This study’s large sample size has enabled us to shed further light on conflicting findings about hoarding behaviors and also to replicate and validate some of the analyses of earlier reports. Unlike two previous investigations (Fontenelle, Mendlowicz, Soares, & Versiani, 2004
; Samuels et al. 2002
) we did not find an association between hoarding and an earlier age of OCD onset for our sample as a whole. That being said, female hoarders in our sample did have a younger age of onset compared to female non-hoarders, a finding of interest as individuals with an earlier age of OCD onset tend to have more severe OCD symptomatology and more familial OCD (Fontenelle, Mendlowicz, Marques, & Versiani, 2003; Chabane, et al., 2005
) . We did not find that hoarders were older than non-hoarders as had been reported in some studies (Frost, Steketee, Williams & Warren, 2000
; Saxena et al., 2002
). Our trend-level finding that hoarders were less likely to be married at the time of the study fits in with the findings of Samuels et al. (2002)
. This may relate to hoarders’ increased rate of social phobia, or to their greater global impairment. Additionally, the accumulated clutter associated with hoarding itself might discourage some relationships. We found that hoarders had higher total scores on the Y-BOCS and therefore suffered from greater OCD symptom severity, in agreement with Lochner et al. (2005)
, though this effect was primarily driven by the females in the sample. Further analysis showed that hoarders only scored significantly higher on the compulsions portion of the scale and did not differ from non-hoarders in their obsessions severity. This is an interesting finding that may relate to the nature of hoarding symptoms. However, it could also be related to the fact that hoarders endorsed more total OCD symptoms in general. One of the shortcomings of the Y-BOCS is that it does not specifically asses the severity of each OCD symptom group. The recently developed DY-BOCS (Rosario-Campos et al., 2006
) individually assesses the severity of each OCD symptom category and could help clarify this issue in future studies.
Our finding that hoarders endorsed more ordering compulsions and contamination, sexual, religious, symmetry, and somatic obsessions differs from Samuels et al.’s (2002)
finding of greater symmetry obsessions and counting and ordering compulsions. These differences may in part derive from our use of the self report Y-BOCS-SC, as patients have been found to report more symptoms on the self report form than on the interview based form (Steketee, Frost & Bogart, 1996
We also found that hoarders suffered from a greater degree of global impairment than non-hoarders. The ANCOVA analysis controlling for BDI scores revealed that this increased impairment was not solely the result of increased depressive symptoms. This finding is in line with the investigation by Lochner and colleagues (2005)
, as well as with a number of reports by Frost, Steketee, and colleagues (e.g., Frost, Steketee, Williams & Warren, 2000
) that have found marked impairment in functioning in hoarding samples. This greater global impairment may stem from the phenotypic differences between hoarders and non-hoarders, including greater comorbidity, greater OCD symptom severity, and greater depressive symptoms. Impairment also may arise from the nature of hoarding behaviors per se. That is, the clutter associated with hoarding can be debilitating and the acquisitioning of items can consume much of an individual’s time--and sometimes even their financial resources (Frost, Steketee, & Williams, 2000
). Our finding that hoarders had significantly greater scores on the BDI without having higher rates of major depressive disorder or dysthymia is intriguing and may warrant future investigation. Of note, our finding is not in agreement with other data (Wu & Watson, 2005
), which reports that hoarding is less strongly related to negative affectivity than other OCD symptoms (e.g., checking). However, that study did not exclusively use an OCD sample. Rather, only 54 of the 160 psychiatric patients studied had an OCD diagnosis (Wu & Watson, 2005
). Therefore it is possible that hoarding in the absence of OCD may be associated with fewer negative effects. Indeed, Grisham and colleagues found that hoarders without OCD reported less anxiety, stress and negative affectivity compared to patients with OCD and with OCD and hoarding (2005).
The results of the current study support the general finding that hoarders suffer from more comorbid psychiatric disorders. Our findings of increased prevalence rates of social phobia, substance abuse and a trend towards bipolar I among hoarders are consistent with previously reported findings (Samuels et al., 2002
; LaSalle-Ricci et al., 2006
). Our study sought to use a more fine-grained approach to investigate the relationship between hoarding and the individual eating disorders. Several previous studies (e.g., Samuels et al., 2002
; Fontenelle et al., 2004
; Lochner et al., 2005
) combined a number of diverse eating disorders (e.g., anorexia nervosa and binge-eating disorder) into one general category. Our finding of a trend in which binge-eating disorder was more prevalent in hoarders is meaningful because it supports LaSalle Ricci and colleagues’ (2006)
previously reported association and is in line with the findings of Fontenelle et al. (2004)
of a relationship between hoarding and a combined eating disorders rating that included bulimia nervosa and binge-eating disorder. Follow-up analyses revealed that many of these comorbidity relationships were gender specific. These differences may arise from baseline differences in the disorder prevalence rates between genders. For example, panic disorder is more common in females (Pigott 2003
). Social phobia, which is generally more common in women (Pigott 2003
), has been found to be more common in male OCD patients than in female OCD patients (Tukel et al., 2004
). That being said, prevalence rates most likely only partially account for our finding and further research is needed on gender and hoarding.
Our study included some participants whose data contributed to an earlier report by our group (LaSalle-Ricci et al., 2006
). The current study has, however, more than doubled the sample size of the previous investigation, increasing it from 204 to 473. In further contrast to the study conducted by LaSalle-Ricci et al., our investigation used a newly-developed dichotomous grouping methodology to compare hoarders and non-hoarders based on a combination of interviewer assessments and self-ratings. This hoarding evaluation method was validated by comparison with an independent 23-item hoarding scale, the Saving Inventory-Revised (Frost, Steketee, & Green, 2003
). Given these methodological differences, a considerable number of our findings differ from those of the previous study. For example, while LaSalle-Ricci et al. found no relationship between social phobia and hoarding, the present study found a significant increase in social phobia among hoarders. Also, whereas the previous investigation documented a relationship between hoarding and PTSD and body dysmorphic disorder, we found no significant associations between them.
One of the main findings from this study was that individuals with OCD and hoarding behaviors tended to be more impaired than their non-hoarding counterparts in terms of greater OCD symptom severity, lower global functioning ratings, and more comorbid disorders. These combined factors suggest a possible explanation for why hoarders may have poorer responses to treatments across modalities. For example, hoarders have been found to be less responsive to both cognitive behavioral (Saxena et al., 2002
) and psychopharmacologic treatments (Winsberg, Cassic, & Koran, 1999
), though a recent study found hoarders responded equally well to paroxetine treatment (Saxena, Brody, Maidment, & Baxter, 2006
). If treatment programs are indeed less efficacious for hoarders, the increased incidence of alcohol and substance abuse in some hoarders may represent a form of self-medicating. Clinicians should assess comorbid disorders and make appropriate considerations regarding these disorders when designing treatment plans for hoarders.
Gender seems to play an important role in the phenotypic presentation of OCD patients with hoarding symptoms. The results indicate that the hoarding phenotype may differ across gender, with females hoarders experiencing more severe OCD symptoms, earlier age of OCD onset and a broader range of psychiatric comorbidity, such as bipolar I disorder, panic disorder, binge-eating disorder, alcohol abuse and substance abuse.
One of the limitations of this study was the recruitment method. Although some of our advertisements did specifically mention our interest in hoarding and collecting problems, our recruitment materials were primarily aimed at individuals who met full OCD diagnostic criteria. Individuals who had hoarding as an isolated problem are likely underrepresented in our sample. Grisham and colleagues have suggested that compulsive hoarding may be a clinically distinct syndrome in the absence of OCD (2005), something our study cannot address. All members of our OCD-hoarding group reported other OCD symptoms and on average they endorsed 30 of the 71 Y-BOCS symptoms. This was significantly greater than the number of OCD symptoms reported by the non-hoarding group, which further supports an association between hoarding and a more severe form of OCD. Further evaluation of these analyses in a non-OCD hoarding sample would be valuable to see if these results are true for hoarding in general or specific to hoarding in the context of OCD.
Our findings suggest that OCD patients with hoarding symptoms are clinically distinct from OCD non-hoarders. This general conclusion supports recent investigations seeking to evaluate specific genetic correlates of hoarding behaviors. Hoarding has been investigated as a specific phenotype in two genome-wide scans, one in individuals with Tourette’s syndrome (Zhang et al., 2002
) and one in OCD patients (Samuels et al., in press
). Both studies found evidence of suggestive linkage, with chromosomal regions on 3, 4, 5, 14 and 17 identified. The peak region in the OCD sample that was different in hoarders compared to non-hoarding OCD subjects emerged only when hoarding was considered separately, and represented a peak not identified in the initial scan based on OCD diagnosis alone (Shugart et al. 2006
; Samuels et al., in press
). Clarification of the definition of the hoarding phenotype in this and other studies should benefit future genotype-phenotype investigations. It is noteworthy that a large number of our findings were driven by the females in our sample. Further research into gender-related associations of hoarding will be important in both phenotypic genetic, and clinical investigations.