Main type

Cannabis is one of the most commonly used drugs in the world, and has been illegal in many counties for almost a century. It is thought to have been used by ancient cultures for medicinal purposes as far back as four millennia ago, and its recreational use in western countries has become widespread since the 20th Century, particularly since its popularisation during the ‘flower power’ hippy movement of the 1960s.

Cannabis, also known as Marijuana, is a natural product derived from the cannabis plant (part of the nettle family), which grows wild in some areas of the world and has been extensively cultivated in others. The main psychoactive ingredient of cannabis is a chemical called tetrahydrocannibol, which is often referred to by the acronym THC.

The THC in Cannabis gives users of the drug a ‘high’, which can vary somewhat depending on the exact strain of the drug being taken, the amount taken, the method of use and the individual. In general though, the cannabis high is regarded as producing happy ‘chilled out’ feelings, relaxation and altered perceptions and senses.

Cannabis is used in a number of ways, with smoking it in on its own or with tobacco in ‘joints’ or ‘spliffs’ being one of the most common. It may also be smoked from pipes, ‘bongs’ and other drug paraphernalia, or taken orally with food.

Though cannabis is often thought of as a ‘softer’ drug than many other illegal substances, it has been suggested that it may lead to harder, more dangerous drugs.

Some scientific studies have also found evidence of permanent changes to the brain resulting from Cannabis use.

The legality of Cannabis has been a major source of debate in many countries in the past few decades. In the UK it was downgraded to the status of a Class C controlled drug in 2004, but subsequently reclassified as a Class B in 2009, leading to an increase in the maximum prison sentence that can be imposed for possession of the drug. Often however, jail terms are not given for possession of small amounts of the substance, though larger amounts for supply may be punished severely.

In the US, Cannabis is a schedule I controlled substance under federal law, though some individual states have either decriminalised it or made it legal for medical use.

Other Types

There are different types of cannabis which can be bought on the street, and while each of these may come from the exact same plant, they differ in their appearance, and to some extents their effects. ‘Grass’ or ‘Weed’ refers to the dried leaves, stems, buds and flowering parts of the cannabis plant. ‘Hashish’, ‘Resin’ or ‘Rocky’ is the dried resin of the plant, which usually resembles a hard, rock-like substance.

Cannabis oil may also be used, a tar-like substance made by further processing of parts of the plant. This may be particularly potent, but is less common than other forms.

In addition to these types, different strains of the cannabis plant may be used to produce street sold cannabis, identifiable by names like Purple Haze, Northern Lights, Malawi Gold, Niagra, AK-47 and Island Lady. Particular strong strains have become commonly referred to as ‘Skunk’ by both users and the media.

Common generic street names for cannabis include Pot, Dope, Ganja, Draw, Chronic, Hash, Reefer, Mary Jane, Herb and Puff.

Major Effects

Cannabis has a wide variety of effects and can affect different people in different ways.

When a user smokes or ingests cannabis, the active chemical compounds within it are distributed to the bloodstream, and from there they reach the brain. When smoked, this occurs within just a few seconds, while when consumed orally it can take longer for these compounds to be broken down by the body.

Once in the brain, the THC from the drug and other lesser chemicals known as cannabinoids bind with cannabinoid receptors there, particularly in the part of the brain known as the hippocampus, and in the basal ganglia and cerebellum. These parts of the brain are responsible for a variety of mental functions and for the overall control of the body. By binding to the receptors, THC artificially activates neurons in these areas, leading to disruptions in normal functioning, producing both the ‘high’ that users experience, and the negative effects linked with Cannabis use.

In the short-term, the effects of Cannabis range from talkativeness, relaxation and uncontrollable laughter to more severe hallucinogenic effects, time distortions and other cognitive confusions. Users may also suffer from paranoia and intense anxiety while under the influence of the drug. Frequent users may experience weight gain, as a result of ‘the munchies’ – a substantial increase in appetite that often occurs when using Cannabis.

In long-term regular use, cannabis is known to lead to reduced motivation, poor concentration and co-ordination and slowed reactions. It has also been linked to an increased risk of suffering from certain mental illnesses in those who are genetically susceptible.

Smoking Cannabis can be particularly harmful to the lungs, whether mixed with tobacco or not.

Production countries

According to a 2011 report on drugs by the United Nations Office On Drugs And Crimes (UNODC), Cannabis is the most widely grown illegal drug in the world, and is produced in virtually every country. It goes on to say that the ‘grass’ or herbal form of the drug – the dried buds and leaves- are generally consumed in or near their country of origin, while Cannabis in its resin form is more often trafficked internationally between regions. This trafficking occurs in a variety of ways, by boat, through land borders and even by air.

Afghanistan is thought to be the largest producer of the drug worldwide, while large-scale cultivation also takes place in Morocco, India, Lebanon, Turkey and a number of South/Central American countries. In these countries it is often grown in large scale plantations, in some cases by independent farmers and in others by powerful drug cartels.

But the plant is also grown substantially in more temperate climates, such as the US, the UK and many other European countries, usually indoors using specialised but not difficult to obtain equipment for growth and cultivation. The ease with which the plant can be grown is evident in the fact that is produced not only by organised drug gangs in large-scale warehouse-type settings, but also by small-scale producers in their own homes.

These many different sources of supply for the drug have made it increasingly difficult for authorities to prevent its cultivation, sale and consumption both domestically and internationally.

According to the UN, it is more trafficked and more easily available than any other illegal drug, and although regular seizures are made by the authorities, little is done to stem the supply to users across the globe. While in localised areas certain types of Cannabis may be in short supply at times due to interceptions of trafficked shipments, users are rarely unable to acquire the drug.

Cannabis consumed by users usually arrives on the ‘street’ via a number of different means. Firstly, it may be trafficked from overseas by organised criminals and drug smuggling gangs. In this case, the drug is grown on expansive plantations hidden from or out of reach of the local authorities. It will then be processed to collect the resin of the plant, and the THC-rich leaves, buds and stems. The latter will be dried and is more suited to local consumption due to its ‘freshness. The resin of the plant will be hardened and packaged into large ‘bars’ which can then be smuggled in large quantities across international borders.

Once the smuggled resin reaches its destination it will gradually filter out in smaller quantities to street level dealers, who may in turn sell it on to lower level dealers, who will then sell it to Cannabis users.

Another route for Cannabis to arrive on the street that it is grown illegally domestically in large warehouses equipped with heat lamps and other specialist cultivation equipment. It will then be sold to dealers locally and elsewhere in the country.

Such large-scale operations are often discovered by the authorities due to the large amounts of electricity used to power the equipment, and helicopters equipped with thermal equipment are also used to spot the substantial heat that these methods generate.

Finally, some users and advocates of the drug have been known to cultivate a small number of plants on their own property using the aforementioned methods. These types of Cannabis growing activities usually have a limited scope, and users may retain much of the harvest for their own consumption, and in some instances also supply it to friends, friends of friends and so on.

Regardless of the means of production, once the drug reaches street level dealers it will usually be split up and weighed before sale. In the UK for instance, users buy Cannabis in fractions of an ounce, such as an ‘eighth’ or a ‘quarter’.

Due to the disparate nature of cannabis production and the fact that it is produced all over the world, drug experts have been unable to determine how much of it is produced annually worldwide with any degree of accuracy. The UNODC has however estimated that the equivalent of 200,000 – 642,000 hectares of land is used to grow Cannabis globally.

Production of Cannabis, whether small-scale ‘home-grown’ operations, mass plantations or hydroponic warehouses, is severely punished in many countries. Controversial new guidelines in the UK however have reduced the penalties given to growers of less than nine plants, so that they may avoid a prison sentence.

Facts and stats


  • Cannabis is the most widely abused illegal drug in the world
  • It is a product of the Cannabis plant which is essentially a weed in some parts of the world, leading to the common name ‘weed’ being used for its dried leaves and other parts of the plant.
  • The active chemical that produces the ‘high’ in Cannabis is called tetrahydrocannibinol (THC). This creates its effects by binding to cannabinoid receptors in the brain.
  • The most common way of taking it is to smoke it through a ‘spliff’, ‘joint’ or ‘reefer’ – a long cigarette containing Cannabis. This will often be mixed with tobacco, and can lead to a secondary nicotine addiction in some users.
  • Cannabis is illegal in many countries, though not in all. In Holland it has been decriminalised, and possession of a small amount is generally not prosecuted. Many cities there, such as Amsterdam have a culture of ‘Cannabis cafés’ in which it can be bought and smoked. While cannabis is not technically legal there, as a ‘soft drug’ it is tolerated in small quantities.
  • Use of cannabis has been linked to profound and permanent mental health problems
  • Cannabis has been found to be effective in treating some medical problems, such as Parkinson’s disease, multiple sclerosis and Glaucoma, as well as an analgesic for the relief of chronic pain. In some countries and areas it has been decriminalised for these purposes.
  • Frequent Cannabis use can lead to paranoia, depression, mood swings and decreases in cognitive functioning. Instances of psychosis have also been reported.
  • Tolerance can develop over time, so frequent users require gradually stronger doses of the drug to get the same effect.


  • In the UK, possession is punishable by up to five years in prison, while intent to supply carries a maximum sentence of 14 years. Such sentences are however rarely enforced in the case of small-time casual users.
  • According to a survey on British crime in 2011, 30.6% of adults (aged 16-59) in England and Wales admitted using cannabis at some point in their lifetime. 6.6% said they had used it in this previous year, and 3.9% in the last month, making it the most frequently used drug by far.
  • In Scotland in 2010, 28.3% of 16-64 year olds said they had tried cannabis at some point in their life, 7.6% in the previous year, and 4.5% in the last month.
  • In 2009, the number of UK under-18’s accessing help for cannabis abuse was 13,123.
  • The UNODC estimated that Cannabis was used by 125- 203 million people around the globe in 2009. When contrasted against the estimates for total illicit drug use in that year – 149-272 million – Cannabis’ role as the most abused illegal drug in the world is clear.
  • 70% of ‘herbal’ (weed) Marijuana seizures by authorities took place in North America.
  • In 2009, 1,261 metric tonnes of Cannabis resin were seized globally
  • 35% of Cannabis resin seizures in that year took place in Spain, with Morocco being the most frequent source country. Pakistan saw 16% of global seizures, and Morocco 15%. The entire North American region saw only 0.8% of resin seizures, illustrating that different types of cannabis are prevalent in different areas of the world.

Addiction Signs

There is no conclusive evidence to suggest that Cannabis is physically addictive in the chemical sense, but psychological dependence and addiction to the drug is well documented.

In some cases, users begin to crave the drug for the feelings it gives them, and they will continue to take it frequently, in spite of knowing of the detrimental effects it may be having on their lives, health and relationships.

The signs of heavy and long-term cannabis use are relatively easy to spot. Users may become sluggish and appear to be not ‘entirely with it’ for much of the time. Their responses, both verbal and physical may appear delayed. Cannabis has also been linked to decreased mental agility and academic performance.

One of the most noticeable signs of Cannabis addiction is changes in behaviour and attitude. Frequent users may appear to ‘not care’ about issues in their life that they might have done previously. Often they will centre their day around consumption of pot, and may even turn down social events and activities that do not facilitate their pot smoking. They may appear to have a voracious appetite, as they will frequently get ‘the munchies’ and may gain significant amounts of weight over a short period.

Drug paraphernalia may also suggest an addiction to cannabis. Cigarette paper packets with strips of cardboard torn out from the outer packaging are often an indicator of ‘roaching’- making a small cardboard insert to help them hold and use their joint. Colourful pipes, ‘bongs’ and other devices may also be found on their person or in their possessions. Finally, small dark lumps of a hard, crumbly substance (resin), or a dry greenish herbal material may be found in tobacco tins, wrapped in cling film, or in small ‘baggies’.


Though Cannabis is not thought of as being physically addictive in the same way that drugs like Heroin or Cocaine are, it does have many of the hallmarks of addiction. Users may experience temporary withdrawal symptoms when they attempt to stop smoking it, including irritability, depression, nausea and an intense desire to take more of the drug.

For many long term users, Cannabis has become an integral part of their lives, and so giving up the drug may seem like a radical step, and in some cases does involve an entirely different way of living.

Though Cannabis use is often thought of as an ‘acceptable’ and ‘safe’ form of drug use, it can have a highly detrimental effect on the individual’s wellbeing and their inter-personal relationships when it is abused. Heavy users often lose touch with reality to a greater or lesser extent, and may care about little other than consuming more of the drug to get high.

The problem of addiction, and denial of it, can be enhanced by behaviours that lead the user to spend greater amounts of times with fellow Cannabis users, who view the drug as ‘normal’. Such social circles can reinforce and validate use of Cannabis for the individual.

In order for the user to be treated for their addiction to Cannabis, they must first admit that they have a problem. This is often self-realised over time when the individual is able to see objectively the effect that Cannabis has had on their life. In other cases, intervention by family or friends may occur, particularly when the detrimental effects of Cannabis use have become substantial and highly visible.

It is relatively rare for a drug user to enter a rehabilitation facility as an inpatient to come off the drug, although it is not unheard of. In cases where psychological functioning has been severely impacted or the drug has brought on a pre-existing mental condition this may be a route worth considering.

In serious though lesser cases of Cannabis abuse, a self-help route is often recommended, sometimes accompanied by attending support groups or even talking therapy sessions.

In the UK, the NHS may be able to assist through their substance misuse and recovery programs, and similar government help exists in other countries.

In many cases, recovering from a Cannabis addiction is a case of ceasing use of the drug and then actively adjusting to life without the substance. Particularly heavy users may wish to gradually reduce and taper off their consumption, though without monitoring this approach may fail. Because of the strong emotional dependency and the powerful cravings that can take place, effective coping strategies need to be developed, and social support for the recovering user can be crucial in preventing relapse into drug-taking behaviours.

In some cases, although by no means a majority, cannabis use is secondary to other substance addictions, and these addictions may need to be treated prior to Cannabis cessation or as part of a comprehensive addiction treatment programme.

For most users though, Cannabis is a primary addiction, and though it has been suggested that it may be a ‘gateway’ to harder drugs, statistics indicate that this is not common.