Long-Term Cognitive Effects of Kratom (Mitragyna speciosa Korth.) Use

ABSTRACT

Kratom or Mitragyna speciosa (Korth.) is a medicinal plant of Southeast Asia. As a result of its opioid-like effects, it remains unknown whether consumption of kratom tea is associated with impaired cognitive function. We assessed the cognitive function of 70 regular kratom users and 25 control participants using the Cambridge Neuropsychological Test Automated Battery. Participants performed six neuropsychological tasks that assessed motor, learning and memory, attention and executive function. Relative to control participants, higher consumption (>3 glasses daily or mitragynine doses between 72.5 mg and 74.9 mg) of kratom tea was selectively associated with impaired performance on the Paired Associates Learning task, reflecting deficits in visual episodic memory and new learning. Overall, the performance of kratom users compared to control participants, and the performance of high (>3 glasses per day) as well as low (≤3 glasses per day) kratom using groups, were comparable on all neuropsychological domains. Higher intake of kratom juice (>3 glasses daily) did not appear to impair motor, memory, attention or executive function of regular kratom users.

KEYWORDS:

• CANTAB
• Kratom
• memory
• mitragynine
• Paired Associates Learning

Acknowledgments

We would like to thank all of the respondents who have participated in this study. We thank Azlan Abdul Rahim for conducting the CANTAB tests, and Mohamad Hafifi Jamri and Muhammad Eshal Dzulkapli for their kind assistance in coordinating the field work. We also thank Nur Sabrina Mohd Yusof and Nelson Jeng Yeou Chear for conducting the lab work to determine mitragynine content in the acquired kratom tea/juice samples.

Additional information

Funding

We are highly indebted to the financial support from Higher Institution’s Centre of Excellence (HICoE) (311CDADAH4401009), and Universiti Sains Malaysia Research University (RU) grant (1001CDADAH816306). Murat Yücel was supported by a National Health and Medical Research Council of Australia Fellowship (#APP1117188).