Khat use is associated with impaired working memory and cognitive flexibility

D-Glucosamine is a Potential Urease Inhibitor from Middle Eastern Medicinal Plants for Combatting Helicobacter Pylori Infections; a Molecular Docking and Simulation Approach

Helicobacter pylori stands as a significant risk factor for both peptic and stomach ulcers. Their resistance to the highly acidic host environment primarily stems from their capability to produce urease, an enzyme that rapidly converts urea into NH3 and CO2. These byproducts are crucial for the bacterium's survival under such harsh conditions. Given the pivotal role of medicinal plants in treating various ailments with minimal side effects, there is an urgent need for a natural drug that can effectively eliminate H. pylori by inhibiting urease. Hence, the current study aims to identify the most potent urease inhibitor among the natural compounds found in Middle Eastern medicinal plants, taking into consideration factors such as optimal affinity, drug-like properties, pharmacokinetic characteristics, and thermodynamic attributes. In total, 5599 ligand conformers from 151 medicinal plants were subjected to docking against the urease's active site. The top-ranking natural compounds, as determined by their high docking scores, were selected for further analysis. Among these compounds, D-glucosamine (PubChem code 439,213) exhibited the most interactions with the crucial amino acid residues in the urease's active site. Furthermore, D-glucosamine demonstrated superior absorption, distribution, metabolism, excretion, and toxicity properties compared to other top-ranked candidates. Molecular dynamics simulations conducted over 100 nanoseconds revealed stable root mean square deviations and fluctuations of the protein upon complexation with D-glucosamine. Additionally, the radius of gyration and solvent-accessible surface area values for the D-glucosamine-urease complex were notably lower than those observed in other typical urease-inhibitor complexes. In conclusion, this study provides valuable insights into the potential development of D-glucosamine as a novel urease inhibitor. This promising compound holds the potential to serve as an effective drug for combating H. pylori infections in the near future.

Is chewing khat associated with mental health disorders? A scoping review of the content and quality of the current evidence base

BACKGROUND

Khat (Catha edulis) is a plant commonly found in the horn of Africa whose leaves are chewed for their psycho-stimulant effects. Several studies have demonstrated the association between khat use and mental health problems. Nevertheless, evidence is mixed and inconsistent, warranting further review of available studies. This scoping review is aimed at investigating the content and quality of evidence base on the associations between khat use and mental health disorders and suggesting avenues for further research.

METHODS

We used a scoping review methodology to map the existing evidence using PubMed, SCOPUS, Embase, and CINAHL databases. Primary studies focusing on the association between any pattern of khat use and any form of mental health disorders are included. The review focused on all age groups, any study design, all geographical locations, and any publication year. The terms used for searching eligible studies include khat, mental disorders, and various alternative terminologies. Narrative review is employed to present findings.

RESULTS

7,121 articles were found, of which 108 were eligible, conducted across 12 different countries. The majority of the studies was done during the last ten years and the studies mostly employed cross-sectional design. About 10 different categories of mental health disorders have been identified as showing associations with khat use. Despite many contradictory findings between the studies, most of the evidence base suggests that khat use is associated with mental health disorders. Non-specific psychological distress is the most frequently mentioned mental health problem (reported in 26.9% of the studies). Khat use as a predictor variable is mostly assessed using a 'yes/no' category, and as a result, dose-dependent effects of khat use on mental health are not given much consideration.

CONCLUSION

Although most of the studies associate khat use with mental health disorders, the causal relationships are inconclusive given the cross-sectional design of the studies, and the presence of potential confounders and several forms of biases. Available studies also report contradictory findings. Further studies are recommended using prospective designs, standardized and valid measures of khat use, and focusing on specific types of mental health disorders.

Perceived and misperceived norms about khat and/or cannabis use among adults in southwest Uganda

BACKGROUND

Studies from high-income contexts have found evidence that norms about substance use are misperceived. The accuracy of perceived norms about khat and cannabis use in Uganda have not previously been described.

METHODS

We conducted a population-based study targeting all resident adults across eight villages in southwestern Uganda. Personal khat and/or cannabis use frequency was based on self-report. We measured perceived norms about substance use by eliciting individuals' perceptions about how often most other adult men and most other adult women in their villages used these substances. We compared perceived norms to aggregated village rates of use to assess the extent to which norms were misperceived. We used multivariable Poisson regression to estimate correlates of misperceived norms.

RESULTS

Among 1626 participants (91% response rate), only 29 men (4%) and 9 women (1%) reported any lifetime use of khat and/or cannabis. However, 695 participants (43%) did not think lifetime abstinence was the norm among men in their villages, and 256 participants (16%) did not think lifetime abstinence was the norm among women. Moreover, 219 participants (13%) incorrectly believed most men in their village regularly used khat and/or cannabis (≥4 times per week). Misperceived norms were present across subgroups and were correlated with larger social networks, symptoms of depression, loneliness, and younger age.

CONCLUSION

In this study of all adults across 8 villages in rural Uganda, many participants misperceived norms about khat and/or cannabis use. Providing accurate information about prevailing norms in the local population may help prevent initiation of khat and/or cannabis use among adults in this context.

Effects of Catha Edulis Forsk on spatial learning, memory and correlation with serum electrolytes in wild-type male white albino rats

Background

The burdens of psychostimulant use disorders are becoming a worldwide problem. One of the psychostimulants widely consumed in Ethiopia and East African countries is Catha edulis Forsk (khat). However, no studies have been conducted on the cognitive effects of khat and its correlation with serum electrolytes. The present study was aimed to evaluate the effects of khat on spatial learning and memory and their correlation with serum electrolytes.

Materials and methods

Diethyl ether and chloroform (3:1v/v ratio) were solvents used to obtain the crude khat extract in this study. T80W was used to prepare the khat juice, fresh khat leave extract. The rats were received crude khat extract subchronically (KESC) (100 mg/kg, 200 mg/kg and 300 mg/kg b.w), khat juice (KHJ 2.5 mL/kg), 2% tween 80 in distilled water (T80W- v/v, vehicle) and khat extract subacutely (KESA) (300 mg/kg). For subchronic treatment, each rat was administered for twelve weeks before Morris water maze experiment has been started, while it was administered for a week for acute treatment. Spatial learning and memory were measured using the Morris water maze model and serum sodium, calcium, potassium, and chloride were evaluated using Cobas 6000.

Results

Spatial learning was improved with trials across the groups, while average escape latency (s) of rats received KESC 200 mg/kg (p<0.001), KESC 300 mg/kg (p<0.01) and KHJ 2.5 mL/kg (p<0.05) was significantly greater than rats that received vehicle. There was no significant difference in the latency between rats that received KESA 300mg/kg and vehicle (p>0.05). Thigmotaxis was significantly higher in rats that received all doses of khat extract (p<0.001). The time spent in the target quadrant in rats that received KESC 300 mg/kg was significantly reduced (p<0.05). Serum calcium level was inversely correlated with the escape latency (R = -0.417, p<0.05) in rats that received khat.

Conclusions

Khat extract and juice administered subchronically, but not subacutely, impaired learning and memory and was associated with serum calcium reduction. The neuronal basis for such alteration should be investigated.

Problem-solving deficits in methcathinone use disorder

RATIONALE

The use of methcathinone (MCAT), a psychostimulant drug that can lead to long-term health risks and executive dysfunction, increased to an alarming rate in recent years. Impairments in low-level executive function have been reported in substance use disorder. However, little empirical evidence is available regarding high-level executive function (e.g., problem solving), which may act as a risk factor for relapse.

OBJECTIVES

The present study aimed to investigate whether the problem-solving ability was altered in abstinent individuals with methcathinone use disorder (MCUD). Here, we tested fifty male MCUD individuals (short-term MCUD group: twenty-nine patients with MCAT use less than 3 years, long-term MCUD group: twenty-one patients with MCAT use longer than 3 years, which were split by medium years of drug use) and twenty-four well-matched healthy controls (HC) in the Tower of Hanoi task (TOH) to assess the impact of task difficulty on drug-related changes in problem-solving performance. We used several measures to characterize problem-solving performance: the number of mistakes made, the completion time of the task, and the thinking time before the first move.

RESULTS

In the low task difficulty condition, the MCUD group and HC group showed similar levels of mistakes and completion time, while in the high task difficulty condition, the MCUD group reported more mistakes (the mean number of mistakes in each trial: 1.41 ± 1.15 vs 0.79 ± 0.76, P = 0.019, Cohen's d = 0.635) and longer completion time in the task (the mean completion time in each trial: 45.83 ± 20.51 s vs 33.40 ± 15.10 s, P = 0.010, Cohen's d = 0.690) than the HC group. The thinking time before the first move did not differ significantly between groups (P = 0.257). We further found that the long-term (more than 3 years) MCUD group made more mistakes than the short-term MCUD group and HC group, mainly in the highly difficult subtasks. The longer time than HCs was reported in the long-term MCUD group among high task difficulty of subtasks. In addition, there was a positive correlation between years of MCAT use and the number of mistakes made in high task difficulty TOH task (r = 0.326, P = 0.021).

CONCLUSIONS

Chronic methcathinone use was associated with deficits in problem-solving performance, which depended on the degree of task difficulty. The impairment was more evident in the long-term (> 3 years) MCAT group.

Khat and neurobehavioral functions: A systematic review

Background

Khat is a plant that is used for its amphetamine-like stimulant properties. However, although khat is very popular in Eastern Africa, Arabian Peninsula, and the Middle East, there is still a lack of studies researching the possible neurobehavioral impairment derived from khat use.

Methods

A systematic review was conducted to identify studies that assessed the effects of khat use on neurobehavioral functions. MedLine, Scopus, Cochrane, Web of Science and Open Grey literature were searched for relevant publications from inception to December 2020. Search terms included (a) khat and (b) several cognitive domains. References from relevant publications and grey literature were also reviewed to identify additional citations for inclusion.

Results

A total of 142 articles were reviewed, 14 of which met the inclusion criteria (nine human and five rodent studies). Available human studies suggest that long term khat use is associated with significant deficits in several cognitive domains, including learning, motor speed/coordination, set-shifting/response inhibition functions, cognitive flexibility, short term/working memory, and conflict resolution. In addition, rodent studies indicated daily administration of khat extract resulted in dose-related impairments in behavior such as motor hyperactivity and decreased cognition, mainly learning and memory.

Conclusions

The findings presented in this review indicates that long-term khat use may be contributing to an impairment of neurobehavioral functions. However, gaps in literature were detected that future studies could potentially address to better understand the health consequences of khat use.

An updated review on synthetic cathinones

Cathinone, the main psychoactive compound found in the plant Catha edulis Forsk. (khat), is a β-keto analogue of amphetamine, sharing not only the phenethylamine structure, but also the amphetamine-like stimulant effects. Synthetic cathinones are derivatives of the naturally occurring cathinone that largely entered the recreational drug market at the end of 2000s. The former "legal status", impressive marketing strategies and their commercial availability, either in the so-called "smartshops" or via the Internet, prompted their large spread, contributing to their increasing popularity in the following years. As their popularity increased, the risks posed for public health became clear, with several reports of intoxications and deaths involving these substances appearing both in the social media and scientific literature. The regulatory measures introduced thereafter to halt these trending drugs of abuse have proved to be of low impact, as a continuous emergence of new non-controlled derivatives keep appearing to replace those prohibited. Users resort to synthetic cathinones due to their psychostimulant properties but are often unaware of the dangers they may incur when using these substances. Therefore, studies aimed at unveiling the pharmacological and toxicological properties of these substances are imperative, as they will provide increased expertise to the clinicians that face this problem on a daily basis. The present work provides a comprehensive review on history and legal status, chemistry, pharmacokinetics, pharmacodynamics, adverse effects and lethality in humans, as well as on the current knowledge of the neurotoxic mechanisms of synthetic cathinones.

Relationship between chewing tobacco, smoking, consuming alcohol and cognitive impairment among older adults in India: a cross-sectional study

BACKGROUND

Physical aging increases the sensitivity to the effects of substance use, elevating the risk for cognitive impairment among older adults. Since studies on the association of substance use with cognitive ability in later years are scant in India, we aimed to explore the factors associated with cognitive impairment especially, alcohol consumption, smoking, and chewing tobacco later in life.

METHODS

The present research used nationally representative data from Building a Knowledge Base on Population Aging in India (BKPAI) that was conducted in 2011, across seven states of India (N=9,453). Sample distribution along with percentage distribution was calculated for cognitive impairment over explanatory variables. For finding the association between cognitive impairment over explanatory variables, binary logistic regression models were estimated.

RESULTS

About 16.5 percent of older adults in rural areas consumed smoked tobacco compared to 11.7 percent in urban areas. Nearly, 23.7 percent of rural older adults consumed smokeless tobacco in comparison to 16 percent in urban areas. Alcohol consumption was high among rural residents (7.9%) than urban counterparts (6.7%). The prevalence of cognitive impairment was 62.8% and 58% among older adults from rural and urban areas respectively. Older adults who smoked tobacco had a 24 percent significantly higher likelihood to have cognitive impairment with reference to older adults who did not smoke [OR: 1.24, CI: 1.02-1.49]. Moreover, older adults who consumed alcohol had a 30 percent significantly higher likelihood to have cognitive impairment [OR: 1.02, 1.65]. It was also found that older adults who had smoked along with consuming alcohol were at risk of worse cognitive outcomes than those who neither smoke nor drink alcohol [OR: 1.56, CI: 1.21-2.00] or consumed either of them unlike consuming smokeless tobacco only.

CONCLUSION

The encouragement of older people to stop smoking and smokeless tobacco use could be considered as part of a strategy to reduce the incidence of cognitive impairment. Further, appropriate measures should be taken for the detection of early stages of cognitive decline in older individuals and efforts should be made to improve the availability and quality of care for dementing older adults.

Seven in every ten khat chewers in Gondar City had an intention to stop khat chewing: cross-sectional study using Transtheoretical Model

BACKGROUND

Khat chewing practice is rapidly expanding worldwide and currently, an estimated over 10 million people chew khat daily. The transtheoretical model explains how behavior change occurs across the stages of change. So, this study aimed at assessing the intention to stop khat chewing and associated factors among khat chewers in Gondar City, northwest Ethiopia.

METHODS

Community-based cross-sectional study was conducted from March to April 2019 in Gondar City, northwest Ethiopia. Six hundred five khat chewers participated in the study from six randomly selected kebeles. The data were collected using structured and interviewer-administered questionnaire. Bivariate and multiple logistic regression models were fitted. Adjusted Odds ratio (AOR) with 95% confidence interval (CI) and p-values less than 0.05 were used to declare a significant association.

RESULTS

Of the study participants, 69.3% (95% CI: 65.8-72.9) had the intention to stop khat chewing within 6 months or before. The majority of the participants (55.4%) were at the contemplation stage. Higher self-reevaluation [AOR = 2.8, (95%CI: 1.6-5.0)], environmental reevaluation [AOR = 1.9, (95%CI: 1.1-3.3)] and social liberation [AOR = 1.8, (95% CI: 1.0-3.1)] were associated with intention to quit khat chewing. In addition, using additional substances daily, khat dependency, and early age initiation of khat chewing were associated with lower intention to quit khat chewing.

CONCLUSION

The majority of the khat chewers had the intention to quit khat chewing. Increased self-reevaluation, environmental reevaluation, and social liberation process of changes were associated with enhanced intention of quitting khat chewing. Thus, stage-based interventions should be done to inspire khat chewers to realize their motivation of stopping khat chewing.

Catha edulis Forsk (khat) reduces spontaneous and rewarded alternation in female mice

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Khat is a widely used plant-based psychostimulant.

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Administration of khat leads to disruption of spatial working memory in mice.

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It promotes in mice perseverative behavior rather than alternation behavior.

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Khat treated mice also show right side position preference.

Around 10 million people chew the fresh leaves and twigs of Catha edulis Forsk (khat), which synthesize cathinone, for its psychostimulatory effect. Several studies have reported that regular khat users show executive and cognitive dysfunction, such as impaired inhibitory control and poor performance on memory tests. In this study, the effect of fresh khat extract (100 and 250 mg/kg) on spatial working memory and short-term memory in mice was assessed using spontaneous and rewarded alternation T-maze tests. In the spontaneous alternation test, mice treated with fresh khat extract decreased their spontaneous alternation level to around chance level, and it remained at this level over the 7 days of khat administration and testing. On testing after a 7-day khat free period, the previously khat treated mice showed alternation level above chance but below their pre-khat alternation level. In the rewarded alternation test, acute treatment with khat caused the mice to alternate well below chance level, and then over the next 3 days of khat treatment, the alternation level increased. After a 2 and 9-day khat-free period, the previously khat treated mice alternated above chance level but below their pre-khat level. In both these tests, the mice did not show any position preference before khat treatment; however, during the khat treatment, the mice showed a right side tendency. The results show that khat treatment causes persistent changes in alternation behavior and promotes perseverative behavior, presumably due to its effect on the neural circuits activity and the neurotransmitters and promotion of position preference.

Prevalence and Predictors of Neurocognitive Impairment in Ethiopian Population Living with HIV

BACKGROUND

Modern antiretroviral therapy has extended the life expectancies of people living with HIV; however, the prevention and treatment of their associated neurocognitive decline have remained a challenge. Consequently, it is desirable to investigate the prevalence and predictors of neurocognitive impairment to help in targeted screening and disease prevention.

MATERIALS AND METHODS

Two hundred and forty-four people living with HIV were interviewed in a study using a cross-sectional design and the International HIV Dementia Scale (IHDS). Additionally, the sociodemographic, clinical, and psychosocial characteristics of the patients were recorded. Chi-square and binary logistic regression analysis were used to determine the level of significance among the independent risk factors and probable neurocognitive impairment.

RESULTS

The point prevalence of neurocognitive impairment was found to be 39.3%. Participants' characteristics of being older than 40 years (AOR= 2.81 (95% CI; 1.11-7.15)), having a history of recreational drug use (AOR= 13.67 (95% CI; 6.42-29.13)), and being non-compliant with prescribed medications (AOR= 2.99 (95% CI; 1.01-8.87)) were independent risk factors for neurocognitive impairment.

CONCLUSION

The identification of predictors, in the Ethiopian people living with HIV, may help in the targeted screening of vulnerable groups during cART follow-up visits. This may greatly help in strategizing and implementation of the prevention program, more so, because (i) HIV-associated neurocognitive impairment is an asymptomatic condition for considerable durations, and (ii) clinical trials on neurocognitive impairment therapies have been unsuccessful.

Exploring the Molecular Mechanisms of 17β-HSD5-induced Carcinogenicity of Catha edulis via Molecular Modeling Approach

BACKGROUND

The tradition of khat chewing has been deep-rooted in the African and Arabian Peninsula for centuries. Due to its amphetamine-like psycho-stimulant or euphoric effect, khat has been used by millions in Somalia, Ethiopia, Saudi Arabia and Yemen. The long-term use of khat can induce many major health outcomes, which may be serious and irreversible.

OBJECTIVE

Prolonged use of khat constituents has been associated with different types of cancers such as prostatic, breast and ovarian cancer. However, it has been very difficult to identify the molecular targets involved in khat carcinogenesis that interact with the Khat constituents by in vitro/in vivo experimental tools.

METHODS

In silico tools were used to predict potential targets involved in the carcinogenesis of khat. Pass on-line prediction server was used for the prediction of a potential molecular target for khat constituents. Molecular Dynamics simulation and MM-GBSA calculation of the predicted target were carried out.

RESULTS

Molecular Dynamics simulation and MM-GBSA calculation revealed that among khat constituents, β-sitosterol showed a high binding affinity towards 17β-HSD5. On the other hand, this study highlights for the first time some new interactions, which were observed in the case of cathine, cathinone and nerol during the simulation.

CONCLUSION

In silico molecular dynamic simulation tools were used for the first time to investigate the molecular mechanism of widely used leaves of psychoactive khat (Catha edulis) constituent. The present study provides deep insight to understand the effect of khat constituents involved in the impairment of the reproductive system and its binding to 17β-HSD5. ADMET profiling also suggested that few khat constituents do not fulfill the requirements of the Lipinski rule of five i.e. poor absorption and blood-brain barrier impermeability.

Evaluation of Khat (Catha edulis) Use as a Risk Factor of Cancer: A Systematic Review

Background:

Conducting systematic review to evaluate plant use as a risk factor to cancer could be challenging. A systematic and well-balanced method should be applied to accommodate in vivo and in vitro studies to make a final decision. In this article, khat, a recreational plant used in some Arabic and African regions, was employed as an example to systematically determine its relationships to the premalignant and cancerous conditions.

Methods:

Systematic database search was performed to recruit original human, animal or in vitro studies on khat and cancer. Sixteen studies fulfilled the inclusion criteria and subjected to assessment using Risk of Bias (RoB). Office of Health and Translation (OHAT) approach was used to rate the confidence level in the body of evidence. The evidence was integrated to establish the relationships between khat, premalignant conditions and cancer.

Results:

Seven out of eight studies showed that khat causes premalignant oral lesions with moderate evidence level. Four studies showed that khat causes cancer with low evidence level and another three studies showed that khat has anti-cancer effect with moderate to high evidence level. Only one study suggested that khat is unrelated to cancer.

Conclusion:

RoB and OHAT approach are reliable systematic tools to evaluate plant risk to cancer and provide objective and uniform summary regardless of the study type. In conclusion, our pooled analysis did not find a direct relationship between khat and cancer but anti-cancer effect would require to be proofed on human studies.

Nonfatal Occupational Injuries among Workers in Microscale and Small-Scale Woodworking Enterprise in Addis Ababa, Ethiopia

Background

Microscale and small-scale industries have been widely expanded in low-income countries, including Ethiopia, as a job opportunity for young workers, which makes workers vulnerable to injury. Woodworking is one of the high-risk jobs in this sector due to the use of hazardous tools and machineries. Therefore, the aim of this study was to estimate the prevalence of injury and associated contributing factors of this sector.

Methods

A cross-sectional study design was conducted among 634 workers selected from 194 microscale and small-scale woodworking enterprises in Addis Ababa. Data were collected using a structured interview questionnaire and observation checklist from February to March 2016. Occupational injuries were documented according to the ILO operational definition. Descriptive statistics and multivariable analyses were used to characterize the data and to identify the factors associated with injury at a p value <0.05, respectively.

Result

A total of 625 (98.6%) workers were interviewed. The prevalence of occupational injury was 92 (14.7%) in the past 12 months. Workers with khat chewing behavior (AOR: 2.25, 95% CI (1.04, 4.85)), job dissatisfaction (AOR: 2.89, 95% CI (1.75, 4.76)), work-related stress (AOR: 4.79, 95% CI (1.69–13.58)), job categories (AOR: 3.52, 95% CI (1.08, 11.41)) and workplace characteristics such as unguarded machines (AOR: 3.32 (1.21, 9.11)), and inadequate work space (AOR: 3.85 (1.14, 13.04)) were significantly associated with occupational injury.

Conclusion

The prevalence of nonfatal occupational injuries among workers in this study was substantially high. Workers' behavior, psychosocial issues, and work-related characteristics played a causal role in the occurrence of occupational injury. Therefore, workers' safety protection and behavioral intervention should be initiated.

A Systematic Review of Treatments for Problematic Khat Use

Khat, a psychostimulant cultivated and commonly used in Eastern Africa and the Arabian penin-sula, has a longstanding history of use embedded within the cultures of these regions. Due to changing patterns of use and the adverse effects of dependence, khat has become a growing pub- lic health concern. Despite extensive findings regarding the detrimental psychiatric, physical, and social consequences of khat dependence, research on interventions in this area is glaringly sparse. The present paper aims to summarize the consequences of chronic khat use and review existing research on interventions.

Knowledge and Attitudes on Khat Use among Yemeni Health Sciences Students

Background: Khat chewing has a negative impact on an individual's life. Objectives: The study was execute to assess health sciences students' knowledge and attitudes regarding khat use in Yemen. Methods: This survey involved health sciences students from Aden University. Approximately 500 participants were selected through convenience sampling. The data were collected using a structured and validated self-administered questionnaire. The data were tabulated and descriptively analyzed. Results: The total number of respondents was 500. Almost half of the students reported that they chewed khat (n = 239, 48%). Approximately 66% (n = 330) of the students spent 2000 Yemeni riyals or less (USD1 = YER249.9) per day on khat. The main reasons for chewing khat were 'it is a social habit' (n = 155, 31%), followed by 'it improves my concentration when studying or working' (n = 140, 28%). Students knew that the effects of khat are similar to those of amphetamines (n = 210, 42.0%) and that khat is addictive (n = 254, 50.8%). Additionally, they knew that cathinone is the dependence-producing constituent of khat leaves (n = 269, 53.8%). The students agreed with the following statements: 'I will advise people to cease khat use'; 'Khat chewing is harmful to health'; 'Children and adolescents should not chew khat'; 'Khat chewing helps people stay awake'; and 'Health professionals serve as role models for patients and the public'. Conclusions: Khat chewing is prevalent among Yemeni university health sciences students. Only about half of the students recognized health risks associated with khat use. Also, among those who used khat, students endorsed positive benefits such as improved concentration.

Synthetic cathinones: an evolving class of new psychoactive substances

Synthetic cathinones (SCat) are amphetamine-like psychostimulants that emerged onto drug markets as "legal" alternatives to illicit drugs such as ecstasy, cocaine, and amphetamines. Usually they are sold as "bath salts," "plant food," or "research chemicals," and rapidly gained popularity amongst drugs users due to their potency, low cost, and availability. In addition, internet drug sales have been replacing the old way of supplying drugs of abuse, contributing to their rapid spread. Despite the legislative efforts to control SCat, new derivatives continue to emerge on the recreational drugs market and their abuse still represents a serious public health issue. To date, about 150 SCat have been identified on the clandestine drugs market, which are one of the largest groups of new psychoactive substances (NPS) monitored by the United Nations Office on Drugs and Crime and the European Monitoring Center for Drugs and Drug Addiction. Similar to the classical stimulants, SCat affect the levels of catecholamines in the central nervous system, which results in their psychological, behavioral and toxic effects. Generally, the effects of SCat greatly differ from drug to drug and relatively little information is available about their pharmacology. The present work provides a review on the development of SCat as substances of abuse, current patterns of abuse and their legal status, chemical classification, known mechanisms of action, and their toxicological effects.

Toxic effect of khat (Catha edulis) on memory: Systematic review and meta-analysis

BACKGROUND

People use khat (Catha edulis) for its pleasant stimulant effect of physical activity, consciousness, motor, and mental functions. Although there are reports assessing the effect of khat on memory, there was no study based on formal systematic review and meta-analysis.

OBJECTIVE

We have therefore conducted this meta-analysis to determine the level of evidence for the effect of khat (C. edulis Forsk) on memory discrepancy.

METHODS

MEDLINE, Cochrane Library, PubMed, Academic Search Complete, SPORTDiscus, ScienceDirect, Scopus, Web of Science, and Google Scholar were searched to retrieve the papers for this review. Keywords utilized across database search were khat, cat, chat, long-term memory, short-term memory, memory deficit, randomized control trial, and cross-sectional survey. The search was limited to studies in humans and rodents; published in English language.

RESULT

Finding of various studies included in our meta-analysis showed that the effect of acute, and subchronic exposure to khat showed that short-term memory appears to be affected depending on the duration of exposure. However, does not have any effect on long-term memory.

CONCLUSION

Although a number of studies regarding the current topic are limited, the evidenced showed that khat (C. edulis) induced memory discrepancy.

Prevalence of Cognitive Impairment and Its Predictors among HIV/AIDS Patients on Antiretroviral Therapy in Jimma University Medical Center, Southwest Ethiopia

Background

Cognitive impairment among human immunodeficiency virus (HIV) infected patients can lead to treatment nonadherence, faster progression of the illness, disability, and bed ridden state if we fail to detect it early. However, there is scarcity of previous published studies in Ethiopia on the assessment of cognitive impairment among HIV-positive patients. Hence, this study aimed to determine the prevalence and associated factors of cognitive impairment among HIV-positive patients receiving antiretroviral therapy (ART) at Jimma University Medical Center, Ethiopia.

Methods

Hospital-based cross-sectional study was conducted among 328 HIV-positive patients attending Jimma University Medical Center, Ethiopia. Data were collected from a face-to-face interview and review of medical records using semistructured questionnaire. Validated International HIV Dementia Scale (IHDS) was used to screen for cognitive impairment. Data was analyzed using SPSS version 20.

Results

A total of 328 (191 females and 137 males) HIV-positive patients were included in the study with a response rate of 97.04%. The prevalence of cognitive impairment among HIV-positive patients was 35.7%. Factors significantly associated with cognitive impairment were age group of 41-64 years (adjusted odds ratio [AOR] = 3.1, 95% confidence interval [CI] (1.3, 7.4)], plasma HIV-1 RNA load between 1.7log10 and 3log10 copies/ml [AOR = 2.2, 95% CI (1.1,4.3)] and ≥ 3log10 copies/ml [AOR = 7.5, 95% CI (2.6, 21.5)], khat chewing [AOR = 4.4, 95% CI (2.3, 8.3)], and clinical stage III of the disease [AOR = 5.6, 95% CI (1.7, 19.2)].

Conclusion

Despite the use of ART, the burden of cognitive impairment among HIV patients was high. Older age, khat chewing, advanced stage of the disease, and higher viral load were the independent factors associated with cognitive impairment. Thus, continuous screening of cognitive impairment, identification of the possible risk factors, and proper management strategy should be designed.

Cognitive deficits and neurotoxicity induced by synthetic cathinones: is there a role for neuroinflammation?

RATIONALE

The number of synthetic derivatives of cathinone, the primary psychoactive alkaloid found in Catha edulis (khat), has risen exponentially in the past decade. Synthetic cathinones (frequently referred to as "bath salts") produce adverse cognitive and behavioral sequelae, share similar pharmacological mechanisms of action with traditional psychostimulants, and may therefore trigger similar cellular events that give rise to neuroinflammation and neurotoxicity.

OBJECTIVES

In this review, we provide a brief overview of synthetic cathinones, followed by a summary of cognitive deficits in animals and humans that have been documented following acute or repeated exposure. We also summarize growing evidence from in vitro and in vivo studies for synthetic cathinone-induced neurotoxicity, and provide a working hypothetic model of potential cellular mechanisms.

RESULTS

Synthetic cathinones produce varying effects on markers of monoaminergic terminal function and can increase the formation of reactive oxygen and nitrogen species, induce apoptotic signaling, and cause neurodegeneration and cytotoxicity. We hypothesize that these effects result from biochemical events similar to those induced by traditional psychostimulants. However, empirical evidence for the ability of synthetic cathinones to induce neuroinflammatory processes is currently lacking.

CONCLUSIONS

Like their traditional psychostimulant counterparts, synthetic cathinones appear to induce neurocognitive dysfunction and cytotoxicity, which are dependent on drug type, dose, frequency, and time following exposure. However, additional studies on synthetic cathinone-induced neuroinflammation are clearly needed, as are investigations into the neurochemical and neuroimmune mechanisms underlying their neurotoxic effects. Such endeavors may lead to novel therapeutic avenues to promote recovery in habitual synthetic cathinone users.

DARK Classics in Chemical Neuroscience: α-Pyrrolidinovalerophenone ("Flakka")

Flakka (alpha-pyrrolidinovalerophenone, α-PVP) is a new psychoactive substance, chemically close to cathinone, the primary psychoactive alkaloid of khat ( Catha edulis). Like other synthetic cathinones, α-PVP is a potent inhibitor of the dopamine and norepinephrine transporters. Its robust clinical effects include hallucinations, arousal, aggression/violence, and euphoria. In animal models, α-PVP evokes hyperlocomotion and aberrant/stereotypic behaviors. Here, we discuss the history, synthesis, pharmacological mechanisms, metabolism, abuse potential, and societal impact of α-PVP. Today, α-PVP is a tightly controlled substance, currently banned in the United States and other countries worldwide. However, the growing abuse and complex central nervous system (CNS) effects of α-PVP remain poorly understood, necessitating further pharmacological and pharmacogenetic studies of this drug. Its interesting pharmacological profile (co-inhibition of dopamine and norepinephrine, but not serotonin, transporters) also calls for further studies of α-PVP in animal models, to dissect serotonergic from other monoaminergic mechanisms of action of drugs of abuse. Finally, screening α-PVP and related compounds in vivo may foster discovery of new CNS drugs, including developing novel CNS drugs and identifying their molecular targets.

Pesticide Application and Khat Chewing as Predictors of the Neurological Health Outcomes among Pesticide Applicators in a Vector Control Unit, Saudi Arabia

Background:

Pesticide applicators are at risk of developing neurological symptoms and neurobehavioral deficits. This risk may increase if the applicator chews stimulant plants like khat.

Objective:

To examine the sociodemographic and exposure determinants of neurological symptoms presentation, neurobehavioral performance, and cholinesterase activity among pesticide applicators in a vector control unit, Saudi Arabia.

Methods:

In a cross-sectional study, 30 pesticide applicators and 32 non-applicators from a vector control unit in Jazan region, Saudi Arabia, were studied. The study participants completed an exposure and medical questionnaire, and a neurobehavioral test battery. Their blood samples were also tested for the measurement of butyryl cholinesterase (BChE).

Results:

The mean blood BChE level was no significantly different between the applicators and non-applicators. Working in pesticide application and chewing khat were significant predictors of the neurological symptoms presentation and neurobehavioral deficits among the study participants. Each factor was associated with about 40% of the symptoms included in the questionnaire. Exposure to pyrethroids was significantly associated with a decrement in symbol digit test latency, tapping (TAP) non-preferred hand, and TAP alternating hands measures, representing the executive and motor speed/coordination functions. Khat chewing was associated with TAP preferred and non-preferred hands and serial digit learning measures, representing the memory and motor speed/coordination functions.

Conclusion:

It seems that being exposed to pyrethroids and chewing khat are associated with neurological and neurobehavioral drawbacks among pesticide applicators.

Effects of Khat (Catha edulis) use on catalytic activities of major drug-metabolizing cytochrome P450 enzymes and implication of pharmacogenetic variations

In a one-way cross-over study, we investigated the effect of Khat, a natural amphetamine-like psychostimulant plant, on catalytic activities of five major drug-metabolizing cytochrome P450 (CYP) enzymes. After a one-week Khat abstinence, 63 Ethiopian male volunteers were phenotyped using cocktail probe drugs (caffeine, losartan, dextromethorphan, omeprazole). Phenotyping was repeated after a one-week daily use of 400 g fresh Khat leaves. Genotyping for CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A5 were done. Urinary cathinone and phenylpropanolamine, and plasma probe drugs and metabolites concentrations were quantified using LC-MS/MS. Effect of Khat on enzyme activities was evaluated by comparing caffeine/paraxanthine (CYP1A2), losartan/losartan carboxylic acid (CYP2C9), omeprazole/5-hydroxyomeprazole (CYP2C19), dextromethorphan/dextrorphan (CYP2D6) and dextromethorphan/3-methoxymorphinan (CYP3A4) metabolic ratios (MR) before and after Khat use. Wilcoxon-matched-pair-test indicated a significant increase in median CYP2D6 MR (41%, p < 0.0001), and a marginal increase in CYP3A4 and CYP2C19 MR by Khat. Repeated measure ANOVA indicated the impact of CYP1A2 and CYP2C19 genotype on Khat-CYP enzyme interactions. The median MR increased by 35% in CYP1A2*1/*1 (p = 0.07) and by 40% in carriers of defective CYP2C19 alleles (p = 0.03). Urinary log cathinone/phenylpropanolamine ratios significantly correlated with CYP2D6 genotype (p = 0.004) and CYP2D6 MR (P = 0.025). Khat significantly inhibits CYP2D6, marginally inhibits CYP3A4, and genotype-dependently inhibit CYP2C19 and CYP1A2 enzyme activities.

Prevalence and predictors of khat chewing among Ethiopian university students: A systematic review and meta-analysis

Background

Khat chewing has become a common practice among university students in developing countries like Ethiopia. It has a potential effect on physical, mental, social and cognitive aspects of student functioning. In Ethiopia, study findings regarding the prevalence of khat chewing were highly dispersed and inconsistent. Therefore, this systematic review and meta-analysis estimates the pooled prevalence of khat chewing and its predictors among Ethiopian university students.

Method

A systematic review and meta-analysis was conducted to assess the prevalence and predictors of khat chewing among university students in Ethiopia. We searched literature from the databases of PubMed, Google Scholar, Science Direct, and the Cochrane Library. A total of 24 Ethiopian studies reporting the prevalence of khat chewing among university students were included. Data were extracted using a standardized data extraction format prepared in Microsoft Excel and the analysis was done using STATA 14 statistical software. To assess heterogeneity, the Cochrane Q test statistics and I² test were used. Since the included studies exhibit high heterogeneity, a random effect meta-analysis model was computed to estimate the pooled prevalence of khat chewing. Moreover, the association between predictor variables, and khat chewing practice were examined.

Results

The meta-analysis of 24 studies revealed that the pooled prevalence of khat chewing among university students in Ethiopia was 23.22% (95% CI: 19.5, 27.0). In the subgroup analysis, the highest prevalence was observed in Oromia region (31.6%; 95CI: 21.2, 41.9) whereas the lowest prevalence was observed in Amhara region (18.1%; 95%CI: 12.4, 23.8). Being male OR: 2.76 (95% CI 1.64, 4.63), family khat chewing practice OR: 2.91 (95% CI 1.06, 7.98), friend khat chewing habit OR: 4.74 (95% CI 3.48, 13.06), alcohol drinking OR: 7.06 (95% CI 5.65, 8.82) and cigarette smoking habit OR: 15.11 (95% CI 8.96, 25.51) were found to be predictors of khat chewing.

Conclusion

The study found that the prevalence of khat chewing among university students was quite common, with slightly more than 1 in 5 students engaging in the use of this substance. Being male, family khat chewing practice, friend’s khat chewing habit, alcohol drinking, and cigarette smoking were found to be predictors of khat chewing practice among university students.

Frequent Use of Khat, an Amphetamine-Like Substance, as a Risk Factor for Poor Adherence and Lost to Follow-Up Among Patients New to HIV Care in Ethiopia

Khat, a plant native to East Africa, has amphetamine-like psychoactive constituents, and is a potential risk factor for HIV infection. Chronic use can cause cognitive impairment and other mental disorders, raising concerns about effects on retention and adherence with HIV care. During 2013-2014, 322 Ethiopian patients newly enrolled at HIV clinics in Dire Dawa and Harar were surveyed about khat use and prospectively followed for 1 year; 9% died, 18% transferred care to other clinics, and 22% were lost to follow-up (LTFU) (no clinic visit for >3 months). Of 248 patients who received a 12-month follow-up survey, 37% used khat in the year after enrollment, with a median use of 60 h in a typical month. Those using khat ≥60 h/month (median among users) were more likely than others to be LTFU (31% vs. 16%, p = .014); those using khat ≥150 h/month (upper quartile) had 44% LTFU rates versus 16% for others (p = .002). Complete 3-day adherence (taking all doses) of antiretroviral therapy was reported by 77% of those using khat ≥60 h/month versus 95% of all others (p < .001), and 67% of those using khat ≥150 h/month versus 94% of others (p < .001). In two East African cities, where khat use is common, frequent use was a significant risk factor for higher 1-year LTFU and lower self-reported antiretroviral therapy adherence among people living with HIV entering HIV care. Where khat is widely utilized, interventions to promote either nonuse or reduced use are important as part of a comprehensive HIV care package and national HIV strategies.

Prevalence of khat chewing and its effect on academic performance in Sidama zone, Southern Ethiopia

BACKGROUND

Khat use is a well-established public health problem in Yemen, Arabian Peninsula, and Ethiopia. Along with its large scale production, the magnitude of khat use is increasing among students.

OBJECTIVE

This study was intended to assess the prevalence, determinants, and effect of khat use on academic performance of high school students in Sidama Ethiopia.

METHODOLOGY

A cross-sectional study was conducted from April to June 2015. We used a stratified sampling technique to draw a total of 1,577 students. The data was collected using self-administered questionnaires and analyzed using SPSS version 20. Descriptive statistics and logistic regression models were used to determine the prevalence, effects, and predictors of khat use.

RESULT

The life time and current prevalence of khat use were 14.6% and 13%, respectively. Smoking cigarette (AOR=5.1, 95% C.I: 2.3-14.3), drinking alcohol (AOR=3.0, 95% C.I: 1.4-6.3), having a family growing khat (AOR=2.0, 95% C.I: 1.1-2.5), having friend chewing khat (AOR=3. 95% C.I: 2.0-4.6), were some of factors that increased the odds of students' khat use. Student's khat use increased the odds of student's poor academic performance (AOR=2.1, 95% C.I: 1.1-3.9).

CONCLUSION

The prevalence of khat use in high khat producing districts of Sidama and its contribution to poor academic performance demand prompt intervention.

Prevalence and factors associated with use of khat: a survey of patients entering HIV treatment programs in Ethiopia

Background

Khat, a plant native to East Africa, has psychoactive constituents similar to amphetamine. Chronic khat use can lead to psychological dependence with multiple physical and mental health harms, complicating clinical management of people living with HIV. In two Ethiopian cities where khat is common, we evaluated prevalence and correlates of khat use among patients new to HIV care.

Methods

During 2013–2014, we surveyed 322 patients recently enrolled in HIV clinics in Dire Dawa and Harar about khat use, demographics, smoking and alcohol use, clinical illness, food insecurity, and social support. We analyzed factors associated with khat use in the past year, as well as heaviest use of khat (based on greatest number of hours used in a typical month).

Results

242 (75%) respondents reported lifetime khat use; 209 (65%) reported khat use during the previous year. 54% of khat users started before age 19 years. Although 84% believed that using khat every day is dangerous for health if you have HIV, khat was used in the previous year a median of 5 h/days and 30 days/month; 21% said they felt a need to cut down or control their khat use but had difficulty doing so. Those using khat were more likely to report smoking (46%) and alcohol use (49%) compared to non-khat users (1 and 31% respectively). Those reporting heaviest khat use (≥180 h/typical month) were more likely to rate their health status as poor, have an underweight BMI (≤18.5 kg/m²), report more symptoms of chronic illness, and agree with more statements indicating a negative physical quality of life. In multivariate analysis, heavy users were more likely to be male, Muslim, and non-married.

Conclusions

Khat use was common among HIV patients entering care, and associated with symptoms of poorer physical health. Over half started khat use when they were young. Although most believed khat is harmful for HIV patients, a number of respondents reported some difficulty controlling their drug use. In settings where khat is legal and widely utilized, developing interventions for responsible use represent an important health priority as part of comprehensive care for people living with HIV.

Sleep disturbances and memory impairment among pregnant women consuming khat: An under-recognized problem

Khat (Catha edulis) is a evergreen flowering shrub that is cultivated at high altitudes, especially in East Africa and the southwest of the Arabian Peninsula. The plant contains alkaloids, of which cathinone and cathine have structural similarity and pharmacological action similar to amphetamines. The leaves are, therefore, consumed in some regions as a psychoactive stimulant due to cultural beliefs and misperceptions on the health benefits of khat consumption. This resulted in a growing prevalence of khat consumption among pregnant women. The myriad of physiological changes associated with pregnancy impairs sleep and memory. Moreover, khat has also been shown to have adverse effects on memory and sleep. Therefore, its use during pregnancy may further aggravate those impairments. The purpose of this mini-review is to summarize the changes in sleep and memory during pregnancy and the evidence supporting a relationship between khat consumption and neurocognitive deficits and sleep dysfunctions. The misperceptions of beneficial effects of khat, the high prevalence of consumption among pregnant women, and the possibility of under-reporting of khat abuse do necessitate the development of alternative methodologies to identify cases of unreported khat abuse in pregnant women. It is proposed that screening for sleep problems and memory deficits may help identify under-reported cases of khat abuse in pregnant women.

Identification of novel psychoactive substances 25B-NBOMe and 4-CMC in biological material using HPLC-Q-TOF-MS and their quantification in blood using UPLC-MS/MS in case of severe intoxications

This paper describes cases of poisoning caused by new psychoactive substances such as: 25B-NBOMe (2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine) and 4-CMC (1-(4-chlorophenyl)-2-(methylamino)-1-propanone). The analytical procedure includes rapid and selective method for the extraction and determination of 4-CMC and 25B-NBOMe in blood samples using UPLC-MS/MS technique. To the best of our knowledge, this is the first report, that involves a fully validated method for quantification of new-designer drug - 4-CMC in postmortem blood samples. The biological material was also analyzed with the use of routine analytical methods: immunochemical techniques, gas chromatography with flame ionization detection and gas chromatography with electron impact mass spectrometry. The results of real samples analyses correspond to possible toxicological effects: death resulting from 25B-NBOMe - mediated hallucinations (661ng/mL of 25B-NBOMe and 0.887ng/mL of 4-CMC), fatal overdose of 25B-NBOMe and 4-CMC (66.5ng/mL of 25B-NBOMe and 2.14ng/mL of 4-CMC) and non-fatal intoxication of these drugs (38.4ng/mL of 25B NBOMe and 0.181ng/mL of 4-CMC). Additionally, O-demethylathed O, O-bis-demethylathed and glucuronidated metabolites of 25B-NBOMe in biological specimens were detected.

Memory deficits associated with khat (Catha edulis) use in rodents

Khat products and chewing practices are common in East Africa, Middle East for centuries with concomitant socio-economic and public health repercussions. We assessed memory deficits associated with khat use in rodents. Young male CBA mice, 5-7 weeks old (n = 20), weighing 25-35 g were used. Mice were treated with either 40, 120 or 360 mg/kg body weight (bw) methanolic khat extract, or 0.5 ml saline for 10 days. Spatial acquisition, reversal and reference memory were assessed using modified Morris Water maze (MMWM). Mice treated with 40 mg/kg khat extract had longer (t4 = 4.12 p = 0.015) and t4 = 2.28 p = 0.065) escape latency on first and second day during reversal relative to the baseline. Under 120 mg/kg khat dose, the escape latency was shorter (t4 = -2.49 p = 0.05) vs (t3 = -2.5 p = 0.05) on third and fourth day. Further, treatment with 360 mg/kg khat extract resulted in significantly longer time (49.13, 33.5, 40.2 and 35.75) vs. (23.5 s), compared to baseline. Mice treated with khat or control preferred the target quadrant post acquisition while differential pattern was seen during reversal phase. Mice treated with 40 or 120 mg/kg khat showed significant preference for target quadrant. Substantial time (19.9) was spent in the old target compared to the new (16.9 s) by animals treated with highest dose however, the difference was not significant. There is a biological plausibility that chronic khat use may induce memory deficits and impair cognitive flexibility. The differential patterns of memory deficits may reflect the differences in dose effect as well as time dependent impairment.

Action Video Gaming and Cognitive Control: Playing First Person Shooter Games Is Associated with Improved Action Cascading but Not Inhibition

There is a constantly growing interest in developing efficient methods to enhance cognitive functioning and/or to ameliorate cognitive deficits. One particular line of research focuses on the possibly cognitive enhancing effects that action video game (AVG) playing may have on game players. Interestingly, AVGs, especially first person shooter games, require gamers to develop different action control strategies to rapidly react to fast moving visual and auditory stimuli, and to flexibly adapt their behaviour to the ever-changing context. This study investigated whether and to what extent experience with such videogames is associated with enhanced performance on cognitive control tasks that require similar abilities. Experienced action videogame-players (AVGPs) and individuals with little to no videogame experience (NVGPs) performed a stop-change paradigm that provides a relatively well-established diagnostic measure of action cascading and response inhibition. Replicating previous findings, AVGPs showed higher efficiency in response execution, but not improved response inhibition (i.e. inhibitory control), as compared to NVGPs. More importantly, compared to NVGPs, AVGPs showed enhanced action cascading processes when an interruption (stop) and a change towards an alternative response were required simultaneously, as well as when such a change had to occur after the completion of the stop process. Our findings suggest that playing AVGs is associated with enhanced action cascading and multi-component behaviour without affecting inhibitory control.

More attentional focusing through binaural beats: evidence from the global-local task

A recent study showed that binaural beats have an impact on the efficiency of allocating attention over time. We were interested to see whether this impact affects attentional focusing or, even further, the top-down control over irrelevant information. Healthy adults listened to gamma-frequency (40 Hz) binaural beats, which are assumed to increase attentional concentration, or a constant tone of 340 Hz (control condition) for 3 min before and during a global–local task. While the size of the congruency effect (indicating the failure to suppress task-irrelevant information) was unaffected by the binaural beats, the global-precedence effect (reflecting attentional focusing) was considerably smaller after gamma-frequency binaural beats than after the control condition. Our findings suggest that high-frequency binaural beats bias the individual attentional processing style towards a reduced spotlight of attention.

Neuropsychological functioning among chronic khat users in Jazan region, Saudi Arabia

BACKGROUND

Khat chewing effects in the central nervous system are attributed to cathinone and cathine, which are structurally related to amphetamine. However, studies on neuropsychological problems arising from khat use in humans are not extensive and have only included observational and single-case studies. The aims of this study were to (1) to examine neuropsychological functions among khat chewers, and (2) to determine factors affecting neuropsychological outcomes among khat chewers.

METHODS

A sample of 70 adult male khat chewers and a control group of 72 nonchewers were recruited from the Jazan region in southwest Saudi Arabia. A questionnaire examining socioeconomic background, medical and occupational history, education, and khat chewing behaviors was administered. Neuropsychological performance was assessed using computerized tests from the Behavioral Assessment and Research System (BARS) that assessed learning, episodic and working memory, motor speed/coordination, attention/information processing speed, sustained attention, set-shifting/response inhibition, and perceptual functions; noncomputerized tests, Trail Making A and B, Block Design, and Benton Visual Retention tests were also administered.

RESULTS

Khat chewers performed significantly worse on 3 out of 14 neuropsychological subtests compared with the control group, representing learning, motor speed/coordination, and set-shifting/response inhibition functions. Age and educational level were identified as predictors of neuropsychological outcomes of khat chewers.

CONCLUSIONS

The chronic chewing of khat leaves is associated with deficits in some neuropsychological functions, which may affect the mental and neurological health of communities in which khat chewing is a common habit.

Increasing the role of belief information in moral judgments by stimulating the right temporoparietal junction

Morality plays a vital role in our social life. A vast body of research has suggested that moral judgments rely on cognitive processes mediated by the right temporoparietal junction (rTPJ), an area thought to be involved in belief attribution. Here we assessed the role of the rTPJ in moral judgments directly by means of transcranial direct current stimulation (tDCS)--a non-invasive brain stimulation technique that, by applying a weak current to the scalp, allows modulating cortical excitability of the area being stimulated. Participants were randomly and equally assigned to receive anodal stimulation (to increase cortical excitability), cathodal stimulation (to decrease cortical excitability), or sham (placebo) stimulation over the rTPJ before completing a moral judgment task. Participants read stories in which protagonists produced either a negative or a neutral outcome based on either a negative or a neutral belief that they were causing harm or no harm, respectively. Results revealed a selective group difference when judging the moral permissibility of accidental harms (belief neutral, outcome negative), but not intentional harms (belief negative, outcome negative), attempted harms (belief negative, outcome neutral), or neutral acts (belief neutral, outcome neutral). Specifically, participants who received anodal stimulation assigned less blame to accidental harms compared to participants who received cathodal or sham stimulation. These results are consistent with previous findings showing that the degree of rTPJ activation reflects reliance on the agent's innocent intention. Crucially, our findings provide direct evidence supporting the critical role of the rTPJ in mediating belief attribution for moral judgment.

γ-Aminobutyric acid (GABA) administration improves action selection processes: a randomised controlled trial

In order to accomplish a task goal, real-life environments require us to develop different action control strategies in order to rapidly react to fast-moving visual and auditory stimuli. When engaging in complex scenarios, it is essential to prioritise and cascade different actions. Recent studies have pointed to an important role of the gamma-aminobutyric acid (GABA)-ergic system in the neuromodulation of action cascading. In this study we assessed the specific causal role of the GABA-ergic system in modulating the efficiency of action cascading by administering 800 mg of synthetic GABA or 800 mg oral of microcrystalline cellulose (placebo). In a double-blind, randomised, between-group design, 30 healthy adults performed a stop-change paradigm. Results showed that the administration of GABA, compared to placebo, increased action selection when an interruption (stop) and a change towards an alternative response were required simultaneously, and when such a change had to occur after the completion of the stop process. These findings, involving the systemic administration of synthetic GABA, provide the first evidence for a possible causal role of the GABA-ergic system in modulating performance in action cascading.

Before the ban--an exploratory study of a local khat market in East London, U.K

BACKGROUND

Khat is a green leaf with amphetamine-like effects. It is primarily used among people in Africa, the Middle East and in the diaspora communities from these countries. Prior to the prohibition of khat in the UK on 24 June 2014, there was almost no information available on key aspects of the local khat market.

METHODS

A cross-sectional study was conducted in 2012 using snowball sampling, Privileged Access Interviewing and area mapping in order to identify khat sale establishments. Data was collected via face-to-face interviews using mixed methods for data collection. This included information about the establishments selling khat, khat pricing and its use among different ethnic minority groups, in addition to the potential sale of khat to children and risk assessment (e.g., use of pesticides on khat).

RESULTS

Five out of seven sellers identified agreed to participate. Sellers described their khat sale establishments as 'community centres' which included, for example, a restaurant basement. The sellers' history of selling khat ranged between 1-15 years and khat's sale took place between 2pm-10pm. Miraa (e.g., Lara) from Kenya was the most popularly used khat variety, sold in pre-wrapped bundles of approximately 250 g costing £3 each and delivered four days a week. Harari (e.g., Owdi) from Ethiopia was sold in 200 g, 400 g and 1 kg bundles, priced between £5 and £20 and delivered two days a week. The primary benefit of khat use was reported to be social interaction. The customers were predominantly adult males of Somali origin. Most sellers claimed a self-imposed ban on sales to children under 18 years old. Khat bundles had no labelling describing variety or weight and sellers had no knowledge of the use of pesticides on khat and did not advertise the risks associated with khat use.

CONCLUSIONS

Khat selling establishments were businesses that did not adhere to trade standards regulations (e.g., labelling khat bundles). They claimed to provide a community service (facilitating social interaction) to their predominately Somali customers. Without a better understanding of the dynamics of the khat market there is a risk that both health and social needs of the vulnerable populations involved in the market continue to go unaddressed. Future research should track changes in the now illicit khat market in order to evaluate the social and public health implications following the recent changes to the current U.K. regulatory environment regarding khat.

Khat Use: What Is the Problem and What Can Be Done?

The chewing of khat leaves is an established tradition in East Africa but is much less prevalent in other areas of the world and is mostly limited to Somali communities. However, our understanding of what constitutes problematic khat use in the Somali community in Victoria, Australia, is limited. The objectives of this study were to better understand the views of Somali community representatives and primary care practitioners regarding problematic khat use, to consider relevant harm minimisation strategies, and to develop resources to assist individuals with problematic khat use and their families. Qualitative research methods were used to investigate the experiences and perceptions of khat use among Somalis and mainstream primary care practitioners. Six focus groups were conducted with 37 members of the Somali community and 11 primary care practitioners. Thematic analysis was used to analyse transcripts. Various indicators of the problematic use of khat were identified, including adverse physical and mental health effects, social isolation, family breakdown, and neglect of social responsibilities. Potential harm minimisation strategies were identified including the adoption of health promotion through education, outreach to the community, and the use of universal harm minimisation strategies specifically tailored to khat use.

"Natural Amphetamine" Khat: A Cultural Tradition or a Drug of Abuse?

Khat, Catha edulis Forsk, is among the most widely used plant-based psychoactive substance in the world. Grown in Eastern Africa, Horn of Africa, and southwestern part of the Arabian Peninsula, its fresh young leaves and twigs are used daily by over 20 million people for the psychostimulatory effects it produces in the user, a practice deeply rooted in the history, tradition, and culture of the indigenous population. Once hardly known outside the regions where it is grown and used, khat use has now spread to other countries. This review will cover the, phytochemistry, pharmacokinetics of the active ingredients-cathinone, cathine, norephedrine, neurochemistry, effects on cognitive and executive functions as well as its ability to produce dependency in the user. Whether it is an innocuous cultural practice or a drug of abuse is debatable as the preclinical and clinical data needed to arrive at an authoritative conclusion is lacking.

Khat chewing among Ethiopian University Students--a growing concern

Background

Khat has amphetamine like effect. Students chew khat to stay alert. It has various negative physical, mental, social and cognitive effects. Poor academic performance has been associated with khat. The purpose of this study was to determine the prevalence and identify factors associated with khat chewing among Ethiopian University students.

Methods

A cross sectional study was conducted on Bahir Dar University Students. A self-administered questionnaire was completed by 3268 students. Proportion was calculated to estimate prevalence of khat chewing. Logistic regression was used to identify factors associated with khat chewing.

Results

Lifetime prevalence of khat chewing was 24% (95% Confidence Interval: 22.5%, 26.6%). Half of these are current khat users with a prevalence of 12.7% (95% Confidence Interval: 11.5%, 13.9%). Male students Adjusted Odds Ratio (AOR) = 3.3 (95% Confidence Interval: 1.8, 6.0), students living in off campus housing AOR = 3.0 (95% Confidence Interval: 1.5, 6.0), students who have khat user friends AOR = 4.2 (95% Confidence Interval: 2.6, 6.9), and students who perceive khat use improves academic performance AOR = 6.6 (95% Confidence Interval: 4.6, 9.5) are more likely to use khat.

Conclusions

Prevalence of current use of khat reported in this study is higher than recent study done on university students in Ethiopia and heavily influenced with peer practice.

Prevalence and predictors of harmful khat use among university students in ethiopia

Comprehensive assessment of harmful khat use is lacking because often researchers rely on a simple tool for studying it. The aim of this study was to determine the prevalence and predictors of harmful khat use among Ethiopian university students by developing a comprehensive scale based on Alcohol Use Identification Test, Severity of Dependency Syndrome scale, and International Classification of Diseases definition of harmful substance use. Logistic regression was performed to identify predictors of harmful khat use. One in five current khat user students were identified as harmful khat users [20.6% (95% CI: 14.3-22.3)]. Harmful khat use in this study was strongly associated with chewing at commercial places [adjusted odds ratio (AOR) = 2.32 (95% CI: 1.01-5.33)], and having non-student friends accompanying the khat-chewing ceremony [AOR = 3.77 (95% CI: 1.09-13.03). Students who started chewing khat at the age of 20 years or later [AOR = 0.19 (95% CI: 0.07-0.55)] and those who preferred to study in the library [AOR = 0.31(95% CI: 0.12-0.81)] were less likely to be harmful khat users. The university authorities, in addition to provision of student guidance on substance-use prevention, need to work in collaboration with the surrounding community and responsible public authorities in order to reduce harmful use of khat by their students.

Daytime Sleepiness, Circadian Preference, Caffeine Consumption and Khat Use among College Students in Ethiopia

OBJECTIVES

To estimate the prevalence of daytime sleepiness and circadian preferences, and to examine the extent to which caffeine consumption and Khat (a herbal stimulant) use are associated with daytime sleepiness and evening chronotype among Ethiopian college students.

METHODS

A cross-sectional study was conducted among 2,410 college students. A self-administered questionnaire was used to collect information about sleep, behavioral risk factors such as caffeinated beverages, tobacco, alcohol, and Khat consumption. Daytime sleepiness and chronotype were assessed using the Epworth Sleepiness Scale (ESS) and the Horne & Ostberg Morningness /Eveningness Questionnaire (MEQ), respectively. Linear and logistic regression models were used to evaluate associations.

RESULTS

Daytime sleepiness (ESS≥10) was present in 26% of the students (95% CI: 24.4-27.8%) with 25.9% in males and 25.5% in females. A total of 30 (0.8%) students were classified as evening chronotypes (0.7% in females and 0.9% in males). Overall, Overall, Khat consumption, excessive alcohol use and cigarette smoking status were associated with evening chronotype. Use of any caffeinated beverages (OR=2.18; 95%CI: 0.82-5.77) and Khat consumption (OR=7.43; 95%CI: 3.28-16.98) increased the odds of evening chronotype.

CONCLUSION

The prevalence of daytime sleepiness among our study population was high while few were classified as evening chronotypes. We also found increased odds of evening chronotype with caffeine consumption and Khat use amongst Ethiopian college students. Prospective cohort studies that examine the effects of caffeinated beverages and Khat use on sleep disorders among young adults are needed.

Bath salts and other emerging toxins

Novel classes of synthetic drugs, including synthetic cathinones ("bath salts") and synthetic cannabinoids ("spice" or "K2"), have recently emerged as popular drugs of abuse. Salvia divinorum, a naturally occurring herb, has gained popularity in the last decade as a hallucinogenic as well. The legal status of these substances has been undergoing rapid changes and has been confusing to lawmakers and medical practitioners alike. We present an up-to-date information about the legality of these substances. We also discuss the historical background, chemical composition, patterns of abuse, clinical presentations, laboratory analysis, and management strategies for these drugs, with an emphasis on synthetic cathinones.

Khat and synthetic cathinones: a review

For centuries, 'khat sessions' have played a key role in the social and cultural traditions among several communities around Saudi Arabia and most East African countries. The identification of cathinone as the main psychoactive compound of khat leaves, exhibiting amphetamine-like pharmacological properties, resulted in the synthesis of several derivatives structurally similar to this so-called natural amphetamine. Synthetic cathinones were primarily developed for therapeutic purposes, but promptly started being misused and extensively abused for their euphoric effects. In the mid-2000's, synthetic cathinones emerged in the recreational drug markets as legal alternatives ('legal highs') to amphetamine, 'ecstasy', or cocaine. Currently, they are sold as 'bath salts' or 'plant food', under ambiguous labels lacking information about their true contents. Cathinone derivatives are conveniently available online or at 'smartshops' and are much more affordable than the traditional illicit drugs. Despite the scarcity of scientific data on these 'legal highs', synthetic cathinones use became an increasingly popular practice worldwide. Additionally, criminalization of these derivatives is often useless since for each specific substance that gets legally controlled, one or more structurally modified analogs are introduced into the legal market. Chemically, these substances are structurally related to amphetamine. For this reason, cathinone derivatives share with this drug both central nervous system stimulating and sympathomimetic features. Reports of intoxication and deaths related to the use of 'bath salts' have been frequently described over the last years, and several attempts to apply a legislative control on synthetic cathinones have been made. However, further research on their pharmacological and toxicological properties is fully required in order to access the actual potential harm of synthetic cathinones to general public health. The present work provides a review on khat and synthetic cathinones, concerning their historical background, prevalence, patterns of use, legal status, chemistry, pharmacokinetics, pharmacodynamics, and their physiological and toxicological effects on animals and humans.

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.

Poor working memory and reduced blood pressure levels in concurrent users of khat and tobacco

INTRODUCTION

The purpose of this study was to examine the extent in which concurrent use of khat and tobacco was associated with decrements in working memory. We also tested whether cardiovascular activity during a cognitive task was related to performance outcomes, as research has shown linkages between maladaptive physiological adjustments and cognitive functions.

METHODS

Seventy-four concurrent users of khat and tobacco, 49 khat-only users, and 52 nonusers (M age ± SD: 23.8±4.8) completed a laboratory session including 10 min of a mental arithmetic challenge task. Systolic blood pressure (SBP) and diastolic blood pressure and heart rate were collected throughout the task. Analyses of variance and correlational analyses were conducted.

RESULTS

We found that concurrent users evidenced the lowest number of correct responses on the math task among these 3 groups (ps < .05). Concurrent users also showed fewer number of attempts than khat-only users (ps < .01) and lower accuracy rate than nonusers (ps < .05). The performance of khat-only users and nonusers were comparable on these 3 measures (p > .76). Overall blood pressure levels were lower in concurrent users than in nonusers (p < .05). Correlational analysis found that lower SBP during the math task was associated with fewer number of correct responses and attempts and lower accuracy rate on the task (ps < .05). Multiple regression analysis controlling for gender found that concurrent use predicted math performance (ps < .05). Reported duration and frequency of khat and tobacco use and nicotine dependence predicted performance measures (ps < .05).

CONCLUSIONS

These findings suggest potential linkages between concurrent use of khat and tobacco and impaired working memory.