel of experts, representing Brazil, Israel, Italy, Mexico, Portugal, Spain, and the United States, at a symposium on obsessive-compulsive disorder (OCD) and its possible subtypes. Presentations concerned both OCD proper, as well as putative obsessive-compulsive-spectrum disorders (autistic disorders, eating disorders, pathological gambling, and schizo-obsessive disorder). Projects discussed included a study assessing impulsive temperament in eating disorder patients, a study on serotonin receptor sensitivity in autism, a study of sleep EEG abnormalities in OCD, a study of dissociation in pathological gamblers, papers on aspects of schizo-obsessive patients, a study addressing biological alterations in OCD, data from a new family study on OCD, data from a molecular genetic study of OCD, a factor analytic study of Tourette disorder, a study hypothesizing the existence of an OCD continuum, and, finally, a paper on early- vs late-onset OCD. General discussion followed leading to a consensus that 1) OCD is likely heterogeneous with multiple subtypes; 2) division of patients by age-at-onset probably represents a robust and valid subtyping scheme; 3) the presence of schizophrenic features probably identifies a valid subtype; 4) the validation of subtypes in the future will be informed by both family-genetic studies, as well as studies of biological alterations in OCD; and 5) the study of obsessive-compulsive spectrum disorders adds to our understanding of the OCD phenomenon, and helps in our search to identify valid subtypes.


Author(s):  
Lior Carmi ◽  
Naomi A Fineberg ◽  
Oded Ben Arush ◽  
Joseph Zohar

The prevalence of obsessive–compulsive disorder (OCD) in the general population has been changed dramatically in the last 40 years, from less than 0.5% in the early 1980s to about 2% in the 1990s. Nowadays, with the inclusion of OCD spectrum disorders in the OCD category (DSM-5), the estimated prevalence of OCD (and OCD-related disorders) is 9%. Despite the high prevalence of OCD and due to its ego-dystonic nature, OCD and OCD-related disorders will not appear on the ‘clinical radar’, unless specific screening questions are included in every mental status examination. OCD is a disorder in which environmental factors (for example, family accommodation) play a key role in its trajectory. Other environmental factors, such as increased use of digital tools, turn Internet-related compulsions to a more frequent clinical presentation and might contribute to the increase in prevalence of OCD-related disorders (for example, Internet addiction).


BMJ Open ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. e050329
Author(s):  
Johannes Julian Bürkle ◽  
Johannes Caspar Fendel ◽  
Stefan Schmidt

IntroductionCognitive–behavioural therapy (CBT) with exposure and response prevention is the recommended standard for the treatment of obsessive–compulsive disorder (OCD). However, a high proportion of patients refuse this treatment, do not respond or relapse shortly after treatment. Growing evidence suggests that mindfulness-based and acceptance-based programmes (MABPs) are an effective option for the treatment of OCD. This systematic review and meta-analysis will examine the effectiveness of MABPs in treating OCD. We also aimed to explore potential moderators of the programmes’ effectiveness.Methods and analysisWe will systematically search MEDLINE, Embase, PsycINFO, PSYINDEX, Web of Science, CINAHL and Cochrane Register of Controlled Trials (no language restrictions) for studies that evaluate the effect of MABPs on patients with OCD. We will conduct backward and forward citation searches of included studies and relevant reviews and contact corresponding authors. The primary outcome will be pre-post intervention change in symptom severity. A secondary outcome will be change in depressive symptoms. Two reviewers will independently screen the records, extract the data and rate the methodological quality of the studies. We will include both controlled and uncontrolled trials. Randomised controlled trials will be meta-analysed, separately assessing between-group effects. A second meta-analysis will assess the within-group effect of all eligible studies. We will explore moderators and sources of heterogeneity such as the specific programme, study design, changes in depressive symptoms, hours of guided treatment, control condition and prior therapy (eg, CBT) using metaregression and subgroup analyses. We will perform sensitivity analyses using follow-up data. A narrative synthesis will also be pursued. We will use the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to assess the quality of the evidence.Ethics and disseminationEthical approval is not required. Results will be published in peer-reviewed journals and presented at international conferences.


2009 ◽  
Vol 195 (5) ◽  
pp. 393-402 ◽  
Author(s):  
Joaquim Radua ◽  
David Mataix-Cols

BackgroundSpecific cortico-striato-thalamic circuits are hypothesised to mediate the symptoms of obsessive–compulsive disorder (OCD), but structural neuroimaging studies have been inconsistent.AimsTo conduct a meta-analysis of published and unpublished voxel-based morphometry studies in OCD.MethodTwelve data-sets comprising 401 people with OCD and 376 healthy controls met inclusion criteria. A new improved voxel-based meta-analytic method, signed differential mapping (SDM), was developed to examine regions of increased and decreased grey matter volume in the OCD group v. control group.ResultsNo between-group differences were found in global grey matter volumes. People with OCD had increased regional grey matter volumes in bilateral lenticular nuclei, extending to the caudate nuclei, as well as decreased volumes in bilateral dorsal medial frontal/anterior cingulate gyri. A descriptive analysis of quartiles, a sensitivity analysis as well as analyses of subgroups further confirmed these findings. Meta-regression analyses showed that studies that included individuals with more severe OCD were significantly more likely to report increased grey matter volumes in the basal ganglia. No effect of current antidepressant treatment was observed.ConclusionsThe results support a dorsal prefrontal–striatal model of the disorder and raise the question of whether functional alterations in other brain regions commonly associated with OCD, such as the orbitofrontal cortex, may reflect secondary compensatory strategies. Whether the reported differences between participants with OCD and controls precede the onset of the symptoms and whether they are specific to OCD remains to be established.


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