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Article
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October 01, 2006
Estimated
Prevalence of Compulsive Buying Behavior in the United States
Lorrin M. Koran; Ronald J. Faber; Elias Aboujaoude; Michael D. Large; Richard T. Serpe
Am J Psychiatry
2006;163:1806-1812.
Abstract
Objective: Compulsive buying (uncontrolled urges to buy, with resulting significant adverse consequences) has been estimated to affect from 1.8% to 16% of the adult U.S. population. To the authors’ knowledge, no study has used a large general population sample to estimate its prevalence. Method: The authors conducted a random sample, national household telephone survey in the spring and summer of 2004 and interviewed 2,513 adults. The interviews addressed buying attitudes and behaviors, their consequences, and the respondents’ financial and demographic data. The authors used a clinically validated screening instrument, the Compulsive Buying Scale, to classify respondents as either compulsive buyers or not. Results: The rate of response was 56.3%, which compares favorably with rates in federal national health surveys. The cooperation rate was 97.6%. Respondents included a higher percentage of women and people ages 55 and older than the U.S. adult population. The estimated point prevalence of compulsive buying among respondents was 5.8% (by gender: 6.0% for women, 5.5% for men). The gender-adjusted prevalence rate was 5.8%. Compared with other respondents, compulsive buyers were younger, and a greater proportion reported incomes under $50,000. They exhibited more maladaptive (patterns of thinking and behavior that cause and maintain emotional problems. A maladaptive thinking pattern sometimes can be accompanied by "irrational beliefs," which are beliefs that are held even though they are not true) responses on most consumer behavior measures and were more than four times less likely to pay off credit card balances in full. Conclusions: A study using clinically valid interviews is needed to evaluate these results. The emotional and functional toll of compulsive buying and the frequency of comorbid psychiatric disorders (co-occurrence of one or more diseases or disorders in an individual) suggests that studies of treatments and social interventions are warranted. -------------------- Buying usually serves utilitarian/practical needs. For some adults, shopping is also a leisure activity (1), a means of managing emotions (2), or a way to establish and express self-identity (3). For others, the inability to control buying urges brings significant adverse consequences (4, 5). Uncontrolled problematic buying behavior has been referred to as uncontrolled buying (4), compulsive buying (6), compulsive shopping (7), addictive buying (8), excessive buying (9), and "spendaholism" (10). Although compulsive buying is not specifically described in DSM-IV, diagnostic criteria have been proposed. These include being frequently preoccupied with buying or subject to irresistible, intrusive, and/or senseless impulses to buy; frequently buying unneeded items or more than can be afforded; shopping for periods longer than intended; and experiencing adverse consequences, such as marked distress, impaired social or occupational functioning, and/or financial problems (5). The proposed diagnostic criteria are consistent with the reports of individuals who acknowledge problematic and uncontrolled buying behaviors (5, 6, 1113). The adverse consequences include guilt or remorse, excessive debt, bankruptcy, family conflict, divorce, illegal activities, such as writing bad checks and embezzlement, and even suicide attempts (6, 12, 14, 15). Estimates of the prevalence of compulsive buying in the adult U.S. population range from 1.8% (16) to 16% (17). However, no study, to our knowledge, has used a large general population sample to estimate prevalence. A more accurate prevalence estimate would help indicate the disorder’s impact on the public’s mental health. If the prevalence is substantial, interest in finding treatments will intensify. In addition, establishing a baseline prevalence would help elucidate the contributions to compulsive buying of differing or changing social conditions versus biological factors. Some authors, for example, have asserted that compulsive buying results from the conditions of modern life, including the easy availability of credit cards; increased and more effective advertising; the ease of shopping in malls, through TV, and the Internet; the dilution of family structure; and a breakdown in the sense of community (2, 1821). To establish a more accurate prevalence estimate, we conducted a nationwide random telephone survey using a validated screening instrument embedded in a structured interview. MethodData and Sampling
The data were generated in the spring
and summer of 2004 from our national household telephone
survey, which interviewed 2,513 adults ages 18 and
older. The survey addressed shopping and buying
attitudes and behaviors and their consequences and
respondents’ financial and demographic data. The
interviews were conducted from the Social and Behavioral
Research Institute, California State University, San
Marcos, by interviewers with an average of 14 months of
experience in health-related telephone surveys and
specific training for this project. The Social and
Behavioral Research Institute conducts health surveys
for the federal Health and Human Services Agency and the
Centers for Disease Control and Prevention, numerous
health agencies, and academic researchers. The
interviewers used a computer-assisted telephone
interviewing system that guarded against errors of
omission and presentation. As an additional quality
control measure, the first author monitored pilot
interviews and provided feedback. During the
data-collection phase, supervisors monitored performance
during random interviews. To obtain informed consent,
interviewers identified themselves, the survey
organization, the study sponsor and survey topic, and
stated that the interview was voluntary, anonymous,
included no incentive, was terminable by the respondent
at any time, and might be monitored by a supervisor. The
interview was conducted with the first person ages 18 or
older answering the telephone. Interviews averaged 11.3
minutes.
The sample was obtained through
random-digit-dial telephone calls within the continental
U.S., stratified by state. All listed and unlisted
residential telephone numbers had an equal chance of
inclusion. Cell phone numbers were not included. This
household sampling method oversamples women and
undersamples younger individuals and some minorities. To
ensure that busy individuals were represented, telephone
numbers were called until finalized or 15 call attempts
had been made. A respondent was defined as a person who
completed a full or partial interview. A status of
"unknown study eligibility" could arise, for example,
from persistent busy signals or repeated answers by a
telephone answering device. The proportion of those with
unknown eligibility who were then assumed eligible was
set as equal to the proportion of known eligible persons
among people actually reached. Additional response rate
information accompanies the online version of this
article.
Measurement Scales
To estimate the prevalence of
compulsive buying, we used the Compulsive Buying Scale
(16) (available from the first author). The seven
scale items reflect a need to spend money (items 1 and
6), awareness that spending behavior is aberrant (item
2), loss of control (items 3 and 4), buying things to
improve mood (item 5), and probable financial problems
(item 7).
An individual’s Compulsive Buying
Scale score was generated from the responses to these
seven items through a formula. Individuals whose
Compulsive Buying Scale score was ≤1.34 are classified
as "compulsive buyers". This cutoff score (—1.34) was 2
standard deviations below the general population mean in
the original study and produced a prevalence estimate of
8.1%
(16). Further data in support of these score
thresholds are presented in a supplement that
accompanies the online version of this article. For
comparison purposes, we also examined in separate
analyses individuals with scores 3 standard deviations
below the general population mean in the original study.
Lacking clinical interviews to
validate that compulsive buyers suffer from a clinically
significant disorder, we investigated one possible
measure of "severity" by conducting a post hoc analysis
of three preplanned questions that suggest loss of
control over buying: how often the individual 1) "just
wanted to buy things and did not care what you bought,"
2) "bought something and when you got home were not sure
why you bought it," and 3) "went on a buying binge and
could not stop." The three questions had an internal
consistency Cronbach alpha of 0.59. We compared the
proportions of compulsive buyers and other respondents
who engaged in these behaviors "often" or "almost
always" and calculated the mean of the three items’
summed scores (1 for "never" to 5 for "almost always").
In addition, we compared the shopping and buying
attitudes and behaviors of the compulsive buyers and
other respondents using five other questions not
included in the Compulsive Buying Scale.
Data Analysis
The analyses included
1) descriptive and comparison statistics for the sample’s demographics, 2) the prevalence of compulsive buying, 3) cross-tabulation and t test comparisons of those classified as compulsive buyers versus the remaining respondents in terms of demographics and shopping and buying attitudes and behaviors, and 4) logistic regression analysis to investigate the independent contribution of demographic and other variables to prevalence rates in subgroups. The significance level was set at p≤0.05, two-tailed, for comparisons of demographic variables and p≤0.05, one-tailed, for shopping or buying attitudes and behaviors, with compulsive buyers hypothesized to exhibit more maladaptive responses. For each analysis, cases were dropped list-wise when data were missing. Although missing data were minimal, missing cases resulted in some variation in the number of cases used in different analyses.
Compared with the U.S. adult
population, the respondents included a substantially
higher percentage of women and, to a lesser extent, a
higher percentage of people ages 55 and older (Table
1). A little over one-half (56.7%) of the
respondents were married compared to 52.5% in the U.S.
population (χ 2=17.33, df=1, p<0.001). The
respondents’ racial distribution closely resembled that
of the U.S. population but included a smaller proportion
of Hispanic individuals. Because the study sampling
method was stratified by state, the respondents were
representative of the U.S. population with regard to
distribution by state.
The Compulsive Buying Scale scoring
algorithm with a criterion score of ≤1.34 for
"compulsive buyers" (i.e., scores ≤2 standard deviations
below the mean) gave an estimated point prevalence of
compulsive buying of 5.8% and, by gender, a point
prevalence for women of 6.0% (90 of 1,501) and one for
men of 5.5% (44 of 800). Adjustment of the overall
prevalence figure to the gender distribution of the U.S.
adult population, i.e., multiplying the gender-specific
prevalence figures by the U.S. population gender
proportions and summing the results, also gave a point
prevalence rate of 5.8%. Using a Compulsive Buying Scale
score criterion of 3 standard deviations below the mean
for "compulsive buyer" produced an estimated prevalence
rate of 1.4% (33 of 2,301). Again, the estimated
prevalence was similar for women (1.5%, 23 of 1,501) and
men (1.3%, 10 of 800).
Compulsive buyers had a significantly
lower mean age (mean=39.7 years, SD=15.7) than other
respondents (mean=48.7 years, SD=16.5) (t=6.04, df=2234,
p<0.001). The two groups did not differ in the mean
number of people per household (mean=3.04, SD=1.80,
versus mean=2.83, SD=1.48).
Multiple logistic regression
analysis, including income group, gender, age, marital
status, and race/ethnicity as predictors of compulsive
buying status indicated that only income group (Wald χ
2=5.79, df=1, p<0.02) and age (Wald χ 2=11.81,
df=1, p=0.001) were significant.
The income distribution of compulsive
buyers was shifted significantly toward those with a
lower income compared with those of other respondents. A
greater proportion of compulsive buyers reported incomes
under $50,000 (54.7% versus 39.3%) (χ 2=10.79,
df=1, p=0.001).
The demographic characteristics of
those with Compulsive Buying Scale scores 3 standard
deviations beyond the normal mean (N=33), including
gender distribution and mean number of people per
household, closely resembled those of the remaining
compulsive buyers (N=101) with scores 2 standard
deviations beyond the normal mean.
Compulsive buyers did not have more
credit cards than other respondents, but more of their
cards were within $500 and $100 of the credit limit (Table
2). The compulsive buyers were more than four times
as likely as other respondents to "very often" or
"often" make the minimum payment on credit card balances
(Table
2). This greater propensity was present within each
of the eight pre planned income groups between under
$10,00 and under $150,000; the number of compulsive
buyers with incomes of ≥$150,000 was only four,
precluding meaningful description.
Compulsive buyers did not differ
significantly from other respondents in mean total
credit card balances, but the Compulsive Buying Scale
compulsive buyers’ lower income level was a confounding
factor. To control for income, we performed a post hoc
analysis of total credit card debt. We collapsed the
respondents as equally as possible into four income
subgroups that became the following: <$25,000 (N=335),
$25,000 to <$50,000 (N=403), $50,000 to <$75,000
(N=522), and ≥$75,000 (N=614). The post hoc comparisons
indicated a non significant tendency for compulsive
buyers to have higher credit card balances in each
category, with the largest differences occurring in the
<$25,000 ($2,660 versus $1,530) and the ≥$75,000
categories ($6,130 versus $3,850). The large variances
within each category, however, limited the power of the
analysis.
As hypothesized, the compulsive
buyers exhibited more maladaptive shopping and buying
attitudes and behaviors than the other respondents,
thus, supporting the validity of the dichotomy.
Compulsive buyers engaged in "problem shopping" more
often and for longer periods (Table
2). They took greater pleasure in shopping and
buying, more often make senseless and impulsive
purchases, more often feel depressed after shopping, and
more often experiencing uncontrollable buying binges (Table
3). The compulsive buyers also exhibited
substantially higher scores on the post hoc "severity"
measure (mean=2.73, SD=0.83, versus mean=1.67, SD=0.54),
but given its post hoc nature, no statistical testing
was performed.
With regard to the variables
displayed in
Table 1,
Table 2, and
Table 3, those with Compulsive Buying Scale scores 3
standard deviations beyond the normal mean differed from
the remaining compulsive buyers with scores 2 standard
deviations beyond the normal mean only in that a smaller
proportion were white (42.4% versus 65.4%; χ 2=5.1,
df=1, p<0.03) and a greater proportion went on buying
binges and could not stop "almost always" or "often" (Table
3, question 27) (30.4% versus 13.8%) (χ2=9.78,
df=4, p<0.05).
This large random sample nationwide
telephone survey that used a validated screening
instrument suggests that compulsive buying is a common
problem among U.S. adults,
affecting more than one in 20
adults. Previous research has documented significant
suffering and impairment associated with this behavior.
The gender-adjusted point prevalence (5.8%) produced by
the recommended Compulsive Buying Scale cut-off score was
considerably higher than those for major depression
(about 1.5%
[22]) and generalized anxiety disorder (1.5%—3.0%
[23]), disorders that command substantial clinical
and research attention.
A self-help book has apparently
been apt in referring to compulsive buying as "the
smiled-upon addiction"
(24). An extremely conservative 3 standard deviation
Compulsive Buying Scale cut-off point below the
respondents’ mean produced a point prevalence estimate
(1.4%) similar to those for major depression and
generalized anxiety disorder. For both the 2 standard
deviation and 3 standard deviation compulsive buyers,
the gender-specific prevalence rates were quite similar,
as are the identified individuals’ demographic and
clinical characteristics.
The validity of the larger prevalence
estimate is supported first by the finding, albeit in
small samples, that subjects meeting the 2 standard
deviation Compulsive Buying Scale criterion almost
always meet the suggested clinical diagnostic criteria
(12,
25) and vice versa
(26). The estimate’s validity is further supported
by the observation that the present study’s compulsive
buyers exhibited more maladaptive shopping/buying
attitudes and behaviors and more adverse financial
consequences than the remaining respondents. Finally,
the developers of the Compulsive Buying Scale pointed
out that using a criterion score of 3 standard
deviations below the respondents’ mean "would mean a
high likelihood of excluding many people who truly are
compulsive buyers."
Still, without a structured clinical
interview such as the
Minnesota Impulsive Disorders
Interview
(12) administered by a mental health professional,
we cannot be certain that any of the compulsive buyers
suffered from the clinical condition termed "compulsive
buying" or merit clinical attention. As in any telephone
survey, some respondents may have exaggerated responses
(e.g., income) or been reluctant to admit unpleasant
truths (e.g., credit card debt). The prevalence figure
derived from the Compulsive Buying Scale may be too
high, if, for example, there is a response bias toward
considering shopping and buying as prestigious and thus
to overstate one’s involvement. The figure could be too
high if those meeting the Compulsive Buying Scale
criterion do not meet the suggested clinical diagnostic
criteria
(5). The Compulsive Buying Scale does not include
items, for example, that reflect preoccupation with
buying or buying unneeded items, and the scale’s adverse
consequences item is limited to writing uncovered
checks. Furthermore, a small proportion of those meeting
the Compulsive Buying Scale criterion may have done so
because they were hypomanic or manic. Finally, the
prevalence figure may be accurate but include many cases
with minimal "severity." Our post hoc severity indices,
however, argue against this. Compulsive buyers were
significantly more likely to answer in the maladaptive
range on each of the index questions (numbers 24, 26,
and 27). They also exhibited a substantially higher mean
score on the post hoc severity measure, although this
measure does not capture all potential aspects of
"severity."
By contrast, the Compulsive Buying
Scale prevalence figure may be too low, if, for example,
respondents were embarrassed to admit how much time and
money they devoted to shopping and buying and the
negative consequences. The figure could be too low
because we were less successful contacting groups that
appear to have a higher prevalence, i.e., younger
individuals who more frequently use cell phones and
individuals of a lower socioeconomic status who are less
likely to have a telephone. It could be too low if
compulsive buyers were less likely to be home to answer
their telephones (because they were out shopping).
To determine the true prevalence of
clinically significant compulsive buying will require
administering a structured, validated, diagnostic
interview to a large and representative sample of the
population. Comparing the diagnostic results of these
interviews to the interviewed individuals’ Compulsive
Buying Scale scores would provide an indication of the
false positive and false negative rates of potential
cut-off points, including the cutoff score (—1.34) that
we used as our primary criterion. Because a screening
instrument’s false positive and false negative rates are
specific to the sample examined
(27), we could not use the rates observed in the
original Compulsive Buying Scale study
(16) or in a subsequent clinical study
(26) to correct the prevalence figure we observed.
Our estimate is constrained by our
rate of response: 56.3%. Although substantial, it does
not guarantee that our sample is representative of the
U.S. adult population with regard to shopping and buying
attitudes and behaviors. This response rate compares
favorably, however, with those obtained in nationwide
health surveys. Our estimate is also constrained by
differences between the study sample and the U.S. adult
population. First, the sample contained a smaller
proportion of younger individuals and somewhat fewer
Hispanic individuals. Logistic regression demonstrated,
however, that after we controlled for income and age,
race/ethnicity did not contribute to differences in
prevalence rates. Third, the sample contained a higher
proportion of women. To compensate for this, we provided
a gender-adjusted prevalence estimate, but the result
was unchanged.
If we accept this study’s point
prevalence estimate as approximately accurate, certain
additional conclusions follow.
Received
Feb. 16, 2005; revisions received June 22 and Sept.
7, 2005; accepted Sept. 27, 2005. From the
Department of Psychiatry and Behavioral Sciences,
Stanford University School of Medicine; the
Department of Journalism and Mass Communication,
University of Minnesota, Minneapolis; the Department
of Sociology and the Social and Behavioral Research
Institute, California State University, San Marcos;
and the Department of Sociology, Kent State
University, Kent, Ohio. Address correspondence and
reprint requests to Dr. Koran, OCD Clinic, Rm. 2363,
401 Quarry Rd., Stanford, CA 94305; lkoran@stanford.edu
(e-mail). Dr. Koran reports being on the speaker’s
bureau for Forest Pharmaceuticals and receiving
grants from Ortho-McNeil, Eli Lilly and Company,
Forest Pharmaceuticals, Somaxon, and Jazz. Dr.
Aboujaoude reports being on the speaker’s bureau for
Forest Pharmaceuticals during the time the study was
conducted. Drs. Faber, Large, and Serpe report no
competing interests.Supported by an unrestricted
educational grant from Forest Pharmaceuticals, Inc.
18. Boundy D: When money is the drug, in I Shop Therefore I Am: Compulsive Buying and the Search for Self. Edited by Benson AL. Northvale, NJ, Jason Aronson, 2000, pp 3—26 19. Cushman P: Why the self is empty: toward a historically situated psychology. Am Psychologist 1990; 45:599—611 20. Langman L: Neon cages: shopping for subjectivity, in Lifestyles Shopping: The Subject of Consumption. Edited by Shields R. London, Routledge, 1992, pp 40—82 26. Koran LM, Chuong HW, Bullock KD, Smith SC: Citalopram for compulsive shopping disorder: an open-label study followed by double-blind discontinuation. J Clin Psychiatry 2003; 64:793—798 35. Black DW, Monahan P, Schlosser S, Repertinger S: Compulsive buying severity: an analysis of compulsive buying scale results in 44 subjects. J Nerv Ment Dis 2001; 189:123—126 36. Aizcorbe AM, Kennickell AB, Moore KB: Recent changes in U.S. family finances: evidence from the 1998 and 2001 survey of consumer finances. Fed Res Bull 2003(Jan):1—32 |
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