"Science!" So sang English new wave crooner Thomas Dolby way back in 1982. Back then, cannabis was practically a different plant. Its potency averaged just three percent THC by weight. Now, the cannabis that any adult can buy at a store in Bend is around seven times more powerful.
Most commercially-available cannabis strains today are around 20 percent THC by weight, with some medical strains as high as 40 percent THC. Prohibitionists are fond of pointing out this great leap in potency, implying that cannabis is now much more harmful than it used to be. But as any good scientist knows, anything multiplied by zero is still zero. Or, as Billy Preston once sang, "Nothin' from nothin' leaves nothin'."
Over the past 30 years, cannabis growers in places like Humboldt County, California, Southern Oregon, and the Matanuska Valley of Alaska—indeed in closets and basements all over America, Canada, and Europe—have selectively bred the cannabis plant to create a continuously better and better user experience. The War on (Certain) Drugs drove cannabis cultivation indoors, having the unintended consequence of creating the ideal conditions for selectively breeding cannabis. As growers created a better product, they were able to charge more, increasing their profits and ensuring that cannabis growing continued to be a profitable, if risky, venture.
But cannabis is not just about THC. There are hundreds of chemical compounds in cannabis, many of which are probably also psychoactive (involved in getting users high). Consider, for example, terpenoids, a diverse and complex class of compounds that—as far as we know—create the scents and flavors of eucalyptus, cinnamon, cloves, ginger and, yes, cannabis. Some scientists and cannabis users also believe they enhance the potency of THC.
Menthol is perhaps the best-known terpenoid. Citral smells like lemon, myrcene smells like hops or mango, and beta-caryophyllene smells like pepper. Unique combinations of terpenoids create the different aromas, flavors, and possibly highs, of the numerous different strains of cannabis now available. And terpenoids are one big reason why the experience of using cannabis is as complex and varied as the experience of tasting beer or wine.
Other cannabis compounds are not psychoactive, but are still therapeutic. Consider CBD, known to slow the effects of epilepsy (among other diseases), even if the federal government still refuses to admit it. The role of hundreds of other compounds in producing the medicinal value and the high of cannabis is still poorly understood.
Genetic modification of crops has greatly benefitted from federal scientific funding. Sequencing the genome of corn, for example, took $32 million in public funding and has resulted in corn that grows faster, uses less water and is more disease resistant. But since the federal government essentially refuses to allow research on cannabis, that research is taking place in secret, in closely-guarded commercial labs around the country in states where cannabis is legal. This means that, unlike everything else we consume, the public may never know why a new strain of cannabis works so well, only that it does.