Khat

Khat or qat ( ''ch’at''; Oromo: ''Jimaa'', so, qaad, khaad, khat or chat, ar, القات ''al-qāt'') is a flowering plant native to eastern and southern Africa. Khat contains the alkaloid cathinone, a stimulant, which is said to cause excitement, loss of appetite, and euphoria. Among communities from the areas where the plant is native, khat chewing has a history as a social custom dating back thousands of years analogous to the use of coca leaves in South America and betel nut in Asia.

The World Health Organization (WHO) classified it in 1980 as a drug of abuse that can produce psychological dependence, although the WHO does not consider khat addiction to be a serious problem.

The legality of khat varies by region. In many countries, khat might not be a specifically controlled substance but may nevertheless be illegal under more general laws. It is a specifically controlled substance in some countries including Canada, Germany, the United Kingdom, and the United States. By contrast, the production, sale, and consumption are legal in the nations where its use is traditional of those cultures, including Djibouti, Kenya, Uganda, Ethiopia, Somalia, Sudan and Yemen. In Israel, which hosts a population of Yemenite Jews, only the consumption of the plant's leaves in its natural state is permitted.

Nomenclature

The genus name ''Catha'' is a Latinization of the Arabic name ''قات'', which is regularly romanized as ''qāt''. Other romanizations include ''kat'', ''quatt'', ''qaad'', ''qhat'', ''ghat'', and ''chat''.

The khat plant is known by a variety of names, such as ''qat'' and ''gat'' in Yemen, ''qaat'' and ''jaad'' in Somalia, and ''chat'' in Ethiopia. It is also known as ''jimaa'' in the Oromo language, ''mayirungi'' in Luganda, and as ''miraa'' in Kenya. In the African Great Lakes region, where ''Catha edulis'' is in some areas cultivated, it is known as ''miraa'', ''muhulo'' and ''muirungi''.

It also goes by various descriptive names, such as ''Abyssinian tea'', ''Somalian tea'', ''miraa'', ''Arabian tea'', ''jimaa'', and ''kafta'' in its endemic regions of the Horn of Africa and the Arabian peninsula. In South Africa, the plant is known as ''bushman's tea''. The plant is also known as ''chat tree'' and ''flower of paradise''.

Description

Khat is a slow-growing shrub or tree that typically attains a height of . However, it can reach heights of up to in equatorial areas. The plant usually grows in arid environments, at a temperature range of . It has evergreen leaves, which are long and broad.

It takes seven to eight years for the khat plant to reach its full height. Other than access to sun and water, khat requires little maintenance. Ground water is often pumped from deep wells by diesel engines to irrigate the crops, or brought in by water trucks. The plants are watered heavily starting around a month before they are harvested to make the leaves and stems soft and moist. A good khat plant can be harvested four times a year, providing a year-long source of income for the farmer.

The shrub's flowers are produced on short axillary cymes that are in length. Each flower is small, with five white petals.

The samara fruit is an oblong, three-valved capsule, which contains one to three seeds.

Cultivation and uses

Khat has been grown for use as a stimulant for centuries in the Horn of Africa and the Arabian peninsula. There, chewing khat predates the use of coffee and is used in a similar social context. Its fresh leaves and tops are chewed or, less frequently, dried and consumed as tea, to achieve a state of euphoria and stimulation. The leaves or the soft part of the stem can be chewed with either chewing gum or fried peanuts to make it easier to chew.

In Uganda, it is grown in the central region, especially in Kasenge (Wakiso), Butambala District, Mabira Forest, and in some parts of the western region of the country. In Kenya, it is grown in Meru County.

Although the practice of khat-chewing is still primarily restricted to its original area of cultivation in the Red Sea area, the khat plant has over the years found its way to southern Africa as well as tropical areas, where it grows on rocky outcrops and in woodlands. The shrub is today scattered in the KwaZulu-Natal, Eastern Cape, Western Cape and Mpumalanga provinces of South Africa, in addition to Eswatini and Mozambique. In recent years, however, improved roads, off-road motor vehicles, and air transportation have increased the global distribution of this perishable commodity, and as a result, the plant has been reported in England, Wales, Rome, Amsterdam, Canada, Israel, Australia, New Zealand, and the United States. In the US, freshly packed khat leaves are sold on the markets of New York, Los Angeles, Boston, and Dallas, where the demand is highest.

Traditionally, khat is used as a socialising drug as in Yemen where khat-chewing is predominantly a male habit. Khat is so popular in Yemen that its cultivation consumes much of the country's agricultural resources. An estimated 40% of Yemen's water supply goes towards irrigating it, with production increasing by about 10% to 15% every year. One "daily bag" of khat requires an estimated of water to produce. Water consumption is high and groundwater levels in the Sana'a basin are diminishing, so government officials have proposed relocating large portions of the population of Sana'a to the coast of the Red Sea.

One reason for the widespread cultivation of khat in Yemen is the high income that it provides for farmers. Some studies done in 2001 estimated that the income from cultivating khat was about 2.5 million Yemeni rials per hectare, while fruits brought only 0.57 million rials per hectare. Between 1970 and 2000, the area on which khat was cultivated was estimated to have grown from 8,000 to 103,000 hectares. In 2000, according to a World Bank estimate, khat accounted for 30% of Yemen's economy.

In countries outside the core area of growth and consumption, khat is sometimes chewed at parties or social functions. It may also be used by farmers and labourers for reducing physical fatigue or hunger, and by drivers and students for improving attention.

More recently, in 2019, reports indicate that child soldiers in Yemen have been chewing khat in order to remain alert on the battlefield.

Effects

Khat consumption induces mild euphoria and excitement, similar to that conferred by strong coffee. Individuals become very talkative under the influence of the plant. Animal testing has shown that khat causes an increase in motoric activity. The effects of oral administration of cathinone occur more rapidly than the effects of amphetamine pills; roughly 15 minutes as compared to 30 minutes in amphetamine. Khat can induce manic behaviours and hyperactivity, similar in effects to those produced by amphetamine.

The use of khat results in constipation. Dilated pupils (mydriasis) are prominent during khat consumption, reflecting the sympathomimetic effects of the drug, which are also reflected in increased heart rate and blood pressure. Long-term use can precipitate permanent tooth darkening (of a greenish tinge), susceptibility to ulcers, and diminished sex drive. Khat is an effective anorectic, causing loss of appetite.

It is unclear if the consumption of khat directly affects the mental health of the user or not. Occasionally, a psychotic episode can result, resembling a hypomanic state in presentation. In humans, its prolonged consumption creates an uplifted mood and a sense of release from time and space.

Effects by timeframe

Immediate
*alertness
*arousal
*concentration
*confidence
*constipation
*dilated pupils
*euphoria
*friendliness
*increased blood pressure
*increased heart rate
*insomnia
*mania
*psychosis
*suppressed appetite
*talkativeness
* thought disorder
*verbosity

Long-term
* depression
*infrequent hallucinations
*impaired inhibition (similar to alcohol)
*increased risk of myocardial infarction (heart attack)
*oral cancer
*psychosis in extreme cases in the genetically predisposed
*weight loss

Indeterminate
*death
*stroke following acute coronary syndrome (clogging of the artery)either from impaired insight into symptoms by the khat chewer, delay to care, or poorly understood pathophysiological mechanisms

Chemistry and pharmacology

The stimulant effect of the plant was originally attributed to "katin", cathine, a phenethylamine-type substance isolated from the plant. However, the attribution was disputed by reports showing the plant extracts from fresh leaves contained another substance more behaviourally active than cathine. In 1975, the related alkaloid cathinone was isolated, and its absolute configuration, (S)-2-Amino-1-phenylpropan-1-one, was established in 1978. Cathinone is not very stable and breaks down to produce cathine and norephedrine. These chemicals belong to the PPA (phenylpropanolamine) family, a subset of the phenethylamines related to amphetamines and the catecholamines epinephrine and norepinephrine. In fact, cathinone and cathine have a very similar molecular structure to amphetamine. Khat is sometimes confused with methcathinone (also known as ''cat''), a Schedule I substance that possesses a similar chemical structure to the khat plant's cathinone active component. However, both the side effects and the addictive properties of methcathinone are much stronger than those associated with khat use.

When khat leaves dry, the more potent chemical, cathinone, decomposes within 48 hours, leaving behind the milder chemical, cathine. Thus, harvesters transport khat by packaging the fresh leaves and stems in plastic bags or wrapping them in banana leaves to preserve their moisture and keep the cathinone potent. It is also common for them to sprinkle the plant with water frequently or use refrigeration during transportation.

When the khat leaves are chewed, cathine and cathinone are released and absorbed through the mucous membranes of the mouth as well as the lining of the stomach. The action of cathine and cathinone on the reuptake of epinephrine and norepinephrine has been demonstrated in lab animals, showing that one or both of these chemicals cause(s) the body to recycle these neurotransmitters more slowly, resulting in the wakefulness and insomnia associated with khat use.

Receptors for serotonin show a high affinity for cathinone, suggesting this chemical is responsible for feelings of euphoria associated with chewing khat. In mice, cathinone produces the same types of nervous pacing or repetitive scratching behaviours associated with amphetamines. The effects of cathinone peak after 15 to 30 minutes, with nearly 98% of the substance metabolised into norephedrine by the liver.

Cathine is somewhat less understood, being believed to act upon the adrenergic receptors