Cannabis Use

Editor: Justin Healey
ISBN 978 1 921507 22 9
Year 2010

Price: $20.95

  

Cannabis Use
Volume 311, Issues in Society

Cannabis (marijuana) has been used for medical and recreational purposes for thousands of years. It is the most commonly used illicit drug in Australia. According to the latest national survey, over 5.5 million people have used it. This book comprises two chapters: Cannabis and Health; and Cannabis and the Law. What are the short and long term health effects of this depressant, especially on those who are dependent? The association between cannabis use and psychotic disorders is well established, however there is still considerable debate over a possible causal relationship between cannabis use and mental illness. The use, possession, cultivation and sale of cannabis is illegal throughout Australia, though several states and territories have decriminalised minor cannabis offences. Should cannabis be decriminalised, or even legalised – or should law enforcement take a stronger abolitionist approach, before the whole nation goes to pot?

Glossary; Fast Facts; Web Links; Index



fast facts
FAST FACTS from this volume
  • Cannabis is referred to as a ‘depressant’ drug in that it affects the central nervous system, slowing down the messages between the brain and the body.
  • Consumption of large quantities of cannabis on almost every day of the week is likely to lead to the neglect of some important priorities such as relationships, parenting, careers and community responsibilities. However there is currently a lack of robust evidence for an amotivational syndrome (characterised by a loss of motivation, energy and initiative) associated with the use of cannabis.
  • Dependence on cannabis involves compulsive use but not usually physiological dependence.
  • Although the number of people seeking assistance for treatment of cannabis increases and research indicates that cannabis can be addictive there has been little research on the effectiveness of treatment options for cannabis misuse.
  • The gateway hypothesis is that the use of cannabis may act as a ‘gateway’ to the use of other illicit drugs such as cocaine and heroin. It is a controversial hypothesis with proponents arguing that the use of so-called harder drugs is almost always preceded by cannabis use. The alternative theory to the gateway is known as the ‘common cause’ theory whereby the use of cannabis and other illicit drugs is due to a range of common causes such as socio-economic circumstances and personal factors.
  • Research indicates that the introduction of liberal drug laws may result in a slight increase in temporary drug use but that it is unlikely to increase, and may even decrease, drug-related health costs.
  • In Australia, cannabis is most usually taken as a cluster (“cone”) of the flowering heads of the female plant. The next most common form used is leaf. It is, much less commonly, produced in two other forms “hash”, which is the resin produced by the plant, and “hash oil”, which is the concentrated resin. Cannabis can be taken in a variety of ways. It is usually smoked using a “bong” or a “joint”.
  • The Australian Medical Association considers cannabis may be of medical benefit in HIV-related wasting and cancer-related wasting; and nausea and vomiting in people with cancer, undergoing chemotherapy, which does not respond to conventional treatments.
  • Cannabis consists of some 60 chemicals which are technically termed ‘cannabinoids’. The prinicipal one is delta-9-tetrahydrocannabinol, known as THC.
  • The various parts of the marijuana plant differ widely in their concentration of THC. Leaf typically contains between 0.5%-4%. The flowering heads contain about 3-4 times this concentration. Hash contains about 4-20% THC concentration. The relative concentration of the cannabinoids varies between plants. This may explain the different effects that various forms of cannabis have on people.
  • How cannabis affects the brain is gradually being revealed. Like other drugs such as heroin, alcohol and cocaine, cannabis causes the brain to produce more of a chemical named dopamine. This seems to be the mechanism by which it results in a feeling of euphoria.
  • Heavy cannabis use can cause dependence. Cannabis use over time causes a range of respiratory (breathing) problems, such as wheezing, episodes of bronchitis, aggravation of asthma and chronic obstructive airways disease.
  • Most people who experience psychosis after cannabis use have a vulnerability to developing a mental health disorder or actually have such a disorder. Cannabis use by these vulnerable individuals may trigger an episode of their illness. In addition people who have a family history of mental illness (and this may not be known by many people) may experience negative mental effects, including episodes of psychosis, if cannabis is used regularly.
  • While there are serious concerns about the potential effects of cannabis use on memory and learning, it is still unclear whether cannabis causes lasting problems in these areas. Adolescent cannabis use has been linked to a range of social problems. Many of these effects may be due to younger cannabis users being more likely to mix with peers who are involved in a range of risky behaviours.
  • Around one in ten people who ever try cannabis will become dependent on it at some point in their lives.
  • The association between cannabis use and psychotic disorders appears to be well established. However, there is still considerable debate over whether there is a causal relationship between cannabis use and mental health problems.
  • A study of more than 3,800 21-year-olds has revealed those who use cannabis for six or more years have a greater risk of developing psychotic disorders or the isolated symptoms of psychosis, such as hallucinations and delusions.
  • It is illegal to use, possess, grow or sell cannabis in Australia, but the penalties for cannabis offences are different in each state and territory. In some states, if someone is caught with a ‘small amount’ of cannabis they may be given a $50 fine, while in other states they may be charged with a criminal offence and receive a much larger fine, or even be sentenced to jail.
  • Despite decreases in reported use, cannabis remains the most commonly used illicit drug in Australia. Cannabis accounted for 67 per cent of national drug arrests. This proportion is consistent with previous years. Cannabis was also the most seized drug in 2007-08, representing 68 per cent of all seizures in terms of number and 64 per cent in weight.
  • Marijuana/cannabis is the most used illicit drug in Australia across all age groups. In 2007, over 5.5 million people aged 14 years or older (33.5%) had used marijuana/cannabis in their lifetime and more than 600,000 people had used it in the week before the survey (3.5%). Males were more likely than females to have used marijuana/cannabis in their lifetime (37.1% compared with 30%). People aged 20-29 were most likely to have used marijuana/cannabis in the previous month (one in ten or 11.1%).
  • The majority of recent users of marijuana/cannabis (87.3%) had used alcohol at the same time, according to the 2007 National Drug Strategy Household Survey. Almost three in ten recent users (28.3%) had used ecstasy or a designer drug at the same time. Males were more likely to have used another drug with marijuana/cannabis than were females for all other drugs except antidepressants (males 5.1%, females 7.7%).