Predisposing and maintaining factors in OCD and hoarding disorder

• Main Author: Monzani, Benedetta
• Other Authors: Mataix-Cols, David ; Rijsdijk, Fruhling Vesta
• Published: King's College London (University of London) 2018
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.762376

Background: The causes of Hoarding Disorder, a newly recognised psychiatric disorder, are unknown. A number of recent twin studies have suggested that hoarding symptoms are heritable but heritability estimates vary across studies and the reasons for this remain unclear. Findings from two recent twin studies have suggested a dynamic picture with age- and gender-specific risk factors accounting for the variation across studies. Aim: The present systematic review aims to provide the first, comprehensive, and up-to-date review of twin studies of hoarding symptoms, with a view of clarifying and shedding light on gender- and age-related changes in heritability for HD. Methods: PubMed, PsycINFO, Medline, Embase, and Web of Science were searched up to March 2016 using relevant key search and MeSH terms, according to PRISMA guidelines. The quality of studies was assessed using a revised 11-items checklist for cross-sectional/prevalence studies assessing the three major domains of risk of bias. Results: a total of six studies met inclusion criteria. The methodological quality of included studies was moderate-to-high for selection and methodological bias, but overall poor for confounding bias. Genetic factors play an important role in the aetiology of hoarding symptoms across all studies. Genetic factors seem to play a stable and significant role for male hoarding behaviours. For women, on the other hand, these influences appear to vary across development, with shared environmental factors predisposing young females to hoarding symptoms and genes playing a more influential role only later in life. Conclusions: hoarding symptoms are moderately heritable; the extent of genetic influences on hoarding however is likely to change during development and differ between genders. The current review supports genetic research and further examination of environmental factors predisposing individuals to hoarding symptoms. More research, including longitudinal twin studies, is needed to conclusively identify and compare risk factors for hoarding across genders and age groups.