Pharmacological Aspects of Chewing Qat Leaves [Archives:2000/21/Health]

May 22 2000

By: Peter Kalix &
Olav Breanden
In certain parts of eastern Africa and southern Arabia, the stimulating properties of the leaves of the Qat bush were probably known before those of coffee, and the habit of Qat chewing has been common on those areas for many centuries. The effects of Qat were reported in the literature as early as 1237 by the Arabian physician Naguib Ad Din, who recommended the use of Qat for the treatment of depressive states. Other writers of the same period reported that it was effective in blunting the sensations of hunger and fatigue.
Since the Qat leaf rapidly loses its effect upon wilting, the Qat habit has remained, until recently, endemic to the areas where the plant was grown. During the last decades, however, due to the development of road networks and the availability of air transport, the habit has spread considerably in those regions and to countries where the plant does not grow. Thus, shipments of Qat have even been observed by customs authorities in France, Great Britain, and the United States.
The growing use of Qat has motivated an interest in further knowledge of its active ingredients and their pharmacological effects. A number of studies have therefore been made in an attempt to throw light on these problems. The investigations have led to the discovery of the alkaloid (-) cathinone, which is now considered to be the constituent mainly responsible for the stimulating properties of Qat leaves. The present review is intended to describe the medical aspects of Qat chewing, to summarize the pharmacological data concerning Qat constituents that have thus far been reported in the literature and to provide some background information.
The Habit of Chewing Qat
In some countries where the use of Qat is widespread, the habit has a deep-rooted social and cultural tradition. This is particularly true for Yemen, where many houses have a room called a muffraj specially arranged for regular sessions of Qat chewing. In the Yemen Arab Republic, more than 4% of the arable land is used for Qat cultivation. The bush grows on moist slopes at altitudes of 3000 to 8000 ft, and it is quite adaptable to varying ecological conditions. The first Qat crop is ready for harvesting 3 to 5 years after planting and, although there are marked seasonal differences in regrowth, Qat can be harvested throughout the year. The shoots at the tips of the branches are cut in the early hours of the day, bundled, and then usually wrapped in banana leaves to preserve their freshness. The material is then speedily transported to the markets, where it is sold by late morning. The buyers select from among various types of Qat available, which also vary considerably in price, the most expensive (because the most potent) material being, in general, the freshest and with the youngest leaves.
For the consumption of Qat in the traditional social setting, the chewers meet in a house some time in the after noon, usually bringing their own supply. After being welcomed and carefully seated according to their social position, the guests begin to masticate the leaves thoroughly one by one. The juice is swallowed, while the residue of the leaves is stored in the cheek as a bolus of macerated material for further extraction, and is finally ejected. Altogether, each person takes some 100 to 200g of the leaves; young leaves being the most favored, mainly because they are more potent and tenderer to chew. During the session, the group may smoke from water pipes, and there is a generous supply of beverages. After the Qat leaves have been chewed, the guests stay on for most of the afternoon, passing their time in animated discussions, often devoted to matters of general interest, such as community affairs. From this point of view, Qat can be seen as a factor furthering interaction and structuring social life. The Qat session also plays an important role at weddings and other family events. Qat is frequently used during work by craftsmen, laborers, and especially by farmers, in order to reduce physical fatigue. Besides these traditional forms of consumption, Qat is nowadays also chewed by single individuals idling in the streets, particularly in towns and cities where it has been introduced within the last decades. In these regions, Qat is also consumed (sometimes along with alcoholic beverages and other drugs) at gatherings which lack the restraint and well-defined social setting described above. The social aspects of Qat use are discussed extensively in the publications of Hughes, Kennedy et al., Nelhans, and Schopen.
The Effects of Qat Chewing:
During the first part of a Qat session, there is an atmosphere of cheerfulness characterized by optimism, high spirits, and a general sense of well-being. The excitement brought out by the consumption of Qat reduces social inhibitions and causes loquacity. After 2 hours, a certain degree of tension reflecting emotional instability and irritability becomes apparent. The talking becomes louder, less relevant to the subject under discussion, and there is greater awareness of problems. Later, depressive tendencies appear, and a mood of sluggishness prevails. At this point, the guests leave the Qat session with the feeling of depletion.
The desirable effects of Qat leaves, as perceived by experienced users, are relief from fatigue, increased alertness in energy levels, feelings of elation, improved ability to communicate, enhanced imaginative ability and capacity to associate ideas, and a heightened self confidence. These effects seem to be more readily perceived by the habitual user. Since the social environment in which the drug is consumed appears to play a role in the response, it is important to take into account not only the effects of Qat itself, but those of the Qat session as well. Interestingly, the response appears to be influenced by conditioning, since in Djibouti, where Qat is flown in daily, the effects of the drug are commonly to begin when the incoming plane is heard in the sky.
The objectively observable effects of Qat use consist of mild euphoria and excitement accompanied by episodes of logorrhea and then verbal aggressiveness. There is also an increased sensitivity to sensory stimulation; excessive Qat use may cause hyperesthesia. Hyperactivity may be observed and the associated behavioral syndrome can be described as hypothemania. A manifestation of irresponsible fearlessness has also been reported. In exceptional cases, Qat consumption may produce an immediate dysphoric reaction which might, however, be due to excessive expectations with regard to potency of a given batch of Qat. The late effects of Qat use are mainly an inability to concentrate, and insomnia. It is important to note that high doses of Qat or exceptionally potent material can induce psychosis, presumably by enhancing a subacute prepsychotic or psychopathic condition. However, such symptoms are mentioned only occasionally in literature, probably because in many cases they are considered as being at the extreme limit of normal behavior. Nevertheless, a number of case reports on Qat-induced toxic psychosis have appeared. The usefulness of phenothiazines has been reported for reducing the central nervous system (CNS). Toxicity of Qat was reported some time ago. At present, thioridazine is suggested for the symptomatic treatment of Qat psychosis. Impairment of mental health may also be the result of long-term Qat consumption; long-term chronic users may develop personality disorders and suffer mental deterioration.
The symptoms described above, particularly that of toxic psychosis are reminiscent of those induced by amphetamine. Similarity of effects of the two drugs has already been reported, and it has been concluded that the differences between the effects are essentially quantitative. Indeed, Hughes has stated from personal experience that the effect of a portion of Qat is very similar to that of about 5 mg of amphetamine. A further analogy with amphetamine is that the habitual use of Qat is in many instances compulsive, as indicated by the tendency of the chewers to secure their daily supply of the leaves at the expense of vital needs. Drug dependence of the Qat type has been described by Eddy et al., and it appears that its only major difference from amphetamine-type dependence is the physical impossibility of increasing the ingested dose beyond a certain limit. This probably explains why tolerance to the physical or to the psychostimulant effect of Qat has not as yet been observed. Similarly, no clear abstinence has been found to occur after prolonged Qat use, although a mild depressive reaction during the period of withdrawal from Qat is sometimes seen. Any definitive investigation of tolerance or with drawal symptoms would, however, require a thorough clinical study involving monitoring of the blood levels of the active Qat constituents.
An important effect of Qat, the induction of anorexia, was already reported in the early Arab literature. This anorexia, along with the tendency of habitual Qat users to divert their funds from food to Qat, would account for the generally observed malnutrition which predisposes the users to disease. Ingestion of the leaves seems to have no effect on the blood level of glucose. On the other hand, Qat has been reported to cause an increase in respiration and induction of hyperthermia; a case of lethal hyperthermia following Qat consumption has also been described.