What is cannabis?
Cannabis is the short name for the plant Cannabis sativa. Cannabis contains a chemical called THC (Delta-9 tetrahydrocannabinol). THC is a mind-altering drug. People usually take it for the effects it has on their mood and their feelings. THC is also a depressant drug, that is, it slows the brain down, particularly if taken in high doses. It can give people hallucinations, make them feel sedated or sleepy or it can act as a stimulant.
Marijuana is the dried leaves and flowers of the cannabis plant. It may range in colour from green to grey or brown. It may be fine like dried tea, or leafy. Marijuana is usually smoked as a rolled cigarette, but it can be eaten if combined with food (eg, baked in cookies). Other names for marijuana include dope, pot, grass, spliff, dak, buds, ganga, hooch and weed.
Hashish, commonly referred to as hash, is made from the resin of the cannabis plant. Hashish is often sold in hard cubes and may be brown to black in colour. It is usually smoked with tobacco (rolled into a cigarette) but can be eaten as well. Hashish is more potent or powerful in its effects than marijuana.
Hashish oil is a concentrated form of hashish. It is very potent and small amounts can produce marked effects. Marijuana, hashish and hashish oil are often taken through a pipe or bong which cools the smoke through water. Sometimes hashish oil is taken by a process called spotting. Spotting involves heating implements to combine with hashish to produce smoke (often cutlery knives are used on a stove). Burnt tips of knives are usually a sign they have been used for this purpose.
Improved cultivation of cannabis has produced significant increases in the amount of THC in marijuana over the past decade.
Cannabis use is illegal in New Zealand. People who use or sell it can be charged under the Misuse of Drugs Act (1975).
How cannabis works
When smoked, cannabis is rapidly absorbed through the lungs into the blood, its level peaking in the blood about 30 minutes after being taken. However, cannabis is highly lipid soluble - that means it is attracted to fat cells. It is quickly taken from the blood and stored in fat cells. The THC is then released very slowly, and unevenly, back into the blood.
Different figures are sometimes quoted about how long THC can remain in the body's fat stores. The general answer is that it stays in the body for a very long period compared with other drugs, potentially for several months.
Effects of cannabis use
It is not possible to accurately summarise or predict the immediate effects of using cannabis because each person may experience individual and different effects.
These effects will depend on:
- how much cannabis is taken, the way it is taken and the form in which it is taken
- how strong it is
- how experienced the user is
- the general physical health of the user
- the mental health of the user
- the user's mood when they start taking the drug
- the setting in which they take the drug
- whether other drugs are taken as well.
Although cannabis is a depressant or brain-slowing drug, people often say that being intoxicated (stoned, wasted, out of it) is a very stimulating experience. The user feels very happy or high, loose or uninhibited.
Some people find that using cannabis is a negative experience. They may feel anxious, self-conscious or have paranoid thoughts. Some experience acute anxiety and panic.
People who are intoxicated on cannabis usually feel more sensitive to things around them and sensations can seem different. For example, time can seem to slow down, colours seem brighter and richer and new details and meanings can be seen in things. People concentrate less well, often talk and laugh more than usual and can have problems with their balance.
Physically, the pulse rate increases (from between 20 to 50 per cent above the usual heart rate), the eyes become bloodshot, appetite often increases (they get the 'munchies') and coordination can be affected, making activities such as driving a car or operating machinery difficult and dangerous.
If large doses of cannabis are taken, the resulting toxicity can cause symptoms of confusion, paranoia, panic attacks, hallucinations and feelings of unreality. New users may also experience acute paranoid experiences which usually stop after intoxication wears off.
Cannabis also often impairs short-term memory and attention and makes it harder to complete complex tasks, ie, tasks which involve doing several things at once.
What about during pregnancy?
There is some evidence that women who smoke cannabis during the time of conception or while pregnant may increase the risk of their child being born with birth defects. Pregnant women who continue to smoke cannabis are probably at greater risk of giving birth to low birthweight babies.
Longer-term and chronic effects
A number of longer-term effects have been seen in people who use cannabis heavily. Some New Zealand researchers define heavy use as using 10 times or more in a 30-day period.
Heavy cannabis use effects can include the following.
- An increased risk of developing cancer of the respiratory tract. These risks are more likely to do with smoking as the method of taking cannabis, rather than the properties of the drug itself.
- An adverse effect on people with pre-existing cardiovascular disease, since cannabis use significantly raises the heart rate. (There is no evidence that cannabis use will cause permanent damaging effects to a normal, healthy cardiovascular system.)
- A risk of developing chronic bronchitis, possibly irreversible obstructive lung disease, possibly lung cancer and cancers of the aero-digestive tract.
- Heavy use of cannabis is sometimes associated with a reduction in energy and drive. This has been referred to as "amotivation" (not having any motivation). This problem is more likely to be an acute effect which will go away if cannabis use stops. There is poor evidence of this syndrome existing even among heavy, long-term cannabis users.
- Heavy cannabis use affects the ability to learn. This is related to decreased concentration levels, reduced short-term memory and difficulties with thinking. These problems go away if cannabis use stops.
- Chronic, heavy cannabis use can reduce sex drive in some people. It can lower sperm count in males and lead to irregular periods in females. This problem goes away if cannabis use stops.
- People can become dependent on cannabis (see Cannabis - overcoming problem use).
Many people with mental health problems also use cannabis. Generally, it is not a good drug for such people to use. People with mental health problems need to try to keep their brain level or stable. Cannabis excites and then slows the brain down. In particular, it can make anyone who has ever been paranoid, more paranoid.
People who use cannabis include those:
- who have experimented once or twice, usually out of curiosity about the effects
- who use it occasionally or in a social situation
- whose use is problematic
- who experience serious cannabis and cannabis-related problems.
See also: Cannabis - what is your level of use?
Cannabis - acknowledging problem use;
Cannabis - overcoming problem use
See the support organisations (which include helplines) under Further information and support below.
Original material provided by the Mental Health Foundation of New Zealand, 2002. Edited by everybody, June 2005.