Newswise — Alcohol and cannabis are commonly used together, and their co-use has public health implications. A preliminary study looked at the effects of two cannabinoids – delta-9-tetrahydrocannabinol (THC), and cannabidiol (CBD) – on drinking and craving. The study found thathigher levels of THC are associated with greater co-use of alcohol, whereas CBD-based products may be associated with lower levels of alcohol co-use. These results and others will be shared at the 42ndannual scientific meeting of the Research Society on Alcoholism (RSA) in Minneapolis June 22-26.

“The cannabis plant expresses more than 100 different chemical compounds or ‘cannabinoids,’” explained Hollis Karoly, research associate in the Institute for Cognitive Science at the University of Colorado Boulder, “but THC and CBD are the two most likely to be consumed by a recreational or medical user. THChas psychotropic properties and is responsible for intoxicating effects, such as feeling ‘high,’ sedated, or euphoric. CBD is thought to be non-intoxicating and potentially therapeutic for conditions such as inflammation, anxiety, and epilepsy; however, its effectson the brain and body are not yet fully understood.”

Karolywill discuss these findings at the RSA meeting on Tuesday, June 25.

“Cannabis is commonly used by people who drink alcohol, but there is conflicting evidence regarding whether it increases or decreases drinking,” said Karoly. “Given the different effects of THC and CBD in the brain and throughout the body, we wanted to explore whether or not the effects of cannabis on alcohol consumption depend upon the actual cannabinoids ingested. Much of the research on the specific THC/CBD impact on drinking in humans is limited, and most findings have come from rodent studies. Some studies have found that medical-cannabis users cut down on drinking, but other studies suggest that cannabis – and THC in particular –increases the rewarding effects of alcohol and thus increasesalcohol intake. Conversely, a limited body of emerging evidence – mostly from animal studies – suggests that CBD decreases the rewarding effects of alcohol, thereby decreasing drinking and motivation to drink.”

In other words, while human studies are lacking, preliminary research suggests that CBD use maybe associated with decreased drinking. Karoly stressed that THC effects on drinking are even less straightforward, and likely depend on various factors such as THC potency, route of administration, and individual user characteristics. 

“The route of cannabis administration is extremely important for determining the effects that cannabis has on a user,” said Karoly. “Smoking is still the most common way to use cannabis. People typically feel its effects quickly, and so they can modulate or ‘titrate’ the amount they use to reap desired effects. With time, smoking cannabis may lead to respiratory problems. ‘Vaping” refers to ‘vaporized cannabis,’ using a device that electronically heats cannabis to a high temperature to produce a mixture of water vapor and cannabinoids for inhalation. This method can also be titrated. Edible cannabis reduces respiratory risks associated with smoking; however, the amount of time between ingestion and experiencing effects from cannabis can be lengthy and difficult to titrate. Cannabis extracts or ‘concentrates’ can potentially contain very high THC potencies and may cause various negative side effects such as development of tolerance and withdrawal symptoms.”

“There is much that we still do not know about alcohol/cannabis synergy,” cautioned Karoly. “It is important that individuals who use both cannabis and alcohol be aware of the potential impact that cannabis use may have on their drinking.”


Meeting Link: Research Society on Alcoholism (RSA) in Minneapolis, June 22-26, 2019