Today's Weed Really Is Not 'Your Father's Marijuana'

One of the favorite claims of opponents of marijuana legalization is that pot today "is not your father's marijuana"—it is instead much stronger, and therefore, the unspoken corollary implies, somehow more dangerous. It increasingly looks like those folks are correct about pot being stronger, but off the mark when it comes to it being riskier.

As someone who has been smoking the stuff since 1969, my personal opinion is, well, duh! I remember all too well the Mexican brick weed from back in the day and the relatively crappy high it produced. I also remember being exposed to stronger weed, even way back then.

Back in 1972, one of my Midwestern teenage weed head buddies traveled to Southern California and returned bearing the fabled Thai Stick. I have no idea what its THC content was, but it was in an entirely different order of highness than the Mexican brick and left us drooling in our basement hideouts. I also remember getting so high on my first Colombian weed (around 1976) that I had to pull over to the side of the highway and puke my guts out. Maybe the bag of chocolate chip cookies I ravenously consumed after smoking that stuff had something to do with it, but that Colombian was noticeably stronger than the Mexican brick, too.

Sitting in the middle of the brick weed highway coming out of Mexico in Austin in the mid-1980s, I had my first chance to try domestically grown sinsemilla, and it was a revelation! Not only were those buds sweeter smelling and better looking, the high was a mile above Mexican brick. No question about it, at least in my mind.

Some other pot people trying to fend off anti-pot attacks like "not your father's marijuana" argued that the claim wasn't true—that marijuana then really was as strong as marijuana now. I was never one of those. I always argued that, yes, pot is stronger today, but that just means you smoke less of it to get the high you desire.

There is some scientific support for the contention that access to stronger pot simply means that people smoke less. At least one study has found that pot smokers adjust their habits based on potency, smoking less pot when the THC content is higher.

And there is increasing scientific support for the notion that today's marijuana is stronger than the pot of yore. At the meeting of the American Chemical Society earlier this year, the Colorado potency testing lab Charas Scientific reported that the amount of THC—the active ingredient in pot that gets you high—has tripled in the last 30 years. THC levels in the 1980s were well below 10% then, while the average today is above 20%, said Charas's Andy LaFrate. Some strains measured up to 30%, he added.

Other studies have found similar results. A study in the journal Neuropsychopharmacology found that THC content doubled from about 5% in 1990 to 10% in 2005. Those researchers also found THC levels of up to 40% in hash oil.

It seems clear from personal observation and the scientific evidence that pot has gotten stonier over the years. It only makes sense, given the intense marijuana breeding activity that has gone on since the 1970s. Until recently, with the rise of awareness of the medicinal properties of CBD, breeders had been hybridizing pot strains only or primarily to increase the THC content.

Still, there have been quibbles. The notion that pot is stronger now has been challenged repeatedly. A 2008 review of the research in the journal Addictionadded the caveat that while "increased potency has been observed in some countries ... there is enormous variation between samples, meaning that cannabis users may be exposed to greater variation in a single year than over years or decades."

The Australian researchers in that study scoffed at reports of 20-fold and 30-fold increases in pot potency.  "In the United States," they wrote, "the THC concentration of confiscated marijuana rose from 2.0% in 1980 to 4.5% in 1997, and reached 8.5% by 2006." 

But there's something funny about that potency finding of 8.5%. I can walk into the local dispensary today and easily finds strains with 20% THC or more, and lists of the strongest strains routinely show THC concentrations well over 20%.

And that sheds a light on one problem with these pot testing numbers. Just what is being tested? Mexican brick weed still accounts for a huge percentage of all the pot consumed in this country. If samples of brick weed are being tested, that's going to bring the average potency down, because while its potency may have increased over the decades, it is still no match for those hybrid strains being cultivated north of the border.

There's another problem, too. As a 2012 research review noted, most potency studies fail to factor in the age of the sample, and that's important because THC degrades over time. A fresh sample is going to test stronger than a year-old sample of the same pot. There is even one recent study suggesting that a significant portion of the reported rise in potency could be because the pot being tested today is fresher than that sampled in previous decades.

Or it could be the obvious reason: For the past three or four decades, people around the world have been breeding pot for potency, and at least some of them know what they're doing.