SpringerLink Header: Shopping Addiction (A Müller & J Mitchell, Section Editors)
New Assessment Tools for Buying Disorder
Astrid Müller1, MD, PhD, James E. Mitchell2, MD, Birte Vogel1, Martina de Zwaan1, MD
1. Hannover Medical School, Department for Psychosomatic Medicine and Psychotherapy, Germany
2. Neuropsychiatric Research Institute, Fargo, North Dakota, USA
Corresponding author:
Astrid Müller, Department of Psychosomatic Medicine and Psychotherapy, Hannover Medical School, Carl-Neuberg-Str. 1, 30265 Hannover, Germany.
E-mail:
Keywords: compulsive buying; pathological buying; buying disorder; shopping addiction; assessment; questionnaire
Abstract
Purpose of review: To summarize studies concerning the development and evaluation of assessment tools for buying disorder (BD) between 2000 and 2016.
Recent findings: There is still a lack of formal diagnostic criteria and field-tested structured interviews for BD. With regard to questionnaires, the following psychometrically sound instruments assessing symptoms of BD have been developed within the last decade: 1) the Richmond Compulsive Buying Scale (RCBS), which conceptualizes BD as an obsessive-compulsive spectrum disorder, 2) the Bergen Shopping Addiction Scale (BSAS), which regards BD as ‘shopping addiction’, and 3) the Pathological Buying Screener (PBS), which reflects addictive and impulse-control-disorder aspects of BD.
Summary: Future studies should make use of the new questionnaires assessing symptoms of BD. Furthermore, diagnostic criteria for BD should be developed and validated in order to better establish the diagnosis of BD and to accomplish its recognition as a mental disorder.
Introduction
There is an ongoing debate as to how best to classify pathological buying behavior. To present, it is not included in the Diagnostic and Statistical Manual of Mental Disorders [1] or in the International Classification of Diseases [2], and terms such as compulsive buying, pathological buying, shopping addiction, and buying disorder are used interchangeably in the literature to name the phenomenon. Considering the wording for other disorders in the DSM-5 (e.g. gambling disorder, hoarding disorder) [1], we will use the term buying disorder (BD) hereafter.
Lately, most researchers have conceptualized BD as a behavioral addiction due to its commonalities with other addictive behaviors and based on research indicating that cue-induced craving, impaired control, maintenance of shopping and buying regardless of negative consequences, withdrawal, and other characteristics are of relevance to BD [3-7]. Among experts in the field agreement exists that the diagnosis of BD at best requires clinical exploration assessing in detail the functionality of shopping and spending [8]. It is important to note that the diagnosis of BD and the development of valid screening tools have been hindered by the absence of approved diagnostic criteria for BD. More than 20 years ago, Susan McElroy and colleagues [9] had proposed diagnostic criteria for compulsive buying based on reports of 20 psychiatric patients. While these criteria have provided a workable tool to assess BD over the past several studies, they have never been formally tested and remain preliminary.
Although face-to-face assessment may be the best option for diagnosing BD, questionnaires may represent a useful tool to screen for BD or to complement clinical interviews. They are often convenient to use, cost- and time-saving, and particularly useful in collecting large-scale data sets. Furthermore, it has to be considered that people tend to be secretive about their spending habits, particularly if it is inappropriate and associated with indebtedness, family conflicts and mental problems. For some individuals, it may be more useful for them to answer an anonymous questionnaire than to ask them to disclose within an interview.
The aim of this article is to provide an overview concerning assessment tools for BD which have demonstrated psychometric strengths, focusing on instruments developed since 2000. After a brief summary of the most widely used measures for BD developed between the late 1980s and 2000, we will detail and discuss new instruments.
Assessment Tools for Buying Disorder Developed Prior to 2000
Questionnaires
There are several self-rating instruments published in the late 1980s and early 1990s (see Table 1) [10-15]. The most widely used questionnaire is the Compulsive Buying Scale (CBS), which was developed in the United States by Faber and O’Guinn [13]. The 7 items of this unidimensional scale refer to impulse-control deficits while shopping and buying, distress at the thought of others’ knowledge of the individual’s spending behavior, tension when not shopping, shopping and buying to regulate mood, and unreasonable use of credit cards or checks. Lower scores on this scale indicate more BD symptoms.
In Europe, most studies have utilized the German Addictive Buying Scale (GABS) [11, 12]. The GABS was modeled on the Canadian Compulsive Buying Measurement Scale [10], leading to a 16-item unidimensional scale which was subsequently translated into other languages. Given that this instrument is theoretically based on the concept that BD represents a non-substance-related addiction, it consists of items assessing craving to buy something in addition to items pertaining to post-purchase guilt, hiding of purchased goods or consumption of products one cannot afford. The CBS and the GABS were both created by consumer and marketing researchers. Surveys using these scales generated a number of significant findings concerning the prevalence and correlates of BD [16-20]. Nevertheless, the scales are not without criticism with regard to potentially outdated items or perhaps offering a restricted view of BD [21-23].
Structured Interviews
Research studies often made use of structured clinical interviews developed in the field of psychiatry in the early 1990s, particularly the Minnesota Impulse Disorder Interview (MIDI) [24] and the “Impulse Control Disorders Not Elsewhere Classified” module of the Structural Clinical Interview for DSM-IV-TR (SCID-ICD)[25]. Both instruments include specific sections for BD. To our knowledge, information on the validity of the BD module of the SCID-ICD is not available. The BD module of the MIDI showed a sensitivity of 100% and a specificity of 96.2% for BD when comparing the instrument to the above mentioned preliminary diagnostic criteria proposed by McElroy et al. 1994 [9, 26].
(Table 1 about here)
Assessment Tools for Buying Disorder Developed Since 2000
The Richmond Compulsive Buying Scale
The Richmond Compulsive Buying Scale (RCBS) was developed by marketing researchers in the United States using the theoretical foundation of obsessive-compulsive-spectrum disorders [27]. The final version of the RCBS contains 6 items reflecting obsessive-compulsive (“My closet has unopened shopping bags in it. / Others might consider me a ‘shopaholic. / Much of my life centers around buying things.”) and impulse-control-disorder (“ I buy things I don’t need. / I consider myself an impulse purchaser. / I buy things I did not plan to buy.”) aspects of BD. All items are answered on a 7-point Likert scale rating the level of agreement or frequencies, whereas higher scores indicate greater severity of BD. Individuals who score higher than midpoint on all six items can be defined as ‘compulsive buyers’ [27]. Cronbach’s alpha coefficients for the total scale ranged between .81 and .84 [27].
To create the questionnaire, 121 initial items were developed based on a literature review and brainstorming. These items were then examined by three consumer researchers. The authors aimed at, “identifying underlying behavioral tendencies rather than potential consequences” [27,p. 623] of BD. They argued that BD should not be measured with regard to precursors or consequences. Accordingly, items considering the latter aspects were excluded, together with items with wording problems or ambiguous items. The remaining 15 items were subjected to an exploratory factor analysis in 352 undergraduate students and subsequent confirmatory factor analyses in 551 university staff members and 309 customers of an Internet women’s retailing store [27].
In our opinion, the omission of items considering the consequences of BD is questionable given that harmful consequences of inappropriate shopping and spending on patients’ lives (e.g., psychological distress, financial problems, social conflicts) are part of the clinical diagnosis of BD [9]. Not reflecting the consequences of BD, the RCBS is likely to overestimate the occurrence of BD. This concern is supported by the elevated estimates of BD reported by Ridgway et al., who reported point prevalence rates of 15.5% in students, 8.9% in university staff respondents, and 16% in participants in an online survey [27]. In contrast, findings from a Hungarian study that investigated the validity of different BD measures suggested that the RCBS may underestimate the prevalence of BD because it captures BD mainly from a cognitive perspective, which might not fit for certain individuals with addictive shopping [23]. These conflicting results point to the need to further investigate the construct validity of the RCBS.
The Bergen Shopping Addiction Scale
Conceptualizing BD as ‘shopping addiction’, Andreassen et al. developed the Bergen Shopping Addiction Scale (BSAS) [28]. This scale consists of seven items reflecting the following core elements of addiction originally proposed by Brown [29] and modified by Griffiths [30]: 1) salience (“I think about shopping/buying things all the time.”), 2) mood modification (“I shop/buy things in order to change my mood.”), 3) tolerance (“I feel I have to shop/buy more and more to obtain the same satisfaction as before.”), 4) withdrawal (“I feel bad if I for some reason are prevented from shopping/buying things.”), 5) conflict (“I shop/buy so much that it negatively affects my daily obligations.”), 6) relapse (“I have decided to shop/buy less, but have not been able to do so.”), and 7) resulting problems (“I shop/buy so much that it has impaired my well-being.”). All items are answered on a 5-point Likert scale from 0 (completely disagree) to 4 (completely agree). Higher scores indicate greater severity of BD.
Initially, four items for each construct were created based on diagnostic criteria for gambling disorder [1], the Game Addiction Scale [31] and a literature review, resulting in an initial version with 28 items. A questionnaire package including these 28 items, the Compulsive Buying Measurement Scale [10], questions concerning sociodemographic variables, and some other collateral measures was distributed via the online editions of five newspapers in Norway. In total, 23,537 individuals (65% women, age M = 35.8, SD = 13.3 years) participated in the study. To identify the best items to retain in the final questionnaire, a set of factor analyses was conducted. Confirmatory factor analyses indicated a good to excellent fit of a one-factor solution. The instrument showed good internal consistency (α = .87). Convergent validity was indicated by the strong correlation (r = .80) between the total score of the BSAS and the Compulsive Buying Measurement Scale [10]. In line with past research [16], women scored higher on the BSAS than men, and BSAS scores were inversely related to age. The study did not attempt at validating a BSAS threshold value for shopping addiction.
Strengths and limitations of the scale and the study summarized above were discussed by the authors [28]. The use of web-based data, the self-selected sample and the strong theoretical restriction may be viewed as shortcomings that may have biased the results. However, the shortness and good psychometric quality of the BSAS and the large sample size of the study are strengths.
The Pathological Buying Screener
Table 2 displays the Pathological Buying Screener (PBS) [21]. This questionnaire represents another new, psychometrically sound measure to assess symptoms of BD, which was developed in Germany. The questionnaire contains 13 items, belonging to the subscales loss of control / consequences (10 items; e.g. cannot stop buying things despite financial problems. / having problems at work or school or in other areas due to buying behavior / hiding buying habits from other people / cannot stop thinking about buying) and excessive buying behavior (3 items; buying more than had planned / buying more things than needed / spending more time buying than intended). In addition, the scale contains three supplementary items. The first supplementary item refers to symptoms of mania / hypomania that should be differentiated from BD [9], the second item asks for symptoms of hoarding disorder that are common in BD [32-34], and the third item pertains to buying with the primary goal of personal enrichment.
All items are answered on a 5-point Likert scale ranging from 1 (“never”) to 5 (“very frequently”). Based on the 13 main items, a tentative PBS total score cutoff point of 29 or above was suggested to categorize those with probable BD, which needs further investigation [21].
(Table 2 about here)
Within the process of item generation, 33 items were generated based on a facet theoretical approach. These items reflected characteristics of both behavioral addictions and impulse-control disorders and considered the following aspects of BD: preoccupation / craving, impaired control, emotion regulation, not using purchased goods / hiding purchases / lying about spending / deception, degree of suffering, interference with other life aspects and financial aspects / consequences, and resistance against excessive spending. These initial items were modified based on the results of pretests in a predefined sample of 119 participants (mainly students) and a sample of 19 treatment–seeking patients with BD, leading to a preliminary 20-item pool. The 20 preliminary items, the three supplementary items, questions regarding sociodemographic aspects, and the German translation of Faber and O’Guinn’s Compulsive Buying Scale [17] were answered by a representative German sample (N = 2,403; 53% women; age M = 49.2, SD = 17.7 years). A set of exploratory and confirmatory factor analyses in different subgroups of the total sample was utilized to extract the number of factors, to select items for the final version, and to confirm the factor structure. The findings indicated a final version with 13 items (without supplementary items), loading on the two subscales relating to loss of control / consequences and excessive buying behavior. It is noteworthy that hierarchical regression analyses in the total sample with Faber and O’Guinn’s CBS as the dependent variable and the two subscales of the new instrument as the predictors indicated incremental validity of the two factors in adults aged 65 years. Particularly the subscale excessive buying behavior added significant variance explanation within the model. This suggested that the PBS provides some information that is not captured by the CBS. Accordingly, the correlation between the PBS total score and the CBS was only moderate (r = -.57), indicating an overlap (convergent validity) as well as differences between the two measures. Reliability of the PBS total score as well as the two subscales was good to excellent with Cronbach’s α coefficients ranging from .83 to .95 [21]. Similar to studies using other BD measures [16, 18, 20], the PBS had women and younger individuals tending to score more highly.