Anyone who has walked into a legal weed store has heard this question. The majority of pot stores divide their products into these groups, and people who buy weed are used to the distinction—it’s older than the pot shops themselves. Supposedly, indica sedates and sativa uplifts. But here’s the thing: That’s all bullshit.
The cannabis classification system was first proposed by French biologist Jean Baptist Lamark in the 18th century. Through his observations of various cannabis plant samples from India, he described cannabis indica plants as being shorter with thick, stubby leaves, while sativa plants were taller and had feather-like leaves. Due to their different appearance, he then proposed that each plant had different uses and effects.
The differences between indica and sativa plants are physical. Indicas are short and squat and supposedly come from the mountains of Pakistan. Sativas are tall and thin and supposedly come from the tropics. But according to Ethan Russo, a board-certified neurologist and one of the country’s leading cannabis researchers, these outward physical attributes have no bearing on predicting what kind of high you’ll experience.
“You cannot tell the effects a plant will have based on its shape—the shape of its leaflets, its size, or how tall it is,” Russo says. “What we really should be homing in on is the chemical composition of the plant.”
You’re Starting to Sound Like You Don’t Know What You’re Talking About
Looking at a tall pot plant and deciding that smoking its flower will uplift you is like deciding how sweet an apple variety is by examining its tree trunk in June. Wouldn’t it make more sense to decide the apple’s qualities by tasting its fruit in September?
That’s what Russo is advocating for—looking at what is actually in the pot flower to try to predict how it will affect you. There is scientific evidence that certain strains produce wildly different effects, and each strain’s specific effects are complicated by each individual person’s mood, body chemistry, and environment. That’s partly why the indica versus sativa distinction is pervasive—it offers an easy delineation when the reality is complicated.
Scientists are just starting to understand how these terpenes affect people and have begun attributing effects to individual terpenes. For example, alpha-pinene, a terpene that smells like pine needles, has been found to induce alertness and memory retention. Limonene, which smells like citrus, can elevate your mood and may be anticarcinogenic.
What science have to say
“You can’t extrapolate too far from what basic science has done with only one terpene. It’s really whole cannabis compositions that we need to start to understand better,” Raber said. “Terpinolene is known to be a sedative, but it’s typically found with an energetic effect. By itself it might have one response that the rat or rabbit has in a lab, but together with many other terpenes and cannabinoids it’s a very different physiological response.”
But we do know this: There are hundreds of active chemicals in weed, called cannabinoids and terpenes, that work together to get you high. Cannabinoids interact with your brain’s endocannabinoid system; THC and CBD are the most commonly known cannabinoids, but close to a hundred others have been identified. Terpenes are aroma compounds found in all plants, and there’s growing evidence that pot’s terpenes play a big role in psychoactivity.
Both terpenes and cannabinoids can be precisely quantified with simple laboratory tests. Providing these lab reports to consumers would be a big step toward more informed shopping. But it’s more complicated than seeing a terpene on a lab report and being able to predict that strain’s effect. Alpha-pinene might produce alertness by itself, but there’s evidence that each individual chemical’s effect is mitigated and changed by other chemicals in the strain. Jeffrey Raber, a chemist with a PhD from University of Southern California and the scientific director of Bellevue, Washington’s WERC Shop cannabis lab, explained this at a panel on terpenes at Seattle’s Hempfest in August.
For decades, marijuana growers, sellers, and consumers have classified strains as “indica” or “sativa” to explain the type of effect they would have when consumed. But that classification system was faulty to begin with, and the advent of molecular testing proved that there is no sense in splitting them up into indica and sativa. There’s not a simple way to create a more accurate system, however, so the indica-sativa dichotomy endures.
This of course results in problems for consumers who may take the substance and become disappointed as it did not give them the desired effect. Would a more accurate classification system exist, this of course would happen less. Until then however, the researchers recommend users take a trial and error approach to find their ideal strain of cannabis.
[Updated, originally published 4.10.2020]