Serotonin system genes and hoarding with and without other obsessive-compulsive traits in a population-based, pediatric sample: A genetic association study

Genomics of Obsessive-Compulsive Disorder and Related Disorders: What the Clinician Needs to Know

A wealth of evidence has shown that genetics plays a major role in susceptibility to obsessive-compulsive disorder (OCD) and all of its related disorders. Several large-scale, collaborative efforts using modern genomic methods are beginning to reveal the genetic architecture of these traits and identify long-sought risk genes. In this article, we summarize current OCD and related disorder genomic knowledge and explain how to communicate this information to patients and their families. The article concludes with a discussion of how genomic discovery in OCD and related disorders can inform our understanding of disease etiology and provide novel targets for therapeutic development.

Hoarding Disorder: The Current Evidence in Conceptualization, Intervention, and Evaluation

Hoarding disorder is characterized by difficulty parting with possessions due to strong urges to save the items, leading to the excessive accumulation of items. High clutter levels result in varied personal, social, and legal consequences. Specialized treatments, including individual, virtual, and group cognitive and behavioral therapies, community-based interventions, and peer support approaches have shown preliminary effectiveness. Animal, attachment, and neurobiological models are expanding our understanding of the etiological bases of the disorder. Specialized populations such as children, older adults, and involuntary patients are highlighted as requiring special consideration for intervention and risk mitigation. Directions for future research are identified.

Meta-analysis of genome-wide association studies of hoarding symptoms in 27,537 individuals

Hoarding Disorder (HD) is a mental disorder characterized by persistent difficulties discarding or parting with possessions, often resulting in cluttered living spaces, distress, and impairment. Its etiology is largely unknown, but twin studies suggest that it is moderately heritable. In this study, we pooled phenotypic and genomic data from seven international cohorts (N = 27,537 individuals) and conducted a genome wide association study (GWAS) meta-analysis of parent- or self-reported hoarding symptoms (HS). We followed up the results with gene-based and gene-set analyses, as well as leave-one-out HS polygenic risk score (PRS) analyses. To examine a possible genetic association between hoarding symptoms and other phenotypes we conducted cross-trait PRS analyses. Though we did not report any genome-wide significant SNPs, we report heritability estimates for the twin-cohorts between 26-48%, and a SNP-heritability of 11% for an unrelated sub-cohort. Cross-trait PRS analyses showed that the genetic risk for schizophrenia and autism spectrum disorder were significantly associated with hoarding symptoms. We also found suggestive evidence for an association with educational attainment. There were no significant associations with other phenotypes previously linked to HD, such as obsessive-compulsive disorder, depression, anxiety, or attention-deficit hyperactivity disorder. To conclude, we found that HS are heritable, confirming and extending previous twin studies but we had limited power to detect any genome-wide significant loci. Much larger samples will be needed to further extend these findings and reach a "gene discovery zone". To move the field forward, future research should not only include genetic analyses of quantitative hoarding traits in larger samples, but also in samples of individuals meeting strict diagnostic criteria for HD, and more ethnically diverse samples.

Prevalence and correlates of hoarding behavior and hoarding disorder in children and adolescents

Although hoarding symptoms are reported to begin in childhood and adolescence, the true prevalence of the disorder in this age group is unknown. This study aims to estimate the prevalence of hoarding disorder (HD) in children and adolescents. The present study was planned as a two-stage epidemiological research. In the first stage, the Children's Saving Inventory (CSI) and informed consent forms were delivered to a group of students' parents. In the second stage, one-on-one psychiatric interviews with a physician were planned with the families and children who had hoarding behavior (HB), as described by their parents. The DSM-5-based HD interview and the Development and Well-Being Assessment (DAWBA) diagnostic tool were used to detect prevalence of HD and comorbid psychiatric disorders. A total of 3249 children were included in the study, and 318 children and their parents were evaluated in the second stage. As a result of the second assessment, 32 out of 318 children met the HD diagnostic criteria. The estimated prevalence of HD was 0.98% (95% CI 0.7-1.4). Hoarding disorder was found more frequently in females (F/M = 3/1). After a logistic regression analysis, variables such as female sex and the presence of any psychopathology were identified as independent correlates of HD. More than half (56.2%) of the children diagnosed as having HD also had a comorbid psychiatric disorder. In the present study, the two-stage evaluation method was used in a large pediatric sample to determine the estimated prevalence of HD, as well as the factors associated with the disorder and comorbid psychiatric disorders.

Hoarding Disorder: Development in Conceptualization, Intervention, and Evaluation

Hoarding disorder is characterized by difficulty parting with possessions because of strong urges to save the items. Difficulty discarding often includes items others consider to be of little value and results in accumulation of a large number of possessions that clutter the home. Cognitive-behavioral therapy (CBT) with exposure and response prevention and selective serotonin reuptake inhibitor medications traditionally used to treat obsessive-compulsive disorder are generally not efficacious for people with hoarding problems. A specialized CBT approach for hoarding has shown progress in reaching treatment goals and has been modified to be delivered in group, peer-facilitated, and virtual models. Research on hoarding remains in the early phases of development. Animal, attachment, and genetic models are expanding. Special populations, such as children, older adults, and people who do not voluntarily seek treatment need special consideration for intervention. Community-based efforts aimed at reducing public health and safety consequences of severe hoarding are needed.

Genetic and epigenetic architecture of Obsessive-Compulsive Disorder: In search of possible diagnostic and prognostic biomarkers

Obsessive-Compulsive Disorder (OCD) is a prevalent and severe clinical condition whose hallmarks are excessive, unwanted thoughts (obsessions) and repetitive behaviors (compulsions). The onset of symptoms generally occurs during pre-adult life and typically affects subjects in different aspects of their life's, compromising social and professional relationships. Although robust evidence suggests a genetic component in the etiopathogenesis of OCD, the causes of the disorder are still not completely understood. It is thus of relevance to take into account how genes interact with environmental risk factors, thought to be mediated by epigenetic mechanisms. We here provide an overview of genetic and epigenetic mechanisms of OCD, focusing on the modulation of key central nervous system genes, in the attempt to suggest possible disease biomarkers.