Cannabis is also known as marijuana, Mary Jane, dope, pot, spliff, hash(ish), weed, puff, grass, herb, draw, wacky backy, smoke, ganja, hemp, or skunk which is a much stronger variety.
It’s a psychoactive (mood changing) drug made from the buds or flowers of the cannabis plant. It can come as a block of soft, greenish/brown resin or can look like dried herbs, in which case it’s known as weed, marijuana or grass. THC (delta-9-tetrahydrocannabinol) is the main active chemical in the drug that causes the high.
Cannabis resin is usually mixed with tobacco and smoked in joints. It can be smoked using a bong which is a kind of water pipe, eaten, for example baked in cakes, or drunk in warm drinks.
You can be high or stoned for up to four hours after taking cannabis. This can make you feel chilled out, sociable, talkative and giggly. You might feel you have new insights into life and experience touch, sounds and colours differently. It can also cause a distorted sense of space and time, and you might hallucinate. Cannabis can also make you feel hungry, sleepy or light-headed, and it can dull pain.
Cannabis can leave you feeling ‘woolly headed’ and can cause short-term memory loss, confusion, co-ordination difficulties, and slower reflexes which makes driving dangerous. Higher doses can make you feel sick, anxious, paranoid, or panicky.
Cannabis can make you feel horny, increase your sense of touch and lower your inhibitions. If you take too much its tranquillising effects get in the way. Orgasms may seem weaker but more sensual and not just felt in the dick. There can be a stronger sense of connection to who you’re with, with sex being more ‘touchy feely’.
But the drug can also make people feel withdrawn and less interested in sex. If you smoke it with tobacco, you have the same long-term higher risk of erection problems that cigarette smokers have.
You can become dependent on cannabis. It can leave some people with a poor memory and less able to concentrate or stay motivated -- the classic ‘dope head’.
Researchers are looking at the link between cannabis and mental illness as the drug seems to trigger mental health problems, including schizophrenia, in a small number of people. This is more likely to happen in people who already have depression or anxiety or who are vulnerable to mental health problems, although they usually won’t know they’re vulnerable.
Mental illness seems more likely if you use cannabis as a teenager, if you use it a lot, or if you use the stronger types.
Tobacco – smoking cannabis with tobacco has a high risk of addiction to nicotine and smoking-related illness like cancer, heart disease and breathing problems. People smoking both cigarettes and cannabis take in very high levels of cancer-causing tar.
Alcohol -- using cannabis and alcohol together can have negative effects. You may feel sick or lose track of how much of each substance you've taken. This also leaves you open to taking risks you might not otherwise.
HIV drugs – there are no known dangerous interactions, however, one study has shown that marijuana decreases the levels of Atazanavir in the blood.
Cannabis smoke contains more harmful substances than cigarette smoke.
Smoking it with tobacco has the same health risks as smoking cigarettes, such as cancer, chest and breathing problems. The risk may be higher because cannabis smokers breathe in deeper and for longer.
Eating it gets round these drawbacks but it’s harder to control the dose and the effects can be much stronger than you might want.
Using bongs is more harmful than joints because you breathe in more drug and smoke.
Cannabis is illegal. In 2009 it was reclassified upwards from a Class C drug to Class B. Possession can now mean up to five years in prison and/or an unlimited fine. Intending to supply cannabis, which includes giving it to your mates, can mean up to 14 years in prison and/or an unlimited fine.
You can be arrested, taken to a police station and can expect a reprimand for your first offence, a final warning for your second offence or a criminal charge if it's your third offence.
You can expect a warning for your first time offence, a £80 on-the-spot fine for your second offence and a criminal charge on your third offence.
This new 'three strikes' penalty system applies to England and Wales. In Scotland and Northern Ireland the traditional penalty system covering class B drugs applies instead.
The law treats smoking cannabis openly in public or near children, for example, near a school, more seriously.
Driving under the influence of cannabis can lead to the same penalties as drink driving.
Growing cannabis plants is illegal, so is letting people smoke it in a place you’re responsible for, like your home.
Read our page on Drugs and the police for advice if you’re arrested.
This article was last reviewed on: 28/10/11
Date due for next review: 28/10/13