What cannabis does to your brain
Just as Australia looks to take a small step towards relaxing its cannabis laws, the Federal Government seems determined to bring the stoner dream crashing down.
The laws - containing a couple of bizarre loopholes - would allow adults over the age of 18 to possess up to 50 grams of the green stuff and grow two plants for personal use.
The bill to make this happen passed without much fuss and there didn't seem to be any major outcry against the territory's democratic decision.
However, Federal Attorney-General Christian Porter is weighing up whether he should step in and override the legislation.
It's understood he's awaiting a copy of the final version of the ACT bill this week before making the call.
In the meantime, a three-page briefing document has landed on Health Minister Greg Hunt's desk and it could cement the government's position.
Mr Hunt has said legalising weed was "dangerous and medically irresponsible".
Nonetheless, his department worked to compile this paper, which would inform him of the links between cannabis use and adverse mental health affects.
Seen by The Weekend Australian, the Health Department's document points to research from the US state of Colorado, Australia and Canada that found daily or near daily use of cannabis was associated with the development of a psychotic disorder.
It states that regular cannabis users doubled their risk of experiencing psychotic symptoms, including schizophrenia, and were at an increased risk of screening positively for psychosis.
"Adverse health outcomes as a result of regular cannabis use are not limited to mental health and psychotic symptoms," the document states.
SO HOW BAD IS BUD?
While there's no doubt among medical researchers that smoking high-grade weed every day will very likely have an negative impact on mental health, exactly what will happen to you is still unclear.
A lot of this uncertainty is down to the fact that the plant is still illegal in most nations and, even in countries that are liberalising their stance on weed such as the US, researchers have to jump through hoops to properly look at the drug's effects.
This means the research is limited and often contradictory.
The main area of contention for those opposing legalisation is marijuana's impact on mental health, particularly the link between smoking and developing schizophrenia.
Despite the alleged risks, no evidence has been found of links between, for example, cannabis and inflammation of the arteries or cancers of the lung, head and neck, science journal Nature reports.
Also, despite its popularity as a recreational drug, only one death has ever been attributed to cannabis consumption - and even that is heavily disputed.
Compare that with the number of annual deaths in the US resulting from the use of legal substances such as opioids (more than 75,000 in 2017) or alcohol (about 88,000).
Some in the anti-cannabis camp say weed is a gateway drug that leads to the use of more harmful substances, a claim that has also been vigorously debated.
They also raise concerns about driving under the influence and smoking in public, but these concerns could be addressed with sensible policies such as testing drivers for impairment and banning smoking in public places.
The Health Department's document points to decreased cognitive outcomes, such as memory loss and the ability to learn.
And, according to a number of studies, it's certainly an area that should be of concern for regular smokers.
In one recent study, University of Wollongong brain researcher Nadia Solowij and her colleagues found that, after 12 to 24 hours of abstinence, heavy smokers performed worse than others on verbal learning and memory tests.
However, it's worth comparing this to the impacts of alcohol, which is legal despite impacting memory, mental function and physical co-ordination, and being linked to acute hepatitis and cirrhosis of the liver.
The Health Department document also points to negative pregnancy outcomes.
One the plus side, there is evidence to suggest using marijuana's non-intoxicating compound CBD in moderation may lead to some benefits.
A separate Australian study from Professor Solowij and her colleagues found that, after giving weed smokers CBD daily for 10 weeks, the researchers saw improvements in brain structure, cognition, depression and psychotic symptoms.
However, despite being well-known to treat childhood epilepsy and kill pain, many of the touted health benefits of using cannabis are, again, unproven.
WHAT ABOUT SCHIZOPHRENIA?
So that leaves us with the big area of contention among those trying to overturn the ACT's new laws and the one that makes the headlines so often, the link between cannabis and mental health.
The Health Department's paper includes Australian research that concluded regular cannabis users doubled their risk of experiencing psychotic symptoms, including schizophrenia, and were at an increased risk of screening positively for psychosis.
While it's been argued those predisposed to psychotic mental illnesses are more likely to use cannabis, it's becoming increasingly accepted in the scientific community that there is a direct link between cannabis and these illnesses.
In the largest study yet, scientists looked at data from about 900 people who visited 11 psychiatric-service sites across Europe and Brazil for treatment for their first episode of psychosis.
The researchers said the statistics showed a strong association between daily cannabis use and the likelihood of developing a psychotic disorder - and for those using particularly strong weed, the risk was five times greater.
In a review for the Canadian government, health-policy researcher Fiona Clement and her colleagues found people who smoked weed heavily had a higher risk of developing schizophrenia than people who never used it.
However, Dr Clement said the exact nature of the link was not clear.
"It should give us pause," she told Nature. "We may not understand exactly the relationship between cannabis and these psychosis-related mental illnesses, but there's definitely something there."
It's hoped the link will become clear as a wave of legalisation helps scientists accumulate more data, partly because it is easier for doctors and patients to talk about cannabis.
ARGUMENTS FOR OVERTURNING THE LAW
Many on the anti-legalisation camp say the link with psychosis is clear - and it is causing cannabis-linked violence to spread in the US and nations that have legalised weed for recreational use.
Former New York Times reporter, Alex Berenson, whose book The Truth About Marijuana, Mental Illness, and Violence stoked a massive debate about weed and violence, says you just have to look at the crime statistics US states that have legalised to see the link.
"In the four states that first legalised, murders have risen 25 per cent since legalisation, even more than the recent national increase," he wrote. "In Uruguay, which allowed retail sales in July 2017, murders have soared this year."
In Australia, Drug Free Australia president Brian Watters has urged the Prime Minister to overturn the ACT legalisation, saying Australians "do not want more drug use".
He argues legalisation of recreational cannabis will not only substantially increase drug use in the ACT, but everywhere else in Australia too.
He points to research from Colorado that shows the doubling of frequent users of cannabis within the first three years of legalisation.
He also points to stats from Colorado that show driving while under the influence of cannabis increased 62 per cent in two years and hospitalisations due to cannabis leapt from 6715 in 2012 to 11,439 in 2014, the year after legalisation commenced.
Furthermore, anti-legalisation activists point to 2016 National Drug Strategy Household Survey statistics that show 86 per cent of Australians do not approve the regular use of cannabis, and two out of every three Australians do not want cannabis legalised.
"Despite Australians clearly signalling what kind of society they want to live in, in terms of drug non-use, a political elite in Canberra has decided that they know better than their fellow Australians and has enacted policy that flies in the face of Australian attitudes," Major Watters said in a statement.
"The result will be a constant flow of home and criminal-grown cannabis from the ACT to other surrounding states such as NSW and Victoria."
TAKING THE POWER OUT OF THE HANDS OF CRIMINALS
Those wanting to legalise cannabis for recreational use, such as the Greens, don't claim smoking weed is harmless.
Rather they claim an unregulated market is pushing stronger and more harmful weed to vulnerable people, some of whom would be at risk of developing psychotic disorders.
Senator Richard Di Natale said legalisation was about taking the power out of the hands of criminals and putting the tax money raised back into education and treatment.
"Nearly seven million Australians choose to use cannabis," he told the ABC. "They're sourcing products of unknown quality and purity, and of course all they're doing is feeding the mega profits of criminal syndicates and criminal gangs."
So, for now, it looks as though Canberra might buck the trend and try a different approach starting January 31.
Reacting to the Health Department document, a spokeswoman said the ACT government consulted experts on the health impacts that might arise from legalising cannabis and stressed the laws related to personal cultivation and use of cannabis.
"It does not allow for the sale of cannabis or large-scale commercialisation and development as has been seen elsewhere, particularly in the US," she told The Australian, adding that direct comparisons between the ACT legislation and that of other countries should be treated cautiously.
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