Cannabis
Effects
Tolerance and dependence
Cannabis and driving
Cannabis and adolescent development
Cannabis testing
Cannabis as a 'Gateway' Drug
Cannabis and psychosis
Cannabis and the law
Further Information
Cannabis
Cannabis is a general term given to drug products derived from the cannabis plant. Cannabis (or marijuana) usually refers to the dried flowers and leaves of the plant, which are smoked or eaten to produce a psychoactive effect. Other names for cannabis include grass, dope, pot, weed, and mull. The main active ingredient in cannabis that produces a 'high' is called delta-9 tetrahydrocannabinol, or more commonly, THC.
The cannabis plant has green foliage and flowering tops which range in colour from green to various muted shades of brown, red, gold, orange or purple. The dried flowers, or 'heads', have the highest THC concentration of the cannabis plant. Hashish or hash is the dried resin from the heads of the cannabis plant, and ranges in colour from light brown to nearly black. It is a more concentrated form of cannabis, with higher levels of THC. Hashish oil is a thick oil obtained from the heads or leaves of the cannabis plant. It usually has very high concentrations of THC.
Cannabis in its various forms is often smoked in a 'joint', which may sometimes include tobacco as filler. Heads may be smoked in a small pipe or larger water pipe (a 'bong'), a pipe-full usually referred to as a 'cone'. Hash or hash oil may be added to tobacco cigarettes, joints or cones. The different forms of cannabis can also be eaten mixed with food.
Cannabis is the most commonly used illegal drug in Australia. In South Australia, adults found possessing or using small amounts of cannabis can be issued with a Cannabis Expiation Notice, or 'on-the-spot fine'. Payment of the prescribed expiation fee means that a criminal conviction for a drug offence is avoided.
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Effects
Short-term effects
When cannabis is smoked, the effects usually commence within a few minutes, and last for 2 to 3 hours, with a peak in the first hour. When it is eaten, the effects are slower to commence, last longer, and may be experienced as more intense. The initial effects from smoking or eating cannabis may include:
- laughter and talkativeness
- feeling of well-being
- some loss of concentration, problem-solving ability and short-term memory
- slower reaction times (which means that driving ability is impaired)
- changes in heart rate and blood pressure (sometimes including a drop in blood pressure on standing , which can result in dizziness)
- increased diameter of larger air passages in the lungs
- bloodshot eyes
- altered perception of time
Sometimes, novice users or people who have consumed large amounts of cannabis may experience problems such as:
- confusion
- anxiety or panic attacks
- feelings of paranoia
No one has died of a cannabis overdose.
Long-term effects
Regular and continued use of cannabis may cause or contribute to a number of health problems, including:
- a chronic cough, wheeze, shortness of breath, or chronic bronchitis - cannabis smoke contains many substances which irritate the airways, and many smokers tend to hold the smoke in for longer, which aggravates respiratory problems
- an increased risk of cancers of the lung, mouth, throat and tongue - cannabis smoke contains numerous carcinogens
- an increased risk of psychotic symptoms, especially if the person has a history of psychotic illness, such as schizophrenia
- cannabis dependence
- reduced fertility in both men and women
- an increased risk of low birth weight babies, or possible birth defects, if cannabis is used during pregnancy
Other problems
A number of other problems can be caused or made worse by involvement with cannabis:
- decreased motivation or energy to accomplish tasks
- poor school or work performance
- family and relationship problems
- legal problems - cannabis and its use are illegal, so users may come to the attention of police, and receive fines and criminal convictions
-
financial problems - from buying cannabis, or paying fines/fees
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Tolerance and Dependence
Cannabis dependence and tolerance are quite common among regular users of cannabis. Tolerance means that the user requires more cannabis to achieve the same effects they used to get with smaller amounts. Dependence, or addiction, means that cannabis has become central in their life, they may spend much of their time thinking about cannabis and obtaining it, they may have trouble controlling their use, or continue to use cannabis despite experiencing problems.
Dependent users who abruptly stop their cannabis use may have mild withdrawal symptoms, such as sleep disturbance, anxiety and irritability.
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Cannabis and Driving
Performance of complex tasks such as driving motor vehicles is impaired after smoking even small amounts of cannabis. Higher doses result in poor performance of simple manual tasks. The degree of impairment depends on the amount of cannabis consumed.
While cannabis affects driving performance in different ways from alcohol, and may make some drivers overly cautious on the road, drivers under the influence of cannabis are still impaired and putting themselves and others at risk.
The use of cannabis and alcohol together, or separated by a few hours, besides making some of the unpleasant effects of both drugs much worse (e.g. nausea), can severely impair driving. These effects on driving of the two drugs taken together are considerably greater than the effects of either substance taken alone.
Information on Cannabis Laws in South Australia
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Cannabis and Adolescent Development
Prolonged use of cannabis impairs young people's ability to learn and develop social skills, and lowers achievement in a number of areas. Young users may observe that performance at school or work suffers. Some describe decreased concentration, poorer memory, and problems with learning. Regular users may find that they begin to lose energy, drive and interest in other activities. Furthermore, they may spend less time with friends who do not use cannabis, and those friends may feel that cannabis use has had a negative effect on their using friend's motivation and attitudes. These problems usually disappear gradually when cannabis use stops.
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Cannabis Testing
THC and other compounds from cannabis can be detected in the blood and urine for some time after cannabis has been used. These compounds can be stored in body fat, to be gradually excreted from the body. For infrequent users of cannabis, a single occasion of use may be detectable in the urine for several days. Long-term heavy users of marijuana may have cannabis compounds detectable in their urine for many weeks after their last use of cannabis. However, it is difficult to determine how recently a person has used cannabis from blood or urine tests.
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Cannabis as a 'Gateway' Drug
Cannabis does not of itself necessarily lead to the use of 'harder' drugs such as heroin. While most heroin users have used cannabis at some time, most users of cannabis will never become users of heroin.
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Cannabis and Psychosis
Cannabis can produce unpleasant experiences for some users, usually when too large a dose has been taken, resulting in anxiety, panic reactions or paranoia. These reactions last only as long as the effects of the drug. Inexperienced users who have such reactions may not care to try marijuana again for a long time, if at all.
Occasionally, people who use large amounts of cannabis over an extended period may experience a short-term psychotic reaction, with symptoms such as confusion, delusions, hallucinations, anxiety, and loss of memory. These cases of 'toxic psychosis' are uncommon and generally show a rapid recovery after cannabis use is stopped.
Cannabis use can also sometimes precipitate psychotic episodes or symptoms in vulnerable individuals, such as people who have schizophrenia. For people with schizophrenia, cannabis use is likely to aggravate their symptoms, and should be avoided. People with a family history of schizophrenia should also avoid using cannabis.
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Cannabis and the Law
In South Australia, cannabis is prohibited, and possessing, using, cultivating, selling, or dealing in cannabis is illegal. Offences relating to personal possession or use of cannabis or related smoking equipment by adults can be dealt with by paying an on-the-spot fine, which results in the offender avoiding a criminal conviction.
More information on cannabis laws in South Australia
Drug Driving
In South Australia, legislation introduced from 1 July 2006 enables police to conduct random roadside saliva tests to detect the presence of THC (the active component in cannabis), methylamphetamine (speed) and MDMA (ecstasy).
Under the Road Traffic Act it is an offence to drive or attempt to drive a motor vehicle with THC, methylamphetamine or ecstasy present in your oral fluid or blood.
Penalties for refusal or failure to undertake a drug screening test, oral fluid analysis or blood test will also apply.
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Further Information
Alcohol & Drug Information Service
(24-hour information and counselling)
Tel: 1300 13 1340
(South Australian callers - local call fee)
National Cannabis Prevention and Information Centre
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