Home Culture Culture Features

Interview with a Cannabis Expert

As cannabis legalisation sweeps the globe, now is a good time to look at the implications of legalising weed in Australia


Fergus Strickland

As cannabis legalisation sweeps the globe, now is a good time to look at the implications of legalising weed in Australia. Using data from countries and US states that have already legalised the sale and possession of cannabis, we can combine their findings with drug research in Australia to forecast some of the likely outcomes these changes will bring about.

Researcher Jack Wilson is an expert in this field. He has gleaned many insights into the long-term effects of cannabis use from his work with the Department of Addictions at King’s College London, and the Matilda Centre for Research in Mental Health and Substance Use. As well as this, Jack has interviewed many cannabis users about their experiences. 

Having conducted his PhD at the University of Sydney, with a degree in psychology from the University of Newcastle, Jack is the perfect person to speak to about mental health and substance use. So, we asked him a bunch of questions related to the effects of cannabis use, what legalisation means for Australians, and how people can seek help if they feel their cannabis use is negatively affecting them. 

1. To what degree does age play a part in the extent of harm cannabis can cause?

We now know that the short and long-term harms associated with cannabis use largely depend on when a person uses it. The brain keeps developing until you’re around 25 years old. This is a critical period of neural growth and improvement in brain functioning. Unfortunately, cannabis, or cannabinoids (the compounds within cannabis), interact with areas of the brain key to this development, which in turn could disrupt or alter normal brain functioning. 

Many studies have suggested that young people regularly using cannabis are at a greater risk of exhibiting cognitive impairments and poorer mental health outcomes compared to those initiating cannabis use in adulthood. It is therefore important that young people are aware of their potential vulnerability to the negative effects of cannabis use. 

2. How much greater are the risks for people who have pre-existing conditions?

There are a number of pre-existing conditions that place people at additional risk of harm from cannabis use. 

Like other substances, cannabis use is typically more prevalent among those with a mental health condition. Often referred to as the ‘self-medication hypothesis’, some people use cannabis to manage their mental health. While it may appear helpful at times, cannabis has actually been shown to intensify mental health symptoms, making the condition even worse. 

It is estimated that around half of the risk of developing a substance use disorder is related to genetics. Similar studies have also found that those with a family history of substance use disorders and mental health conditions (e.g. schizophrenia, depression) are at an elevated risk of developing cannabis-related problems. 

Cannabis use while pregnant may also be associated with poorer outcomes for offspring, both short and long-term, particularly when smoked. Studies have also detected cannabinoids such as THC in the breastmilk of mothers who use cannabis, although it is unclear whether this may result in harm to infants

And for those with cardiovascular diseases, cannabis can increase the risk of acute cardiovascular events, especially when combined with tobacco.

Experts recommend that those with a personal or family history of mental health conditions, people experiencing cardiovascular/respiratory issues, and those pregnant or planning pregnancy, should avoid or reduce their use of cannabis.

3. Cannabis is often cultivated to deliberately increase its THC levels. How does this contribute to the rate or extent of cannabis harm?

Two of the most common compounds within cannabis are THC (delta-9-tetrahydrocannabinol) and CBD (cannabidiol). THC is responsible for the ‘high’ that people experience, while CBD is non-intoxicating and has been explored as a treatment for a range of health conditions. The amount of THC and CBD differ according to plant genetics, growing conditions, and method of preparation.

Over the last 50-years, the amount of THC in cannabis has increased three-fold, while CBD has remained relatively stable. There has also been an increasing demand for high-THC cannabis products, such as cannabis concentrates, ‘wax’, or ‘dabs’. This is particularly concerning because higher THC consumption is associated with greater cognitive impairment, anxiety, and psychotic-like symptoms when intoxicated.

Increasing THC also poses greater risk to long-term outcomes such as developing a cannabis use disorder, psychotic conditions, and perhaps anxiety and depression. Although those using stronger cannabis products might attempt to counter the potential harms by reducing their inhalation volume or preparing smaller joints/bongs, they still typically consume more THC than those using less potent cannabis. 

To reduce harm, it is recommended that people refrain from using high THC cannabis products. This is incredibly difficult in Australia where cannabis is often illegally sourced without accurate information on THC content. However, people may choose to avoid products that typically contain high THC, such as cannabis concentrates, hash/resin, or indoor hydroponically grown cannabis. 

4. As an interviewer who has spoken to many people seeking treatment for cannabis use, what are some misconceptions cannabis users have about the drug (that you think are important to share with potential cannabis users)? 

I’m sure many of us have heard people talk about different ‘strains’ of cannabis that reportedly have different effects. A lot of legal and illegal cannabis markets capitalise on this (e.g. ‘Blueberry Block – cerebral high and deep relaxing effect’). But the evidence for this is weak! Rather, the effects of cannabis are largely due to the THC content and a range of personal factors, such as set (e.g. mood, expectation) and setting (i.e. environment in which experience takes place). 

So I urge people to forget about whether ‘Black Widow’ will give you a ‘body high’ or a ‘head high’, and instead think about the THC content, your previous experience of using cannabis (if any), and the circumstances in which you will be using it. 

5. With cannabis users, does scientific evidence ever contradict anecdotal evidence? For instance, cigarette smokers often report that having a cigarette calms them, when biologically it is actually stimulating them. 

Around 219 million people worldwide reported using cannabis in 2021, most of whom did not find their use to be harmful. The scientific literature often focuses on the harms of cannabis, so it is not surprising that most people feel like there is a gap between their own experience and the science. So, let’s take a step back and put things in perspective.

Most people who have used cannabis will not experience any severe problems associated with their use. We also know that cannabis use accounts for far less disease than other drugs such as tobacco and alcohol, and rarely contributes to death. Adding to further confusion, doctors are now increasingly prescribing medicinal cannabis for a range of health conditions. It is no wonder why more Australians than ever before are in favour of legalising cannabis. 

Despite this, we must remember that cannabis is not harmless, and that some people may not be aware that they are experiencing health issues related to their use. It is also clear that young people using it regularly are at an elevated risk of harm. We are also witnessing a staggering increase in THC content, making it more unsafe than ever before. 

6. Regardless of how much information is out there, curiosity is most certainly going to get the better of some people. For anyone that is going to try cannabis no matter what (or try it again) what advice do you have that may help them reduce their risk of harm?

Unsurprisingly, the most effective way to reduce the risk of harm is to abstain from use, at least until after that critical period of development (< 25 years of age). As for those using cannabis, there are strategies for improving your safety. 

As I have mentioned previously, try to avoid high-THC cannabis products. If trying for the first time, feel the effects of a small amount before using more. 

Consumers should reduce their inhalation volume and refrain from frequent or large quantities of use. Those experiencing any cognitive impairment or mental health condition, as well as those who might be genetically vulnerable to such conditions, should consider abstaining or reducing their use. 

Given the acute cognitive impairment following use, people should avoid driving or operating heavy machinery while intoxicated. 

Try to stay away from ‘synthetic cannabis’ or ‘spice’, which were designed to mimic the effects of cannabis, but exhibit far more severe physical and psychiatric effects, including death. 

Lastly, refrain from combining cannabis with other substances or medications, as this can elevate the risk of acute harm and cause further problems down the track (e.g. tobacco dependence). 

7. Long term use, habit and dependence are obviously worse than occasional use. For people that regularly use cannabis, what advice do you have that may help them? 

For those that find themselves experiencing problems with cannabis, remember that you are not alone. Approximately 1 in 9 Australians (11.5%) used cannabis in 2022-23, and around 10-30% of those people would go on to develop a cannabis use disorder. 

Some people may choose to stop all together, but this may be difficult. Alternatively, try to reduce your use over time, and avoid situations in which you may obtain or use cannabis. 

It is often helpful to talk to a friend or family member about your use. Further support can be provided by a GP, drug and alcohol counsellor or psychologist. People can also speak confidentially with qualified counsellors by calling the Alcohol and Drug Support Line. They are available 24/7 to provide counselling, information and referrals for anyone seeking help for their own or another person’s drug use. The number is (08) 9442 5000. 

 8. With legalisation occurring around the world, cannabis use is set to increase, as an industry grows around it. How do you feel about this, and what do you anticipate will be the societal ramifications of this rise?

We are currently experiencing a global shift towards cannabis legalisation and decriminalisation. To clarify, legalisation permits the use of cannabis products, and typically involves the regulation and taxation of cannabis sales. Decriminalisation, however, aims to reduce or remove the criminalisation of minor possession offences (e.g. cannabis warnings), often referring people to health or social services. 

To date, Canada, Uruguay, Thailand, Malta, Georgia, Mexico, South Africa, Germany, Luxembourg, and 28 states/territories in the US have adopted some form of legalisation for recreational cannabis use. While most parts of Australia only approve the medical use of cannabis products, the Australian Capital Territory (ACT) recently permitted adult residents to grow a limited amount of cannabis for their personal use. 

It is reasonable to expect future changes in cannabis legalisation within Australia, and this will likely affect how many people use cannabis, and rates of cannabis-related harm, especially among young people. So what have we learned from other countries and regions that have legalised cannabis for recreational use? 

Studies in the US suggest that cannabis use, and rates of cannabis use disorder, increased among adults following legalisation. This does not seem to be the case for young people though, where findings range from a slight decrease to a slight increase in use. 

While Europe isn’t known for legalisation, some countries have more relaxed laws towards cannabis use. A great example is the Netherlands, which decriminalises cannabis use through sales and consumption at coffee shops. A review of cannabis use across European countries found that use did not change among young people following the relaxation of laws. While this may be good news, some harms from cannabis use have increased following legalisation. There has been a rise in the number of people presenting to emergency services with cannabis-related harms, which may be due to unexpectedly high THC content in legal cannabis products.

Unfortunately, most of these studies are limited in detecting the long-term effects of legalisation given that these policies are relatively new. Laws also vary across regions in terms of the amount people can possess, method of obtaining cannabis, or legal age of use and purchase. It is therefore extremely important to monitor the ongoing effects of legalisation so that countries like Australia can design laws that protect young people. 

Concerningly, the rapid legalisation of cannabis in parts of North America created largely unregulated industries, with limited controls on product marketing and availability. Similar to what we have experienced with alcohol, cannabis products have been extensively marketed to young people (e.g. cannabis pop-tarts), explaining an increase in hospitalisations, and increasing the risk of long-term harm. It would be inadvisable to allow this same scenario to play out in Australia.

Learn more at cannabis.drugaware.com.au