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Protocol Details

Real-world Momentary Assessment of Kratom use Accompanied by Product Assays: A Natural-history Study for Interdisciplinary Characterization of Kratom use and Pharmacology

This study is NOT currently recruiting participants.

Summary | Eligibility | Citations | Contacts




Sponsoring Institute

National Institute on Drug Abuse (NIDA)

Recruitment Detail

Type: Completed Study; data analyses ongoing
Gender: Male & Female
Min Age: 18 Years
Max Age: N/A

Referral Letter Required


Population Exclusion(s)

Non-English Speaking;


Alkaloid Content;
Mitragyna Speciosa;
As Serotonergic, Dopaminergic, Adrenergic, And Adenosinergic Receptors;
Natural History

Recruitment Keyword(s)



Chronic Pain;
Substance Use Disorders

Investigational Drug(s)


Investigational Device(s)




Supporting Site

National Institute on Drug Abuse


Mitragyna speciosa, also called kratom, is a plant used in Southeast Asia for its psychoactive effects. Its use has increased in the US, and an estimated 10 million adults may take it at least semiregularly. Most scientific research on human use of kratom has consisted of surveys in which people looked back on their experiences with it. Results from those surveys have been useful, but, like many behaviors, kratom use can be more fully understood if it is also studied as it happens. The technical term for this procedure is ecological momentary assessment (EMA). In EMA, people report their moods and activities in real time, a few times per day, usually with a smartphone app.


This natural history study will collect data about how people use kratom and how it affects them.


People aged 18 and older who use kratom 3 or more times per week


Most participants will be remote only.

They will fill out an online consent form. They will also answer an initial set of questions about their kratom use.

They will download an app on their smartphones for EMA (described above). They will use this app to answer short sets of questions for 15 days in a row about their ongoing behaviors and moods, including kratom use.

They will use a prepaid envelope to mail in a sample of their kratom product.

Some participants, after doing the EMA part of the study, can also come to a clinic. They will have 1 visit for informed consent (1-3 hours) and 1 visit for a monitoring session (8 hours) where we can directly assess the effects of their usual dose of kratom. They will bring their kratom produce with them to take on site.

Before they take the kratom, they will have a physical exam. They will have blood and urine tests. They will answer questions about their sleep, driving, and general feelings. They will complete tasks on a computer to measure their reflexes and response times. Their driving performance will be assessed in a simulator.

Researchers will watch participants consume their kratom. A sample of their product will be taken for analysis.

After taking their kratom, those participants will repeat some questionnaires and tests, including the driving simulation. They will also be interviewed about their use of kratom.

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For the Main EMA Study

- Regular kratom use.

-Passing data validity checks on the online screening questionnaire.

- Reporting ownership of a smartphone.

- Age >= 18 years.

-Currently residing in the US .

-Willingness to complete all study activities as described in the online study preamble and informed consent, including willingness to provide a small sample of their kratom product.

- Passing online Main Study consent quiz with at least 8/10 correct answers.

-English language proficiency.

-Not incarcerated.

Additional inclusion criterion for the In-person Substudy:

-Residing in or near MD.


For the Main EMA Study

-Missing data validity checks on screening questionnaire

- Decisionally impaired adults..

Additional exclusion criterion for the In-person Substudy:

- Pregnancy by urine test.

-Self-reported proneness to experiencing motion sickness or feelings of vertigo. This is a precaution, because motion sickness could interfere with the task or cause discomfort.

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Berthold EC, Kamble SH, Raju KS, King TI, Popa R, Sharma A, Le(SqrRoot)>=n F, Avery BA, McMahon LR, McCurdy CR. Preclinical pharmacokinetic study of speciociliatine, a kratom alkaloid, in rats using an UPLC-MS/MS method. J Pharm Biomed Anal. 2021 Feb 5;194:113778. doi: 10.1016/j.jpba.2020.113778. Epub 2020 Nov 21. PMID: 33277117.

Anwar M, Law R, Schier J. Notes from the Field: Kratom (Mitragyna speciosa) Exposures Reported to Poison Centers - United States, 2010-2015. MMWR Morb Mortal Wkly Rep. 2016 Jul 29;65(29):748-9. doi: 10.15585/mmwr.mm6529a4. PMID: 27466822.

Babu KM, McCurdy CR, Boyer EW. Opioid receptors and legal highs: Salvia divinorum and Kratom. Clin Toxicol (Phila). 2008 Feb;46(2):146-52. doi: 10.1080/15563650701241795. PMID: 18259963.

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Principal Investigator

Referral Contact

For more information:

David H. Epstein, Ph.D.
National Institute on Drug Abuse (NIDA)
National Institute on Aging
Biomedical Research Center, Room 01B606
251 Bayview Boulevard
Baltimore, MD 21224-6825
(443) 740-2328

NIDA IRP Screening Team
National Institute on Drug Abuse (NIDA)

(800) 535-8254

NIDA IRP Screening Team

(800) 535-8254

Clinical Trials Number:


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