Khat chewing from the pharmacological point of view: an update

Khat chewing and its associated factors among pregnant women in Chiro district, eastern Ethiopia: a community-based study

Introduction

Despite its deleterious consequences, khat chewing is escalating worldwide. However, there is a lack of evidence about the extent of khat chewing among pregnant women in Ethiopia, particularly in the current study area. Therefore, this study aimed to assess the prevalence of current khat chewing and its associated factors among pregnant women in Chiro district, eastern Ethiopia.

Methods

This community-based cross-sectional study was conducted in Chiro district from November 1 to 30, 2022 G.C. Study participants were selected using the systematic random sampling technique. An interview-administered structured questionnaire was used to collect data through a house-to-house survey. The data were entered into EpiData version 3.1 and analyzed in STATA 14 software. Characteristics of study participants were summarized using descriptive analysis, and binary logistic regression was used to identify determinants of khat chewing.

Results

A total of 409 pregnant women participated in this study, with a response rate of 99%. The overall prevalence of khat chewing was 60.4% (95% CI: 55.5%, 65.2%). Religion (AOR: 2.08; 95% CI: 1.13, 3.82), khat cultivation (AOR: 0.43; 95% CI: 0.25, 0.77), partner khat use (AOR: 5.54; 95% CI: 3.11, 9.88), pre-pregnancy khat use (AOR: 9.95; 95% CI: 5.55, 17.81), antenatal care (ANC) visit (AOR: 2.71; 95% CI: 1.41, 5.21), and mental distress (AOR: 4.89; 95% CI: 2.38, 10.02) were significantly associated with current khat chewing.

Conclusion

The majority of pregnant women in the study area practice khat chewing. Thus, accessible and comprehensive pre-conception and pre-natal care incorporating the prevention and management of antenatal khat chewing is crucial to overcome this problem. Provision of mental healthcare involving partners of pregnant women is also important to reduce the extent and impacts of khat chewing during pregnancy. Further longitudinal studies triangulated with qualitative designs are recommended.

Protein-Ligand Identification and In Vitro Inhibitory Effects of Cathine on 11 Major Human Drug Metabolizing Cytochrome P450s

Cathine is the stable form of cathinone, the major active compound found in khat (Catha edulis Forsk) plant. Khat was found to inhibit major phase I drug metabolizing cytochrome P450 (CYP) enzyme activities in vitro and in vivo. With the upsurge of khat consumption and the potential use of cathine to combat obesity, efforts should be channelled into understanding potential cathine-drug interactions, which have been rather limited. The present study aimed to assess CYPs activity and inhibition by cathine in a high-throughput in vitro fluorescence-based enzyme assay and molecular docking analysis to identify how cathine interacts within various CYPs’ active sites. The half maximal inhibitory concentration (IC₅₀) values of cathine determined for CYP2A6 and CYP3A4 were 80 and 90 μM, while CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP2J2 and CYP3A5 showed no significant inhibition. Furthermore, in K_i analysis, the Lineweaver-Burk plots depicted non-competitive mixed inhibition of cathine on both CYP2A6 and CYP3A4 with K_i value of 63 and 100 μM, respectively. Cathine showed negligible time-dependent inhibition on CYPs. Further, molecular docking studies showed that cathine was bound to CYP2A6 via hydrophobic, hydrogen and π-stacking interactions and formed hydrophobic and hydrogen bonds with active site residues in CYP3A4. Both molecular docking prediction and in vitro outcome are in agreement, granting more detailed insights for predicting CYPs metabolism besides the possible cathine-drug interactions. Cathine-drug interactions may occur with concomitant consumption of khat or cathine-containing products with medications metabolized by CYP2A6 and CYP3A4.

Abuse Potential of Cathinones in Humans: A Systematic Review

Introduction and objective: Assessing the abuse potential of new substances with central nervous system activity is essential for preventing possible risks of misuse and addiction. The same methodology is recommended for the evaluation of the abuse potential of recreational drugs. This systematic review aims to assess the pharmacological effects related to the abuse potential and pharmacokinetics of cathinones, which are evaluated in both experimental and prospective observational studies in humans. Materials and Methods: A systematic search of the published literature was conducted to retrieve studies that had administered cathinone, mephedrone, methylone, and diethylpropion to evaluate their acute pharmacological effects related to abuse potential. Results: The search yielded 583 results, 18 of which were included to assess the abuse potential of cathinone (n = 5), mephedrone (n = 7), methylone (n = 1), and diethylpropion (n = 5). All four substances induce stimulant and euphorigenic effects that resemble those of amphetamines and MDMA, and their different intensities may be associated with varying levels of abuse potential. Conclusions: Cathinone, mephedrone, methylone, and diethylpropion induce a range of desirable and reinforcing effects that may, to some extent, result in abuse potential. Further investigation is needed to minimize and prevent their impact on society and public health.

Progress and Research Trends on Catha edulis (Vahl) Endl. (Catha edulis): A Review and Bibliometric Analysis

Catha edulis (Vahl) Endl., known as Catha edulis or Khat is a traditional and regional plant for chewing, smoking and drinking, that has posed a worldwide public health problem due to its recent emerging abused consumption. In the face of the massive use of Catha edulis, we reviewed related publications to analyze the progress and research trends through bibliometric methods. After screening, a total of 514 scientific publications published from 1997 to 2020 were included by systematic retrieval from the Web of Science (WoS) database. According to further scientometric analysis, the annual number of publications output kept rising in most of the years. Ethiopia and the United States of America (USA) have been devoting significant contributions to the field. Though the research emphasis had been the chemical composition and pharmacological and toxicological effects for several years, the hot spots were transferred; the mechanism investigations of Catha edulis have been the focus in recent years, which might be continued in the future. Furthermore, co-operations of multi-disciplinary researchers are needed to minimize abuse harms and maximize the medicinal benefits of Catha edulis to human beings.

Prevalence of Khat (Catha edulis) Chewing and Its Determinants: A Respondent-Driven Survey from Hossana, Ethiopia

BACKGROUND

Ethiopia is a leading khat producer in East Africa, and almost all regions are involved in khat production. Hossana, a small town in Southern Ethiopia, is also actively involved in khat production and its use. However, very few studies have been conducted to investigate the habit of khat chewing in this area. This study was conducted to assess the prevalence and predictors of khat chewing among Hossana residents.

METHODS

The study was conducted on 1700 individuals in Hossana town from March 2018 to June 2019. A structured pre-tested self-administered questionnaire was designed and used for data collection. Descriptive statistics and logistic regression were carried out to study the prevalence and predictors of khat chewing in the study area.

RESULTS

The overall prevalence of khat chewing among the respondents was 58.0% (95% CI 53.4-63.3) of which 68.4% were daily khat users and 31.5% used it occasionally. About 24.7% of females and 75.2% of males had chewed khat. Muslim religion (AOR 2.37; 95% CI 1.58-4.32), male gender (AOR 3.48; 95% CI 2.16-5.61), Older age (AOR 1.36; 95% CI 0.84-2.21), participants having habitual khat chewing friends or a khat chewer family associate (OR 1.70; 95% CI 1.17-2.20) were found to be independent predictors of chewing.

CONCLUSION

Significant portion of the population in the study area chew khat. Khat use is significantly associated with the Muslim religion, gender, age, and habit of family and friends. Further studies with larger demographic area are warranted from the study area to reproduce these findings.

Effect of Khat (Catha edulis Forsk) extract on testicular maturation in pre-pubertal and pubertal rats: A morphological and biochemical study

The present study aimed at analysing the effect of Khat plant extract on rat testicular development. Thirty-two weaned male albino rats (4 weeks old) were divided into four groups consisting of eight animals each. While control animals received normal saline, rats of groups I, II and III received 100, 200 and 300 mg Khat extract per kg body weight dissolved in distilled water by oral gavage daily for 8 weeks, respectively. Blood samples were collected in separate heparinized tubes by cardiac puncture from each rat and processed for measuring plasma levels of reproductive hormones LH, FSH, testosterone and prolactin. Five-µm sections were stained with haematoxylin and eosin and examined by light microscope. Some sections were immunostained for protamine-1 representing a biomarker for intact sperm differentiation. The present study clearly demonstrated that Khat extract has a pronounced effect on testicular maturation of developing albino rats at both the morphological and functional levels. Khat-treated groups revealed a significantly low serum testosterone level and severe impairment of spermatogenesis when compared with control animals. The current findings also verified, for the first time, that the final stages of sperm maturation (spermiogenesis) were strongly impaired after administration of Khat extract to experimental rats particularly at a higher dose (300 mg/kg body weight). This was proved by the very weak, if any, expression of protamine-1 in the maturing spermatids in Khat-treated rats.

Coenzyme Q10 nullified khat-induced hepatotoxicity, nephrotoxicity and inflammation in a mouse model

Ethnopharmacological relevance

The consumption of khat (Catha Edulis, Forsk) is on the rise despite the much publicized associated deleterious health effects. How chemicals present in khat, affect various physiological and biochemical processes requires further scrutiny. A clear understanding of these processes will provide an avenue for countering khat-driven negative effects using appropriate pharmacological and/or nutritional interventions.

Aim of the study

The current study investigated the effect of khat on vital physiological and biochemical processes such as oxidative stress, inflammation and immune responses and the role of Coenzyme-Q₁₀ (CoQ₁₀), a potent antioxidant and anti-inflammatory, in modulating any negative effects due to khat exposure.

Methodology

Three (3) weeks old forty (40) Swiss albino mice were randomly assigned into four treatment groups (n = 10). The first group was the control that was not administered with khat or CoQ₁₀. The second group received 200 mg/kg body weight (b/w) of CoQ₁₀, while the third group received 1500 mg/kg b/w of khat extract and finally the forth group was co-treated with 200 mg/kg b/w of CoQ₁₀ and 1500 mg/kg b/w of khat extract. The experiment was conducted for 90 days after which samples were collected for physiological and biochemical analyses.

Results

The effects of khat and CoQ₁₀ on the weights of brain, liver, kidney and spleen was determined. Administration of khat decreased the levels of RBCs and its subtypes (MCV, MCH, RDW-SD and RDW-CV), a clear indicator of khat-induced normochromic microcytic anemia. White blood cells (lymphocytes, monocytes, neutrophils and eosinophil) which are vital in responding to infections were markedly elevated by khat. Moreover, these results provide evidence for khat-induced liver and kidney injury as shown by increased biomarkers; AST, ALT, GGT and creatinine respectively. Standard histopathological analysis confirmed this finding for khat-driven liver and kidney injury. Further studies showed evidence for khat-induced inflammation and oxidative stress as depicted by increased levels of the pro-inflammatory cytokine TNF-alpha and elevation of GSH in the brain, liver and spleen. Remarkably, this is the first study to demonstrate the potential of CoQ₁₀ in ameliorating khat-induced negative effects as outlined. CoQ₁₀ supplementation restored the khat-induced reduction in RBC subtypes, and was protective against liver and kidney injury as shown by the appropriate biomarkers and standard histopathology analysis. The other significant finding was the CoQ₁₀-driven normalization of GSH and TNF-α levels, indicating a protective effect from khat-driven oxidative stress and inflammation respectively.

Conclusion

From this study, we conclude that CoQ₁₀ may be useful in nullifying khat-driven deleterious events among chronic khat users.

Development of the Khat Knowledge, Attitudes and Perception Scale

INTRODUCTION AND AIMS

Khat (Catha edulis) is a stimulant plant widely used in East Africa and the Arabian Peninsula. Tobacco is often co-used with khat and its use has expanded to other parts of the world. Chronic khat use is associated with negative health consequences. There is a lack of research to develop a tool to assess attitudes toward khat use. This study aimed to develop a brief tool to assess attitude and perception related to khat (i.e. the Khat Knowledge, Attitudes and Perception Scale).

DESIGN AND METHODS

Four-hundred and three participants in Yemen (151 concurrent users of khat and tobacco, 141 khat-only users and 92 non-users of khat and tobacco) were asked about knowledge and attitudes related to khat. A principle component analysis with Promax rotation, Scree-plot and Cronbach's α coefficients was performed to examine psychometric properties of the Khat Knowledge, Attitudes and Perception Scale.

RESULTS

Principle component analysis revealed five factors: negative beliefs, positive beliefs, idleness, weight control and family issues. Internal consistency of items in negative beliefs, positive beliefs, idleness, weight control and family issues were 0.88, 0.62, 0.62, 0.72 and 0.53, respectively. Greater negative beliefs was inversely correlated with positive beliefs but positively associated with idleness, weight control and family issues. Concurrent users and khat-only users had lower scores on negative beliefs than non-users. Concurrent users had higher scores on positive beliefs than khat-only and non-users.

DISCUSSION AND CONCLUSIONS

These results provide initial support of the usefulness of the Khat Knowledge, Attitudes and Perception Scale.

Using the Severity of Dependence Scale to screen for DSM-5 khat use disorder

OBJECTIVE

This study aimed to determine the efficacy of the Severity of Dependence Scale (SDS) as a screening tool for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition-defined khat use disorder.

METHODS

Cross-sectional, purposive sample of past-year khat consumers aged 16 and above were recruited from khat markets and cafes from university and general community in Adama, Ethiopia. Participants self-completed a survey comprising current substance use disorder.

RESULTS

The SDS formed a unifactorial structure, consistent with the dependence construct. Almost three quarters (73%) of the sample were identified as experiencing Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition khat use disorder. The SDS demonstrated excellent discrimination (area under the curve = 0.92) and an optimal cut-off as a score of 3 or greater, with sensitivity of 81% and specificity of 96%. This classification validly identified a group with more frequent and higher dose khat use than participants that did not screen positive.

CONCLUSION

Although khat is a mild stimulant, there is clear evidence that some consumers are both concerned with their use and experience problems associated with their use. Consistent with its application for other drugs, the SDS is a brief and simple screening tool that appears to validly identify individuals experiencing a khat use disorder syndrome and experiencing high rates of adverse consequences in association with use.

Pharmacological and Toxicological Effects of Catha edulis F. (Khat)

Khat chewing is deeply rooted in the culture and tradition of communities in khat belt countries, and its consumption is spread to other countries through the suitcase trade. The aim of this article is to review current knowledge on the chemistry, social, pharmacology and toxicology of khat and its use. Khat produces effect invariably in every system, which is harmful or beneficial in some instances. Harmful effects are observed in heavy users, although firm evidence is lacking. Chewing khat acutely elicits states of euphoria, which is followed by low mood. Khat contains alkaloids with psychostimulant properties, but the effect cannot be totally explained by these alkaloids. It is also not clear whether the effect produced in some organs like liver could be attributed to khat or pesticides sprayed during farming. Although the evidence indicates that khat has adverse effects in most organs, our understanding of the complex interaction between use and effect is incomplete, and causal relationships have not yet been described. Moreover, khat has positioned itself well in the social, economic and political arena. Thus, a multidisciplinary research is required to understand the different dimensions and come up with ways that maximize the benefit while minimizing the risk. Copyright © 2017 John Wiley & Sons, Ltd.

Gender differences in the effects of cathinone and the interaction with caffeine on temperature and locomotor activity in the rat

We have investigated gender differences in the effects of cathinone and the interaction with caffeine on temperature and movement activity in Wistar rats. Telemetry probes were implanted in rats under isoflurane anaesthesia, and 7 days later, temperature and activity were recorded in conscious unrestrained animals. Caffeine (10mg/lkg) or vehicle, and 30min later, cathinone (5mg/kg) or vehicle, were injected subcutaneously. Cathinone produced significant and marked increases in activity, and the response to cathinone was significantly greater in female animals. The combination of caffeine and cathinone causes a short lived potentiation followed by a prolonged inhibition of the activity response to cathinone. Cathinone alone had minor effects on temperature. However, the combination of caffeine and cathinone produced a significant acute rise in temperature only in male rats in the 90min after cathinone injection. Hence, cathinone caused greater increases in activity in female than in male rats. Secondly, caffeine produced an initial potentiation followed by a prolonged inhibition of the activity response to cathinone. Thirdly, cathinone in combination with caffeine significantly raised temperature acutely in male but not female rats. These differences highlight the need to carry out gender studies of the actions of stimulants.

Effects and risks associated with novel psychoactive substances: mislabeling and sale as bath salts, spice, and research chemicals

BACKGROUND

The number of newly reported psychoactive substances in Europe is now higher than ever. In order to evade legal restrictions, old and novel psychoactive substances from medical research and their derivatives are commonly mislabeled as "not for human consumption" and offered for sale on the Internet and elsewhere. Such substances are widely taken by young people as "club drugs." Their consumption must be considered in the differential diagnosis of psychiatric, neurological, cardiovascular, or metabolic disturbances of unclear origin in a young patient.

METHOD

Selective review of pertinent literature retrieved by a PubMed search, including publications by government-sponsored organizations.

RESULTS

From 2010 to 2012, 163 substances were reported to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), mostly either synthetic cannabinoids (39.3%) or synthetic cathinones (16.6%). Synthetic cannabinoids alter mood and perception; intoxications cause agitation, tachy cardia, and arterial hypertension. Synthetic cathinones are hallucinogenic stimulants with predominantly cardiovascular and psychiatric side effects. Severe intoxications cause serotonin syndrome and potentially fatal rhabdomyolysis. Substances in either of these classes often escape detection in screening tests.

CONCLUSION

Young persons who present with agitation and cardiovascular and/or psychiatric manifestations of unclear origin and whose drug screening tests are negative may be suffering from an intoxication with a novel psychoactive substance. Physicians should know the classes of such substances and their effects. Targeted toxicological analysis can be carried out in a toxicology laboratory or a facility for forensic medicine.

Catha edulis chewing effects on treatment of paranoid schizophrenic patients

BACKGROUND

The current study's aim is to evaluate the possible interaction effects of khat chewing on treatment of paranoid schizophrenic patients.

PATIENTS AND METHODS

In the study group, 42 male subjects suffered from paranoid schizophrenia and were classified according to their khat chewing habits into two subgroups: either khat-chewer subgroup (SKc; n=21; r=11, h=10) or non-khat-chewer subgroup (SNKc; n=21, r=11, h=10). Each subgroup was further subdivided according to type of treatment into r (risperidone) and h (haloperidol). Healthy male subjects (37) were subdivided into healthy khat-chewer as positive controls (HKc, n=17) and healthy non-khat-chewer as negative controls (HNKc, n=20). Plasma dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid, 5-hydroxytryptamine (serotonin), 5-hydroxyindoleacetic acid, epinephrine, and norepinephrine were estimated.

RESULTS

ANOVA and post hoc analysis showed that dopamine was illustrating significant elevation in all khat chewing groups. DOPAC was illustrating significant decrease in all khat chewing groups with an interesting outcome showing significant increase in DOPAC in SNKcr group due to risperidone effect. Homovanillic acid, serotonin, hydroxyindoleacetic acid, and norepinephrine were illustrating significant elevations in all khat chewing groups. Epinephrine was illustrating significant elevation in all chewers than non-chewers groups. Unexpected significant decrease in epinephrine in the SNKcr group indicated that risperidone drug is decreasing epinephrine through indirect mechanism involving calcium.

CONCLUSION

Khat chewing in schizophrenic patients is contraindicated because it aggravates the disease symptoms, attenuates all used treatment medications, and deteriorates all biochemical markers of the patients.

Dose-response inhibitory effects of purified cathinone from khat (Catha edulis) on cortisol and prolactin release in vervet monkeys (Chlorocebus aethiops)

This study reports acute and sub-chronic effects of cathinone on hormonal alterations in single-caged vervet monkeys. Fourteen adult vervet monkeys were used, 12 of which were treated and 2 controls. Pre-treatment phase of 1 month aimed at establishing baseline levels of hormones while treatment phase of 4 months considered the dose- and time-response effects of cathinone on serum cortisol and prolactin levels. Test animals were allocated four groups of three animals each and administered 0.8, 1.6, 3.2 and 6.4 mg/kg body weight of cathinone orally while controls were administered normal saline. Treatment was done at alternate days of each week. Serum prolactin and cortisol immunoassays were done. Hormonal data was analysed by repeated measures ANCOVA. Results indicate a dose [F (4, 8) = 218, P < 0.001] and time [F (18, 142) = 21.7, P < 0.001] dependent effect of cathinone on cortisol levels with a significant dose by week interaction [F (71, 142) = 4.86, P < 0.001]. Similarly, there was a decrease in serum prolactin [F (4, 8) = 267, P < 0.001] with escalating doses of cathinone with a significant dose x week interaction [F (59, 118) = 13.03, P < 0.001]. The findings demonstrate that at high doses and long-term exposure, cathinone causes hormonal alterations probably via changes in hypothalamo-hypophyseo-adrenocortical and gonadal axes integrity.

The likelihood of khat chewing serving as a neglected and reverse 'gateway' to tobacco use among UK adult male khat chewers: a cross sectional study

BACKGROUND

Chewing khat leaves is often accompanied by tobacco use. We assessed aspects of tobacco use and explored factors associated with tobacco use patterns (frequency of use per week) among khat chewers who used tobacco only when chewing khat ("simultaneous tobacco and khat users", STKU).

METHODS

A sample of 204 male khat chewers was recruited during random visits to khat outlets. Data collected included socio-demographic items, tobacco use and khat chewing behaviours. Both psychological and physical dependence on khat were assessed using the Severity of Psychological Dependence on Khat (SDS-Khat) Scale, the Diagnostic Statistical Manual IV (DSM-IV) and adapted items from the Fagerström Test for Nicotine Dependence (chewing even when ill, and difficulty in abstaining from khat chewing for an entire week). Descriptive statistics and non-parametric analyses were conducted.

RESULTS

Of the 204 khat chewers, 35% were khat chewers only, 20% were STKU, and the remainder were daily cigarette smokers. The mean age of STKU was 38.12 (±14.05) years. Fifty seven percent of STKU smoked tobacco and chewed khat for two days per week and 43% smoked and chewed more frequently (three to six days: 33%, daily: 10%). Three quarters (74%) were former daily tobacco users. Khat chewing initiated tobacco smoking among 45% of STKU and 71% reported attempts to quit tobacco smoking during khat chew. Among STKU, smoking tobacco for more than two days per week was significantly associated (p < 0.05) with psychological dependence (increased levels of SDS-Khat), physical dependence (increased levels of DSM-IV symptoms, chewing even when ill, difficulty in abstaining from chewing for an entire week and self-reported health conditions) and behavioural factors (e.g. amount of khat chewed in typical khat session).

CONCLUSIONS

Khat chewing may promote different patterns of tobacco smoking, initiate and sustain tobacco smoking, and trigger tobacco cessation relapses among STKU. Increased frequency of tobacco smoking among STKU was linked to psycho-physical and behavioural factors. Further investigation within large and representative samples of both sexes of STKU in different contexts should be considered for health research and policy development. Khat chewing should be considered when designing tobacco prevention uptake, cessation interventions and relapse prevention programmes.

Concurrent use of khat and tobacco is associated with verbal learning and delayed recall deficits

AIMS

The present study assessed whether cigarette smokers who are also regular khat users would demonstrate greater impairments in verbal learning and recall compared to both non-smokers who are khat users and control subjects.

DESIGN

An independent-measures, between-subjects design with two covariates.

SETTING

An out-patient, university research center in Taiz, Yemen.

PARTICIPANTS

Subjects were 175 Yemeni college students (90 men, 85 women) ranging in age from 18 to 38 years. Seventy-five subjects were self-reported chronic cigarette smokers and khat users, 48 non-smoking subjects were self-reported to be chronic khat users and 52 non-smoking subjects reported no current use or history of khat use.

MEASUREMENTS

Verbal learning and verbal memory recall was assessed by subject performance on the Arabic version of the Rey Auditory Verbal Learning Test (RAVLT).

FINDINGS

Statistically significant differences (P < 0.05) were observed in RAVLT acquisition learning trials 2-5 and on delayed recall measures between concurrent khat and cigarette users compared to both the khat-only group and the control group of non-users of khat and cigarettes. On each of these trials, concurrent users recalled fewer words, demonstrating a slowed rate of verbal learning. This same pattern of performance was also seen on delayed recall measures. Khat use alone did not affect immediate or delayed recall of previously learned words.

CONCLUSIONS

Khat users who smoke cigarettes have a lower rate of verbal learning and delayed recall of previously learned verbal material than khat users who do not smoke cigarettes. This may be due to pre-existing differences between these groups of subjects.

Khat (Catha edulis): A systematic review of evidence and literature pertaining to its harms to UK users and society

The use of khat ( Catha edulis) has been associated with a large number of physiological and societal harms, leading to calls for it to be controlled in the UK. The evidence of these harms is often equivocal, limited by confounding factors, or entirely anecdotal: high-powered, quality-controlled studies are lacking. Regardless, the body of relevant literature indicates that the once socially-regulated use of khat has been eroded. Some individuals have developed excessive consumption patterns, either using khat daily or in binge-sessions, though daily consumption is not necessarily problematic per se. The majority of users seem to use khat in moderation, where the associated harms appear low. For excessive users, harms associated with khat are greater, particularly relating to mental health. Social harms also seem to be largely related to excessive khat use rather than khat use itself. Even in cases of excessive khat use, however, causal relationships between chewing and harms have not been described. More research is required to establish the role of khat in liver disease, coronary problems, cancers of the digestive tract and incidents of domestic violence. Studies should consider the likeliness that certain users are more vulnerable to developing patterns of excessive khat use due to an interwoven set of factors such as social health determinants and pre- and post-migration experiences.

Working memory and speed of information processing in chronic khat users: preliminary findings

To date there are very few laboratory data available regarding the long-term effect of the psychostimulant khat on human neurocognitive functioning. The purpose of the present study was to assess whether chronic khat users would demonstrate impairments in working memory and speed of information processing compared to control subjects. Working memory was assessed using the forward and backward digit span test. Speed of information processing was assessed using the Digit Symbol Substitution Test. Results of the present study indicate that chronic khat use may have a long-term deleterious effect on working memory, particularly on digit backwards measures of short-term/working memory. The finding is consistent with results seen by several investigators in samples of methamphetamine users.

The health impacts of khat: a qualitative study among Somali-Australians

OBJECTIVES

To identify patterns of khat use among Somali-Australians in Australia and to explore their views about the links between khat use and personal health.

DESIGN, SETTING AND PARTICIPANTS

Qualitative study using semistructured focus groups among adult members of Somali communities in Brisbane, Sydney, Melbourne and Perth who volunteered to attend focus groups in January and December 2010.

MAIN OUTCOME MEASURES

Emergent themes related to Somali-Australians' understanding of the links between khat use and personal health.

RESULTS

Nineteen focus groups included 114 participants. Khat use was reported to be common among the Somali community, and more common among men than women. Khat was usually chewed in prolonged sessions, producing mild psychostimulant effects such as increased energy, enhanced mood, reduced appetite and reduced sleep. Khat was widely perceived to be a food, not a drug, and as harmless, or even beneficial, to the user's health. Many users reported discontinuation effects such as lethargy, sleep disturbances and mood problems after sessions of heavy khat use, and some reported self-medicating with alcohol to cope with such problems. Problems of addiction to khat were identified by some participants, but not all believed it is addictive. Many khat users reported visiting their health professionals for treatment of adverse effects and failing to disclose their khat use.

CONCLUSIONS

Health professionals require greater awareness of khat use and related health problems. Health promotion activities targeting communities with high levels of khat use are required to increase understanding of the potential risks of regular khat use, to promote harm-reduction strategies, and to increase awareness of services available for those experiencing harm. Health professionals should consider targeted screening for khat use among individuals from Horn of Africa communities who present to health services.

Reproductive parameters are differentially altered following subchronic administration of Catha edulis F. (Khat) extract and cathinone in male rats

AIMS OF THE STUDY

Controversy surrounds on the effect of khat, a widely chewed herb for its stimulant effect on sexuality. This study investigated the effect of fresh Catha edulis F. (Khat) extract, synthetic cathinone and vehicle on reproductive parameters, including sexual motivation and performance, serum testosterone and cortisol levels, epididymal sperm count, and histoarchitecture of testis in male rats.

OBJECTIVE

This study investigated the effect of fresh Catha edulis Forsk (Khat, Celastraceae) extract, synthetic cathinone and vehicle on reproductive parameters, including sexual motivation and performance, serum testosterone and cortisol levels, epididymal sperm count, and histoarchitecture of testis in male rats.

MATERIALS AND METHODS

Rats were treated with either Tween 80 (3%, v/v) in water, khat extract (100mg/kg, K100; 200mg/kg, K200; and 300mg/kg, K300 doses) or cathinone (5mg/kg, CAT5) intragastrically for four weeks and subjected to a battery of behavioral tests. Three days following the last administration, blood was drawn for hormonal analysis and the animals were sacrificed for sperm count and morphologic-pathology studies.

RESULTS

K100 significantly decreased mount latency (ML) (p<0.05) and intromission latency (IL) (p<0.01) compared to controls. K200 whilst significantly reduced IL (p<0.01) and intromission frequency (IF) (p<0.01), increased postejaculatory latency (PEL) (p<0.01). K300 significantly reduced IF (p<0.01) and ejaculatory latency (EL) (p<0.01), but increased mount frequency (MF), IL, PEL, and ML (p<0.01, in all cases). With CAT5, MF (p<0.05) and IL (p<0.01) were significantly greater but EL and IF were lower (p<0.05, in both cases) than controls. Serum levels of testosterone were doubled in K100 (p<0.01), but a significant decrease was recorded in both K200 (18%, p<0.01) and K300 (50%, p<0.01) rats. Whereas K100 did not have any effect on cortisol levels, K200 and K300 significantly increased by 83% (p<0.05) and 164.5% (p<0.01), respectively. CAT5 affected neither serum testosterone nor cortisol levels. Khat extract demonstrated a dose-dependent decline in epididymal sperm count: 50% with K100 (p<0.05), 78% with K200 (p<0.01) and 89% with K300 (p<0.01). CAT5 did not, however, produce any significant change in sperm count. Khat extract and cathinone did not produce any discernible damage on testis.

CONCLUSION

Mild dose of khat improves sexual motivation, without much effect on performance. With increasing dose, however, both motivation and performance are reduced. Although testosterone levels correlated well with motivation, there was dissociation with sperm count, indicating optimum level might be required for normal spermatogenesis.

Effect of khat chewing on periodontal pathogens in subgingival biofilm from chronic periodontitis patients

AIMS

Existing in vitro and in vivo data suggest that khat may have a favorable effect on periodontal microbiota. The purpose of this study was to assess the effect of khat chewing on major periodontal pathogens in subgingival plaque samples from subjects with chronic periodontitis.

MATERIALS AND METHODS

40 subgingival plaque samples were obtained from periodontitis and healthy sites of 10 khat chewers (40 y median age) and 10 khat non-chewers (37.5 y median age) with chronic periodontitis. Absolute and relative counts of 6 periodontal pathogens were determined in each sample using highly sensitive and specific Taqman real-time PCR assays. Data were analyzed using an ordinal regression model.

RESULTS

Significantly more total bacteria were detected in samples from the periodontitis sites of the khat chewers (OR=20). Treponema denticola was present at significantly higher absolute counts at the healthy as well as periodontitis sites of the khat chewers (OR=3.13 and 13, respectively). However, the khat chewers harbored significantly lower absolute counts of Porphyromonas gingivalis at the healthy sites (OR=0.07). Furthermore, khat chewing was significantly associated with lower relative counts of Porphyromonas gingivalis, fusobacterium ssp., prevotella ssp. and Parvimonas micra-like species in subgingival plaque samples from both healthy and periodontitis sites (OR=0.11-0.33). Only Treponema denticola was found in higher relative counts at the healthy sites of the khat chewers (OR=2.98).

CONCLUSIONS

Overall, there was a lower burden of pathogens in the khat chewers. Findings from the current study are suggestive of a potential prebiotic effect for khat on periodontal microbiota.

Khat use and neurobehavioral functions: suggestions for future studies

Although there is a rich body of research available regarding the effect of acute and chronic khat dosing in animal models, research on the behavioral and cognitive effects of khat in human subjects is not extensive and several of the available studies have been done only in the context of observational and single-case studies. In light of the absence of a substantial literature on the neurobehavioral deficits associated with khat use and to provide a context that could be used to identify themes for future research we review previous research that has focused on other stimulant drugs. This review highlights multiple areas of neurocognitive deficit that have been identified in previous studies of individuals who have been chronic users of stimulants, such as amphetamines and methamphetamines. The review highlights a substantial body of evidence demonstrating a wide range of learning and memory impairments including deficits that persist during abstinence from active drug use. This review does not imply a similar khat effect, but due to some similarities pharmacologically between the active components of khat (cathinone and cathine) and amphetamines, future studies examining these same domains of cognitive functioning in chronic khat users and abstinent khat users appears to be warranted, if possible using some of the same or similar laboratory measures.

Association of khat chewing with increased risk of stroke and death in patients presenting with acute coronary syndrome

OBJECTIVE

To evaluate the prevalence and significance of khat chewing in patients with acute coronary syndrome (ACS).

PATIENTS AND METHODS

From January 29, 2007, through July 29, 2007, 8176 consecutive patients presenting with ACS were enrolled in a prospective, multicenter study from 6 adjacent Middle Eastern countries.

RESULTS

Of the 8176 study patients, 7242 (88.6%) were non-khat chewers, and 934 (11.4%) were khat chewers, mainly of Yemeni origin. Khat chewers were older (57 vs 56 years; P=.01) and more likely to be men (85.7% vs 74.5%) compared with non-khat chewers. Non-khat chewers were more likely to have diabetes mellitus, hypertension, dyslipidemia, obesity, and prior history of coronary artery disease and revascularization. Cigarette smoking was more prevalent in khat chewers, and they were more likely to present greater than 12 hours after onset of symptoms compared with non-khat chewers. At admission, khat chewers had higher heart rate, Killip class, and Global Registry of Acute Coronary Events risk scores. Khat chewers had a significantly higher risk of cardiogenic shock, stroke, and mortality. After adjustment of baseline variables, khat chewing was an independent risk factor for in-hospital mortality (odds ratio, 1.9; 95% confidence interval, 1.3-2.7; P<.001) and stroke (odds ratio, 2.7; 95% confidence interval, 1.3-5.9; P=.01).

CONCLUSION

In this large cohort of patients with ACS, khat chewing was prevalent and was associated with increased risk of stroke and death. In the context of increasing global migration, a greater awareness of potential widespread practices is essential.

Khat - a controversial plant

Khat (Catha edulis) is a shrub or tree whose leaves have been chewed for centuries by people who live in the Eastern part of Africa and the Arabian Peninsula. It has recently turned up in North America and Europe, particularly among emigrants and refugees from countries such as Somalia, Ethiopia and Yemen. Khat contains a number of chemicals, among which are two controlled substances, cathinone (Schedule I) and cathine (Schedule IV). Both chemicals are stimulant drugs with effects similar to amphetamine. Chewing the leaves makes people feel more alert and talkative, and suppresses appetite. Chewing khat leaves releases cathinone, a stimulant that produces the feeling of euphoria. When cathinone is broken down in the body, it produces chemicals including cathine and norephedrine, which have a similar structure to amphetamine and adrenaline (epinephrine). Regular khat use is associated with a rise in arterial blood pressure and pulse rate, corresponding with levels of cathinone in the plasma. Moreover, regular khat chewers have gingivitis and loose teeth, but there appears to be no convincing unusual incidence of oral cancer. Among khat users in Yemen there is, however, a higher incidence of esophageal cancer compared with gastric cancer. Long term use or abuse can cause insomnia, anorexia, gastric disorders, depression, liver damage and cardiac complications, including myocardial infarction. Manic and delusional behavior, violence, suicidal depression, hallucinations, paranoia and khat-induced psychosis have also been reported. On the basis of the scientific data it seems clear that khat use has negative consequences on the economic development of a country and on the health of the society.