Validation of Krathom (Mitragyna speciosaKorth.) Dependence Scale (KDS): A Dependence Screen for Internationally Emerging Psychoactive Substance

ABSTRACT.Background:Krathom (Mitragyna speciosaKorth.) is the most commonly used illicit substance in Thailand, and its use has become widespread internationally. Studies on krathom dependence and its health impact are scarce, as there has been no instrument to measure its dependence syndrome and classify krathom users. This study aimed to develop and explore the factor structure, reliability, and validity of a Krathom Dependence Scale (KDS). Methods:This study comprised 2 phases. First, cross-sectional surveys were conducted with 523 (Phase I) and 595 (Phase II) male villagers aged >25 years who were regular, occasional, ex-, or nonusers of krathom. Scale construction was based on the qualitative results from users and previous literature. Exploratory factor analysis (EFA) using maximum likelihood extraction with oblimin rotation was conducted in Phase I and confirmatory factor analysis (CFA) in Phase II to confirm the construct of the scale. Internal consistency of the KDS was assessed using Cronbach's alpha coefficient. Discriminative validity was examined by checking its ability to differentiate between regular and occasional users and patterns of krathom use and its concurrent validity by comparing its levels of score with the Fagerstrom Test for Nicotine Dependence (FTND). The KDS contains 16 items on a 0–3 (never–always) rating scale, making a total score of 0–48. Results:Phase I EFA revealed a single-factor solution for the scale, which was confirmed by the CFA in Phase II, with an alpha coefficient of .98. The KDS discriminates regular from occasional users reasonably well and is highly correlated with the FTND score. Two cutoffs were suggested: 34/35 for distinguishing moderate from high dependence and 13/14 for low from moderate. Conclusions:The KDS appears to capture key theoretical constructs and correlates with indices of drug dependence by standard criteria. It should be useful in early intervention for those with krathom use disorders in community and primary care settings.