Information about Cannabis

Cannabis (marijuana, weed, pot, hash, ganja, skunk) is the leaves and flowering tops of the cannabis plant. These are dried and smoked (often called ‘weed’ or ‘green’) whereas hash or resin refers to a sticky resin scraped from the leaves and solidified. Both the dried leaves and resin can be smoked in rolled ‘joints’, in a pipe or ‘bong’ or eaten.

Some people also use cannabis oil, which is very strong and can be added to cigarettes and smoked or inhaled through a special vaporiser. The active ingredient in cannabis is tetrahydrocannabinol (THC). Cannabis is a Class B drug; for more information about drug classifications and swentences, click here.

Effects generally begin within a few minutes after smoking and can last up to a couple of hours depending on how much is taken. If eaten, the effects take longer to start (sometimes over an hour), can last up to 12 hours, and can be much harder to control.

Effects: Physical effects include increased pulse rate, decreased blood pressure, bloodshot eyes, dry mouth, dizziness, and increased appetite (‘the munchies’). Usual psychological effects include relaxation, feeling more sociable and talkative, greater awareness of your own and other people’s emotions, a distorted perception of time and greater appreciation of music and colour. Some people find cannabis helps with pain relief. Inexperienced users may find the effects a bit overwhelming. Negative psychological effects like forgetfulness, confusion, paranoia, anxiety and panic attacks are also reported, and are more common with higher doses.

Risks: The risk of overdosing from smoking cannabis is very low – the few reported deaths due to a single use of cannabis alone (with no other drugs involved) have been due to inhaling vomit while unconscious. However, there are longer-term health risks such as increased risk of chest infections and lung cancer. Smoking cannabis while pregnant can cause effects similar to smoking tobacco, such as low birth weight. Some people find that they have less motivation (for things like work or college) when they have been smoking cannabis, but these effects are often temporary. There is growing concern about the possibility that THC may trigger mental health problems in some people or make existing conditions worse. 

There is some debate over whether cannabis is physically addictive – some people may experience severe withdrawal symptoms when they stop using it including restlessness, anxiety, insomnia and digestive problems, while other people stop using with no effects at all. Some people can also become psychologically addicted to cannabis and may feel that they cannot face the world without being stoned.

Minimising the risks: Most people find that the effects of smoking cannabis are easier to control and less overwhelming than eating it. Heavy long-term cannabis use is associated with greater physical and psychological health risks than occasional use, and people with any mental health issues should not use cannabis as it could potentially make any problems worse.