Khat

Abstract

Khat is a shrub the leaves of which are used as a stimulant or a medicine in certain regions of East Africa and Arabia. The question of khat has been placed by the Narcotics Commission on the provisional agenda of its twelfth session scheduled to meet in April 1957 on the proposal of the representative of Egypt. The following article is a compilation of information from existing published sources on the subject which are of varying degrees of authority; and it should be regarded as of a background character pending closer examination of the question by the Commission.

Details

Pages: 6 to 12
Creation Date: 1956/01/01

Khat

Khat is a shrub the leaves of which are used as a stimulant or a medicine in certain regions of East Africa and Arabia. The question of khat has been placed by the Narcotics Commission on the provisional agenda of its twelfth session scheduled to meet in April 1957 on the proposal of the representative of Egypt. The following article is a compilation of information from existing published sources on the subject which are of varying degrees of authority; and it should be regarded as of a background character pending closer examination of the question by the Commission.

Historical Background

Khat was probably known and used on the Ethiopian uplands, where it seems that it originated, in very ancient times. It is, however, impossible to fix accurately its original habitat and the region where it first developed. As is usual in such cases, some authors state that it was not unknown to classical antiquity. Merab, for instance [58] , thinks that it was the smoke of khat that inspired the Delphic pythoness, that Homer s nepenthe offered by Helen to Telemachus was none other than khat and that Alexander the Great used it to cure his army of an epidemic disease. There are equally unverifiable suggestions with regard to cannabis and opium, and no importance can be attached to such suppositions.

The first historical reference, as far as could be determined from the literature consulted, occurs in a medieval Arab manuscript (MS.143, Bibliothèque nationale, Paris), where it is stated that the King of Ifat, Sabr Ad-Din decided to plant khat in the town of Marad (the period in question seems to be the first half of the fourteenth century). According to Rochet d'Héricourt[ 75] , khat was introduced from Ethiopia into the Yemen in 1424 by Sheikh Abu Zerbin. Another reference to its cultivation in the fourteenth century in the region of Aden and in the Yemen is found in a sixteenth-century Arab chronicler, Abdul-Kadir. Its cultivation in that region is thought to be earlier than that of coffee [ 82] . Khat was not known to the scientific world until the end of the eighteenth century. During an expedition organized by King Frederick V of Denmark, the physician and botanist Peter Forsskal collected, among many other plants, specimens of khat, which he described under the name of Catha edulis. The only survivor of the five members of the expedition, the Hanoverian geographer, Karsten Niebuhr, published the botanical papers in 1775, and in memory of his friend called Catha edulis " Catha edulis forssk" [ 65] .

In the first half of the nineteenth century, various travellers and scientists visiting Arabia and East and South East Africa referred to and described khat either under that name or variants of it: Celastrus edulis Vahl, by Ferret and Galinier [ 37] , Catha Forsskali A. Richard, by R. Petit, Methyscophyllum glattcum, by Ecklen and Zeyher [ 27] , etc.

Description

Khat is a. shrub with persistent leaves of the Celastraceae family, relatively of little importance, which includes the spindle-tree, Celastrus, etc.; mention may be made, however, of a Philippines plant of the same family, Lophopetalum toxicum, containing a poisonous substance lophopetalin, which is used in the composition of arrow-head poisons [ 67] . Khat grows to between 3 ft and 6 ft (1-2 m) in high and dry soils, reaches 20 ft (6 m) on the moist slopes of the Ethiopian mountainsand may even in the equatorial region under favourable circumstances reach a height of 80 ft (25 m). The trunk may be some 24 in (60 cm) in circumference and the bark is thin, smooth and brown; in appearance the tree is not unlike the tea shrub.

The new leaves are reddish-brown, becoming greenish-yellow when fully grown. They are bifarious, elliptical, lanceolate, sharp, coriaceous and almost tasteless. Dimensions vary widely from 0.2 in (0.5 cm) to almost 3 in (7 cm). The limb, which at the base is smooth, has over the remainder of the leaf. short, mossy serrations; the median vein projects on the under, reddish side; the secondary veins meet before the margin of the limb; between the secondary veins the smaller ones form a reticulate venation. From the histological point of view, Perrot [ 67] gives the following description: "Glabrous epidermis; bi-facial messophyl with two palisade layers and spongy parenchyma with ramous cells of twin crystals, isolated or sometimes grouped in clusters in the Same cell. Fasciculate system in an arc almost closed by two superior phl?em-lignous strands. Many periphl?em units. Crystalliginous phl?em".

FIGURE 2

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Fruit and seed of khat (note the "wing" of the seed)

The flowers are small, white or greenish and arranged in axillary cymes. They have five equal sepals, deeply indented, and five oblong petals. The fruit is a linear capsule, dark brown, with three valves, each loculus containing one to three small seeds at the base of a thin brown wing. The seeds, brown-red in colour are about one-eighth of an inch (3 mm) long.

Variants and Vernacular Names

It is generally recognized that the genus Catha edulis consists of only one species; however, in view of its extreme polymorphism, it is certain that it comprises several cultural varieties which seem not to have the same properties. A. Chevalier (20) points out that A. Richard noted in Ethiopia a variety which he calls Celastrus padinus Rich. with longer petioles and broader limbs. The Natal form, called Methyscophyllum glaucum Eckl. and Zeyher is certainly a distinct variety with narrow glaucous leaves; it is called Catha glauca comb. nov.

Given this polymorphism and also the many races repre-sented by those who use khat, the plant is known by a wide range of names which designate either the whole shrub or a quality of the product utilized. The Arab name of khat is the commonest-mainly because Arabic is by far the most widely used language of those which refer to the shrub or its parts. This is the term used in Europe, with variants which are simply phonetic transcriptions according to the language (catha, khat, kat, qat, ciat, etc.). Khat is the name designating the whole plant in Somali and in Amharic, (variant: tschat). The name which is, practically speaking, the most important after khat is" mira "or" miraa "-found in Masai, Kikuyu, Tukuyu and frequently in official or scientific texts in South and East Africa.

In view of the confused state of the literature of the subject in this respect, a list of terms used in East Africa to indicate the plant khat is given below (according to Greenway [40] :

Gazaland

Mutsawhari (Chendao).

Kenya

Kat (Somali); mirungi, muirungi and miraa (Kikuyu); ol meraa (Masai); liss (Mar.); tumayot (Dor.); muraa (Mer.); mairongi (Mt. Kenya); meongi, maonj and miungi (Kamb.).

Nyasaland

Mutsawari (Mlanje); mdimamadzi (Dedza).

Uganda

Musitate (Lumwege).

Tanganyika

Mlonge (Swahili); mulungi (Somali); warfo, warfi and waifo (Mbulu); seri (Fiome); mandoma, mwandama, m'mke and mfeike (Shambaa).; mzengo (Nguru); msekera (Kilongo, Uzinza); nangungwe (Mwera); mhulu, muhulu and muhulo (Hehe); liruti (Hehe, Fuagi); msabukinga (Kinga); msuruti, msuvuti and mbungula mabwe (Rungwe); mira and mbungula mabwe (Tukuyu); ikwa (Nyika).

On the other hand, some authors [20, 39, 68, 83] give lists of terms which distinguish the various qualities of khat. The definitions do not always exactly agree and the chief conclusion to be drawn is that in whatever region it is consumed, khat is regarded as are tea and coffee by connoisseurs, the criteria being the part of the plant utilized (leaves, buds, twigs or a mixture of two or all of these forms), the degree of maturity and, consequently, of size (the young shoots and the small red leaves are the most appreciated), and lastly the region of origin. It seems that there are "vintage" khats and, in all probability, the fraud and the snobbery that accompany that idea. Obviously the choice will depend on the use to be made of khat (see below) and also on the price, which varies considerably with the quality of the product.

Chemical and Pharmacological Aspects

The above-mentioned differences are empirical and subjective in 'character, and no thorough scientifc investigation has been made of them because the authors working on khat never had at their disposal the complete collections of samples of leaves, etc., which would 'allow the establishment of valid conclusions. From the point of view of the effect, it is quite clear that there is little-connexion between the small, thin leaf of a bush some 3 ft (1 m) high, growing at 5,000 ft -(1,500 m) in an arid soft, and that of a 16-foot (5 m) tree growing in the equatorial zone. In fact, experience in the case of other alkaloid plants shows that the effects vary with the soil' and climatic conditions in which the plant grows (and obviously of cultivation, if the plant is cultivated), that the alkaloid content changes and that under certain conditions some effects may disappear entirely (for instance, the variations in the opium alkaloids). Further practical proof as regards khat. is provided by Mustard [(62)] , who reports the introduction of khat into Florida, where it has been successfully cultivated, and where leaves eaten experimentally had no effect on those who chewed them.

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FIGURE 4

Khat twig with fruit (from Cape Province).

The leave are small and elongated

It is therefore impossible at this stage to draw up an overall scientific table of the properties of khat. That is why the following approach has been chosen : first, to give a description of what is known of the chemical analysis of the plant and of the effects of its alkaloids, and to deal in a later chapter with the effects in practice upon man of the plant as cultivated.

The first studies were those of Flückiger & Gerock [86] and of Paul [86] & Mosso [63] . The first two isolated an alkaloid that they called cathine, the last an alkaloid to which he gave the name celastrine. In fact, these studies were of little use, for the substances discovered were quite impure. The second stage of research was in 1901 when Beitter [8] claimed to have extracted a certain number of salts of cathine (sulphate, hydrochloride, hydrobromide, salicylate) and described cathine as crystallizing into needle crystals; bitter in taste, with no smell, soluble in ether, alcohol and chloroform. The formula he gave was C 10H 18NO 2. Subsequently, J. Chevalier studied khat and published an important work in 1911 [ 21] . He suggested the possible utilization of khat or carbine in the withdrawal cure from morphine, a suggestion which does not seem to have been followed up.

In 1912 the Pharmaceutical Journal and Pharmacist published a communication made to the Pharmaceutical Society by Dr. K. Stockman [79] . This important article gives details of his discovery of three alkaloids of khat : cathine, cathidine and cathinine. The author had at his disposal dried leaves, but--because of either experimental obstacles or difficulties inherent in the substances-he obtained only a low and variable yield. In addition to the alkaloids, the leaves contained sugar, tannin, a small quantity of rubber, a wax-like substance, and a small quantity of a yellowish essential oil that was pleasant to smell and to taste. The first alkaloid isolated, cathine--as a sulphate--was in the form of white, needle crystals, of bitter taste, easily soluble in water and diluted alcohol, but not in pure alcohol, chloroform, ether, etc.

Cathidine is a white amorphous powder insoluble in water, soluble in ether, pure alcohol, acetone, etc.

These descriptions were repeated more or less exactly in subsequent publications (up to and including the Merck Index 1940) (59). The proportions given for the three alkaloids (which, as has been seen, must be taken with reserve) are 0.27 per cent for cathine, 0.32 per cent for cathidine and 0.15 per cent for cathinine. Even admitting possibilities of wide error, these percentages are such that commercial extraction does not seem very promising.

In 1930, Wolfes [ 86] gave for cathine a different formula from that of Beitter (perhaps the latter had isolated the substance in the form of glycoside): C 9H 13NO 2. He showed that it is identical with d-nor-iso-ephedrine C 6H 5CHOH. CH(NH 2)CH 3. This substance is one of the alkaloids which in the Ephedra vulgaris of Japan (Ma-Huang) are the satellites of the l-ephedrine used commonly in medicine as a sympatheticocomimetic. Possibly, according to Hesse's theory [46] , the other two alkaloids also closely resemble ephedrine.

On account of the difficulties of obtaining leaves of khat, whether fresh or not, and perhaps also because of their small commercial value as shown by the early analysis, original studies on the chemical composition of khat are rare. In 1952, Miss Mustard [62] published the results of research into tropical plants in order to determine their ascorbic acid content. She made five analyses of a mixture of leaves and twigs-" commercial khat "-and found an ascorbic acid content of 135.7 mg/100 g. Analysis of leaves only gave the high content of 324 mg/100 g. Obviously, it might be stated that the khat consumers use it unconsciously on account of the high ascorbic acid content, but even if that were relevant to the consumption of khat, it is probably only one, and not the most important, among many considerations (it is true that scurvy is endemo-sporadic in the region where khat is consumed, but there are in such regions many other plants containing ascorbic acid that are not chewed).

Lastly, Peters [68] draws attention to a very interesting fact: "In a recent series of analyses (1952) carried out by the government laboratories, London, it was demonstrated that there was no appreciable difference between the alkaloidal properties of fresh samples of khat and samples that had been dried and preserved for a period often days. It would appear from this that, if indeed there is a difference between the properties of the fresh leaves and those of the dry-and local opinion substantiates this-there is an additional factor to be considered, which might well be a property contained in the resin of the plant."

Just as the habit of coffee drinking cannot be entirely explained by the presence of caffeine, so the chewing of the khat leaves is not exclusively dependent on the alkaloid content. That is why, in order to determine their action, laboratory experiments on the pharmacodynamics of the khat alkaloids are not enough, and why clinical research would have to be carried out on the spot by using the different categories of khat consumed, a long-term task which remains to be undertaken.

For that reason, it seems advisable to describe separately the pharmacodynamics of the alkaloids, as is done briefly below, and the effects of consumption based on empirical observations of those who have seen khat users. These effects will, therefore, be described in the following chapter after a summary of the methods of cultivation and consumption.

One of the first to carry out accurate experiments on khat, Leloup [49] about 1890, found that the substance excited the nervous system, delayed sleep and increased muscular strength. His experiments, carried out on himself, are extremely subjective.

In 1911, J. Chevalier [ 21] experimented on animals with cathine that he had isolated; according to him, small doses induce excitation of voluntary movements but not reflex excitability. He gave 3 mg as a "weak dose "and 6-10 mg as "lethal doses ". (Unfortunately the animals dose/weight ratio is not given, and the author refers merely to a " large" frog.) In the initial stage of excitability, the animal jumped about, foaming at the mouth, and then calmed down, showing symptoms of paralysis; sensitivity was retained, but motor action and reflex excitability gradually disappeared. The heart slowed down and then stopped in systole. These phenomena were more marked with guinea-pigs and rabbits, and, after an intravenous injection of 3-4 cg/kg, death took place in three or four hours, accompanied by convulsions and muscular rigidity. Smaller doses produced signs of excitation, with dilation of the pupil, rapid breathing, etc. Dogs are more resistant, and 5-6 cg/kg are required to bring on convulsions.

Stockmann also conducted experiments with these alkaloids, but his account[ 79] does not give any quantitative determinations. He states that cathine has an action on the nervous and muscular system of the frog similar to that of a combination of morphine and caffeine. Cathinine is a stimulant, rather, and cathidine is both a "muscular poison" and a stimulant. It is interesting to note that an infusion of khat leaves in water produces the same effects as cathine, cathidine being insoluble in water and acting only if the leaf is chewed, and not drunk as an infusion.

As far as is known to the writer of the present paper, the pharmacopoeias consulted do not appear to mention khat or its alkaloids except that the British Pharmaceutical Index of 1949 refers to khat (p. 902)as one of the "substitutes and adulterants of tea ". However, the following commercial experiments were undertaken: in 1910, a Lyons pharmacist introduced a speciality based on khat, which he called the "New Abyssinian tonic" which, as its name indicates, was sold as a restorative, but he was unable to obtain sufficient supplies of raw material and production came to an end at the outbreak of the first World War [ 76] ; in 1913, a London pharmacist began to manufacture products based on khat.

Dr. Martindale [2] marketed three products: "(1) catha-cocoa milk, (2) catha-cocoa glycero-phosphate.., a nervous tonic and stimulant in which milk powder is combined with catha extract and calcium glycero-phosphate, and (3) effervescent phenol-phtalein with catha... a mild tonic laxative. Extract of catha is also put up in tablet form."

Dr. Martindale said that he procured khat leaves in Arabia, but that recently (1936) he had had some difficulty in obtainlng a supply. The demand for the product was "general, but limited ". He exported a certain amount of his products to India. During more than ten years' experience of selling his preparations, he had never had any complaints or heard of any bad effects. Neither the 1948 edition of the British Pharmacopoeia nor the British Pharmaceutical Index of 1949 mentions these preparations.

Habitat and Cultivation

Khat is found wild in the relatively humid mountainous regions of East and South Africa, but not, it seems, in Southern Ethiopia, although it is cultivated there; in natural conditions it grows at a height of from 5,000 to about 6,500 ft (1,500-2,000 m). As a rule, it grows in association with conifers. It is found in the following regions: Arabia: North Hedjaz and East Hadramaut (not confirmed) [ 20] ; Belgian Congo: Sake region--near Lake Kivu-- Albert Park, Ruwenzori region, Lake Mujunga; Eritrea: information is contradictory, some authors stating that it is found here, while others deny it; Ethiopia : regions of Abba Yerma, Axum, Adowa, Chire, Choa; Kenya : Northern Frontier District from Mount Kenya to the Chyulu Hills[ 17] ; Nyasaland: Dedza district, Mount Mlanji, Blantyre district [ 31] ; Uganda: Kigezi, Karamoga, Bugishu distriCtS, region of Mounts Oebasian and Elga [ (29)] ; Southern Rhodesia : regions of Salisbury and Umtali[ 34] ; Tanganyika : Khat has been reported in practically all mountain districts at heights of from 4,000 to about 8,000 feet (1,200-2,500 m) [ 4] ; Union of South Africa : region of Queenstown.

It may be assumed that in most of the above-mentioned regions growth is sporadic. However, in addition, there are references to other regions that do not specify whether the plant is cultivated or grows wild (e.g., Afghanistan, Turkistan, etc.). The main zones of genuine cultivation are Ethiopia (particularly Harar), the Yemen, the region of Aden and Hadramaut and Kenya. Attempts at cultivation have been made in many parts of the world, either in the open (Ceylon, Bombay district, Florida, Algeria, Portugal, France (Villa Thuret at Cap d'Antibe)), or under glass in the various botanical gardens. Obviously khat grows best where the conditions are most like those of its normal habitat--i.e, on fairly moist slopes between 5,000 and about 8,500 ft (1,500-2,500 m), depending on the latitude.

The literature on the subject is full of contradictions with regard to methods of planting, maintenance and harvesting, which may be due--particularly when found in travellers' writings--to too hastily gathered information or to the impossibility of collecting details, such as questions of reproduction by seeds or cuttings, number of crops, etc. The description given by Peters (68) and cited below is one of the most recent and, besides, covers practically all the points of earlier observers, and the author states that in order to write his articles he visited the Harar plantations, which are probably the largest. It may be taken that, mutadis mutandis, his description will fit all plantations:

"Khat grows best at an altitude of between 5,500 and 8,500 ft (1,650-2,500 m); the Harar plantations are in the region of 6,000 ft (1,800 m). The trees are to be found growing in rows of five or six, with rows of coffee trees interspersed with the khat trees; millet was found growing in the spaces between the trees. Artificial irrigation is not employed, the trees relying entirely on rainfall. They are cultivated from cuttings; seed is sometimes, though rarely, sown. The cuttings are planted and artificially watered for a period of approximately 40 days : they are then allowed to grow to three or four years old before the first crop is taken; they then yield two crops a year. The average height of the trees is about 16 ft (5 m), and the older trees, from which the main crops are obtained, are about twenty to twenty-five years old.

"The trees are pruned yearly to keep their height to approximately 16 ft, as without this they have been known to grow to well over 60 ft (20 m). No disease seems to be known amongst the khat trees on the plantations visited, and although adjacent coffee trees have been known to die, no disease is transmitted to the khat trees. The trees are grown and tended with the same primitive agricultural implements as used by the farmers' ancestors for many centuries. The khat is picked two or three times a week and sent to the markets in Harar, where it is accepted as fresh for a period of up to four days after picking. After this, it depreciates in value, and, apparently, in potency."

The usual method of transporting khat for sale is to make it up into small packages, the most common measure being the bundle of 40 twigs of approximately 16 in (40 cm) long, wrapped in leaves and carried to the market either by caravan or, nowadays, by rail or air. There are few details known to the present writer of the extent of the trade and the price paid. The following figures were available: Tanret [80] mentions a price of 20 French francs a kilogramme (1933) in Ethiopia and it was said that in certain villages of the region of Aden the men consume daily two U.S. dollars' worth of khat. [1]

It is difficult to evaluate the fluctuations of khat cultivation. It is, however, interesting to note that a document submitted to the sixth session of the Eastern Mediterranean Regional Bureau of the World Health Organization (document EM/ RC6/5, 9 July 1956) stated that its use was spreading so rapidly that cultivators grew khat instead of food and other cash crops.

Thus the cultivation of khat has become more and more important, and the governments of the different areas in which it is grown have taken measures to control it, principally by way of taxation and registration of the users. The first attempt seems to have been made in British Somaliland (4), where in 1921 the cultivation of khat was prohibited, as was its sale, except by licensed vendors, who were permitted to sell it only to properly registered consumers. Owing to difficulties of application, however, that measure was subsequently withdrawn. In 1939 there were further measures of control in British Somaliland providing for right of search and penalties of imprisonment and fine for its cultivation.

In certain districts of Kenya the possession of khat was made an offence (3): the council of the Isiolo district took that decision in 1934, and in 1935 the native council of the Maru district adopted a resolution prohibiting the use of khat by those who were not inveterate consumers. There is practical control at the present time in Kenya through a system of taxation similar to that on alcohol. The annual report of the Kenya Department of Agriculture (3) for 1947 states that after khat (miraa) had been controlled a quantity to the value of ?92,793 was exported from the Maru district of the Central Province. From the point of view of the district revenue, khat was the second most important export item (this sum apparently refers to the period beginning April to the end of the year, 1947). Several authors state without giving details that the tax on khat constitutes an important source of revenue for the Government of Yemen.

It may be added that, although there is no regular trade or exploitation, khat wood is used for the construction of dwelling huts. Moreover, in view of its golden-brown colour, its very fine texture and the fact that it is easily polished, it has been suggested [29] that it might be used for joinery and marquetry. According to Greenway it gives a pulp out of which excellent blotting paper could be made[40] .

Many of the authors have suggested that apart from the taxation measures there should be measures of control in view of the dangers presented by the consumption of khat. Such a suggestion is found, for instance, in the Pharmaceutical Journal of July 1952. [2]

There have been indications in the French press that measures of control were being taken by the French Government. [3]

Khat is not covered by the conventions relating to narcotic drugs. The Advisory Committee (of the League of Nations) on Traffic in Opium and Other Dangerous Drugs, however, took up the question at its twentieth Session. In considering the survey of the annual reports of governments, the Chairman of the Committee referred to the mention of khat in the annual report of British Somaliland and asked the United Kingdom representative to supply further information on the matter. On 16 November 1935, the United Kingdom representative communicated to the Secretariat two reports on the question: one from Dr. Donaldson, Medical Senior Officer, British Somaliland, the other from Mr. A. W. Exell, of the Natural History Department of the British Museum (2).

The question was not taken up again internationally until the eleventh session of the Commission on Narcotic Drugs (23 April- 18 May 1956). The question was placed on the provisional agenda of that session at the request of the representative of Egypt who communicated a report (1) from the laboratory of the Egyptian Medico-legal Institute. This document gives the general characteristics of khat and provides some information on its use in the Yemen. The Commission decided to defer the study of the question of khat until its next session and placed it on the provisional agenda for that session (item 11) [4] expressing its intention of inviting Ethiopia and Yemen to participate in the discussion.

Methods of consuming Khat

Methods of consuming khat vary according to a certain number of factors: the regions concerned, and of course, the kind of khat that the consumer has available, the price he can pay and, lastly, the purpose of using it - that is to say, his own personal tastes. Fifty years ago the methods were relatively the same for all the regions, since transport, being by caravan, was slow, and, consequently, khat was necessarily consumed dry by those who did not cultivate it. The methods have changed since transport is now either by rail or, particularly, by air. Whereas nineteenth-century travellers and explorers nearly always described the Arabian use as being in the form of infusions of the dried leaf, nowadays this method seems to be giving way to mastication of the fresh leaf, since khat is imported to Aden and the Yemen and elsewhere by air from Harar. This shows that the methods of consuming khat were not necessarily the result of choice or particular taste, but depended rather on circumstances.

The three normal methods of consuming khat are : (1) chewing-in this case the fresh plant is used-i.e., khat picked four or five days previously (at most), which has kept its moisture, since for that purpose it has been wrapped in leaves which are moistened from time to time. The more tender and juicy the leaves (either because they are taken from a plant variety with small leaves or because they are picked from the end of a branch), the easier it is to chew them and consequently the more they are appreciated. Thus, according to Peters[66] , there is in Amharic a special name for this kind of leaf (koda) and also in Somali (hagafa). According to Vaughan [83] , this kind of khat, called malhani, is more sought after in Southern Arabia, Aden, the Yemen, Hadramaut, etc. According to the size and the freshness of the leaves, therefore, there are "vintage" of khat, which are highly appreciated by the connoisseurs, and the price of which varies with the demand. A consumer used to goodquality khat chewed fresh would find it as difficult to get used to the dried leaves as, for instance, a cigar-smoker would to chewing tobacco. When the khat to which the consumer is accustomed is unobtainable, he would rather go without than try an inferior quality.

To chew the khat, the twigs are stripped of their leaves, which are made into a kind of quid, which is chewed until all the juice is extracted. To help the process, the chewer drinks large quantities of water. The process may last ten minutes or a quarter of an hour; when it is over, the residue is swallowed. During chewing, cigarettes are sometimes smoked. It may be remarked that when the leaf is fresh, the saliva is sufficient to extract the active elements-the alkaloids alone or combined with some other part-whereas with the dried leaves chewing alone does not seem to be sufficient.

The second method consists in using the large leaves which would be too hard for chewing or the leaves that have lost their freshness on too long a journey. In this case, the leaves are used dry-either the large leaves after drying in the sun or the others used as received from the seller. The dried leaves are powdered in a mortar; the powder is placed in a bowl and, after adding sugar and sometimes spices and water, a kind of paste is made, which is then chewed. As before, the residue is swallowed-and large quantities of water are drunk-probably to facilitate the extraction of the active elements. It may be added that, according to individual taste or to regions-always where fresh leaves are not available-a khat infusion is made in the same way as tea. This method is not very common and is followed mainly in South Africa [64] . It is more usual to add to ordinary tea fragments of khat twigs to alter the taste and the effect of the tea. It may be pointed out that with infusion, at least one of the alkaloids, cathidine, is lost, being insoluble in water, for so far as is known the residue of the infusion is not consumed. Since it seems that the effect is not different from that produced by chewing, it may be concluded that cathidine is not responsible for the effect produced by khat, although the action of khat is still not very well known. Merab [58] points out that the Ethiopian Christians use khat in preparing certain of their beverages (tedgee and talla).

Lastly, in certain parts of Arabia, khat is smoked like tobacco or cannabis, the ends of the twigs and the leaves being first crushed and then rolled in cigarettes (no mention of khat smoked in a narghile has been found).

The taste for the different varieties of khat seems as strange to those who are not accustomed to it as the choice between different qualities of wine or tea to non-initiates: it has probably not much to do with the alkaloid content. Khat is taken not only for its stimulating or inebriating effect, but also for the pleasure given at the time of taking it. From that point of view, therefore, it must be ranked with substances such as tea, tobacco, alcohol, etc., at any rate as regards occasional use. According to observations made on the spot it appears that after some time, once the need has been created, khat is no longer used for the pleasure derived from its taste, but mainly or solely for its effect; that marks the transition between the occasional and the habitual user. It may be observed that it is about the same with alcohol, which is taken by the occasional consumer for the pleasure derived from it, whereas the confirmed drunkard seeks principally or solely for the effect, whatever the taste or the appearance of the product consumed. In this connexion, some authors have wondered whether the real difference between occasional consumption, which might be styled pleasure or" sociability" consumption, and harmful habits does not lie precisely in the fact that the pleasure, which is sought at the time of consumption, is complex in nature-taste plus knowledge of the effect-whereas in the case of a harmful habit there is mainly or exclusively the craving for the effect.

Before considering the effects of khat, it may be remarked that it is consumed-when it is consumed for pleasure-in a group; that is to say it is a part of social life. In almost all the regions of habitual use, travellers mention this social habit-for instance, the fact of offering the stranger or the guest a twig of khat to chew or to welcome him in offering him a cup of khat, just as elsewhere he would be given a cup of coffee or a cocktail. Moreover, khat is very frequently taken socially, either in shops or public places where men meet to pass the time of day, or in private houses, where one is invited to "take khat ". Here again, as with alcohol and the like, there is a marked difference between the occasional consumer, who uses it in company, and the inveterate consumer who looks for the effect, and for whom in consequence the social aspect is a drawback rather than an advantage.

Effects of Khat

The foregoing analyses show that the effects of khat are quite different on the occasional and on the habitual consumer. On the former they will be strictly proportionate to the quantity of khat taken. The case of the latter is much more complex. First, the effects obviously include the consequences of the khat taken as such -and the habitual user consumes increasingly large quantities in order to obtain the same effect; then there is a whole series of secondary physiological effects. The inveterate consumer loses his appetite and eats less and less; his body becomes emaciated, and he falls a victim to various deficiency diseases, not to mention secondary complications, such as constipation, etc. Among the psychological effects, the person who sleeps and eats less falls a victim to various illnesses. He clearly loses intellectual and will power. That situation gives rise to certain social consequences. The inveterate consumer no longer bothers about himself, his family or the rest of society. If he has the means for procuring khat, he becomes a mere human wreck. If he has not got the necessary money, he turns to begging or some kind of anti-social activity, such as crime.

Little is known of the effect of khat on a normal individual without considering the period of use. Since it has not been thoroughly studied from the scientific point of view, but only empirically observed by travellers or, less frequently, reported by those who have taken it occasionally, the descriptions of it are sometimes contradictory. Generally speaking, there is a kind of exaltation, beginning with a feeling of being liberated from space and time, accompanied by extreme loquacity and inane laughter, until a semi-coma intervenes, out of which the consumer awakes in a painful condition. In the first stage, therefore, there is intellectual excitation with euphoria, in the second stage the numbing of the intellectual faculties, and in the third the eclipse of these faculties -lack of attention and memory accompanied by the liberation of violent instincts.

A distinction must be made between occasional and chronic use:

In the case of occasional use khat abolishes sensations of fatigue and hunger, soothes passions such as anger, then degenerates into a state of veritable poisoning, accompanied by dilatation of the pupil, cold sweats, convulsions, hyperaesthesia, etc. and, if taken in excessive quantities, may even result in death. (Heisch [44] describes a specific case that he had observed of a khat-chewer who, when taken to hospital, showed the above-mentioned symptoms, then passed into a coma and died after four days. At the post-mortem, the stomach was discovered to be full of khat and death could not be attributed to any other cause than its consumption.)

In the case of chronic use, khat numbs the intellectual faculties and leads to complete stupor or madness. Carrothers [17] reports two cases of madness brought on by khat in which he observed incoherence, feverish excitation, marked troubles with a schizophrenic character and, finally, manifestations akin to delirium tremens. Incidentally, both patients quickly returned to normal when the khat was withdrawn.

To sum it, there is a quasi-medical use of khat: it has been used for a long time by couriers carrying urgent messages as sustenance during the journey when there was no time to stop for eating or sleeping. It is also used in traditional medicine in Ethiopia, Arabia and elsewhere for all sorts of purposes -e.g., as a diuretic in the treatment of gonorrhoea-as a prophylactic against malaria, asthma, coughing and diseases of the chest, stomach trouble and even as a preventive against plague. This list shows that in the therapeutic practice of primitive traditional medicine khat becomes a panacea.

Khat has also a religious or magic significance. According to Tanrer, [80] Mgr. Jaros3eau, Bishop of Harar, noted this phenomenon in the following terms: "The whole country is persuaded that this shrub enjoys divine blessing; no private or public religious ceremony can take place without the ritual chewing of the leaf accompanied by much praying and singing. In the Moslems of Harar it induces a strong religious exaltation, which they regard as a gift from heaven."

There is again the use of khat for pleasure. Since khat is regarded as an excitant and a stimulant like coffee, tea and the like, it is generally not considered prohibited by Koranic law and consequently there is no moral objection in the Moslem countries affected against its abuse.

Khat is used in relatively poor regions, where the frequent lack of food encourages deficiency diseases. Consequently, in view of its stimulating effect, it is often not unnaturally regarded as a divine blessing.

For populations with relatively few sources of distraction it constitutes a simple and convenient form of escapism.

The observations, however superficial, that have been made show that khat may produce a definite intellectual and moral deterioration and that its social consequences may be serious.

Except in sporadic cases such as the utilization of the wood of the shrub, it is generally not used for industrial purposes.

1

Long Island Daily Press, 16 August 1954.

2

Pharmaceutical Journal, Vol. 169, 4629, page 55.

3

See Le Monde, 7 December 1956, page 5.

4

Commission on Narcotic Drugs: Report to the Economic and Social Council on the Eleventh Session of the Commission, document E/2891 E/CN.7/315.