Marijuana may be a lot safer than we previously thought, a new study suggests, while the risks of alcohol may have been vastly underestimated.
The research, published in the journal Scientific Reports, compared the risks associated with 10 substances using the margin of exposure approach. This method compares a lethal dose of the drug with the dosage typically taken by recreational users. Substances tested included alcohol and nicotine, as well as illicit drugs including cocaine, heroin, ecstasy (MDMA) and methamphetamines.
It found that the mortality risk to individuals posed by cannabis was approximately 114 times less than that of alcohol. In fact, cannabis was the only substance to be classified as ‘low risk’. In contrast, alcohol posed the highest risk to individuals and was ranked alongside nicotine, cocaine and heroin as ‘high risk’.
In terms of risk posed to a population, alcohol was the only substance classified as ‘high risk’. However, the researchers noted that this was partly due to its wide availability and a lack of data on other illicit drugs.
This chart, by Vox, shows the rankings of alcohol and common drugs by the degree of harm they pose to individuals and society.
The report said that many European governments adopted restrictive policies towards cannabis and other illicit drugs due to the perception that they are more harmful than alcohol and tobacco. “Specifically, the results confirm that the risk of cannabis may have been overestimated in the past,” the report said. “In contrast, the risk of alcohol may have been commonly underestimated.”
“The results make perfect sense. The ultra-low mortality of cannabis has long been recognized, with health harms greatly exaggerated,” said lead researcher Dr. David Nutt, chair of neuropsychopharmacology at Imperial College London and former chair of the Advisory Council on the Misuse of Drugs I would recommend that cannabis be reinstated as a medicine, as the clear harms are well outweighed by the health benefits.”
The researchers go out of their way to point out that their results do not say what the actual risk specific to you would be — for instance, if you downed three beers vs. shot up a little bit of heroin. In that comparison, you’re probably going to be harmed more by the heroin. But extrapolate out to humans as a group and alcohol will kill many more people than heroin.
“Therefore,” the researchers state, “we can assess only in regards to mortality but not carcinogenicity or other long-term effects. The absence of such data is specifically relevant for compounds with low acute toxicity (such as cannabis), the risk of which may therefore be underestimated.”
The study concluded by suggesting that alcohol and tobacco should be prioritized in terms of risk management. It also suggested that governments legalize and regulate the distribution and use of cannabis, as opposed to the widespread current practice of prohibition.
As the Washington Post pointed out, the findings reaffirm drug-safety rankings developed over the past decade. But the timing of the study’s publication was rather apt as this week Alaska became the third U.S. state to legalize recreational use of marijuana.
Despite widespread decriminalization, cannabis is still classified as illegal in most European countries. Even in the Netherlands, famous for its liberal stance towards the drug, cannabis can only be purchased from licensed coffee shops. In 2001, Portugal decriminalized all drugs, meaning that most cases of personal use would not lead to prosecution.