The Anxiety Depression Distress Inventory–27 (ADDI–27): New Evidence of Factor Structure, Item-Level Measurement Invariance, and Validity

ABSTRACT

Three studies examining the factor structure and psychometric properties of the Anxiety Depression Distress Inventory–27 (ADDI–27) extended the initial instrument development studies for this recently introduced inventory. The ADDI–27 is an empirically derived short form of the Mood and Anxiety Questionaire–90 (MASQ–90) comprising three scales: Positive Affect, Somatic Anxiety, and General Distress. The main objectives of Study 1 (N = 700) were to examine the factor structure of the ADDI–27 and its measurement invariance across gender at the item level. The objective of Study 2 (N = 538) was to examine evidence for the convergent and discriminant validity of scores on the ADDI–27. The objective of Study 3 (N = 240) was to assess further evidence for the nomological network and convergent and discriminant validity of the ADDI–27 scores. Results of exploratory structural equation modeling yielded strong support for a 3-factor model, with approximate fit indexes meeting or exceeding the conventional cutoffs. With p ≤ .001 as the criterion for detecting noninvariance, results of measurement invariance analysis suggested that all of the ADDI–27 items were invariant across gender. Results of multivariate validity analyses across 2 studies provided support for the convergent and discriminant validity of scores on the ADDI–27 scales.

Notes

¹ We also estimated an oblique four-factor solution. However, only two items (17 and 21) featured loadings > .35 on the fourth factor (λ = .45 and λ = .37, respectively). In addition, these items featured strong cross-loadings (λs ≥ .70) on PA. Because F4 did not feature the minimum number of items required for viability, the four-factor solution was discarded.

² This finding suggests that men and women had a tendency to respond differently to these two items only. This result might have been due to a real (population) difference between genders (e.g., men might be less likely to experience sadness) or it could be a sample-specific result. Without statistically significant results or further evidence of noninvariance for the full set of items, it appears more likely to be due to sampling error.

³ One common way in which the SA45 scales are used is in exploratory factor analysis to identify clusters of internalizing (e.g., SA45-ANX, SA45-DEP) and externalizing dimensions (e.g., SA45-HOS).

⁴ A full discussion of the tripartite model is beyond the scope of this article. For a thorough treatment, see Watson (2005), Watson, Gamez, and Simms (2005), and Watson, Kotov, and Gamez (2006).

Additional information

Funding

This work was supported in part by a National Institute of General Medical Sciences (NIGMS-RISE GM060655) awarded to Antonio F. Garcia. The data underlying these studies are available on request to the corresponding author.