Prevalence, Comorbidity and Heritability of Hoarding Symptoms in Adolescence: A Population Based Twin Study in 15-Year Olds

Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
PLoS ONE (Impact Factor: 3.23). 07/2013; 8(7):e69140. DOI: 10.1371/journal.pone.0069140
Source: PubMed

ABSTRACT Hoarding Disorder (HD) is often assumed to be an 'old age' problem, but many individuals diagnosed with HD retrospectively report first experiencing symptoms in childhood or adolescence. We examined the prevalence, comorbidity and etiology of hoarding symptoms in adolescence.
To determine the presence of clinically significant hoarding symptoms, a population-based sample of 15-year old twins (N = 3,974) completed the Hoarding Rating Scale-Self Report. Co-occurring Obsessive Compulsive Disorder (OCD), Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) were estimated from parental report. Model-fitting analyses divided hoarding symptom scores into additive genetic, shared, and non-shared environmental effects.
The prevalence of clinically significant hoarding symptoms was 2% (95% CI 1.6-2.5%), with a significantly higher prevalence in girls than boys. Exclusion of the clutter criterion (as adolescents do not have control over their environment) increased the prevalence rate to 3.7% (95% CI 3.1-4.3%). Excessive acquisition was reported by 30-40% among those with clinically significant hoarding symptoms. The prevalence of co-occurring OCD (2.9%), ASD (2.9%) and ADHD (10.0%) was comparable in hoarding and non-hoarding teenagers. Model-fitting analyses suggested that, in boys, additive genetic (32%; 95% CI 13-44%) and non-shared environmental effects accounted for most of the variance. In contrast, among girls, shared and non-shared environmental effects explained most of the variance, while additive genetic factors played a negligible role.
Hoarding symptoms are relatively prevalent in adolescents, particularly in girls, and cause distress and/or impairment. Hoarding was rarely associated with other common neurodevelopmental disorders, supporting its DSM-5 status as an independent diagnosis. The relative importance of genetic and shared environmental factors for hoarding differed across sexes. The findings are suggestive of dynamic developmental genetic and environmental effects operating from adolescence onto adulthood.

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Available from: Christian Rück, Sep 28, 2015
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    • "The etiology of hoarding is complex, with evidence of involvement of genetic factors (Ivanov et al., 2013; Samuels et al., 2007b), adverse life experiences (Cromer, Schmidt, & Murphy, 2007; Landau, Iervolino, Pertusa, & Santo, 2011; Przeworski, Cain, & Dunbeck, 2014), and deficits in executive functions (Grisham, Norberg, Williams, Certoma, and Kadib, 2010; Mathews, Perez, Delucchi, & Mathalon, 2012; McGrath et al., 2014; Morein-Zamir et al., 2014). Moreover, there is an evidence for an association between hoarding behavior and autism. "
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    ABSTRACT: Compared to studies in adults, there have been few studies of hoarding in children and adolescents with obsessive–compulsive disorder (OCD). In the current study, we evaluated OCD clinical features, Axis I disorders, and social reciprocity scores in 641 children and adolescents with OCD, of whom 163 (25%) had hoarding compulsions and 478 did not. We found that, as a group, youth with hoarding had an earlier age at onset and more severe lifetime OCD symptoms, poorer insight, more difficulty making decisions and completing tasks, and more overall impairment. The hoarding group also had a greater lifetime prevalence of panic disorder, specific phobia, Tourette disorder, and tics. As measured with the Social Reciprocity Scale, the hoarding group had more severe deficits in parent-rated domains of social communication, social motivation, and restricted interests and repetitive behavior. In a multivariable model, the overall social reciprocity score, age at onset of OCD symptoms, symmetry obsessions, and indecision were independently related to hoarding in these children and adolescents with OCD. These features should be considered as candidate risk factors for the development of hoarding behavior in pediatric OCD.
    Journal of Obsessive-Compulsive and Related Disorders 10/2014; 3(4). DOI:10.1016/j.jocrd.2014.08.001 · 1.18 Impact Factor
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    ABSTRACT: Background: Until recently, hoarding was considered an obsessive-compulsive symptom (OCS). However, current evidence suggests that these two phenotypes may be clinically, and perhaps etiologically, distinct. Both hoarding and OCS have a genetic etiology, but the degree of unique and shared genetic contributions to these phenotypes has not been well studied. Method: Prevalence rates were assessed for hoarding and OCS in a sample of adult twin pairs (n = 7906 twins) and their family members from The Netherlands Twin Register (total sample = 15,914). Using Mplus, genetic analyses using liability threshold models were conducted for both phenotypes, for their co-morbidity, and for specific hoarding symptoms (cluttering, discarding and acquiring). Results: Of the total sample, 6.7% met criteria for clinically significant hoarding; endorsement of all three hoarding symptoms was > or = 79%. Men had slightly higher rates than women. Also, 5.7% met criteria for clinically significant OCS; rates were similar in males and females. Genetic factors accounted for 36% of the variance for hoarding and 40% of the variance for OCS. The genetic correlation between hoarding and OCS was 0.10. There was no evidence of sex-specific genetic contributions for hoarding or OCS. There was evidence for a genetic contribution to all hoarding symptom subtypes. Only cluttering showed evidence of a contribution from the shared environment. Conclusions: OCS and hoarding are common in this population-based sample, have prevalence rates similar to those previously reported, and show significant heritability. Genetic factors contributed to the co-morbidity of both traits, although the genetic correlation between them was low.
    Psychological Medicine 02/2014; 44(13):1-10. DOI:10.1017/S0033291714000269 · 5.94 Impact Factor
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