Validation of the Problematic Khat Use Screening Test: A Cross-Sectional Study

Abstract

Aim: The study aimed to evaluate the psychometric properties of the Problematic Khat Use Screening Test (PKUST-17) in Ethiopia. Methods: A validation study of PKUST-17 was carried out among 510 khat users, using a house-to-house survey. Confirmatory factor analysis and 2-parametric item response theory (IRT) were used to evaluate the construct validity of PKUST-17. We also used Spearman's rank-order correlation coefficient and other test statistics to assess the convergent validity of PKUST-17 with depression symptoms, functional impairment, and other characteristics of participants. We generated latent classes of problematic khat use using latent profile analysis (LPA) and validated the classes using multinomial logistic regression. Results: The data confirm the unidimensional model of the PKUST-17. The internal consistency of PKUST-17 was excellent (Cronbach's alpha = 0.93). IRT discrimination parameters indicated that each item had a strong ability to distinguish participants across the spectrum of problematic khat use (α thresholds range from 1.02 to 2.9). The items were fairly or moderately severe to be endorsed by participants (β thresholds vary from 1.43 to 5.57). The LPA identified three latent classes which have severity differences: mild (34%), moderate (34%), and severe (32%) problematic khat use. Depression symptoms, functional impairment, and other khat use patterns were also associated with moderate and severe problematic khat use class membership compared to mild problematic khat use class. Conclusion: We found that the PKUST-17 is a culturally appropriate, brief, easy to use, and psychometrically sound screening test. PKUST-17 can be used to screen khat users with different levels of risk for providing stepped care at different healthcare levels, including integration of services in primary care. Future studies need to test the predictive capacity of the PKUST-17 for khat-related harms.