Purchase Task Methods Identify Kratom Use Disorder via Quantity but Not Likelihood Approach

Why it matters

Behavioral economic demand measures successfully identified kratom use disorder indicators, but the type of assessment tool used matters — quantity-based purchase tasks outperformed likelihood-based tasks in identifying past-year kratom use disorder criteria.

The big picture

As researchers and clinicians increasingly apply addiction science methods to kratom, this study provides a validated framework for measuring the reinforcing efficacy of kratom and identifying problematic users — a critical step toward clinical screening tools.

Key findings

• • Higher demand intensity (OR=2.16) and lower demand elasticity (OR=0.45) were significantly associated with past-year kratom use disorder on the Quantity purchase task
• • The Likelihood-based task showed only breakpoint (OR=1.44) as associated with past-year KUD; other indices were non-significant
• • Neither approach significantly predicted lifetime KUD criteria, suggesting temporal specificity in demand-disorder associations
• • Study is the first to apply purchase tasks to kratom, with 117 participants with lifetime kratom use history

What they say

Cross-sectional study using two versions of a hypothetical kratom purchase task (Quantity and Likelihood); Johns Hopkins University School of Medicine; published in Addictive Behaviors Reports 2025.

Bottom line

Quantity-based behavioral economic demand tasks can identify kratom use disorder, but tool selection matters — findings provide the first validated demand framework for clinical kratom screening research.