Cannabis has a complicated relationship with anxiety. While it is one of the most common conditions for which people use cannabis, it is also avoided by many for causing spikes in anxiety.

Research confirms this apparent paradox. Tentative conclusions in the scientific literature propose this may be because THC and CBD, two of marijuana’s main active components, relieve anxiety at low doses but exacerbate it with higher doses. On top of this, different cannabis strains vary considerably in their chemical composition and effects.

Up until recently, differences between strains have been largely neglected in research into the possible therapeutic applications of marijuana. A novel study by researchers from Whistler Therapeutics in British Columbia, Canada, seeks to redress this by determining which cannabis strains composed of varying blends of cannabinoids and terpenes (otherwise known as a “chemotype”) seem best-suited to relieving anxiety. While their initial study was limited in scope, the research team’s preliminary results suggests a direction for future research.

The first step, as outlined by Daniel Lantela, co-founder and drug development director at Whistler Therapeutics, was to determine what choices patients make when choosing a particular strain to help with their anxiety.

“Patients report having distinct preferences for certain strains over others and little research has been done on what, if anything, is different between strains they like or dislike for a condition” said Lantela. “By asking patients which strains they liked or disliked, we could correlate their choices to the chemotype.”

To do this, the researchers asked 442 patients from one dispensary to rank the most and least effective of the 25 available strains for managing anxiety on a ten-point scale. The four most effective strains according to the responses were:

  1. Bubba Kush
  2. Skywalker OG Kush
  3. Blueberry Lambsbread
  4. Kosher Kush

The four least effective strains were:

  1. Chocolope
  2. Blueberry Lambsbread
  3. CBD Shark
  4. Tangerine Dream

The researchers then analyzed the chemical composition of the most and least effective marijuana strains through two independent lab tests. The results of these tests showed the most effective strains tended to be high in THC and the terpene trans-nerolidol, which is known for its sedating effects and is found in other strong aromatics such as lemongrass and jasmine. Three of the four strains reported to be most effective were Kush varieties originating from its namesake mountain range in Central Asia. They are therefore chemically similar, with high concentrations of trans-nerolidol, b-caryophyllene, and D-limonene.

Chocolope was ranked the least effective strain for reducing anxiety. It contains the terpene terpinolene in high concentrations, as is often the case in other sativas. This leads the researchers to speculate terpinolene may play a role in Chocolope failing to relieve anxiety. But the main common thread between three of the four least-effective strains is the terpene guaiol. While the researchers said it may induce anxiety, guaiol is found in such small quantities that it’s not clear how it could bring about such a strong effect.

The study’s authors warn against drawing hard conclusions from their research so far. Rather, they see self-reporting studies as a starting point for moving on to controlled research that is more immune to the placebo effect.

“Eventually researchers should start to look deeper into the terpene profiles in controlled studies” Lantela said. “Having blinded studies on cannabis products with varying cannabinoids and terpene levels is much needed.”

With this new study, the researchers think they may have found good candidates, namely the Kush varieties, for controlled studies into their chemical composition and how this corresponds to their reported effects on anxiety. But it is also likely that further self-reporting studies on which strains are most effective at relieving anxiety will throw up new strains. What’s more, as the study’s authors note, there’s currently no way to really know whether the chemotype of a particular Kush variety in one dispensary is the same as that sold elsewhere.

Of most importance at this stage for Lantela is that Whistler Therapeutic’s research indicates the strain choices patients make are not random and are seemingly linked to the presence of certain terpenes.

“This study demonstrated that patients’ choices for strains was not random, and the choices were correlated to specific terpene content,” Lantela said.