RESUMEN
BACKGROUND AND AIMS: Mitragyna speciosa ('kratom') contains mu opioid partial agonists. It is widely available, and occasionally used as a home remedy for opioid use disorder. The Drug Enforcement Agency considers kratom a drug of concern; however, prevalence of use and role in drug misuse are unknown. This study aimed to characterize kratom use in the United States. DESIGN: Cross-sectional Survey of Non-Medical Use of Prescription Drugs (NMURx) Program, 2018 third quarter and 2019 first quarter. SETTING: A validated non-probability online survey in the United States. PARTICIPANTS: A total of 59 714 respondents aged 18 years or older, weighted to represent the adult US population (n = 252 063 800). MEASUREMENTS: In addition to prevalence of past-year kratom and other drug use, behavior proportions were estimated. The Drug Abuse Screening Test (DAST-10) estimated consequences of drug abuse. FINDINGS: The estimated prevalence of past-year kratom use in the adult US population was 0.8% [95% confidence interval (CI) = 0.7-0.9], representing 2 031 803 adults. Life-time prevalence was 1.3% (95% CI = 1.2-1.4), representing 3 353 624 adults. Kratom users were younger (mean 35 years, P < 0.001), with higher proportions of males (61.0 versus 48.6%, P < 0.001), students (14.1 versus 7.5%, P < 0.001) and health-care professionals (9.7 versus 4.5%, P < 0.001) and fewer bachelor's/advanced degree graduates (33.4 versus 42.6%, P < 0.001) compared with non-users. Results were inconclusive on whether there was a difference in kratom use by race, household income or employment status. Among those with past-year kratom use, 36.7% (95% CI = 32.1-41.3) non-medically used prescription opioids, 21.7% (95% CI = 18.0-25.5) used illicit opioids, 54.4% (95% CI = 49.5-59.3) used another illicit drug and 67.1% (95% CI = 62.5-71.8) used cannabis. The DAST-10 profile was more often substantial/severe in kratom users (21 versus 1%, P < 0.001) compared with non-users. CONCLUSIONS: Estimated United States past-year prevalence of kratom use is 0.8%, and kratom users tend to have more serious substance abuse profiles than non-users or users of cannabis, alcohol or cigarettes. To our knowledge, this is the first description of kratom use at the national level.