Measurement of compulsive hoarding: saving inventory-revised

Behaviour Research and Therapy 42 (2004) 1163–1182 www.elsevier.com/locate/brat

Measurement of compulsive hoarding: saving inventory-revised Randy O. Frost a,
, Gail Steketee b, Jessica Grisham c b

a Department of Psychology, Smith College, Northampton, MA 01063, USA Boston University School for Social Work, 264 Bay State Road, Boston, MA 02215 USA c Department of Psychology, Boston University, Boston, MA 02215 USA

Received 26 February 2003; received in revised form 21 July 2003; accepted 23 July 2003

Abstract Four studies examined a new measure of compulsive hoarding (Saving Inventory-Revised; SI-R). Factor analysis using 139 hoarding participants identified 3 factors: difficulty discarding, excessive clutter, and excessive acquisition. Additional studies were conducted with hoarding participants, OCD participants without hoarding, community controls and an elderly sample exhibiting a range of hoarding behavior. Internal consistencies and test–retest reliabilities were good. The SI-R distinguished hoarding participants from all other non-hoarding comparison groups. The SI-R showed strong correlations with other indices and methods of measuring hoarding (beliefs, activity dysfunction from clutter, observer ratings of clutter in the home) and relatively weaker correlations with non-hoarding measures (positive and negative affect and OCD symptoms). The SI-R appears to be an appropriate instrument for assessing symptoms of compulsive hoarding in clinical and non-clinical samples. # 2003 Elsevier Ltd. All rights reserved. Keywords: Acquisition; Clutter; Discarding; Hoarding; Obsessive–compulsive disorder

1. Introduction Compulsive hoarding, ‘‘the acquisition of, and failure to discard, possessions which appear to be useless or of limited value’’ (Frost & Gross, 1993) occurs in 20–30% of OCD patients (Frost, Krause, & Steketee, 1996). Hoarding has been observed in a number of other disorders


Corresponding author. Tel.: +1-413-585-3804; fax: +1-413-585-3786. E-mail address: [email protected] (R.O. Frost).

0005-7967/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.brat.2003.07.006

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as well, including schizophrenia (Stein, Laszlo, Marais, Seedat, & Potocnok, 1997), anorexia (Frankenburg, 1984), organic mental disorders (Greenberg, Witzhum, & Levy, 1990), and depression (Shafran & Tallis, 1996). Severity of hoarding behaviors range from mild to severe and even life threatening (Frost & Gross, 1993; Frost, Steketee, & Williams, 1999). Although recent research has identified a number of important features of the problem (Frost & Hartl, 1996; Frost & Steketee, 1998), to date little emphasis has been placed on the measurement of hoarding and related symptoms. Until recently, existing research has relied on unsystematic descriptions of hoarding (Frankenburg, 1984; Greenberg, 1987) or yes/no responses to 2 items on the Yale Brown Obsessive Compulsive Inventory checklist (Baer, 1994; Black et al., 1998; Calamari, Wiegartz, & Janeck, 1999; Leckman et al., 1997; Summerfeldt, Richter, Antony, & Swinson, 1999). These indices of hoarding problems have not been validated and are not complete enough for the task of assessing this complex problem. In an earlier investigation of compulsive hoarding, we (Frost & Gross, 1993) developed a 22-item Hoarding Scale based on the available, albeit limited, information about the topic. This measure was subsequently revised to a 24-item scale (Frost et al., 1998). Items assessed agreement with statements reflecting difficulty discarding, emotional reactions to discarding, problems with deciding to discard, infrequent use of saved items, concern that discarded items may be needed in the future, and sentimental attachments to possessions. The Hoarding Scale has excellent internal reliability, and a number of studies have established its validity (Frost & Gross, 1993; Frost, Hartl, Christian, & Williams, 1995; Frost, Krause, & Steketee, 1996; Frost et al., 1998; Frost, Steketee, Williams, & Warren, 2000; Frost, Steketee, & Williams, 2002). However, it has significant limitations. The items on the Hoarding Scale were generated early in research on hoarding and consequently do not reflect important symptoms unknown at the time the original scale was developed. For instance, compulsive acquisition has been found to be an important aspect of compulsive hoarding (Frost et al., 1998, 2002), but is not reflected among the original items on the Hoarding Scale. Second, a number of items on the hoarding scale measure beliefs about possessions (their nature and function) rather than symptoms of the disorder (e.g., ‘‘I see my belongings as extensions of myself, they are a part of who I am.’’). While we have identified a number of relevant beliefs, no single set of beliefs characterizes all people with this problem. Rather than including all relevant beliefs in this measure and having a number of them not apply, it seems prudent to separate symptoms of hoarding from beliefs thought to be associated with it. Separate assessment of hoarding beliefs may help to explain hoarding symptoms (Steketee, Frost, & Kyrios, 2003). Third, several items on the Hoarding Scale refer to specific types of possessions (e.g. papers, containers) which are likely to have relevance to some, but not all people with this problem. Finally, the wording of the items on the existing scale does not capture the distress or impairment associated with clinically significant pathology. While the original Hoarding Scale has been useful in studying both nonclinical and clinical populations (Frost et al., 1998, 2002), it is likely to be less sensitive at the more severe ranges of the problem. The purpose of the present study was to develop and validate a new measure of compulsive hoarding in which the items (1) adequately sample the content domain of the prominent symptoms of compulsive hoarding, (2) reflect symptoms and not beliefs about possessions, (3) do not refer to specific types of possessions, and (4) adequately capture the levels of distress and impairment seen in severe hoarding cases.

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Elsewhere, we (Frost & Hartl, 1996) have defined clinically significant compulsive hoarding as ‘‘(1) the acquisition of and failure to discard a large number of possessions that appear to be useless or of limited value; (2) living spaces sufficiently cluttered so as to preclude activities for which those spaces were designed; and (3) significant distress or impairment in functioning caused by the hoarding’’ (p. 341). This definition emphasizes 3 key symptoms, as well as the distress and impairment associated with each. The first symptom is excessive acquisition of possessions. Recent research has shown that compulsive acquisition (including both compulsive buying and the compulsive acquisition of free things) characterizes people who have hoarding problems (Frost et al., 1998), and that hoarding behavior is significantly elevated in people who meet criteria for compulsive buying (Frost, Steketee, & Williams, 2002). The second key symptom is difficulty discarding. People with compulsive hoarding problems tend to place higher values on possessions and have great difficulty discarding them as a result (Frost, Hartl, Christian, & Williams, 1995). Third, the hallmark of serious compulsive hoarding problems is clutter that prevents normal use of living spaces (Frost & Hartl, 1996). Although ‘‘clutter that prevents normal use of living spaces’’ can be considered a form of interference, we have given it more prominence in the definition because it is ubiquitous in this population. Other forms of interference vary from person to person. While each of these 3 components exists to some extent in nonclinical populations (Frost & Gross, 1993), the factors that make hoarding clinically significant are the distress and impairment/interference associated with the symptoms. To develop a scale that adequately represented all of the factors that define hoarding, items from earlier versions of the scale and from pilot testing were generated to measure each of the components of compulsive hoarding outlined above: Problems with acquisition (5 items), difficulty discarding (5 items), clutter (6 items), as well as distress (5 items) and impairment/interference (5 items) associated with each of the 3 substantive symptoms. Thus, the original Saving Inventory- Revised (SI-R) contained 26 items in a self-report format that used a Likert-type scale from 0 to 4. Distress and impairment/interference items were modeled after elements of the Y-BOCS (Yale–Brown Obsessive Compulsive Scale, Goodman et al., 1989). Subjects were instructed to circle the most appropriate response. In the present study we examined the factor structure of the 26-item SI-R among a sample of people with compulsive hoarding problems in order to identify symptom-relevant subscales (Study 1). Following this, we examined known groups validity of the SI-R by comparing hoarding participants with non-hoarding participants in both OCD and non-OCD samples (Studies 2 and 3). We also studied the construct validity of the scale in relation to other measures of hoarding and of other less closely related psychopathology (Studies 2 and 3). Finally, in a sample of elderly people we examined the validity of the SI-R in relation to observer ratings of clutter in the home (Study 4). An elderly sample was chosen since hoarding has been identified as an especially difficult problem among the elderly (Steketee, Frost, & Kim, 2001). Four studies examining the psychometric properties of the SI-R are described below followed by a discussion of the overall findings. 1.1. Study 1: Factor analysis of the SI-R in a clinical sample In a previous study, a factor analysis of the 26-item SI-R in a large college student sample revealed a 4-factor solution that included 3 strong factors corresponding to the 3 symptom

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components, and a somewhat weaker factor in which distress and impairment items were combined (Coles, Frost, Heimberg, & Steketee, 2003). We sought to determine the scale’s factor structure in a sample of people who self-identified as having hoarding problems. 1.1.1. Method 1.1.1.1. Participants. The factor analysis sample included 139 participants from 4 separate hoarding projects. All subjects suffered from problems with compulsive hoarding and represented a range of severity. Among these, 32 came from a sample of people who reported receiving a diagnosis of OCD and who reported hoarding as one of their symptoms (see Study 2 for details), 70 were recruited from among people across the country seeking help from the authors for their hoarding problem and from several self-help groups devoted to compulsive hoarding (see Study 3), 24 came from a study of hoarding, trauma and ADHD recruited in a similar fashion in the Eastern Massachusetts and Central Connecticut areas (Hartl, Duffany, Allen, Steketee, & Frost, 2003), and 13 subjects were people seeking treatment for hoarding problems at the Center for Anxiety and Related Disorders at Boston University. Ages ranged from 18 to 75 with a mean of 50.7 (s:d: ¼ 11:1). Thirty-six men and 101 women completed the SI-R (2 subjects failed to report their gender). Due to missing items, complete SI-R data were available for only 131 of these subjects. 1.1.1.2. Measures. The 26-item SI-R described earlier was completed by participants as part of the study in which they were involved. 1.1.2. Results Because this was the first study examining the psychometric properties of the SI-R in a clinical sample, there was insufficient empirical basis to merit a confirmatory factor analysis. Therefore, initial analyses were conducted in an exploratory fashion. The data to be submitted to factor analysis were found to be normal (Bartlett’s Test of Sphericity <0.0001) and have adequate sampling variance (KMO index >0.5). An exploratory maximum likelihood factor analysis with Promax rotation and Kaiser normalization initially revealed 4 factors. Twentythree SI-R items loaded strongly (>0.4) and uniquely (difference >0.2) onto one of the 4 factors. Items 24, 25, and 26 had no significant loading. When these items were dropped from the analysis, a 3-factor solution emerged that accounted for 61.2% of the variance. The scree plot also suggested a 3-component solution (see Table 1). These 3 factors were similar to those found in a non-clinical population, except no Interference/Distress factor emerged (Coles, Frost, Heimberg, & Steketee, 2003). The three factors mirrored the 3 hypothesized domains of compulsive hoarding: Clutter (9 items), Difficulty Discarding (7 items), and Acquisition (7 items). Of six items originally selected to represent the clutter dimension, five loaded on a Clutter factor (items 3, 6, 12, 18, 21), and the sixth (item 24) did not load on any factor. Four additional items loaded on the Clutter factor, three representing impairment/interference associated with clutter (items 7, 14, 20) and one describing distress from clutter (item 13). For Difficulty Discarding, all five originally selected items loaded on this dimension (items 1, 11, 16, 17, 23), as well as 2 additional ones from the original distress domain (items 2, 4), both referring to distress associated with discarding. For Acquisition, 4 of the original 5 items generated for this factor loaded on it (items 8, 9, 10, 15), whereas item 25 did not load on any factor. In addition, two

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Table 1 Results of Maximum Likelihood Factor Analysis of the Saving Inventory-Revised (SI-R) for 136 participants with hoarding problems Percentage of variance accounted for

1

2

3

37.97

14.77

8.50

SI-R item content

Factor 1 Clutter

Factor 2 Difficulty Discarding

Factor 3 Acquisition

18. clutter restricts navigation through home 20. clutter prevents normal activities 6. clutter in living areas 12. clutter prevents use of home 14. clutter prevents inviting people over 7. clutter interferes with functioning 3. extent of clutter 21. lack of control over clutter 13. clutter causes distress 1. extent of difficulty throwing things away 4. avoid discarding because of distress 2. how distressing is discarding 16. strength of urge to save 11. frequency of saving things not needed 23. inability to discard 17. lack of control over urges to save 8. feel compelled to acquire? 10. lack of control over urges to acquire 5. distress if can’t acquire 9. strength of urge to acquire 15. frequency of buying unneeded items 22. financial difficulties from saving/buying 19. distress over acquiring habits

0.90 0.83 0.82 0.80 0.75 0.72 0.61 0.53 0.50 0.11 0.00 0.00 0.00 0.00 0.00 0.19 0.00 0.11 0.14 0.00 0.00 0.00 0.23

0.27 0.00 0.00 0.00 0.00 0.00 0.16 0.27 0.11 0.83 0.77 0.75 0.73 0.69 0.66 0.59 0.00 0.00 0.15 0.17 0.26 0.00 0.00

0.12 0.00 0.17 0.00 0.00 0.00 0.16 0.00 0.23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.88 0.87 0.82 0.71 0.57 0.55 0.54

Note: Items 24, 25, and 26 loaded <0.40 on any factor or double loaded and were dropped from the final solution. 61.2% of the variance was accounted for by the 3 factor solution. Kaiser–Meyer–Olkin measure of sampling adequacy = 0.89. Bartlett’s test of sphericity chi square ðdf 253Þ ¼ 1795, p < 0:0001.

distress items (items 5 and 19) and one impairment item (item 22), all of which related to acquisition, loaded on this factor. Thus, distress and impairment/interference items were divided among the 3 factors as described above, and one impairment item (item # 26) did not load on any factor. Because the 3-factor solution was consistent with the three observed types of hoarding symptoms, analyses in subsequent samples were conducted on the reduced 23-item measure (see Appendix) and its unit-weighted subscales. Internal consistency of the reduced scale was high (0.92), and alpha coefficients for the three subscales exceeded 0.87 (see Table 2). The three subscales were correlated (see Table 2) suggesting some overlap among subscales. The Difficulty Discarding subscale showed a small but significant correlation with age (r ¼ 0:17, p < 0:05), indicating that older hoarding participants had more difficulty discarding possessions. The SI-R total score, Clutter and Acquisition subscales were not correlated with

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Table 2 Reliabilities (diagonals) and intercorrelations among Saving Inventory-Revised (SI-R) subscales SI-R Total SI-R Total Discarding Clutter Acquisition

0.92 0.80 0.82 0.73

Difficulty discard- Clutter ing 0.88 0.56 0.45

0.91 0.31

Acquisition

0.87

0

All p s < 0:001.

age (p0 s > 0:05). This is somewhat surprising since earlier research has found age-related effects. However, the present sample contained only people suffering from compulsive hoarding which would restrict the range of scores on the SI-R. There were no differences between males and females on SI-R total, Difficulty Discarding or Clutter subscales. However, females had significantly higher Acquisition scores (M ¼ 15:3, s:d: ¼ 5:7) than males (M ¼ 12:5, s:d: ¼ 4:9), tð133Þ ¼ 2:59, p < 0:05. 1.2. Study 2: Comparison of self-identified OCD subjects with and without hoarding symptoms To examine the validity of the SI-R, a second study compared self-identified hoarding participants with non-hoarding participants and examined correlations of the SI-R with a measure of hoarding-related beliefs and attitudes. This was part of a larger study that included a series of self-report measures and an experimental study of attachment to possessions which is reported elsewhere (Kim, Frost, Steketee, Turkoff, & Hood, 2003). 1.2.1. Method 1.2.1.1. Participants. Participants were 66 attendees of the Obsessive Compulsive Foundation Conference (OCF). OCF is a consumer-based organization whose conference is designed for OCD sufferers and their families. Fifty-eight of the subjects reported having received an OCD diagnosis from a mental health professional and were retained for analysis. Thirty-two reported hoarding as one of their symptoms, 26 did not. Among the participants for whom hoarding was a symptom, 11 (34%) reported that it was their primary symptom. Other frequent primary symptoms for the 32 hoarding participants included contamination/washing (N ¼ 6, 19%) and multiple obsessions and compulsions (N ¼ 7, 22%). Among the non-hoarding OCD participants, the most frequent primary symptoms were contamination/washing (N ¼ 9, 35%) and multiple obsessions and compulsions (N ¼ 5, 19%). Eighteen of the participants were male (31%), and 40 were female (69%). Ages ranged from 17 to 71, with a mean of 43.2 (s:d: ¼ 13:1). 1.2.1.2. Measures. All participants completed the SI-R described above. The 23-item total score and the 3 subscales corresponding to the 3 factors of the SI-R were used in this study. Subjects also completed the Saving Cognitions Inventory (SCI; Steketee et al., 2003), a 24-item scale reflecting beliefs related to possessions. Subjects indicate the extent to which they had each thought when deciding whether to throw something away; ratings were done on a Likert-type scale range from 1 (not at all) to 7 (very much). Factor analyses of the SCI indicate four

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subscales: Emotional Attachment (10 items, a ¼ 0:96), Memory (5 items, a ¼ 0:82), Control (3 items, a ¼ 0:89), and Responsibility (6 items, a ¼ 0:91). The SCI has been found to be a valid measure of hoarding beliefs and is correlated with hoarding symptoms after controlling for age, other OCD symptoms and other cognitive variables (Steketee et al., 2003). 1.2.1.3. Procedure. Participants were solicited from a table in the conference exhibition area. The study was described to potential participants as one concerning saving behavior and all conference attendees were invited to participate. Participants were given a set of questionnaires which included the SI-R and the SCI to complete and return to the investigators. In addition, participants were asked their age, education level, whether they had received an OCD diagnosis from a mental health professional, if hoarding was one of their symptoms, and to list their primary symptom. 1.2.2. Results Hoarding and non-hoarding samples did not differ in the proportion of males (Chi Sq: ¼ 0:8, ns) or in education level, tð55Þ ¼ 1:34, ns. Consistent with previous research (Frost, Steketee, Williams, & Warren, 2000), however, hoarding participants were significantly older, M ¼ 47:2, s:d: ¼ 11:2, than non-hoarding ones, M ¼ 38:2, s:d: ¼ 13:7, tð56Þ ¼ 2:77, p < 0:01, and the SI-R total score (23 items) was correlated with age (r ¼ 0:33, p < 0:05). Examination of the SI-R subscales indicated that age was correlated with Difficulty Discarding (r ¼ 0:37, p < 0:01) and Clutter (r ¼ 0:38, p < 0:01), but not with Acquisition (r ¼ 0:08, ns). A t-test revealed that hoarding subjects scored significantly higher on the SI-R total than non-hoarding subjects, tð55Þ ¼ 8:19, p < 0:001. They also scored significantly higher on each of the subscales, Difficulty Discarding, tð55Þ ¼ 8:62, p < 0:001; Clutter, tð55Þ ¼ 6:66, p < 0:001; and Acquiring, tð55Þ ¼ 4:66, p < 0:001. Table 3 contains the means, standard deviations and range of participants’ scores. Examination of the frequency distribution of SI-R total scores for each group indicated that no non-hoarding participants scored at or above the mean for the hoarding group (53.7), and no hoarding subjects scored at or below the mean for the nonhoarding group (24.0). Further, only 4 non-hoarding participants scored above one standard deviation below the mean for the hoarding group (38.8). Only two subjects in the hoarding group scored at or below one standard deviation above the mean for the non-hoarding group Table 3 Means, standard deviations and range on the Saving Inventory-Revised (SI-R) and its subscales for hoarding and non-hoarding OCD participants Scale

SI-R Total Difficulty Discarding Clutter Acquisition

Hoarding participants

Non-hoarding participants

(N ¼ 32)

(N ¼ 26)

Mean

s.d.

Min.

Max.

Mean

s.d.

Min.

Max.

53.7 18.5

14.9 4.9

29 8

88 28

24.0 7.8

12.0 4.5

5 2

51 19

20.9 14.3

7.3 5.6

7 4

36 26

8.1 8.1

7.1 4.1

0 2

31 17

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(36.0). Thus, despite the fact that for some of the hoarding subjects, hoarding symptoms were not their primary or even a prominent symptom, there is clear separation of these subject samples on SI-R scores. There were no differences between participants who listed hoarding as their primary symptom versus those who listed hoarding as a symptom but not their primary one any of the SI-R variables (SI-R totaltð30Þ ¼ 1:02; DDtð30Þ ¼ 1:78; CLtð30Þ ¼ 0:62, ACQtð30Þ ¼ 0:47, all p’s > 0:05). Correlations between the SI-R and its subscales and the Saving Cognitions Inventory and its subscales were all significant (see Table 4). Correlations between SI-R Acquisition and hoarding beliefs were somewhat lower (r’s ranged from 0.38 to 0.55; mean ¼ 0:47) than correlations between the other SI-R dimensions and hoarding beliefs (r’s ranged from 0.52 to 0.70; mean ¼ 0:62). 1.3. Study 3: Comparison of hoarding participants and non-clinical controls This study further examined the validity of the SI-R by comparing self-identified hoarding participants to a community control sample and by examining correlations of the SI-R with measures of clutter severity in the home, mood state, and OCD symptoms. 1.3.1. Method 1.3.1.1. Participants. Participants for this study consisted of 70 people with hoarding problems and 23 community controls. The hoarding participants were solicited from self-help groups for problems with clutter and from among people contacting the first author seeking assistance with a hoarding problem. Community controls were solicited by nomination from hoarding participants of friends and family who did not have hoarding problems, and from newspaper ads asking for volunteers to participate in a psychological study. There were 17 males and 74 females in the sample (two people did not specify their gender). The mean age was 49.1 (s:d: ¼ 11:3) and ranged from 24 to 72. The mean education level was nearly 4 years of college (15.6, s:d: ¼ 2:0). Thirty-six of the subjects were married or cohabitating, 31 were single, 18 were separated or divorced, and 4 were widowed. Thirty-three subjects lived alone and 57 lived with at least one other person. Three people did not report their living situation. Table 4 Correlations among the Saving Inventory-Revised (SI-R) and its subscales and the Saving Cognitions Inventory (SCI) and its subscales for 58 individuals with OCD

SI-R total Difficulty discarding Clutter Acquisition

SCI Total

Emotional attachment

Responsibility

Control

Memory

0.73 0.72

0.59 0.57

0.70 0.70

0.61 0.59

0.6 2 0.65

0.67 0.53

0.54 0.47

0.65 0.49

0.61 0.38

0.54 0.46

All correlations significant at p < 0:005.

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1.3.1.2. Measures and procedures. Participants in both groups completed the SI-R and a demographic information sheet that inquired about age, education level, gender, marital status and whether anyone else lived in the home. The self-report version of the Yale Brown Obsessive Compulsive Scale (YBOCS; Goodman et al., 1989) was completed. This a 10-item scale assesses the severity of obsessive and compulsive symptoms on 0–4 rating scales, with scores of 16 or greater generally used to identify clinical samples. Both the clinician-rated and self-report versions of the YBOCS have good reliability and validity (see Taylor, 1998). For the present study, the hoarding obsession and compulsion items were removed from the Y-BOCS Checklist to ensure that subjects’ ratings of OCD symptom severity were independent of hoarding symptoms. Subjects also completed the Positive Affect Negative Affect Scale (PANAS; Watson, Clark, & Tellegen, 1988) which contains 20 items measuring positive affect (PA) and negative affect (NA) during the last week. Both scales have adequate reliability and validity for measuring these distinct affective structures (Watson, Clark, & Tellegen, 1988). A subsample of 38 hoarding participants were interviewed via telephone using a structured interview to determine the extent to which clutter in the living areas of their home impaired their ability to carry out basic activities. All 38 participants reported at least moderate levels of clutter that would be considered clinically significant, and 34 of the 38 reported extreme clutter. Participants indicated whether they could complete activities on a 3-point scale (1 ¼ can do without difficulty, 2 ¼ can do only with difficulty, 3 ¼ unable to do) for each of 12 routine household activities (e.g., using the stove, eating at a table, sitting on a sofa). Scores for all items were summed to provide a total activity dysfunction (AD) score. This scale had adequate internal reliability (alpha ¼ 0:83). In addition, a small subsample of hoarding participants were sent a follow-up questionnaire containing a second SI-R to complete and return. Twelve of the 25 participants returned the retest SI-R. Timing of the retest ranged from 2 weeks to 4 weeks. 1.3.2. Results Consistent with other research on hoarding, the hoarding participants were significantly older (M ¼ 50:7) than the community controls (M ¼ 44:4; tð90Þ ¼ 2:36, p < 0:05). The groups did not differ on levels of education (t½83 ¼ 0:52, n.s.) or income (t½85 ¼ 0:78, n.s.), but a higher percentage of hoarding participants lived alone (44.8%) compared to community controls (13.6%; Chi Sq ð1Þ ¼ 5:6, p < 0:05). Test–retest reliability was studied for a small subset of 12 participants who completed a second SI-R two to four weeks after the original questionnaire. Correlations were high: 0.86 for the SI-R total, 0.89 for Difficulty Discarding, 0.90 for Clutter, and 0.78 for Acquisition. Paired t-tests examining changes over time on the SI-R and its subscales failed to reveal any significant effects (all p0 s > 0:15). T-tests comparing hoarding participants to community controls revealed a significant effect for the SI-R total and subscale scores (SI-R total t½91 ¼ 12:4; Difficulty Discarding t½91 ¼ 9:0; Clutter t½91 ¼ 11:5; Acquisition t½91 ¼ 7:3; all p’s < 0:001). In each case, the SI-R measure was significantly higher for hoarding participants than for community controls (see Table 5). Again, there was relatively little overlap in the SI-R total score distributions. No community control participant scored above the mean for the hoarding group, and only one community control

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Table 5 Means, standard deviations and range on SI-R and its subscales for 70 hoarding participants and 23 community controls Scale

SI-R total Difficulty discarding Clutter Acquisition

Hoarding participants

Community controls

(N ¼ 70)

(N ¼ 23)

Mean

s.d.

Min

Max

Mean

s.d.

Min

Max

62.0 19.8

12.7 5.0

37 4

91 28

23.7 9.2

13.2 5.0

0 0

51 18

26.9 15.2

6.6 5.4

6 3

36 28

8.2 6.4

7.1 3.6

0 0

26 13

SI-R=Saving Inventory-Revised.

subject scored within one standard deviation below the hoarding mean (49.3). Similarly, no hoarding participant scored below the mean for the community control group, and no hoarding participant scored within one standard deviation above the SI-R total mean for the community control group (36.9). A further test of the construct validity of the SI-R was provided by correlations between SI-R scores and the interview measure of activity dysfunction on a subsample of 38 hoarding participants. Significant correlations were evident for SI-R total (r ¼ 0:54, p < 0:001), and for Difficulty Discarding (r ¼ 0:36, p < 0:05) and Clutter (r ¼ 0:52, p < 0:001), but not Acquisition (r ¼ 0:23, ns). This finding supports the validity of the SI-R subscales, particularly the Clutter subscale, in predicting other relevant variables, such as interference from clutter. The pattern of correlations also supports the discriminant validity of the subscales of the SI-R. The Clutter subscale correlated with a different measure of clutter (i.e., interview-based assessment of interference from clutter), while the Acquisition subscale did not. As evident from Table 6, among hoarding participants only the Difficulty Discarding subscale of the SI-R was significantly and negatively correlated with Positive Affect from the PANAS. SI-R total, Clutter, and Acquisition were significantly and positively correlated with Negative Affect, and the correlation with Difficulty Discarding approached significance (p ¼ 0:08). These correlations were low to moderate in size (0.21 to 0.38). SI-R subscales Table 6 Correlation of hoarding symptoms (SI-R) with positive and negative affect (PANAS) and with OCD symptoms (YBOCS) among 70 hoarding participants Positive affect SI-R total Difficulty discarding Clutter Acquisition


0.22 0.26
0.15 0.08

Negative affect




0.38 0.21 0.26
0.38




Y-BOCS 0.25
0.24
0.06 0.29


p < 0:05,

p < 0:01,


p < 0:001: SI-R = Saving Inventory-Revised, Y-BOCS = Yale-Brown Obsessive Compulsive Scale, PANAS = Positive Affect Negative Affect Scale.

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showed a differing pattern of correlations with OCD severity on the YBOCS (see Table 6). The total SI-R score and both Difficulty Discarding and Acquisition subscales were moderately positively correlated with the YBOCS, whereas the Clutter subscale was not. Comparisons of these correlations with correlations with activity dysfunction provide additional evidence that the subscales measure slightly different phenomena. For example, correlations of the Clutter subscale with activity dysfunction were significantly larger than the correlations between Clutter and Negative Affect or the YBOCS (t½35 ¼ 2:71, p < 0:05). Research on OCD has suggested that hoarding is a distinct subtype of OCD and may reflect a separate disorder (Calamari, Wiegartz, & Janeck, 1999; Leckman et al., 1997; Summerfeldt, Richter, Antony, & Swinson, 1999). Interestingly, 23 of the hoarding subjects had YBOCS scores below 5 suggesting no other OCD symptoms at all. 1.4. Study 4: Behavioral assessment of hoarding Study 4 examined the validity of the SI-R in relation to a self-rating and an independent observer’s rating of clutter in the main rooms of people’s homes. The SI-R was also studied in relation to self-rated dysfunction in daily activities as a result of the clutter. We hypothesized that the SI-R would be correlated with each of these measures, and in particular, that the Clutter subscale would show the strongest correlation since the observational measures were of clutter. Hoarding has been found to be particularly problematic in elderly populations (Steketee, Frost, & Kim, 2001), so to increase the generalizability of findings related to the SI-R, an elderly sample was chosen for this study. 1.4.1. Method 1.4.1.1. Participants. As part of an interview study examining features of hoarding among elderly clients, 25 individuals from the Boston area were recruited for a study of saving behavior from elder service agencies who agreed to advertise the study among their clients. Included were clients with no evident hoarding problems (N ¼ 13), as well as those whose homes were seriously cluttered (N ¼ 12). Participants’ mean age was 75.0 (s:d: ¼ 7:9) and 19 (76%) were women. Most participants were widowed, divorced or separated (68%), 16% were married and 16% had never married. 1.4.1.2. Measures and procedures. All interviews took place in participants’ homes; these included rented or owned apartments (68%) and single family homes (32%). On arrival in the home, a trained master’s level psychologist obtained informed consent and was given a brief tour of the main rooms of the home, including living room, dining room bedroom(s), kitchen and bathroom. After demographic information was collected, the interviewer read each SI-R question and the possible responses and recorded the participant’s numerical rating. Following this, the interviewer inquired about the person’s perception of the extent of clutter in each of the rooms in the home, on a scale from 0 ¼ none to 4 ¼ very severe. The interviewer also rated these rooms using the same scale based on his observation of the rooms. The interviewer was trained by the authors (GS and RF) in rating severity of clutter using photographs that illustrated a range of clutter severity in various rooms. Because all participants’ homes contained a living room, kitchen, and bedroom, the severity ratings for these three rooms were

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summed and divided by 3 to provide a mean clutter severity score (CS). The interviewer assisted subjects in completing the activity dysfunction (AD) scale as described in Study 3, in addition to several other questions not relevant to the present project. 2. Results The mean score for all subjects on the SI-R was 28.3 (s:d: ¼ 18:1), scores that are slightly higher than those of non-hoarding OCD participants and community controls in Studies 2 and 3. The internal consistency of the SI-R total score in this sample was 0.94. Reliabilities for the subscales were similar to those observed in Study 1 (Difficulty Discarding ¼ 0:93; Clutter ¼ 0:88, Acquisition ¼ 0:80). Comparison of the 2 groups indicated that the hoarding participants scored significantly higher on the SI-R total and each of the subscales than the non-hoarding participants. See Table 7. Pearson correlations were computed for the SI-R total and subscale scores and the average self and observer ratings of clutter severity, as well as dysfunction in daily activities (AD). These are presented in Table 8. Findings indicated that both the residents’ and the observer’s rating of clutter were highly correlated (0.70–0.80) with the SI-R total score and with the Difficulty Discarding and Clutters subscales. Correlations with the Acquisition subscale were only moderate (0.5 range). The SI-R total score and Difficulty Discarding and Clutter subscales were also moderately correlated with activity dysfunction (0.52–0.58). As anticipated, acquisition was not related to this measure of the effect of clutter. 3. Discussion The items for the Saving Inventory-Revised were selected so as to adequately sample the range of hoarding symptoms identified by recent research, especially with respect to problems with compulsive acquisition (Frost et al., 1998). Items were also selected to minimize the assessment of beliefs associated with hoarding which can be assessed separately (Steketee et al., 2003). SI-R items were constructed to avoid references to specific types of possessions since these vary from person to person with hoarding problems and none may apply universally. Finally, items were designed to measure distress and impairment associated with each of the three dimensions of compulsive hoarding. A factor analysis of the SI-R among a sample of compulsive hoarding participants (Study 1) revealed a 3-factor solution using 23 of the 26 original items. The 3 factors correspond to the 3 major symptoms hypothesized in Frost and Table 7 Means, (standard deviations), t and p-values for hoarding and non-hoarding elders in Study 4

SI-R total Difficulty discarding Clutter Acquistion

Hoarding elders

Non-hoarding elders

t(23)

p

44.6 (10.1) 15.9 (3.7) 18.9 (6.2) 9.8 (4.2)

13.3 (7.2) 6.8 (4.5) 3.2 (3.8) 3.3 (2.6)

8.97 5.53 7.70 4.65

0.001 0.001 0.001 0.001

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Table 8 Correlations of the Saving Inventory-Revised (SI-R) and averaged self and observer ratings of clutter severity (CSTotal) and observer rated Activity Dysfunction for a sample of 25 elders Self-rated CS-total SI-R total Difficulty discarding Clutter Acquisition







0.79 0.70

0.79

0.52


Observer CS-total



0.78 0.71

0.79

0.52



Activity dysfunction 0.54

0.52

0.58

0.22

p < 0:001,
p < 0:01.

Hartl’s (1996) model of compulsive hoarding: excessive clutter in the home, difficulty discarding possessions, and excessive acquisition of purchased and free items. Impairment and distress on the SI-R were worded to reflect one of the three behavioral symptoms and this may account for why they loaded onto symptom factors rather than onto a separate factor, as was found by Coles, Frost, Heimberg and Steketee (2003). Discarding items that did not load onto a factor did not appear to reduce the utility of the measure, and thus we retained only the 23 items that loaded clearly onto one of the factors. This factor analysis was similar to one conducted using university undergraduates (Coles et al., 2003). The Coles et al. factor analysis generated 3 strong factors corresponding to the 3 major symptom dimensions (clutter, difficulty discarding, acquisition), and one additional somewhat weaker distress/interference factor. Differences in the subject samples may account for the variation in factor structure. In university students, hoarding behaviors may be displayed, but relatively few undergraduates suffer significant distress or interference (Frost & Gross, 1993). In the compulsive hoarding sample, however, all of the subjects experience significant distress or interference related to the symptoms. Internal consistency was high for the 23-item total scale and each of the subscales. Test–retest reliability was very good, but needs replication with a larger sample. Some overlap among the subscales was evident, as would be expected from clinical observation of hoarding behavior. Interestingly, the Acquisition subscale was less closely associated with the total hoarding score and with Difficulty Discarding and Clutter, suggesting that this component of hoarding may be slightly more independent. As findings from Studies 2 and 3 indicate, scores on the SI-R total and its subscales clearly distinguished self-identified hoarding participants from OCD participants without hoarding, as well as from community controls. Hoarding participants scored significantly and substantially higher than non-hoarding participants on all SI-R scales, usually by a factor of 2 or more. Examination of scores also indicated that rarely did individuals from one group score within one standard deviation of the mean of the other. This minimal overlap in the distributions points to the specificity of the scale. Hoarding and non-hoarding samples also differed in age, as has been found consistently in other studies (e.g., Frost, Steketee, Williams & Warren, 2000); hoarding participants were several years older than other clinical and non-clinical samples drawn from similar sources. In Studies 2 and 3, the mean age for adult hoarding participants approached 50 whereas the mean age for non-hoarding adults was nearer 40. Gender was associated only with acquisition:

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women acquired more things than men, perhaps due to cultural expectations that women buy more things and derive emotional satisfaction from buying. The gender difference observed here is consistent with the literature on compulsive buying (Lejoyeux, Ade`s, Tassain, & Solomon, 1996). Findings from numerous studies report higher levels of compulsive buying among females (Frost, Steketee, & Williams, 2002). In Study 3, hoarding participants tended to live alone (44%) more often than community controls (14%). That more hoarding participants lived alone is consistent with previous findings that a large percentage of elderly people with hoarding problems had never married and lived alone (Steketee, Frost, & Kim, 2001). As Table 8 shows, living alone versus with someone led to a difference only on the Clutter scale of the SI-R, but not on Difficulty Discarding or Acquisition. Our findings do not clarify the direction of the relationship between clutter and living situation: does hoarding lead to social isolation and a tendency to live alone or does having no one else in the home increase the likelihood that clutter will be unrestricted and become a problem? Further research on the causes and consequences of living alone for people suffering from compulsive hoarding is warranted. Examination of the correlations with other measures of hoarding indicates good convergent validity of the SI-R and its subscales. The Total score and the Difficulty Discarding and Clutter subscales correlated significantly and strongly (rs ¼ 0:54 to 0.75) with a measure of hoardingrelated beliefs and attitudes (Study 2). The Acquisition subscale was less strongly related to this measure, again suggesting that acquisition may be a less central and less consistent component of hoarding behavior. In Study 3, the SI-R total, Difficulty Discarding and Clutter subscales were correlated with measures of activity dysfunction resulting from the clutter. Differential subscale validity can be seen in the fact that the highest correlation was between the clutter subscale and the activity dysfunction from clutter, and lowest for Acquisition and activity dysfunction from the clutter. This pattern would be expected since the activity dysfunction measure is an alternate measure of clutter. The magnitude of the correlations with activity dysfunction (rs in the 0.5 range) is noteworthy since the SI-R and its subscales clearly have a restricted range among the hoarding subjects used for these correlations. Further evidence for the convergent validity of the SI-R was provided in Study 4 in which the SI-R, Difficulty Discarding, and Clutter subscales were significantly and highly correlated with both self-rated and observer-rated clutter in the home. Again, since these observational measures focus specifically on how cluttered the homes were, we expected them to be less highly correlated with the Acquisition dimension of compulsive hoarding. Indeed, the correlations with Acquisition, though still significant, were significantly smaller than those between Clutter and observational measures of clutter. Convergent validity of the SI-R is demonstrated by the fact that the SI-R and its subscales are strongly related to other indices of compulsive hoarding. Evidence of discriminant validity comes from the absence of (or smaller magnitude of) correlations with measures less central to the construct of hoarding, particularly positive affect, and to a lesser extent, negative affect and YBOCS. For the latter two scales, the correlations were significant, but small in magnitude. While part of the reason for the small correlations may be the restricted range of SI-R scores among the hoarding subject, the limited range did not result in low correlations with measures of hoarding-related behavior (e.g., activity dysfunction, observer ratings of clutter). In examining the relationship of the SI-R to other measures of psychopathology, it is interesting to note that, although hoarding has been considered a symptom of OCD, the correlation of

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the SI-R and its subscales with the YBOCS were relatively small (rs ¼ 0:24 to 0.29) and a large number of hoarding subjects in Study 2 did not display any other OCD symptoms. More research is needed to examine the possibility that hoarding associated with OCD may have different causes or characteristics than hoarding without OCD. These findings suggest that the SI-R is a reliable and valid measure of compulsive hoarding. The subscales appear to reflect real and meaningful phenomena related to compulsive hoarding. Further work using this measure is warranted. For instance, adding a time frame to the instructions for the SI-R (e.g., in the past month) may make the measure more sensitive to change. One limitation of the research reported here is the use of self-report to determine hoarding status and severity. Independent verification of hoarding status and its significance would have strengthened these findings. Further research on this problem is needed to establish a clearer delineation of when hoarding is clinically significant.

Acknowledgements This research was supported in part by a grant from an anonymous donor.

Appendix. Saving Inventory Revised (Please circle the response that is most appropriate.) 1. To what extent do you have difficulty throwing things away? 0 1 2 3 4

= Not at all = To a mild extent = To a moderate extent = To a considerable extent = Very much so

2. How distressing do you find the task of throwing things away? 0 1 2 3 4

= No distress = Mild distress = Moderate distress = Severe distress = Extreme distress

3. To what extent do you have so many things that your room(s) are cluttered? 0 = Not at all 1 = To a mild extent 2 = To a moderate extent

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3 = To a considerable extent 4 = Very much so 4. How often do you avoid trying to discard possessions because it is too stressful or time-consuming? 0 1 2 3 4

= Never avoid, easily able to discard items = Rarely avoid, can discard with a little difficulty = Sometimes avoid = Frequently avoid, can discard items occasionally = Almost always avoid, rarely able to discard items

5. How distressed or uncomfortable would you feel if you could not acquire something you wanted? 0 1 2 3 4

= Not at all = Mild, only slightly anxious = Moderate, distress would mount but remain manageable = Severe, prominent and very disturbing increase in distress = Extreme, incapacitating discomfort from any such effort

6. How much of the living area in your home is cluttered with possessions? (Consider the amount of clutter in your kitchen, living room, dining room, hallways, bedrooms, bathrooms or other rooms.) 0 1 2 3 4

= None of the living area is cluttered = Some of the living area is cluttered = Much of the living area is cluttered = Most of the living area is cluttered = All or almost all of the living area is cluttered

7. How much does the clutter in your home interfere with your social, work or everyday functioning? Think about things that you don’t do because of clutter. 0 1 2 3 4

= Not at all = Mild, slight interference, but overall functioning not impaired = Moderate, definite interference, but still manageable = Severe, causes substantial interference = Extreme, incapacitating

8. How often do you feel compelled to acquire something you see (e.g., when shopping or offered free things)? 0 = Never feel compelled 1 = Rarely feel compelled

R.O. Frost et al. / Behaviour Research and Therapy 42 (2004) 1163–1182

2 = Sometimes feel compelled 3 = Frequently feel compelled 4 = Almost always feel compelled 9. How strong is your urge to buy or acquire free things for which you have no immediate use? 0 1 2 3 4

= Urge is not at all strong = Mild urge = Moderate urge = Strong urge = Very strong urge

10. How much control do you have over your urges to acquire possessions? 0 1 2 3 4

= Complete control = Much control, usually able to control urges to acquire = Some control, can control urges to acquire only with difficulty = Little control, can only delay urges to acquire only with great difficulty = No control, unable to stop urges to acquire possessions

11. How often do you decide to keep things you do not need and have little space for? 0 1 2 3 4

= Never keep such things = Rarely = Occasionally = Frequently = Almost always keep such possessions

12. To what extent does clutter prevent you from using parts of your home? 0 1 2 3 4

= All parts of the home are usable = A few parts of the home are not usable = Some parts of the home are not usable = Many parts of the home are not usable = Nearly all parts of the home are not usable

13. To what extent does the clutter in your home cause you distress? 0 1 2 3 4

= No feelings of distress or discomfort = Mild feelings of distress or discomfort = Moderate feelings of distress or discomfort = Severe feelings of distress or discomfort = Extreme feelings of distress or discomfort

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14. How frequently does the clutter in your home prevent you from inviting people to visit? 0 1 2 3 4

= Not at all = Rarely = Sometimes = Often = Very often or nearly always

15. How often do you actually buy (or acquire for free) things for which you have no immediate use or need? 0 1 2 3 4

= Never = Rarely = Sometimes = Frequently = Almost always

16. How strong is your urge to save something you know you may never use? 0 1 2 3 4

= Not at all strong = Mild urge = Moderate urge = Strong Urge = Very strong urge

17. How much control do you have over your urges to save possessions? 0 1 2 3 4

= Complete control = Much control, usually able to control urges to save = Some control, can control urges to save only with difficulty = Little control, can only stop urges with great difficulty = No control, unable to stop urges to save possessions

18. How much of your home is difficult to walk through because of clutter? 0 1 2 3 4

= None of it is difficult to walk through = Some of it is difficult to walk through = Much of it is difficult to walk through = Most of it is difficult to walk through = All or nearly all of it is difficult to walk through

19. How upset or distressed do you feel about your acquiring habits? 0 = Not at all upset 1 = Mildly upset

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2 = Moderately upset 3 = Severely upset 4 = Extreme embarrassment 20. To what extent does the clutter in your home prevent you from using parts of your home for their intended purpose? For example, cooking, using furniture, washing dishes, cleaning, etc.?) 0 1 2 3 4

= Never = Rarely = Sometimes = Frequently = Very frequently or almost all the time

21. To what extent do you feel unable to control the clutter in your home? 0 1 2 3 4

= Not at all = To a mild extent = To a moderate extent = To a considerable extent = Very much so

22. To what extent has your saving or compulsive buying resulted in financial difficulties for you? 0 1 2 3 4

= Not at all = A little financial difficulty = Some financial difficulty = Quite a lot of financial difficulty = An extreme amount of financial difficulty

23. How often are you unable to discard a possession you would like to get rid of? 0 1 2 3 4

= Never have a problem discarding possessions = Rarely = Occasionally = Frequently = Almost always unable to discard possessions

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