Chances are, you know your 21 year-old son or daughter gets drunk. They do it in the college bar, get trollied at house parties, sneak a naggin into music festivals, the usual. You did it yourself. But what if they were smoking cannabis just as regularly?

For parents outraged by the thought of weed-smoking offspring, it might be time to take a chill pill. That’s what they’ve done in Colorado.

“It’s safer to get high than to get drunk,” says Mason Tvert, co-author of a book ‘Marijuana is Safer: So why are we driving people to drink?” Tvert co-directed the successful campaign that persuaded the people of Colorado to make recreational marijuana, like alcohol, legal for those over 21. Marijuana for medicinal use has been legal there since 2009.

In a vote that took place alongside the US Presidential election last November, more people in Colorado voted to legalise recreational marijuana that voted for Obama. Tvert attributes the campaign’s success to the fact that for Centennial State voters, the penny has dropped that marijuana is safer than alcohol. In his view, proscribing marijuana and not alcohol defies logic.

“Marijuana is less toxic, less addictive and less harmful for the body that alcohol and there is a great deal of evidence that alcohol contributes to violent behaviours and recklessness, whereas marijuana does not,” says Tvert.

Does marijuana contribute to overdose deaths, long-term health problems, violent crimes and serious injuries? ‘No’ says Tvert. But alcohol does.

Tvert is part of the Marijuana Policy Project a group that says that marijuana gets a bad rap. It says that most Americans have been led to believe that marijuana is dangerous, addictive and is a gateway to harder drugs and that it has destroyed the lives and ambitions of millions of teens and adults. It says we have been ‘conditioned’ to think that those who use marijuana are “dangerous or strange or maybe even dirty”, people who “sit around on couches all day doing nothing”.

But are marijuana users really ‘losers’? Statistics published by the National Advisory Committee on Drugs and Alcohol (NACDA) in July show the typical Irish cannabis user is more likely a winner. Rates of lifetime cannabis use were highest among professionals and managers and those with third level education and lowest among those in semi-skilled and un-skilled jobs.

But with alcohol marketers pumping millions into linking their products with sophisticated dinner parties, elite sporting events and even national pride, it’s no wonder the image of blow has gone to pot. Pop open the champers at your next dinner party to sounds of glee, offer a spliff and guests will think you’ve lost your mind.

The Marijuana Policy Project’s website teems with pro-marijuana arguments, the central plank being that we can’t logically frown on marijuana while wine and beer form part of our weekly shop.

“The U.S. Centres for Disease Control (CDC) attributes 37,000 deaths per year to alcohol use alone, and that includes some overdose deaths,” says Tvert. “That’s not including accidents or homicides, that’s just people using it.” The CDC however, he says, “Does not list marijuana as a cause of death and it’s never been attributed to any sort of overdose death”.

What of the argument that marijuana causes cancer? Tvert retorts that while alcohol use is linked to cancer, there is evidence that marijuana ‘does not contribute to any form of cancer’. “There has never been a marijuana-only smoker that has acquired cancer as a result.”

In fact, the Marijuana Policy Project cites a 2009 study published in the journal, Cancer Prevention Research where researchers found that long-term pot smokers were roughly 62 per cent less likely to develop head and neck cancers than people who did not smoke pot.

The MPP site does not mention that the researchers emphasised that larger studies would be needed to verify this link and that the risks of use may still outweigh this benefit.

What of the effect of marijuana on the brain? Again, Tvert holds that “alcohol kills brain cells, but there is now evidence to show that marijuana does not”. He even posits that marijuana may have a ‘neuro-protective’ effect on brain cells. He refers to a University of San Diego study published in the journal, Neurotoxicology and Teratology that shows ‘white matter integrity in adolescents with histories of marijuana use and binge drinking’. “If you use marijuana and you binge drink, you lose fewer brain cells that if you drink alone”. There were 42 students in the study.

As to a link between use of marijuana and mental illness, he says while there are some situations where marijuana “can be found to contribute” to pre-existing mental illnesses, there are others where it can alleviate the problem. And anyway, alcohol has been tied to far more mental health issues than marijuana, he says.

Whether you agree with Tvert’s arguments or not, the people of Colorado did. Their 2012 approval of a constitutional amendment means those over 21 are permitted to possess up to an ounce of the drug and can own up to six plants. Though policymakers are now wrangling over how to regulate the production, distribution and sale of marijuana while federal law bans it, Tvert is confident stores offering the drug will be open by January.

But won’t such widespread availability to those over 21 also make it more accessible to kids? “I don’t think there is any person in the world that wants kids using marijuana. It’s just that these days, most people realise that our current system of prohibition is failing to protect them.”

Tvert cites evidence that 80 per cent of all high school students, that’s those aged 14- 18, say they can access marijuana easily. “So if the goal of the policy is to keep it out of the hands of young people, then it’s not working.”

The same appears true here. NACDA figures show that cannabis use in Ireland was highest among men and younger adults aged15-34 and the majority of recent cannabis users said it would be easy for them to obtain cannabis in a given 24-hour period.

“We should encourage them not to use either substance until they are an adult,” says Tvert, “But at that time they should know that marijuana is in fact less harmful that using alcohol.”

“Marijuana is Safer: so why are we driving people to drink?” is published by Chelsea Green.