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Depression is one of the most prevalent psychological disorders in the world, and it can be estimated with the help of a number of different instruments. Beck Depression Inventory (BDI) is one of the most popular self-assessment instruments in the world to determine depressive symptoms. This instrument was initially proposed by Aaron Temkin Beck and his colleagues, and has been used in over 7,000 studies (Wang & Gorenstein, 2013).
Revisions of BDI
Since its development, BDI has gone through two major revisions. One revision occurred in 1978, when it was modified into BDI-IA, and the second important revision occurred in 1996, when it was modified into BDI-II. This latest version of BDI has modifications to work on depression as found in the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). In this version, some of the items from previous versions were modified as they were less sensitive for the determination of depressive symptoms. For example, distorted body image, weight loss, inability to work, and somatic preoccupation, were replaced by agitation, difficulty concentrating, worthlessness, and energy loss. Moreover, the items on sleep change and appetite were modified to better check the decrease or increase of these depression-related characteristics. These changes in BDI-II have made it superior to BDI-IA, and have improved the ability of the item to determine different kinds of depression such as atypical depression (Wang & Gorenstein, 2013).
Advantages of BDI-II
BDI-II is one of the most widely accepted inventories to measure depressive conditions, and it has been translated in many other languages. It can be used efficiently for people with problems of concentration and/or reading difficulties. The psychometric properties of the instrument have been established in various cultural groups (The National Child Traumatic Stress Network, n.d.). Most of the patients can complete 21 items of the instrument within 10 minutes, and this is one of the most useful characteristics of the inventory (Farinde, 2013). Moreover, routine clinical assessment with BDI-II can help in assessing the treatment progress (Wang & Gorenstein, 2013).
Credibility and soundness of BDI
Several studies have established the soundness of the instrument by showing the internal consistency of the scale, extensive validation of the instrument against other measures of depression, and its test-retest reliability. It has been found that BDI successfully gives the required outcomes (Farinde, 2013).
Reliability of BDI
Reliability refers to the extent of consistency of assessments, i.e. repeatability of observations without showing any changes. BDI-II is a reliable tool for the estimation of depression (Wang & Gorenstein, 2013). In a study, researchers compared the English and Spanish language versions of BDI in undergraduate students. They found significant level of internal consistency of the instrument in both languages. The test-retest reliability of the instrument was acceptable for both languages. They noted that the reliability of the Spanish translation was slightly more than the original English version of the inventory (Farinde, 2013).
Sensitivity of BDI
BDI-II is a sensitive instrument with an ability to distinguish different grades of depression severity (Wang & Gorenstein, 2013). Studies also show that the inventory is sensitive to daily changes in mood (Farinde, 2013) that is why it can be used effectively to check the treatment progress.
Item characteristics of the instrument
Items of the instrument show a broad range of depressive symptoms, and represent some multidimensionality (Brouwer, Meijer, & Zevalkink, 2013). The item characteristics of BDI-II are different from the previous versions in terms of content coverage, item endorsement rate, and homogeneity. Although those variations brought positive changes in the latest version, but they could also be problematic in certain situations. The wording of some of the items could be presented in such a way that comparison of the current state is made to the previous one (e.g., as ever, than usual), and in this case, problematic response could arise (The National Child Traumatic Stress Network, n.d.).
The items of the instrument are such that most of the non-clinical samples get scores in the lower end of the possible range, which is from 0 to 3. Moreover, the mean item score does not go beyond 2 in many clinical samples (Wang & Gorenstein, 2013). For example, patients of chronic trauma would give a response by circling a zero as their condition has not changed since their childhood and they feel the same “as ever” (The National Child Traumatic Stress Network, n.d.), thereby decreasing the overall score.
Validity of an instrument is usually measured by considering two types of validities, i.e. content validity and construct validity.
Construct validity refers to the extent to which an instrument fulfills its purpose, i.e. it measures what it is claiming or purporting to measure. It helps in providing overall validity of the test. BDI-II items have a general construct, i.e. total scale score of the inventory represents a single construct. Practitioners have to work carefully while interpreting subscale scores, which could show greater relation to heterogenous characteristics of depression (Brouwer et al., 2013).
Use of Beck Depression Inventory in different cultures
BDI-II is one of the most popular instruments used throughout the world, but cross-cultural comparability still needs further research. Researchers are of opinion that the conditions and symptoms of depression in different races, cultures, or languages could be different, and could be compared by checking the measurement variance of the instrument. For example, researchers have found an equivalence problem in the different language versions of the instrument, and observed that participants of a study having the symptoms of depression may respond differently to different language versions of the instrument. Moreover, the construct validity of the instrument may also vary with different language versions (Wang & Gorenstein, 2013). These things are showing that BDI-II has limited generalizability.
Criticism faced by BDI
Several studies have questioned the credibility of BDI (Farinde, 2013). Although BDI-II is superior to previous versions of BDI but experts are of opinion that superior reliability is still not indicative of improvement of the clinical validity of the scale (Wang & Gorenstein, 2013).
One of the most important points to consider in the widespread utilization of BDI-II is its self-report nature that can be affected by social desirability, gender effect, and the educational attainment of the respondent. The instrument is also being criticized for being too transparent to the respondents that it can easily be faked by them. However, this is not considered as an important problem as the instrument tries to get accurate information of the depressive conditions in the respondents (Wang & Gorenstein, 2013). It has also been reported that people with low education would found the instrument difficult (The National Child Traumatic Stress Network, n.d.), but this problem can also be solved by the administration of the intervention orally by an examiner and by making required modifications in the instrument. For example, in a study on rural community in Kenya, researchers found that BDI-II adequately measures depressive symptoms after making appropriate changes in the instrument (Abubakar et al., 2016).
Concluding Remarks
Depression is among the most commonly encountered psychological problems in the world in both clinical as well as non-clinical conditions. This high level of occurrence of depression in the world can easily be assessed with the help of self-assessment scales as people with depression can better describe their conditions. Therefore, it is important to utilize inexpensive as well as easy-to-use instruments having good acceptance and compatibility with the users or respondents. In all these conditions, BDI-II is one of the most helpful instruments to be used by people having depression.
BDI-II can help investigators and clinicians to discriminate non-depressed people from depressed patients as it has high level of internal consistency and validity. Moreover, this tool is simple, reliable, and short that can help working with patients without disturbing their normal schedule. This tool is not only helpful in the diagnosis of major depressive episodes but also helps in examining the treatment efficacy. However, BDI-II is copyrighted and has to be obtained from the publisher, and it is one of the major problems hindering its widespread use. Moreover, further studies are required in improving the generalizability of BDI-II.
References
Abubakar, A., Kalu, R. B., Katana, K., Kabunda, B., Hassan, A. S., Newton, C. R., & Van de Vijver, F. (2016). Adaptation and Latent Structure of the Swahili Version of Beck Depression Inventory-II in a Low Literacy Population in the Context of HIV. PLoS One, 11(6), e0151030.
Brouwer, D., Meijer, R. R., & Zevalkink, J. (2013). On the factor structure of the Beck Depression Inventory–II: G is the key. Psychological assessment, 25(1), 136.
Farinde, A. (2013). The Beck Depression Inventory. The Pharma Innovation, 2(1).
The National Child Traumatic Stress Network. (n.d.). Beck Depression Inventory-Second Edition ( BDI-II ). Retrieved from http://www.nctsn.org/content/beck-depression-inventory-second-edition-bdi-ii
Wang, Y.-P., & Gorenstein, C. (2013). Psychometric properties of the Beck Depression Inventory-II: a comprehensive review. Revista Brasileira de Psiquiatria, 35(4), 416-431.
