The cannabis seen in stores today isn’t like what the hippies rolled in the 1970s. Anyone who follows cannabis news has likely heard a public health official express some version of that sentiment.

In 2019, then U.S. Surgeon General Jerome Adams claimed that today’s cannabis “ain’t your mother’s marijuana,” but was, in fact, three times stronger than weed in the 1990s.

Weed advocate and Canadian author Dana Larsen has actually calculated how strong today’s cannabis would be if similar lawmaker sentiments throughout history were accepted. That includes claims by 2002 White House Drug Czar John Walters, who said cannabis at the time was 30 times stronger than what baby boomers smoked.

President Joe Biden, for his part, once argued that comparing 1990s weed to cannabis in the 1960s was like “comparing buckshot in a shotgun shell to a laser-guided missile.”

Using all of these historical statements would mean that today’s cannabis is 12,600 times stronger than it was in the 1960s, according to Larsen’s calculations. And while that is highly unlikely, how and why cannabis potency has changed in the past decade or so should not be discounted.

The Colorado Department of Public Health and Environment (CDPHE) released a study last year examining THC concentrations of weed products sold in legal dispensaries in response to a request from the Colorado General Assembly.

Given that Colorado and Washington were the first two U.S. states to legalize adult-use cannabis, longitudinal reports like this one provide great insight into the state of legal weed and its effects on consumers.

Growers in both illicit and legal markets have emphasized THC potency over the past 25 years, as consumers associate higher THC levels with getting the most bang for their buck.

A 2016 study found cannabis samples seized by the U.S. Drug Enforcement Administration increased from about four per cent THC in the 1990s to approximately 12 per cent in 2014.

Previous research found that THC levels in medical marijuana products were two to three times stronger than what doctors recommended for pain relief patients.. / PHOTO BY JIM MONE /Canadian Press

But the CDPHE report noted that cannabis flower in Colorado contained an average of 19.6 per cent THC per gram, with potency reaching 35 per cent in some strains.

A 2020 study added that more than 92 per cent of products sold in U.S. retail cannabis stores contain THC levels at 15 per cent or higher. Edible potency actually decreased because Colorado regulators instituted policy changes that set maximum THC concentration to 10 mg per dose, and only allowed 100 mg THC per package.

Those who consumed THC concentrates (i.e. dabbing) used cannabis more frequently day to day compared to flower users.

Previous research found that THC levels in medical marijuana products were two to three times stronger than what doctors recommended for pain relief patients. The study’s authors noted levels up to five per cent THC were sufficient in long-term pain management with minimal side effects.

When THC is too strong, it can lead to dependence problems for users. One study noted that 30 per cent of marijuana users have some form of cannabis use disorder. Research published in May 2020 added that high-potency cannabis doubles the risk for developing anxiety disorders.

“Our ability to make unbiased, evidence-based statements on the potential health effects of marijuana products containing high THC concentration is limited until further scientific research can be conducted and the evidence shared or published,” authors of the CDPHE report concluded.

“Therefore, in the best interest of public health, we suggest funding research to answer these questions,” they added.