What is cannabis?

Bhang, black, blast, blow, blunts, Bob Hope, bush, dope, draw, ganga, grass, hash, hashish, hemp, herb, marijuana, pot, puff, Northern Lights, resin, sensi, sensemilla, skunk, smoke, spliff, wacky backy, weed, zero etc.

Cannabis is a drug derived from a bushy plant found wild in most parts of the world and easily cultivated in Britain. There are three varieties of the plant, Cannabis sativa, Cannabis indica and Cannabis ruderalis. In Western countries it is generally used as a relaxant and mild intoxicant.

cannabisThe most important psychoactive ingredients in cannabis are the tetrahydrocannabinols (THC).

Types of cannabis

Cannabis comes in three different forms:

Hash or cannabis resin – A black or brown lump. Not seen in the UK very much anymore.

Herbal/grass/weed/marijuana – This is the most common way to find cannabis.  It is composed of the dried leaves and flowering parts of the female cannabis plant and resembles compressed dried herbs. Skunk is a strong form of herbal cannabis that consists just of the buds and is often grown indoors in the UK.

Cannabis oil – Rarely seen, cannabis oil is a sticky, thick yellowy/brown liquid.

Skunk – Much of the cannabis in use in the UK is homegrown either under grow lights or in greenhouse conditions using ‘hydroponic’ techniques (ie, growing plants in nutrient-rich liquids rather than in soil). This produces a stronger more potent form of the drug which is sometimes referred to as Skunk.  In fact skunk is only one of 100 or so varieties of cannabis plant which have high levels of tetrahydrocannabinol (THC).

Methods of use

Smoking – Probably the most common way to use herbal cannabis is to roll it up in a cigarette (joint or spliff) and smoke it. Sometimes tobacco is included in the spliff.

Inhaling – Sometimes cannabis may be inhaled via a pipe or bong. There have recently been reports of e-cigarettes being used to smoke cannabis – either by using specialised cannabis ‘vapers’ or by turning the cannabis into a liquid which can be used with a normal e-cigarette.

Eating/drinking – Cannabis may be baked into cookies or brownies, mixed with alcohol or brewed into a tea.

When eaten the effects take longer to start but often last longer too. Eating cannabis may result in a large dose being taken in one go, making it difficult to avoid unpleasant reactions.

Dose and price

Regular users might consume one-eighth of an ounce per week. Heavy and regular cannabis users might use that amount in a day. Roughly one-sixteenth of an ounce of cannabis resin would be sufficient to produce four strong joints.

According to Druglink’s Street Drug Trends 2012 Survey, average prices per quarter ounce of standard quality herbal resin were £37. For good quality herbal cannabis the price rose to £55, while for resin cannabis the average price was £27.


Using cannabis causes a number of physical effects including increased pulse rate, decreased blood pressure, bloodshot eyes, increased appetite, tiredness and occasionally, dizziness.

These effects can start within a few minutes and may last several hours depending on how much is taken.

While the effects of use rely on dose and the expectations and mood of the user, cannabis can often lead to a state of relaxation, talkativeness and the giggles. There is also a greater appreciation of sensory experiences such as music and hallucinations may occur with higher doses. It can be taken to enhance or detract from the effects of other drugs such as ecstasy or cocaine, particularly after long dance sessions.

While intoxicated, cannabis can affect the short-term memory, concentration, and intellectual or manual dexterity, including driving. Higher doses can lead to perceptual distortion, forgetfulness and confusion of thought processes. Temporary psychological distress and confusion can occur, particularly among inexperienced users or if the user is feeling anxious or depressed.

The physical effects of inhaling and smoking cannabis can impact on the respiratory system, leading to oral, throat, and lung cancer.

Psychologically, use of cannabis has been reported to cause anxiety and paranoia in some users and studies have suggested that it can be a trigger for underlying mental health problems.

While cannabis does not produce physical dependence, mild withdrawal symptoms have been observed in experiments.

Skunk’s strength and speed can sometimes catch out inexperienced users. Many report that the ‘stoned’ effect can come on rapidly and be disabling. The results can be quite dramatic, including anxiety attacks. Some of the more common effects include:

  • elation
  • profound relaxation
  • alteration of time and perception
  • transient hallucinations, rarely in the same league as LSD, uncontrollable laughing, increased sociability and talkativeness
  • nervousness, anxiety and mild paranoia
  • the ‘munchies’ – a strong desire to eat and continue eating.
  • The law

Therapeutic use

There is growing evidence that cannabis may be effective in providing symptomatic relief for diseases of the muscular-skeletal system like multiple sclerosis. It has also been reported as useful as an anti-nausea drug in chemotherapy, and to relieve intra-ocular pressure in glaucoma patients. In recent years certain parts of the United States, including California, have issued licenses for the medical consumption of the drug.

Following the high profile case of 12 year old, Billy Caldwell, who suffers from severe epilepsy that has been relieved by the use of cannabis oil, the Government have announced (as of June 2018) the granting of licenses for medical use and a review of the scheduling of cannabis. And on 11th October 2018 the Government announced that medicinal cannabis is now legal and that patients can be prescribed medicinal cannabis by specialist doctors in the UK from 1 November 2018.

However, a government report published in July 2019 reveals that parent’s expectations of the availability of therapeutic cannabis are being unfairly raised and that more research needs to be done to determine which patients could benefit – See: Drugs policy: medicinal cannabis, 2019 

See also:

Barriers to accessing cannabis-based products for medicinal use on NHS prescription Findings and Recommendations, 2019, (PDF)
This review was aimed at addressing the following question: Where they exist, what are the barriers to patients accessing cannabis-based products for medicinal use within the NHS where they are clinically appropriate for the patient, and how might these barriers be overcome? | NHS England and NHS Improvement, UK

Cannabis-based medicinal products, 2019
This guideline covers prescribing of cannabis-based medicinal products for people with intractable nausea and vomiting, chronic pain, spasticity and severe treatment-resistant epilepsy | NICE, UK

Legal Status

Cannabis is controlled as a class B drug under the Misuse of Drugs Act.

This means it is illegal to cultivate, produce, supply or possess the drug, except in accordance with a Home Office licence issued for research or other special purposes.

The maximum sentence for possession is 5 years and a fine or both. For possession with intent to supply the maximum sentence is 14 years or a fine or both. This is also the maximum sentence for production and cultivation.

It is also an offence to allow premises to be used for producing, supplying or smoking cannabis. This last type of offence – allowing the use of a drug – applies only to permitting the smoking of cannabis or opium.

Skunk, like most forms of cannabis, is a Class B drug under the Misuse of Drugs Act. Indoor growing systems may be detectable by police helicopters using thermal imaging equipment, while high intensity lights cause unusually large electricity bills. Anyone using a hydroponic system, or growing more than a handful of plants, is likely to be charged with intent to supply, as well as production and possession. If convicted, even small-scale growers commonly face one to two years’ imprisonment, while commercial growers may face longer sentences.

It is rare for maximum sentences to be given and guidelines put out by ACPO (Association of Chief Police Officers) advise police to take an escalating approach to those over 17 possessing cannabis for personal use, with a warning given the first time a person is caught and an on-the-spot fine for a second offence. If an individual is caught three times in possession of cannabis they may be arrested.

Cannabis warnings could be issued to adults from 2004, while khat warnings could be issued to adults from June 2014. According to the Ministry of Justice 2016 statistics there were 36,300 cannabis and khat warnings issued in the latest year, a decrease of 6,300 (15%) from the previous year.

However on 11th October 2018 the Government announced that medicinal cannabis is legal and that patients can be prescribed medicinal cannabis by specialist doctors from 1 November 2018.

For more information on cannabis and the law please see the Release website

United Nations reschedules cannabis –  On 2nd December 2020, the 53 members states of the UN Commission on Narcotic Drugs voted (27 in favour, 25 against, and one abstention) to remove cannabis from Schedule IV of the 1961 Single Convention on Narcotic Drugs. In rescheduling, the UN recognises that cannabis carries fewer risks than other Schedule IV drugs such as heroin. The decision could drive more scientific research into the plant’s long-heralded medicinal properties and follows recommendations made by the World Health Organisation in 2019.


There are many calls to legalise cannabis including from Nick Clegg, our previous Deputy Prime Minister who wanted to see a shift from punishment to treatment.

While the UK government has no plans to legalise recreational use of the drug, some countries have decriminalised it, allowing the personal possession of small amounts for personal use. An increasing number of countries are making cannabis legal for medicinal uses and on 11th October 2018 the Government announced that medicinal cannabis is legal in the UK too and that patients can be prescribed medicinal cannabis by specialist doctors from 1 November 2018.

The UK situation – production and prevalence

According to Home Office statistics on drug use in from 2018  cannabis continues to be our most commonly used illegal drug, with 7.2 per cent of adults aged 16 to 59 having used it in the last year.

While the UK has a long history of importing cannabis resin, particularly from North Africa, the home grown market expanded significantly over the course of the 2000’s. A 2012 report from the Association of Chief Police Officers found that herbal cannabis cultivated in farms, often located in rented properties and commercial units, now makes up around 70 to 80 percent of the commercial supply. Over 1.1 million plants with an estimated street value of £207 million were recovered during the 2011/2012 survey period.

A gateway drug?

It is often suggested the taking of one drug, particularly cannabis, may lead to the use of other drugs. While it is true that most people who use heroin will have previously used cannabis, they are also likely to have smoked tobacco and consumed alcohol. Only a small proportion of those who try cannabis go on to use heroin. Importantly, though, cannabis use involves people in the buying of illegal drugs, making it more likely that they will meet with an offer of other drugs. In this example, it would be the illegality of cannabis use rather than cannabis use itself that leads most directly to contact with heroin.

See also DrugWise’s printable cannabis factsheet (PDF)


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