Khat Research Program (KRP)

The KRP is a unique, multidisciplinary initiative focused on khat abuse and addiction. Partially funded by the National Institutes of Health (NIH) and the University of Minnesota, the program has demonstrated success through 48 high-impact journal publications authored by faculty and staff from the Medical School over the past 10 years. The KRP collaborates with universities across the United States, Europe, Africa, and the Middle East, and it serves as the core model for future research initiatives on substance use and related mental health challenges.

Why the KRP?

Mental health and substance use disorders represent a significant global health burden, accounting for 13% of the total disease burden, according to WHO reports. This burden is even more pronounced in low- and middle-income countries, where it is compounded by environmental factors such as malnutrition, poverty, and inadequate healthcare. In regions like Africa and the Middle East, the situation is especially dire, exacerbated by ongoing social unrest and security threats.

Recognizing the critical need to address mental health and substance use issues in these regions, we have partnered with various institutions across Africa, the Middle East, and Kenya to build research capacity in these areas. Our team has organized multiple conferences and training sessions through the Africa and Middle East Congress on Addiction (AMECA), which have been well-received by local stakeholders. We aim to build on this momentum by launching a multinational initiative focused on expanding research and services related to mental health and substance use.

Why now?

This initiative is timely given the escalating challenges caused by recent political and social upheaval. These factors are likely to further strain already limited health resources and may contribute to an increase in health threats in the region. Moreover, evidence suggests that the recent rise in violence and social conflict has intensified stress-related mental health issues and substance abuse in both the Middle East and Africa. A key step in addressing these growing risks is developing effective, contextually relevant prevention and intervention strategies—challenges that our team is committed to tackling.

The KRP consortium includes universities from Kenya, Ethiopia, Tanzania, Yemen, Germany, the UK, Sweden, and the US. It was established as a collaborative, multidisciplinary research program examining the cognitive, emotional, and behavioral disorders associated with khat use, as well as the co-use of khat and other substances. Khat, a natural plant widely consumed in East Africa, the Arabian Peninsula, and increasingly in Europe and North America, has few studies available to understand its acute and chronic effects on brain function. The KRP aims to conduct essential research on khat-related cognitive, biobehavioral, and emotion regulation deficits, as well as the mental health risks associated with its use, to inform the development of prevention and treatment strategies. The program brings together international experts with expertise in neurobiology, neurotoxicology, psychology, environmental health, medicine, and global health research.

Funding

This program is supported by the NIH/National Institute on Drug Abuse (NIDA) and the Fogarty International Center (FIC). In addition to funding from the University of Minnesota and the International Brain Research Organization (IBRO).

Examples of published papers

al'Absi, M., Khalil, N. S., Al Habori, M., Hoffman, R., Fujiwara, K., & Wittmers, L. (2013a). Effects of chronic khat use on cardiovascular, adrenocortical, and psychological responses to stress in men and women. American Journal on Addictions, 22(2), 99-107. https://doi.org/10.1111/j.1521-0391.2013.00302.x

al'Absi, M., Khalil, N. S., Al Habori, M., Hoffman, R., Fujiwara, K., & Wittmers, L. (2013b). Effects of chronic khat use on cardiovascular, adrenocortical, and psychological responses to stress in men and women. Am J Addict, 22(2), 99-107. https://doi.org/10.1111/j.1521-0391.2013.00302.x

al'Absi, M., Khalil, N. S., Al, H. M., Hoffman, R., Fujiwara, K., & Wittmers, L. (2013). Effects of chronic khat use on cardiovascular, adrenocortical, and psychological responses to stress in men and women. Am.J Addict., 22(2), 99-107. (NOT IN FILE)

al'Absi, M., Nakajima, M., Dokam, A., Sameai, A., Alsoofi, M., Saem Khalil, N., & Al Habori, M. (2014a). Concurrent tobacco and khat use is associated with blunted cardiovascular stress response and enhanced negative mood: A cross-sectional investigation. Human Psychopharmacology: Clinical and Experimental, 29(4), 307-315. https://doi.org/10.1002/hup.2403

al'Absi, M., Nakajima, M., Dokam, A., Sameai, A., Alsoofi, M., Saem Khalil, N., & Al Habori, M. (2014b). Concurrent tobacco and khat use is associated with blunted cardiovascular stress response and enhanced negative mood: a cross-sectional investigation. Hum Psychopharmacol, 29(4), 307-315. https://doi.org/10.1002/hup.2403

al'absi, M., Nakajima, M., Dokam, A., Sameai, A., Alsoofi, M., Saem Khalil, N., & Al Habori, M. (2014). Concurrent tobacco and khat use is associated with blunted cardiovascular stress response and enhanced negative mood: a cross-sectional investigation. Hum Psychopharmacol, 29, 307-315. https://doi.org/10.1002/hup.2403

Bongard, S., Nakajima, M., & al'Absi, M. (2015). Khat chewing and acculturation in East-African migrants living in Frankfurt am Main/Germany. J Ethnopharmacol, 164, 223-228. https://doi.org/10.1016/j.jep.2015.01.034

Hoffman, R., & Al'absi, M. (2013). Concurrent use of khat and tobacco is associated with verbal learning and delayed recall deficits. Addiction, 108(10), 1855-1862. https://doi.org/10.1111/add.12260

Hoffman, R., & al'Absi, M. (2013). Working memory and speed of information processing in chronic khat users: preliminary findings. In European Addiction Research (Vol. 19, pp. 1-6). Basel. https://doi.org/10.1159/000338285

Kassim, S., & Al'absi, M. (2016). Khat use is a neglected addictive behaviour. Addiction, 111(1), 179-180. https://doi.org/10.1111/add.13148

Lemieux, A. M., Li, B., & al'Absi, M. (2015). Khat use and appetite: an overview and comparison of amphetamine, khat and cathinone. J Ethnopharmacol, 160, 78-85. https://doi.org/10.1016/j.jep.2014.11.002

Lemieux, A. M., Nakajima, M., Saif-Ali, R., Al-Habori, M., Dokam, A., & al'Absi, M. (2018). Anger, anxiety, and depressive affect as predictors of stress-induced cortisol production in khat and tobacco users. Addict Behav, 82, 195-201. https://doi.org/10.1016/j.addbeh.2018.02.033

Nakajima, M., & al'Absi, M. (2021). Influences of Fasting on Stress Response and Withdrawal Symptoms in Habitual Khat Users. Eur Addict Res, 27(1), 49-57. https://doi.org/10.1159/000506737

Nakajima, M., Dokam, A., Alsameai, A., AlSoofi, M., Khalil, N., & al'Absi, M. (2014). Severity of khat dependence among adult khat chewers: the moderating influence of gender and age. J Ethnopharmacol, 155(3), 1467-1472. https://doi.org/10.1016/j.jep.2014.07.030

Nakajima, M., Dokam, A., Kasim, A. N., Alsoofi, M., Khalil, N. S., & al'Absi, M. (2014). Habitual khat and concurrent khat and tobacco use are associated with subjective sleep quality. Prev Chronic Dis, 11, E86. https://doi.org/10.5888/pcd11.130234

Nakajima, M., Dokam, A., Khalil, N. S., Alsoofi, M., & al'Absi, M. (2016). Correlates of Concurrent Khat and Tobacco Use in Yemen. Subst Use Misuse, 51(12), 1535-1541. https://doi.org/10.1080/10826084.2016.1188950

Nakajima, M., Hoffman, R., & Al'Absi, M. (2014). Poor working memory and reduced blood pressure levels in concurrent users of khat and tobacco. Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco, 16(3), 279-287. https://doi.org/10.1093/ntr/ntt139

Nakajima, M., Hoffman, R., & Al'Absi, M. (2014). Poor working memory and reduced blood pressure levels in concurrent users of khat and tobacco. Nicotine Tob Res, 16(3), 279-287. https://doi.org/10.1093/ntr/ntt139

Nakajima, M., Hoffman, R., & al'Absi, M. (2017). Level of khat dependence, use patterns, and psychosocial correlates in Yemen: a cross-sectional investigation. East Mediterr Health J, 23(3), 161-167.

Nakajima, M., Hoffman, R., Alsameai, A., Khalil, N. S., & al'Absi, M. (2018). Development of the Khat Knowledge, Attitudes and Perception Scale. Drug Alcohol Rev. https://doi.org/10.1111/dar.12828

Nakajima, M., Jebena, M., Tesfaye, M., Hoffman, R., Lemieux, A., Lemessa, F., & al'Absi, M. (2014). Correlates of khat use during pregnancy: a cross-sectional investigation Africa and Middle East Congress on Addiction (AMECA) Conference, Rabat, Morocco.

Nakajima, M., Jebena, M. G., Taha, M., Tesfaye, M., Gudina, E., Lemieux, A.,…al'Absi, M. (2017). Correlates of khat use during pregnancy: A cross-sectional study. Addictive Behaviors, 73, 178-184. https://doi.org/10.1016/j.addbeh.2017.05.008

Nakajima, M., Molla, K., Belachew, B., Mohammed, A., Hassan, A., Kroll, J., & al'Absi, M. (2017). Khat Use is Associated with Tobacco, Alcohol, and Illicit Drug Use: A Cross-Sectional Examination in the United States. J Psychoactive Drugs, 49(5), 413-419. https://doi.org/10.1080/02791072.2017.1342155

Nyongesa, A., Oduma, J., al'Absi, M., & Chirwa, S. (2015). Immunohistochemical localization of anterior pituitary cell types of vervet monkey (Chlorocebus aethiops) following sub-chronic cathinone exposure. J Ethnopharmacol, 174, 168-177. https://doi.org/10.1016/j.jep.2015.08.007

Nyongesa, A. W., Oduma, J. A., Nakajima, M., Odongo, H. O., Adoyo, P. A., & al'Absi, M. (2014a). Acute and sub-chronic effects of purified cathinone from khat (Catha edulis) on behavioural profiles in vervet monkeys (Chlorocebus aethiops). Metab Brain Dis, 29(2), 441-449. https://doi.org/10.1007/s11011-013-9441-z

Nyongesa, A. W., Oduma, J. A., Nakajima, M., Odongo, H. O., Adoyo, P. A., & Al'absi, M. (2014). Dose-response inhibitory effects of purified cathinone from khat (Catha edulis) on cortisol and prolactin release in vervet monkeys (Chlorocebus aethiops). Metab Brain Dis, 29(2), 451-458. https://doi.org/10.1007/s11011-013-9445-8

Nyongesa, A. W., Oduma, J. A., Nakajima, M., Odongo, H. O., Adoyo, P. A., & al'Absi, M. (2014b). Dose-response inhibitory effects of purified cathinone from khat (Catha edulis) on cortisol and prolactin release in vervet monkeys (Chlorocebus aethiops). Metab Brain Dis, 29(2), 451-458. https://doi.org/10.1007/s11011-013-9445-8

Odenwald, M., & al'Absi, M. (2017). Khat use and related addiction, mental health and physical disorders: the need to address a growing risk. East Mediterr Health J, 23(3), 236-244.

Widmann, M., Warsame, A. H., Mikulica, J., von Beust, J., Isse, M. M., Ndetei, D.,…Odenwald, M. G. (2014). Khat use, PTSD and psychotic symptoms among somali refugees in Nairobi - a pilot study. Front Public Health, 2, 71. https://doi.org/10.3389/fpubh.2014.00071