Do traumatic events influence the clinical expression of compulsive hoarding?

Abstract

Traumatic experiences have been posited as one potential catalyst for the abrupt onset of obsessive–compulsive symptoms including compulsive hoarding. To determine whether traumatic life events (TLEs) might influence the expression of compulsive hoarding in obsessive–compulsive disorder (OCD), interview responses to the Posttraumatic Stress Disorder module of the Structured Clinical Interview for DSM-IV (SCID) were examined in 180 individuals with OCD. Compared to individuals with OCD who did not meet criteria for hoarding, participants classified as hoarders (24% of the sample) were significantly more likely to have reported at least one TLE in their lifetime. Patients who met criteria for hoarding and who had also experienced TLEs had significantly greater hoarding symptom severity than those hoarders not exposed to trauma. This association was found to be robust. That is, the relationship between TLEs and hoarding symptom severity was not better accounted for by age, age of OCD onset, depressive symptoms, general OCD symptomatology, or mood and anxiety comorbidity. Closer examination revealed that the clutter factor of compulsive hoarding (and not difficulty discarding or acquisitioning) was most strongly associated with having experienced a traumatic event.

Introduction

From an evolutionary perspective, the propensity for humans to collect or hoard could have been extremely beneficial during times of crisis and need (Leckman & Mayes, 1998). Yet, the modern phenomenon of compulsive hoarding has substantial and negative repercussions for an individual. It can render him or her incapable of completing daily activities and can transform an ordinary home into a discomforting one, with serious health risks. Empirical research on hoarding is still in its nascent stages, and many facets of this phenomenon are still unknown. The aim of this investigation is to clarify the role of traumatic life events (TLEs) that have been offered as one putative risk factor for compulsive hoarding (Hartl, Duffany, Allen, Steketee, & Frost, 2005).

Hoarding is typically defined as the acquisition of, and failure to discard, a large number of possessions, which results in debilitating clutter and subsequent distress or impairment (Frost & Hartl, 1996). Imbedded within this definition are three essential characteristics of compulsive hoarding: clutter, difficulty discarding, and acquisitioning. Each of these features is necessary for a diagnosis, though they can be exhibited to varying degrees within a given individual (Steketee, Frost, & Kyrios, 2003).

Traditionally, hoarding has been considered a symptom or subtype of obsessive–compulsive disorder (OCD). Between 18% and 33% of individuals with OCD endorse hoarding symptoms (Hanna, 1995; Samuels et al., 2002), and recent factor analytic studies have consistently identified the existence of a specific hoarding factor (Leckman et al., 1997; Mataix-Cols, Rosario-Campos, & Leckman, 2005) that is strongly familial (Hasler et al., 2007). Moreover, a sample of individuals diagnosed with compulsive hoarding (OCD diagnosis was not established) was found to endorse significantly more OCD symptomatology than a group of non-clinical controls (Frost & Gross, 1993; Frost, Krause, & Steketee, 1996).

Despite its strong association with OCD, there is evidence to suggest that hoarding may be a stand-alone syndrome (see Steketee & Frost, 2003). Specifically, factor analytic studies consistently indicate a hoarding factor that is distinct and separate from all other OCD symptom factors (Grisham & Barlow, 2005), and not all individuals who hoard meet criteria for OCD. In addition, hoarding behavior has been associated with a range of other psychiatric diseases (e.g., Finkel et al., 1997; Frankenberg, 1984). Regardless of the true relationship between OCD and hoarding, the literature suggests that the two are closely linked and an investigation of one should invariably acknowledge the other.

Despite the fact that the general pathogenesis of hoarding is as of now unknown, emerging research has provided some indication of potential vulnerability factors that may play a role in the etiology of hoarding, including genetics and cognitive variables, such as information processing deficits and unusual beliefs (Steketee et al., 2003). One conclusion that has emerged from genetic investigations is that non-shared environmental experiences constitute important contributing influences for anxiety disorders, including OCD (Hettema, Neale, & Kendler, 2001). Importantly, these factors may not only influence the onset of a disorder, but also shape the expression or course of a syndrome (Clark, Watson, & Mineka, 1994). This set of findings underscores the importance of identifying a range of putative environmental risk factors that may determine an individual's experience of hoarding.

One non-genetic factor that has been consistently associated with mood and anxiety disorders is stressful life events (SLEs; e.g., Paykel & Dowlatshahi, 1988). Although the impact of SLEs and/or TLEs on the development and maintenance of psychiatric disorders has been extensively examined, any direct association with OCD, let alone hoarding, has received relatively little attention.

Three lines of research have provided some evidence linking stressful experiences and OCD. Numerous case studies have suggested a potential association between stress (particularly trauma) and the development of obsessive–compulsive symptoms (Janet, 1903; Pitman, 1987). More systematic support for this connection comes from experimental investigations focusing on general stress in non-clinical populations, such as those finding an increase in intrusive thoughts in response to stressful and aversive stimuli (e.g., Horowitz, 1975). A third line of support for the association between OCD and the experience of SLEs or TLEs, comes from correlational clinical investigations (e.g., Cromer, Schmidt, & Murphy, in press; Gothelf, Aharonovsky, Horesh, Carty, & Apter, 2004; McKeon, Roa, & Mann, 1984). Taken as a whole, the findings from these investigations provide some indication that SLEs, and specifically TLEs, may play a role in the pathologenesis of OCD.

What, then, of the specific relationship between hoarding and stress? In their cognitive–behavioral model of hoarding, Frost and Hartl (1996) remarked on a number of clinical cases where compulsive hoarding was reported immediately following a TLE. Based on some of Rachman's work with individuals with agoraphobia (Sartory, Master, & Rachman, 1989), one hypothesis is that in response to a threatening environment, possessions acquire an association with safety and security. Hartl et al. (2005) were among the first to more systematically investigate a possible relationship between hoarding and trauma. They found that traumatic events were reported more frequently in a general sample of hoarders (not evaluated for OCD or other psychiatric diagnoses) compared with a non-hoarding community control sample. The absence of standardized diagnostic methods for evaluating psychiatric disorders leaves open the question of whether trauma is associated with hoarding above and beyond any relationship between trauma and OCD. A second study found no differences in the experience of trauma between hoarders and non-hoarders within a sample of individuals with OCD (Lochner et al., 2005), though the methods used to identify hoarders were rather ambiguous and the assessment of trauma was limited to childhood. Finally, recent studies by Grisham, Brown, Liverant, and Campbell-Sills (2005) and Grisham, Frost, Steketee, Kim, and Hood (2005) investigated the age of onset of compulsive hoarding. Individuals with a later age of onset were more likely to report a stressful event directly prior to the onset of symptoms, compared with those with an earlier age of onset. Similar to Hartl et al. (2005), this investigation did not evaluate the uniqueness of the association between hoarding and SLEs.

The current literature provides provisional support for a putative non-genetic risk factor for compulsive hoarding. The present study seeks to more fully examine the connection between TLEs and hoarding. This investigation differs from previous research in that it involves a more comprehensive analysis of the relationship between TLEs and hoarding. Rather than attempting to retrospectively tie the onset of hoarding symptoms to the experience of a trauma, we examined whether individual differences in the experience of stressors affect the expression of the clinical syndrome. To accomplish this, we evaluated the presence of hoarding symptoms in relationship to the experience of trauma, the influence of TLEs on the severity of hoarding symptoms, and the association between TLEs and the three facets of hoarding: clutter, difficulty discarding, and acquisitioning. Our hypotheses included the following: (1) TLEs will be associated with hoarding status, (2) TLEs will be related to increased hoarding symptom severity, and (3) the relationship between hoarding and TLEs will be robust, above and beyond the association TLEs have with general OCD and depressive symptomatology, or mood and anxiety disorder comorbidity.