NCPIC website
The NCPIC website has been undergoing quite a renovation of late, as we expand our resources and make it as accessible and up-to-date as possible for the community. Numerous additions have been made, including over 10 new factsheets, covering all sorts of cannabis-related issues such as ‘cannabis and motivation’ and ‘cannabis in the workplace’. These can be found at: http://ncpic.org.au/workforce/cannabisinfo/factsheets/. A series of Research Briefs has also been produced, which provides commentary on the latest cannabis-related research, giving readers a balanced, evidence-based snapshot of the issues. Find these at: http://ncpic.org.au/ncpic/publications/research-briefs.
Guest editorial
Adolescent cannabis dependence and the quality of early adult life
Around one in six adolescents who use cannabis develop dependence on it 1 and those who do are more likely to use other illicit drugs, perform poorly at school, leave school early, and report psychotic symptoms and disorders 2. There has been a debate about whether cannabis dependence is a contributory cause of these outcomes or the associations are due to pre-existing differences between cannabis users and non-cannabis users in their personal characteristics, social environment or genetic risks 2,3.
Recent research by Fergusson and Boden 4 and Patton et al.5, suggests that cannabis dependence can also seriously impair the quality of life of young people in their mid 20s by: reducing their chances of completing secondary education or pursuing post-secondary education; increasing their chances of being unemployed and dependent on social welfare; reducing their income; and decreasing their overall satisfaction with their lives and their relationships. The interpretative challenge, as always, is to disentangle the effects of this pattern of cannabis use from the characteristics of those young people who are most likely to use it in this way. Adolescents from socially disadvantaged backgrounds, with parental alcohol and drug problems, and poor educational performance in late primary and early secondary school are more likely to become regular cannabis users and to experience some of these outcomes 2.
In favour of a causal interpretation is the dose response relationship between cannabis use and these psychosocial outcomes that persisted after statistical adjustment for confounders. More sceptical researchers (e.g. 3,6) argue that not all relevant confounders have been measured in these studies (although Fergusson and Boden’s study comes the closest to doing so) and the relationships are modest after adjustment in terms of relative and attributable risk 1,6.
If we could successfully intervene to treat cannabis dependent adolescents, we could potentially resolve the interpretive disagreement about the causal role of cannabis. But this will require more effective interventions than those now available 2. Dependent cannabis use is difficult to shift because adolescents who are unhappy with their lot in life find that cannabis use makes a dull and unchallenging life much easier to bear. In males, this pattern of use is often reinforced by heavy cannabis-using peers, who celebrate the virtues of cannabis use and deride the value of a good education and social achievement.
The results of these studies suggest that we should focus more of our prevention efforts on these more common adverse outcomes of cannabis dependence in adolescence, namely, educational and social underachievement that increase the chance of less happy and fulfilled young adult lives. This will mean finding more persuasive ways of discouraging vulnerable, young people from becoming regular cannabis users, and more effective ways of helping those who do so, to disengage. These are both core tasks for NCPIC. They have been among my central interests as a researcher on the health effects of cannabis and they are one of the major reasons that I was pleased to serve as an independent member of NCPIC’s Management Advisory Group.
- Anthony, J.C. (2006). The epidemiology of cannabis dependence. In. Roffman, R.A. & Stephens, R.S. (Eds.). Cannabis dependence: Its nature, consequences and treatment. Cambridge, UK: Cambridge University Press.
- Hall, W.D., Degenhardt, L. & Patton, G. (2008). Adolescent cannabis abuse and dependence. In. Essau, C. (Ed.). Adolescent addiction. Amsterdam: Elsevier.
- Macleod, J., Oakes, R., Copello, A., Crome, I., Egger, M., Hickman, M., Oppenkowski, T., Stokes-Lampard, H., & Davey Smith, G. (2004). Psychological and social sequelae of cannabis and other illicit drug use by young people: A systematic review of longitudinal, general population studies. Lancet 363, 1579-1588.
- Fergusson, D. & Boden, J. (2008). Cannabis use and later life outcomes. Addiction 103, 969-976.
- Patton, G.C., Coffey, C., Lynskey, M.T., Reid, S., Hemphill, S., Carlin, J.B., & Hall, W. (2007). Trajectories of adolescent alcohol and cannabis use into young adulthood. Addiction 102, 607-615.
- Macleod, J. (2008). The natural history of cannabis use among young people and the implications of this for health. Addiction 103, 451-452.
Research publications
Relevant publications examining issues to do with cannabis that have been published in the last month include the following:
Appendino, G., Gibbons, S., Giana, A., Pagani, A., Grassi, G., Stavri, M., Smith, E., & Rahman, M.M. (2008). Antibacterial cannabinoids from Cannabis sativa: A structure-activity study. Journal of Natural Products 71, 1427-1430.
Brecht, M.L., Huang, D., Evans, E., & Hser, Y.I. (2008). Polydrug use and implications for longitudinal research: Ten-year trajectories for heroin, cocaine, and methamphetamine users. Drug and Alcohol Dependence 96, 193-201.
Campos, A.C. & Guimarães, F.S. (2008). Involvement of 5HT1A receptors in the anxiolytic-like effects of cannabidiol injected into the dorsolateral periaqueductal gray of rats. Psychopharmacology (Berl) 199, 223-230.
Comelli, F., Giagnoni, G., Bettoni, I., Colleoni, M., & Costa, B. (2008). Antihyperalgesic effect of a Cannabis sativa extract in a rat model of neuropathic pain: Mechanisms involved. Phytotherapy Research 22, 1017- 1024.
Costain, W.F. (2008). The effects of cannabis abuse on the symptoms of schizophrenia: Patient perspectives. International Journal of Mental Health Nursing 17, 227-235.
de Filippis, D., Iuvone, T., d'Amico, A., Esposito, G., Steardo, L., Herman, A.G., Pelckmans, P.A., de Winter, B.Y., & de Man, J.G. (2008). Effect of cannabidiol on sepsis-induced motility disturbances in mice: Involvement of CB receptors and fatty acid amide hydrolase. Neurogastroenterology and Motility 20, 919-927.
Dorard, G., Berthoz, S., Phan, O., Corcos, M., & Bungener, C. (2008). Affect dysregulation in cannabis abusers: A study in adolescents and young adults. European Child Adolescent Psychiatry 17, 274-282.
Dwivedi, S., Kumar, V. & Aggarwal, A. (2008). Cannabis smoking and acute coronary syndrome: Two illustrative cases. International Journal of Cardiology 128, 54-57.
Grauwiler, S.B., Drewe, J. & Scholer, A. (2008). Sensitivity and specificity of urinary cannabinoid detection with two immunoassays after controlled oral administration of cannabinoids to humans. Therapeutic Drug Monitoring 30, 530-535.
Hayatbakhsh, M.R., Mamun, A.A., Najman, J.M., O'Callaghan, M.J., Bor, W., & Alati, R. (2008). Early childhood predictors of early substance use and substance use disorders: Prospective study. The Australian and New Zealand Journal of Psychiatry 42, 720-731.
Lavender, J.M., Looby, A. & Earleywine, M. (2008). A brief cannabis-associated problems questionnaire with less potential for bias. Human Psychopharmacology 23, 487-493.
Mason, O.J., Morgan, C.J., Stefanovic, A., & Curran, H.V. (2008). The Psychotomimetic States Inventory (PSI): Measuring psychotic-type experiences from ketamine and cannabis. Schizophrenia Research 103, 138-142.
Murray, R.M., Lappin, J. & Di Forti, M. (2008). Schizophrenia: From developmental deviance to dopamine dysregulation. European Neuropsychopharmacology 18, Suppl 3, S129-134.
Roser, P., Juckel, G., Rentzsch, J., Nadulski, T., Gallinat, J., & Stadelmann, A.M. (2008). Effects of acute oral Delta(9)-tetrahydrocannabinol and standardized cannabis extract on the auditory P300 event-related potential in healthy volunteers. European Neuropsychopharmacology 18, 569-577.
Sneider, J.T., Pope, H.G. Jr., Silveri, M.M., Simpson, N.S., Gruber, S.A., & Yurgelun-Todd, D.A. (2008). Differences in regional blood volume during a 28-day period of abstinence in chronic cannabis smokers. European Neuropsychopharmacology 18, 612-619.
Tortajada Navarro, S., Valderrama Zurián, J.C., Castellano Gómez, M., Llorens Aleixandre, N., Agulló Calatayud, V., Herzog, B., & Aleixandre Benavent, R. (2008). Drug consumption and perception among Latin American immigrants. Psicothema 20, 403-407.
Van Dam, N.T., Earleywine, M. & DiGiacomo, G. (2008). Polydrug use, cannabis, and psychosis-like symptoms. Human Psychopharmacology 23, 475-485.
Zuccato, E., Chiabrando, C., Castiglioni, S., Bagnati, R., & Fanelli, R. (2008). Estimating community drug abuse by wastewater analysis. Environmental Health Perspectives 116, 1027-1032.
Commentary on research
Trajectories of adolescent cannabis use to problematic use in young adulthood
While for many young people cannabis use is of limited duration and without major consequence, entrenched users are at high risk of cannabis dependence and other related adverse outcomes. The identification of consumption patterns that place cannabis users at long-term risk of continued and/or problematic use has clear relevance for health education as well as early intervention strategies.
In the August issue of Addiction, researchers from the University of NSW, and the Centre for Adolescent Health and Murdoch Children’s Research Institute in Melbourne, examined the associations between patterns of adolescent cannabis use and subsequent problematic use in a cohort of 1943 Victorian adolescents followed from 14 to 24 years1. Adolescent cannabis exposure (frequency, persistence and early initiation) was calculated from self-reported cannabis use data collected at six timepoints in adolescence (age 14-17 years). Young adult (24 years) outcomes were: weekly+ cannabis use and DSM-IV cannabis dependence, referred to collectively as problematic use. Of those interviewed at age 24 (n=1520), 34% had reported cannabis use in adolescence, 12% at a level of weekly or more frequent use. More than one third (37%) of these adolescent cannabis users were using at least weekly at age 24, with 20% exhibiting dependence.
We found a relationship between increasing levels of adolescent cannabis use and problematic use in young adulthood even after adjusting for other background and adolescent factors, with daily adolescent use associated with the greatest odds of problematic cannabis use. Being male, persistently smoking cigarettes, and to a lesser extent having persistent anxiety/depression, were important co-factors that seemed to serve as markers for this risk. In addition to primary prevention efforts to delay or prevent the uptake of cannabis use, intervention efforts need to incorporate appropriate messages about the risks of cannabis use, particularly those posed by the increased exposure to cannabis-related harms accompanying persistent and escalating use. Motivational enhancement techniques and the use of opportunistic assessment and intervention may be particularly appropriate approaches with young people.
1. Swift, W., Coffey, C., Carlin, J.B., Degenhardt, L., & Patton, G. (2008). Adolescent cannabis users at 24 years: Trajectories of ongoing and problematic use. Addiction 103, 1361-1370.
Media stories this issue
Each issue we will examine some of the cannabis-related stories that have received media attention across the country. The headlines are listed below in bold, with a short summary and/or commentary regarding the content of the news story beneath.
If you are interested in obtaining a copy of a particular story, please contact Clare Chenoweth at c.chenoweth@unsw.edu.au.
New ad blitz targets young drug drivers
The Transport Accident Commission (TAC) has launched a graphic new advertising campaign in Victoria to target young drivers who drive under the influence of drugs, with the slogan “if you drive on drugs, you’re out of your mind”. TAC Minister Tim Holding, said 20 percent of drivers killed on Victorian roads had amphetamine-type stimulants and cannabis detected in their systems. The article states, “using drugs triples a driver’s chances of a crash, yet research shows 71 per cent of drug users admit to driving within an hour of taking drugs”.
Developing a habit
This article focuses on the importance of preventing initiation to cannabis use in early adolescence, as it has been shown to predict future problematic use, especially among “vulnerable groups: males, those with ongoing persistent symptoms of anxiety or depression, and persistent [tobacco] smokers”. This finding appeared in an article by Swift et al. in a recent issue of Addiction, along with a warning that there is no “safe” level of cannabis exposure during the adolescent years and that education about the risks of cannabis use should be targeted in particular, to the abovementioned ‘at risk’ groups.
Cannabis chemical clue to colon cancer
This article describes the results of a study by the University of Texas, which “discovered that a key receptor for cannabinoids - compounds similar to the active ingredient of cannabis - is turned off in most type of human colon cancer cells.” The results, published in the journal Cancer Research, also found that mice genetically engineered to produce colon tumours, developed more of them if the receptor was “knocked out”. In addition, when tumours were injected with a cannabinoid, they shrank. This discovery was said to be useful in the development of colon cancer treatments.
Libs take tougher line on cannabis
It was reported that the Liberal party in Western Australia will tighten up laws around cannabis if elected. The planned laws include harsher penalties for drug dealers “preying on children”, and new laws to “ban the sale of paraphernalia”. The Liberals will reinstate their previous government's one-off cautions for those found with cannabis, however the “threshold” would be reduced. People caught cultivating the drug would not be eligible for a caution and education would be compulsory. Colin Barnett, the Liberal leader said, “If elected, a Liberal government will repeal Labor’s soft-on-cannabis laws”.
Is there a drug lab next door?
This article, focussing on recent “high profile raids” of suburban hydroponic cannabis operations in Sydney, mentions the recently published Australian Institute of Criminology report, which is produced in collaboration with NCPIC and can be found on this website. The article draws findings from the report that “hydroponically grown cannabis [is] the most commonly detected form of the plant... [and that] most of the cannabis distributed in greater Sydney was grown in suburban homes by organised crime gangs”.
Mother’s make-ups and break-ups may determine child’s later drug use
Included in this article is the finding from a study, published in the Australian and New Zealand Journal of Psychiatry, that children “with mothers who were young and poor were more likely to become cannabis users”. Additional influences that were found to elevate a child’s risk of substance use included a mother’s “education level...the quality of her relationship with her partner and a child’s aggression levels”.
Waiting on better services: a black and white issue
Cannabis is said to have replaced petrol sniffing among the youth of the Aboriginal community at Anangu Pitjantjatjara Lands in South Australia. The article states that cannabis use has “reached epidemic proportions and the elders...tolerate the practice because of its calming effects” on the young people, however, they are also concerned about the long-term health effects of the drug. Makinti Minutjukur, 2020 Summit participant and State Government disability support worker, wrote in a letter to the Indigenous Affairs Minister, Jenny Macklin and Aboriginal Affairs Minister, Jay Weatherill that “a terrifying marijuana problem has replaced petrol which is a main factor in most suicides among its many other destructive effects”.
The danger of your brain on drugs
The negative effects of cannabis use on the human brain are described in this article, with comment by Australian Medical Association WA psychiatric spokesman, Professor Paul Skerritt. A review of research by Australian psychiatrists has caused them to warn that, “14 per cent of psychosis cases could have been prevented if the patient had not smoked marijuana, [and] cannabis users were now thought to have a 40 per cent increased risk of developing schizophrenia...with the risk 200 per cent higher for those who smoked daily and over long periods”. The article also mentions the findings by scientists at Melbourne University that “long-term users [had] shrinkage in parts of the brain that control emotion and memory”.
Survey finds support for cannabis trials, injecting rooms
This article, distributed to media outlets around Australia by AAP Newswire, reports that “most Australians would support clinical trials of cannabis for medical use”. This finding is sourced from the recent 2007 National Drug Strategy Household Survey, conducted by the Australian Institute of Health and Welfare.
Young SA women use cannabis the most
A further finding from the 2007 National Drug Strategy Household Survey appears in this article: “South Australian women, aged between 14 and 24, are the most prevalent cannabis users in the country...”. Keith Evans, Executive Director of SA Drug and Alcohol Services, expressed surprise at this, saying, “we need to pinpoint why so many young women are using cannabis”.
Cannabis use falls as new laws loom
This article discusses the recent findings from the 2007 National Drug Strategy Household Survey that cannabis use has fallen in Western Australia. In 2001, 17.5% of people in Western Australia reported they had used cannabis, but in 2007, this dropped to 10.8%. Despite this, the Gallop government’s move to decriminalise cannabis for personal use in 2004 received criticism that it would encourage cannabis use and cause it to be more easily available. Proposed, stricter laws, including making children found with cannabis attend compulsory drug education and halving the amount of cannabis allowed for personal use have been championed by Attorney-General and Health Minister, Jim McGinty: “This fine-tuning will [see the laws] enjoy a higher level of public acceptance.”
Amphetamines, cannabis leading us to crisis: drug use a time bomb
Data from the Victorian Institute of Forensic Medicine’s drug-drive testing program, the first of its kind in the world, show a rise in drivers intoxicated with amphetamines and cannabis. Cannabis was detected in the systems of 15% of drivers killed in road accidents, an apparent tripling since 2003.
What do we know?
Cannabis and motivation
There is concern that ongoing, heavy cannabis users can become withdrawn, lethargic, apathetic and unmotivated, a collection of symptoms that has often been referred to as the ‘amotivational syndrome’. However, there is disagreement about whether such a syndrome actually exists, with critics suggesting that these symptoms may alternatively be signs of depression or chronic intoxication.
More research needs to be done for us to be certain whether cannabis use causes a lack of motivation. Evidence from case-histories and observational reports of adult cannabis users suggest that chronic, heavy users can become apathetic and unable to carry out complex, long-term plans, endure frustration or concentrate for long periods of time. Other observations include people becoming introverted or displaying a childlike regression so that they are totally focused on the present at the expense of long-term goals. Unfortunately, these reports show us the experiences of some people, but don’t address how common the syndrome is or if cannabis use in itself is the cause of these symptoms.
The existence of an ‘amotivational’ syndrome in cannabis users remains controversial. Controlled studies have not been able to prove the existence of the syndrome, yet clinical observations suggest that cannabis users experience a loss of ambition and impaired school and work performance. We do know that heavy cannabis use is linked to poorer educational outcomes and higher school drop-out rates. There is also evidence that the use of cannabis can impact on attention and memory.
At the present moment, there has been no conclusive evidence that can ascertain that heavy cannabis use causes an ‘amotivational syndrome’. The existence of such a syndrome remains uncertain because many cannabis users have other personal and lifestyle factors that may cause a loss of motivation, such as unemployment, poverty, lower socioeconomic status or pre-existing personality or mental health issues.
Cannabis and alcohol
Cannabis is a drug that people may find themselves using in conjunction with other drugs such as alcohol or tobacco. Using more than one drug at a time is called ‘polydrug use’. Not counting tobacco, the most common form of polydrug use is alcohol and cannabis. People usually combine these drugs to increase their intoxication or to amplify the effect of the first drug taken. Sometimes people mix two drugs because they are already intoxicated and are no longer making rational decisions about their drug-taking, or the wellbeing of themselves or the people around them. This type of drug use is risky because when more than one drug is used simultaneously, the effects are more difficult to predict than if each drug is used separately.
This is the case when alcohol and cannabis are used together. There is some evidence to suggest that having alcohol in your blood can cause more THC to be absorbed into the blood, leading to unpleasant and stronger effects. These effects are commonly referred to as ‘greening out’. ‘Greening out’ can make people go pale, sweaty, dizzy, feel nauseous and vomit. They may also experience feelings of paranoia or anxiety. Combining cannabis with alcohol can also elevate the risk of vulnerable people experiencing psychotic symptoms.
Another concern with this type of polydrug use arises in regards to driving. When under the influence of both alcohol and cannabis, driving becomes even more risky than if only one drug was used. The driver’s concentration and ability to react in driving situations is compromised, making them a risk to themselves, passengers and other road users. Cannabis and alcohol are not drugs which should be used together, and will simply amplify negative effects and cause unpredictable results.
