As the cannabis referendum draws nearer, we have a look at the chemical make up of the substance there’s been so much debate over

The cannabis referendum is just around the corner, but how much do you actually know about the active ingredient in weed – the stuff that actually gets you stoned – and how it affects your brain and behaviour?

Today on The Detail, Emile Donovan speaks to analytical chemist Dr Joel Rindelaub about tetrahydrocannabinol – more commonly known as THC – and how it compares to the intoxicating ingredient in alcohol, ethanol.

THC is a cannabinoid – this means it interacts with cannabinoid receptors in your brain. It’s also the main psychoactive component in cannabis.

“Psychoactive” might sound a bit scary, but really it just means it’s a substance that affects your brain; the most widely consumed psychoactive drug in the world is caffeine.

When you consume cannabis, whether smoking, eating or drinking it, THC binds to receptors in your brain: think of it like a molecule that binds to an antenna where different cells interact with each other; these cells control things like mood, anxiety, hunger, pain, and so on.

Not all cannabis has THC in it, but if you want to get high, you have to smoke THC.

Much like alcohol, the THC content of cannabis can be measured as a percentage: just as a four percent beer has a very different effect to a shot of 60 percent absinthe, a joint with nine percent THC content will affect you differently to a joint with 30 percent THC.

We hear a lot about the negative effects of drinking too much alcohol – so, are psychoactive drugs inherently bad for you?

It’s a good question, says Dr Joel Rindelaub from Auckland University’s school of chemical sciences.

“We have to look at the collection of all the published literature. When we do this, there’s a lot of uncertainty in something like caffeine in how it affects you long-term.

“Based on the research we’ve been able to do on cannabis, it’s in a similar boat: we don’t know exactly what the long-term effects can be. Just because something is psychoactive doesn’t inherently mean something is bad for you, but it certainly could be.”

Anyone who’s been both drunk and stoned in their lives can tell you they have very different effects on your mood and behaviour; but is there much difference in what’s happening on a chemical level?

Rindelaub’s answer is a solid ‘yes’.

“With ethanol, it’s still binding to the receptors in your brain … but this time it’s targeting a different type of receptor. It’s [targeting] a lot of inhibition – that means you’re seeing a lot of depressed respiratory systems … you’re going to lose co-ordination … lose your inhibitions, you might be talking more. So ethanol is more an inhibitor, a sedative. Whereas THC will be focussing on a different set of receptors.”

Under New Zealand’s proposed legislation, cannabis sold at dispensaries will have a maximum THC content of 15 percent.

A recent documentary by TV3 journalist Patrick Gower showed five illicit strains of cannabis had levels of THC much higher than that – suggesting a lot of ‘street’ cannabis is in fact stronger than what might be theoretically available, should the legislation pass without amendments.

Rindelaub says this does open up the possibility of a secondary black market serving people who want a more intense ‘high’.

“What legalisation tends to do is … cut into the black market. To provide a safer product … and reduce the amount of cashflow going to illicit manufacturing and growing facilities.

Rindelaub says in his opinion, if you weigh up ethanol and THC, one is certainly worse for society than the other.

“Currently in New Zealand, alcohol has the most negative impact on society. Personal harm – it’s a carcinogen, you can die from taking it – but also societal harm through violent crimes and other things as well.”

Want more from The Detail? Find past episodes here.

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