The 7 Most Important Cannabis Research Studies of 2023
In 2023, numerous new research results on the topic of cannabis were published. Below is a selection of some of the studies that caught my attention, with brief summaries of each. The first two studies relate to the area of public health. This was followed by three studies on commercial cannabis, followed by two basic research studies on the endocannabinoid system.
This year we saw a nice review of public health research over the past few years, finding little evidence that legalization increases marijuana use among teenagers, and there is also evidence that it actually leads to lower alcohol consumption among teenagers. There has also been interesting research done on the cannabis plant itself, including non-terpene volatiles that determine its aroma and its susceptibility to Hop Latent Viroid, a devastating infection spreading throughout North America. There was also interesting basic research that provided new insights into how the endocannabinoid system works.
Here you will find a short summary of a selection of studies from 2023.
The Galactic Epicenter of 420: Hippie Hill, San Francisco Golden Gate Park. (David Downs/Leafly)
At the time of publication of this paper, 36 states had legalized medical marijuana and 18 states had legalized cannabis for adult recreational use. This review article summarizes studies that address the public health consequences of legalization. Key outcomes they reviewed the literature on included: marijuana use among youth, alcohol consumption, prescription opioid misuse, traffic fatalities, and crime.
“There is little credible evidence that legalization increases marijuana use among teenagers.”
Topics on which there was a high level of agreement across studies included:
- “There is little credible evidence that legalization increases marijuana use among teenagers.”
- “Compelling evidence that young adults will consume less alcohol if medical marijuana is legalized.”
On other topics, the authors found a lower level of agreement between studies, making it impossible to draw firm conclusions. These included:
- “For other public health outcomes, such as mortality associated with prescription opioids, the impact of medical marijuana legalization has proven more difficult to estimate and, as a result, we are less comfortable drawing firm conclusions.”
Further details on the literature they discuss can be found in the article itself.
How to order weed delivery online from Leafly
The question this study sought to answer was whether state legalization of cannabis was associated with increased rates of psychosis-related health claims. This cohort study examined claims data from over 63 million beneficiaries between 2003 and 2017. They found no statistically significant differences in the frequency of psychosis-related diagnoses or prescribed antipsychotic medications in states where cannabis is legal for medical use or for adults compared to states where Cannabis is not legal.
Terps aren't the whole story. (Courtesy of Abstrax)
Following previous work showing that the “skunky” aroma of some strains comes not from terpenes but from a class of compounds called “volatile sulfur compounds,” a team at Abstrax delved deeper into the chemistry of cannabis aroma. They found that a variety of non-terpene volatile compounds are the primary cause of many of the “exotic” flavors that give the strains various sweet or savory scents.
To learn more about this particular study, check out this Leafly article and listen to the video lecture from Abstrax chemist Dr. Iain Oswald.
The nose knows: It's time to clear the mind of THC and terp levels
This bud shows nitrogen problems as well as thin, wavy cut leaves and airy, narrow bud development. All signs of latent viroid infection in hops. (David Downs/Leafly)
Latent hop viroid is a virus-like infection that is devastating cannabis cultivation across North America. We've already written about what HLV is and how it affects marijuana growers. This was a key study from 2023 that showed the effects HLV has on cannabis plants and how widespread it is already in some locations. Given the huge impact HLV is already having, we can expect to learn more about this bug in 2024.
Some cannabis is grown indoors, some outdoors. Many consumers have clear opinions about which is better. In this 2023 study, researchers conducted a side-by-side comparison of two genetically identical strains grown indoors and outdoors, examining their cannabinoid and terpene content. Key findings included:
- Significantly higher levels of oxidized and degraded cannabinoids in indoor grown samples.
- Significantly more “unusual cannabinoids” like C4 and C6 THCA in outdoor-grown samples.
- Significant differences in terpene profiles for outdoor and indoor grown samples, with outdoor grown samples generally having higher amounts of sesquiterpenes such as caryophyllene, humulene, etc.
The endocannabinoid system regulates many different systems in the brain and body. As we have described in this article, endocannabinoids play an important role in regulating pain perception, fear and anxiety. At any given time, there is a certain “endocannabinoid tone” in your brain. As this rodent study showed, endocannabinoid tone “controls” the stress response generated in the brain’s hypothalamus. In general, endocannabinoids limit activation of the hypothalamic-pituitary-adrenal (HPA) axis, the key brain system that regulates stress levels. Higher endocannabinoid tone had the effect of reducing stress levels in rodents.
Endocannabinoid receptors are one of the most abundant proteins in the brain and are found in many different brain regions and neuron types. This is one reason why the effects of THC can be so diverse. Depending on the dose of THC consumed, different neurons and brain regions can be affected to different degrees and produce different effects. In this rodent study, neuroscientists examined the effects of a specific subset of dopamine neurons in the brain that express CB1 receptors. They found that this particular subset of neurons has some of the negative side effects that cannabinoids like THC can cause (especially at high doses), including anxiety. This illustrates how specific subsets of neurons in the brain can control specific effects that cannabinoids produce.