Optimized Short-Forms of the Cognitive Distortions Questionnaire

Introduction: The Cognitive Distortions Questionnaire (CD-Quest) is a self-report questionnaire that assesses common cognitive distortions. Although the CD-Quest has excellent psychometric properties, its length may limit its use.

Methods: We attempted to develop short-forms of the CD-Quest using RiskSLIM - a machine learning method to build short-form scales that can be scored by hand. Each short-form was fit to maximize concordance with the total CD-Quest score for a specified number of items based on an objective function, in this case $R^2$, by selecting an optimal subset of items and an optimal set of small integer weights. The models were trained in a sample of US undergraduate students ($N = 906$). We then validated each short-form on five independent samples: two samples of undergraduate students in Brazil ($N = 182, 183$); patients with depression in Brazil ($N = 62$); patients with social anxiety disorder in the US ($N = 198$); and psychiatric outpatients in Turkey ($N = 269$).

Results: A 9-item short-form with integer scoring was created that reproduced the total 15-item CD-Quest score in all validation samples with excellent accuracy ($R^2 = 90.4-93.6$%). A 5-item ultra-short-form had good accuracy ($R^2 = 78.2-85.5$%).

Discussion: A 9-item short-form and a 5-item ultra-short-form of the CD-Quest both reproduced full CD-Quest scores with excellent to good accuracy. These shorter versions of the full CD-Quest could facilitate measurement of cognitive distortions for users with limited time and resources.