Has it all ‘gone to pot’ with creating safe cannabis? Audio lay summary

Social Sciences: Psychology

Has it all ‘gone to pot’ with creating safe cannabis?

Let’s get straight to it, research shows it is becoming more common to find high potency cannabis strains that contain low levels of so called Cannabidiol (CBD) and high levels of Tetrahydrocannabinol (THC). Why is this important? Well, several countries are choosing to decriminalise or legalise cannabis use as this would possibly enable better regulation in terms of drug quality, which might reduce its harm. This comes after recent research showing that using cannabis every now and then can increase the risk of memory and attention problems, and even result in psychotic symptoms at least in the short term. However, in the long term, evidence shows that the risk of developing a psychotic disorder or substance use disorder (SUD) is much greater. Despite this, other research shows that CBD may lower the adverse effects of THC I just mentioned, but this is an under researched area. So, the current study wanted to see whether cannabis strains with a high CBD to THC ratio would result in fewer adverse symptoms or side effects than strains with a lower ratio.

Researchers in this 2022 experiment tested four ratios in milligrams of 0 CBD:10 THC, 10:10, 20:10, and 30:10 on forty-six healthy volunteers aged 21-50 (so on average 26.62) who had used non-synthetic strains of cannabis once in the past, but no more than once per week in the past month. Prior to the experiments, urine drug and pregnancy tests were completed alongside an alcohol and a carbon monoxide breath test. Blood samples were also taken before the participants were given cannabis, and at 5, 15, and 90 minutes following final exhalation after using a vaporiser. This allowed the researchers to observe the blood concentration of THC and CBD. The vaporiser filled two opaque bags (different ratios produce different amounts of smoke) that participants used to inhale a comfortable amount of vapour after an 8 second period of holding their breath until each bag was empty. Coughing severity and inhalation duration were recorded. A warm cup of lemon and honey water was provided to help soothe the abrasiveness of breathing in the cannabis. Fifteen minutes after cannabis administration, participants were asked to complete 35 minutes of pencil and paper tests, which assessed their thinking skills and abilities, alongside a test which asked how pleasurable they found the effects of the cannabis. Following this, participants completed the ‘Hospital Walk’ task, which has been seen to increase paranoia following THC. This involves asking the person to purchase an item of their choice from a till operator in the hospital shop using a £2 given to them by the experimenters, remembering to ask for a receipt before returning. Once participants felt that at least 90% of the drug effect had subsided they completed a number of additional psychological questionnaires and a diagnostic interview to see if they experienced psychotic symptoms after using cannabis.

The main finding of this study was that higher concentrations of CBD did not reduce thinking problems or psychotic symptoms following cannabis use. The researchers also found that higher concentrations of THC did not show significant more adverse effects on thinking skills like ‘working memory’ tasks (so this is their ability to hold things in mind and manipulating information, which most people who smoke ‘weed’ often notice can be reduced), psychotic symptoms as rated by the researcher blood pressure, and body temperature. That said, THC did worsen people’s performance on other thinking tests and psychotic symptoms.

It should be noted that some people did drop-out of the experiment after having experienced one experimental dose of cannabis, meaning those who stayed throughout the experiment may have been less sensitive to the effects of the drug. The use of another additional ‘placebo control condition’ where another group people are given a fake drug that has no active chemicals in them (e.g., water vapor) may have made it easier to more clearly see the symptoms from ingesting THC and CBD. It is important to consider that there are other possible ways by which THC and CBD concentrations naturally differ across cannabis strains and plants, where . Particularly, some plants that with a higher CBD:THC ratio produce less THC rather than more CBD. This is an avenue not explored by this experiment but could be looked at by measuring gradual increases of CBD. Like to other previous studies, the researchers found that CBD did not protect against the effects of THC among people who use cannabis every now and then. Future studies may benefit from looking to see if CBD can reduce the adverse effects of THC among long-term or chronic cannabis users.

With decriminalising and legalising cannabis being a topic of much interest currently, based on this study at least it would seem that using high CBD:THC ratio strains as a protective regulatory strategy by governments to reduce the short-term adverse symptoms of THC and prevent mental health problems of those who use the drug recreationally every now and then, might not be so fruitful. Up next in this research, it would be interesting to investigate even higher CBD:THC ratios, which may show more promising protection against the adverse effects of short-term recreational cannabis use.

Image: Pink and green petaled flower photo – Free Cannabis Image on Unsplash: https://unsplash.com/photos/t9jQie6cUhg


Title of lay summary Has it all ‘gone to pot’ with creating safe cannabis? Audio lay summary
Lay Summary Author(s)

Jacob Maspero Bottaio

Vetting Professional Dr Anthony Mark Harrison
Vetting Professional Affiliation(s) / participating organisation(s) The Collaborative Library
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What is the licence for your lay summary? Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) (for all other options selected above)
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Provide the full weblink DOI of the published scientific article: https://doi.org/10.1038/s41386-022-01478-z
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Title of the original peer-reviewed published article: Does cannabidiol make cannabis safer? A randomised, double- blind, cross-over trial of cannabis with four different CBD:THC ratios
Journal Name: Neuropsychopharmacology
Year of publication: 2022

Amir Englund, Dominic Oliver, Edward Chesney, Lucy Chester, Jack Wilson, Simina Sovi, Andrea De Micheli, John Hodsoll, Paolo Fusar-Poli, John Strang, Robin M. Murray , Tom P. Freeman and Philip McGuire

Contributors and funders:

AE has received speakers’ honoraria from GW Pharmaceuticals. RMM has received speakers’ honoraria from Lundbeck, Sunovian, Otsuka, and Janssen. JS has undertaken research supported financially by various pharmaceutical companies, but this has not involved studies of cannabis or cannabis-related products. All remaining authors report no conflicting interests.

Original Article language: English
Article Type: Randomised Controlled Trial (cross-over)
What licence permission does the original e-print have? For more information on this please see our permissions video): Attribution 4.0 International (CC BY 4.0)

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