The Internalized Stigma of Mental Illness Scale-9 (ISMI-9) was developed by Dr. Joseph H. Hammer and Dr. Michael D. Toland and accepted for publication in the peer-reviewed academic journal Stigma and Health in 2016. Here is the current APA-style citation for the instrument, which will be updated when the article goes to paper press:
Hammer, J. H., & Toland, M. D. (in press). Internal Structure and Reliability of the Internalized Stigma of Mental Illness Scale (ISMI-29) and Brief Versions (ISMI-10, ISMI-9) among Americans with Depression. Stigma and Health. doi: 10.1037/sah0000049 *PDF*
The ISMI-9 is a nine-item unidimensional short form of the original English-language version of the ISMI-29, which was developed by Dr. Jennifer Boyd and colleagues and published in 2003 (see Ritsher (Boyd), Otilingam, & Grajales, 2003). Dr. Jennifer Boyd and colleagues have published a ten-item short form of the ISMI-29 (see Boyd, Oitlingham, & DeForge, 2014). Researchers are encouraged to consider both the ISMI-9 and ISMI-10 when designing new studies, as each version may offer certain advantages and limitations (see Hammer & Toland, in press). We thank Dr. Jennifer Boyd and her colleagues for developing the ISMI, which has facilitated groundbreaking research on the nature, impact, and mitigation of internalized stigma of mental illness.
What does the ISMI-9 measure?
The stigma of mental illness is the prejudice and discrimination that results from endorsing negative stereotypes about people with mental illness (Corrigan & Watson, 2002). Internalized stigma of mental illness is the harmful psychological impact that results from internalizing this prejudice and directing it toward oneself.
The ISMI-9 is a self-report instrument designed to measure the overall strength of respondents’ internalized stigma of mental illness (i.e., self-stigma of mental illness) among persons with psychiatric disorders. A higher score indicates more severe internalized stigma of mental illness.
The items assume that respondents self-identify as having a mental illness (e.g., “Because I have a mental illness, I need others to make most decisions for me”) and thus are most appropriately used with clinical populations.
How do I administer the ISMI-9?
The ISMI-9 can be administered via an electronic/internet format or a paper & pencil format.
How do I score the ISMI-9?
The ISMI-9 is a unidimensional instrument that primarily reflects a single common source of variance (Hammer & Toland, in press). Therefore, only the ISMI-9 total score should be calculated and interpreted.
The ISMI-9 contains 9 items which produce a total score. Reverse-code items 2 and 9 before calculating the total score. Add the item scores together and then divide by the total number of answered items. The resulting score should range from 1 to 4 because the four-point Likert rating scale ranges from 1 (Strongly disagree) to 4 (Strongly agree). For example, if someone answers 8 of the 9 items, the total score is produced by adding together the 8 answered items and dividing by 8.
Per Parent (2014)’s 20% recommendation, I do not recommend calculating a mean score for those cases/participants who responded to less than 8 of the 9 items. In many cases, it should be permissible to calculate a mean score for those cases/participants who answered 8 or all 9 of the ISMI-9 items. See Schlomer et al. (2010) for information on best practices regarding the handling of missing instrument data.
How do I interpret the ISMI-9 total score?
The ISMI-9 total score is a measure of overall internalized stigma of mental illness.
More precisely, the ISMI-9 total score is a numerical quantification of the degree to which a person reports overall agreement with five themes of internalized stigma of mental illness: Alienation, Stereotype Endorsement, Perceived Discrimination, Social Withdrawal, and Stigma Resistance (reverse scored).
These five “topic areas” constitute what is known as the “content domain” of internalized stigma of mental illness, as conceptualized by Dr. Jennifer Boyd and colleagues (2003) and operationalized by the ISMI-29. While the nine items of the ISMI-9 are evenly drawn from these five topic areas, these items were selected to form the ISMI-9 specifically because they primarily measure the general internalized stigma of mental illness factor, which is the factor that any short form of the ISMI is designed to measure. In other words, even though the items of the ISMI-9 are drawn from the different subscales of the ISMI-29, they cannot and should not be used to try to form subscales measuring the five separate topic areas (see Hammer & Toland, in press; Boyd, Otilingham, & DeForge, 2014). This same logic applies to the ISMI-10.
Boyd, Oitlingham, and DeForge (2014) describe two methods of interpreting the size of ISMI total scores:
4-category method (following the method used by Lysaker et al., 2007):
1.00-2.00: minimal to no internalized stigma
2.01-2.50: mild internalized stigma
2.51-3.00: moderate internalized stigma
3.01-4.00: severe internalized stigma
2-category method (following the method used by Ritsher [Boyd] & Phelan, 2004).
1.00-2.50: does not report high internalized stigma
2.51-4.00: reports high internalized stigma
What is the factor structure of the ISMI-9?
Hammer & Toland (in press) found evidence that the nine items of the ISMI-9 conform most closely to a unidimensional factor structure. Thus, the ISMI-9 is best conceptualized as a unidimensional instrument that primarily reflects a single common source of variance.
As noted above, the ISMI-9 cannot be said to contain subscales and cannot be used to generate factor scores for the five topical areas.
What evidence exists regarding the reliability and validity of the ISMI-9 total score?
Regarding evidence concerning internal structure (Standard 1.13; AERA et al., 2014), the ISMI-9 demonstrated a clear unidimensional factor structure: S-Bχ2(27) = 70.35, p < .001, RMSEA = .046 [90% CI of .033, .059], CFI = .976, TLI = .967, SRMR = .027. This supports the use of the ISMI-9 total score as a measure of the overall internalized stigma of mental illness.
Regarding evidence of reliability/precision (Standard 2.3), the ISMI-9 total score demonstrated slightly stronger internal consistency (α = .86, 95% CI [.85, .88]) and cleaner measurement of the general internalized stigma of mental illness construct (ωH = .89, ECV = .87, PUC = .89) than the ISMI-10 total score (see Hammer & Toland, in press). Consistent with this, 100% of the ISMI-9 items had IECV values above .80.
Regarding content-oriented evidence of the validity of the ISMI-9 total score (Standard 1.1), like the ISMI-10, the ISMI-9 contains items from each of the five purported factors of the ISMI-29.
However, future research is needed to examine convergent evidence for the validity of the ISMI-9 total score (Standard 1.16). Such evidence has already begun accumulating for the ISMI-10 (Boyd, Otilingham, & DeForge, 2014). The total scores of the ISMI-9 and ISMI-10 (r = .88) were found to correlate .95 and .94, respectively, with the total score of the ISMI-29. Given the strong content overlap of the ISMI-9 and ISMI-10, we might anticipate that the ISMI-9 will demonstrate similar convergent evidence of validity as the ISMI-10. This needs to be tested directly, however.
In summary, Hammer and Toland (in press) found that the ISMI-9 total score demonstrated a slightly cleaner unidimensional structure and stronger reliability than the ISMI-10 total score. However, additional research would help to verify whether these findings are idiosyncratic or generalizable.
What are some current limitations of the ISMI-9?
All instruments have limitations. The ISMI-9 is no exception. I believe it is important that potential users of the ISMI-9 know what these limitations are so that they can make informed choices about how to use the ISMI-9. These limitations also present researchers with opportunities to conduct and publish new research studies on the psychometric properties of the ISMI-9. Feel free to reach out to me if you are interested in conducting such a study with my help.
- Further examination of the cross-cultural reliability and validity of the ISMI-9 among diverse groups (e.g., race/ethnicity, inpatient) is necessary, given that the samples used by Hammer and Toland (in press) were composed primarily of community-dwelling adults living in the United States who self-identified as having a mental illness—depression, in this case. The majority of the sample was also female, white, and reported minimal to mild internalized stigma. Therefore, it is possible that the findings of Hammer and Toland (in press) are unique and only apply to this specific intersectional population.
- As noted above, investigation of convergent and predictive evidence of validity for the ISMI-9 total score is warranted.
How do I obtain a copy of the ISMI-9?
Please note that a full copy of Dr. Jennifer Boyd and colleagues’ ISMI-10 is included in the Appendix of Boyd, Oitlingham, and DeForge (2014). Information regarding the original ISMI-29 can be found in Ritsher (Boyd), Otilingam, and Grajales (2003) and Boyd, Adler, Otilingam, and Peters (2014). Researchers interested in the ISMI-10 and ISMI-29 are encouraged to correspond with Dr. Jennifer Boyd.