Cannabis has been identified as a potential substitute for users of legal or illicit opioids, but a new Vancouver-based study shows the drug may also help reduce people’s cravings for another highly addictive substance: crack cocaine. Scientists at the BC Centre on Substance Use tracked 122 people who consumed crack in and around Vancouver’s Downtown Eastside over a three-year period and found they reported using that drug less frequently when they opted to also consume cannabis. The findings do suggest that cannabinoids might play a role in reducing the harms of crack use for some people. (See also: Study: cannabis may reduce crack use |Therapeutic Use of Cannabis by Crack Addicts in Brazil)

Despite cannabis being the most widely used illegal drug, and therefore the mainstay of the ‘war on drugs’, it has only ever held a relatively marginal position in international drug policy discussions. Amanda Fielding of the Beckley Foundation decided to convene a team of the world’s leading drug policy analysts to prepare an overview of the latest scientific evidence surrounding cannabis and the policies that control its use. The report of the Beckley Foundation's Global Cannabis Commission is aimed at bringing cannabis to the attention of policymakers and guide decision making.

Cannabis Policy: Moving Beyond Stalemate

Extended Summary

Researchers, research funders and policymakers should give greater voice to the risks and harms associated with particular cannabis policies and to the evaluation of alternative regulatory frameworks. Given the decades of research and experience with cannabis prohibition, it seems reasonable to reorient the cannabis policy debate based on known policy-attributable harms rather than to continue to speculate on questions of causality between cannabis use and mental illnesses such as psychosis, depression, and related disorders, that will not be definitively answered any time soon

Download the article (PDF)

A new study suggests that young cannabis users run the risk of a lower IQ. In what is an impressively long-term cohort study, it was found that "those who started using cannabis below the age of 18 - while their brains were still developing - suffered a drop in IQ". Defending drugs is rarely a good move politically, and anti-drug legislation often occurs without the support of scientific evidence. Contrastingly, any scientific finding that suggests drug use may have detrimental effects is seized upon and often exaggerated, sometimes to ludicrous extents. And you know there'll soon be leaflets going around schools that explicitly state that cannabis makes you stupid.

In a new report, Ending the U.S. government’s war on medical marijuana research, researchers at the Brookings Institution call on the federal government to eliminate roadblocks to medical marijuana research in the U.S. "The federal government is stifling medical research in a rapidly transforming area of public policy that has consequences for public health and public safety," authors John Hudak and Grace Wallack, say. "Statutory, regulatory, bureaucratic, and cultural barriers have paralyzed science and threatened the integrity of research freedom in this area."

A new analysis of cannabis research funding in the United States, Canada, and the United Kingdom has found that $1.56 billion was directed to the topic between 2000 and 2018—with about half of the money spent on understanding the potential harms of the recreational drug. Just over $1 billion came from the biggest funder, the U.S. National Institute on Drug Abuse (NIDA), which doled out far more money to research cannabis misuse and its negative effects than on using cannabis as a therapeutic drug. However, overall cannabis research funding in the United States is rising steadily, from less than $30.2 million in 2000 to more than $143 million in 2018, and money to explore cannabis medical treatments is growing—although not as fast as funding for research on harms.

Cannabis resin – or “hash” – has increased in strength by nearly 25% over the past half century, a major international study has revealed. Researchers with the Addiction and Mental Health Group at the University of Bath analysed data from more than 80,000 cannabis street samples tested in the past 50 years in the US, UK, Netherlands, France, Denmark, Italy and New Zealand. The findings reveal concentrations of THC – the intoxicating component of cannabis responsible for giving users a “high” – have changed over time. In herbal cannabis, THC concentrations increased by 14% between 1970 and 2017. This was primarily due to a rising market share of stronger varieties, such as sinsemilla. Concentrations in cannabis resin increased by 24% between 1975 and 2017.

Scientists believe they have identified about 60,000 cases of depression in adults under 35 in the UK, and more than 400,000 in the US, that could be avoided if adolescents did not smoke cannabis. An international team of scientists looked at 11 studies published from the mid-1990s onwards, involving a total of more than 23,000 people, they report in the journal JAMA Psychiatry. They explored the use of cannabis for non-medicinal purposes in under-18s. Participants were then followed into adulthood to see who developed clinical depression, anxiety or suicidal behaviour. No single study looked at all three mental health issues. (See also: Teenage cannabis use linked to depression in later life)

Does smoking reefer lead to using other drugs, in daily practice usually described as cocaine and heroin? Raising the possibility that the answer to this question might be affirmative, is known as the stepping stone hypothesis. Recently this hypothesis has been raised again in slightly other terms: cannabis use as a “gateway” to other allegedly more dangerous drugs.

Download the article (PDF)

Does smoking reefer lead to using other drugs, in daily practice usually described as cocaine and heroin? Raising the possibility that the answer to this question might be affirmative, is known as the stepping stone hypothesis. Recently this hypothesis has been raised again in slightly other terms: cannabis use as a “gateway” to other allegedly more dangerous drugs.

Download the article (PDF)

Numerous studies have now shown that people who use cannabis have a higher likelihood of experiencing mental health problems. The potency of the drug – and how often it’s used – are likely to play a role in this relationship. Different types of cannabis have different levels of a component called tetrahydrocannabinol (THC). “High potency” cannabis has higher amounts of THC. Our recent study compared people who said they used high potency cannabis with those using lower potency cannabis. We found that the people who used high potency cannabis were more than four times as likely to report symptoms of cannabis misuse, and almost twice as likely to report anxiety disorder. (See also: Can we make cannabis safer?)

Global public health campaigns are needed to make clear the risks of heavy cannabis use, particularly for young people who are more susceptible to mental health problems, senior drugs researchers have said. The call for action from scientists in the UK, US, Europe and Australia reflects a growing consensus among experts that frequent cannabis use can increase the risk of psychosis in vulnerable people and lead to a range of other medical and social problems. The researchers are keen not to exaggerate the risks; cannabis alone is neither necessary nor sufficient to cause psychosis.

Cannabidiol (CBD), a chemical derived from the cannabis plant, can counteract the effects of high strength "skunk" strains and may help to reduce the risk of serious mental health conditions like psychosis, according to a new study. After using scans to study the effects of different strains of cannabis on the brain for the first time, the team from the University College London said boosting levels of CBD could act as a “buffer” to ill effects. They found that strains with the same level of THC, which causes users to get “stoned”, but higher CBD caused less disruption to parts of the brain linked to addiction and psychosis. (See also: "Skunk" cannabis disrupts brain networks – but effects are blocked in other strains | High-strength cannabis increases risk of mental health problems)

A study by neuroscientists at Indiana University finds that a nonpsychoactive compound in cannabis called cannabidiol, or CBD, appears to protect against the long-term negative psychiatric effects of THC, the primary psychoactive ingredient in cannabis. "This is the first study in a rigorously controlled animal model to find that CBD appears to protect the brain against the negative effects of chronic THC," lead author Dr. Ken Mackie, said. "This is especially important since heavy use of cannabis with higher levels of THC poses a serious risk to adolescents." An analysis of cannabis seized by the U.S. Drug Enforcement Administration found that while THC levels rose 300 percent from 1995 to 2014, the levels of CBD have declined 60 percent.

Experts at the Institute of Psychiatry in London are publishing research suggesting that smoking cigarettes may be a contributory cause of schizophrenia (a psychotic disorder). These new findings raise a question - could the most obvious fact about cannabis - that it is usually consumed in combination with tobacco - have been neglected in researching the link between cannabis and psychosis?

An ethnographic study of women and drug use in inner city neighborhoods in Kingston, Jamaica, revealed that cannabis is commonly used in conjunction with crack cocaine to minimize the undesirable effects of crack pipe smoking, specifically paranoia and weight loss.

Download the document (PDF)

An ethnographic study of women and drug use in inner city neighborhoods in Kingston, Jamaica, revealed that cannabis is commonly used in conjunction with crack cocaine to minimize the undesirable effects of crack pipe smoking, specifically paranoia and weight loss.

Download the document (PDF)

The prohibition on dagga is the "gateway to harder drug use‚ not the use of cannabis itself"‚ Imperial College Professor David Nutt told the Pretoria High Court. Nutt‚ a psychiatrist and neuropharmacologist is testifying in the trial to have the current ban on dagga use ruled unconstitutional. Johannesburg residents Jules Stobbs and Myrtle Clarke are asking the Pretoria High Court to deem the laws banning the adult use and sale of dagga unconstitutional and thus instruct parliament to make new laws. "The gateway theory is a theory that has very‚ very little in the way of empirical evidence‚" Nutt said. (See also: Is the state trying to lose the dagga case?)

Consuming cannabis every day could delay at-risk youth from moving on to injecting more dangerous drugs, according to a new study that casts doubt upon the age-old assumption that marijuana acts as a gateway for teens to try other more harmful substances. The research, from scientists at the BC Centre on Substance Use, also adds to other work that has suggested marijuana could be used as a substitute for people addicted to opioids. Researchers repeatedly interviewed 481 homeless young people in Vancouver’s downtown core who had never injected any drugs and found - over a decade of tracking this at-risk cohort - that daily cannabis use was associated with a 34 per cent decrease in the rate people started injecting drugs.

Researchers have come up with an unusual proposal to slow, or even reverse, the cognitive decline that comes with old age: small, daily doses of cannabis extract. The idea emerged from tests on mice which found that regular, low doses of tetrahydrocannabinol (THC) – the main psychoactive ingredient in cannabis – impaired memory and learning in young animals, but boosted the performance of old ones. The discovery has raised hopes for a treatment that improves brain function in old age without inducing the behavioural effects well known to recreational users of the drug.