This is the second article in a 6-part series on medical cannabis. Read the other posts here.

THC and CBD are both cannabinoids found in the cannabis plant. They are found in different proportions in different strains of cannabis. THC and CBD each have their own unique effects on the body, and may be used for different therapeutic purposes.

THC is psychoactive, meaning it affects the mind, while CBD is not. THC-containing cannabis appears to have different effects in the short-term and the long-term. THC and CBD also appear to have slightly different, yet overlapping medical uses, although these are still being studied.

Let’s take a look at the main differences between THC and CBD.

What are Cannabinoids?

Cannabinoids are the main active ingredients in cannabis. There are over 100 different cannabinoids found in the cannabis plant, but THC and CBD are two of the most well-known. THC and CBD are also the two most abundant cannabinoids in cannabis, meaning they occur in the highest concentrations.

However, researchers continue to look at the potential benefits of THC, CBD, other cannabinoids, and the “entourage” effect, which describes the way cannabinoids may interact to produce specific effects. There is a lot to learn when it comes to the therapeutic potential of the many lesser-known compounds.

THC

THC stands for delta-9-tetrahydrocannabinol. THC is the compound responsible for many of the quintessential effects of cannabis, including the cannabis “high.”

THC used to occur in relatively low proportions in cannabis, but in recent years, growers have been breeding cannabis to increase the amount of THC. The average THC content in cannabis has risen steadily since the 1980s. According to the Government of Canada:

“THC potency in dried cannabis has increased from an average of 3% in the 1980s to around 15% today. Some strains can have an average as high as 30% THC.”

This means that certain strains of cannabis available today may be up to 10 times stronger than the strains of the past. The Government of Canada warns that the harmful side-effects of cannabis may be exaggerated when the percentage of THC is high.

The increased potency may be a boon to people who use medicinal cannabis, as it means they have to use less to achieve a therapeutic effect.

Those who are concerned about high potency should make sure they purchase cannabis from a licensed producer whose products are lab-tested. You can choose the percentage of THC that you are comfortable with and should always speak to a health care practitioner to select a dose right for you.

CBD

CBD stands for cannabidiol. Unlike THC, CBD does not have any psychoactive effects, and it does not cause a “high.” Some strains of cannabis have been bred to feature mainly CBD, with little to no THC. This cannabis does not produce a “high,” although it may have some subtle effects on the body.

There is currently a lot of medical interest in CBD, and it is being studied for its potential therapeutic effects.

There is also some evidence suggesting CBD may reduce some of the negative side-effects of THC. Some people prefer to use cannabis with a higher level of CBD for this purpose.

Effects of THC and CBD

THC and CBD have different effects on the body because they act on different receptors in the brain. THC activates cannabinoid receptors directly, while CBD indirectly increases levels of an endocannabinoid known as anandamide.

THC

According to Health Canada, THC has a number of different effects on the body. These include psychological, sedative, anti-epileptic, analgesic, anti-nausea, and appetite stimulation effects. THC has a variety of effects on the respiratory, gastrointestinal, cardiovascular, and reproductive systems.

CBD

Unlike THC, CBD does not produce any psychoactive “high.” According to the Ontario Cannabis Store website, CBD produces a “body buzz” rather than a “head high.”

In terms of medical effects, CBD appears to have “anti-inflammatory, analgesic, anti-nausea … anti-psychotic, … anxiolytic, and anti-[epilepsy] effects,” according to Health Canada’s cannabis information page for health care practitioners.

The Entourage Effect

Scientists believe that THC and CBD, among other compounds in cannabis, may work together in a synergistic manner, according to Health Canada. For example, cannabis with lower levels of THC and higher levels of CBD is “associated with self-reported therapeutic efficacy and satisfaction across a number of different medical conditions.” Furthermore, a study conducted in non-human primates found that when THC and CBD were administered in a 1:1 ratio, the CBD attenuated some of the cognitive impairment effects of THC.

Psychoactive vs. Non-Psychoactive: What’s the Difference?

One of the most important differences between THC and CBD is that THC produces psychoactive effects while CBD does not. But what exactly does this mean?

When we say THC is psychoactive, we mean that it affects our mind. This is often described as feeling “high.” The cannabis “high” involves feelings of euphoria and relaxation, as well as altered perception and heightened sensory experience, according to Health Canada. Some people may experience strange thoughts, confusion, and anxiety as a result of THC’s psychoactive effects.

CBD, on the other hand, is non-psychoactive. This means it does not affect our thoughts, feelings, and perceptions significantly. CBD’s effects tend to be more subtle, and this is because of how it works in the body. CBD does not activate CB1 receptors directly like THC does. Instead, it indirectly increases levels of endocannabinoids — naturally occurring cannabinoids in the body.

Short-Term vs. Long-Term Effects of Cannabis

When discussing the effects of cannabinoids, it’s important to distinguish between short-term and long-term effects. Short-term effects are the immediate effects of using cannabis, while long-term effects occur after regular use over a longer period of time. These effects typically refer to cannabis containing THC.

Health Canada advises that you should not use cannabis if you are pregnant or breastfeeding. It poses a risk to the fetus or new born child. Heavy cannabis use has been linked to lower birth weight.

Health Canada also advises that you should not use cannabis if you have a predisposition to or family history of psychosis or problematic substance use.

Short-Term Effects

The short term effects of using THC-containing cannabis include feeling “high,” a sense of wellbeing, relaxation, and heightened sensory perception, according to Health Canada.

Some people may also experience unpleasant effects, including confusion, fatigue, impaired memory and concentration, and anxiety. Other effects include an increased heart rate (tachycardia), increased blood pressure (hypertension), and increased appetite. In rare cases, cannabis may cause a person to experience delusions, hallucinations, psychosis, or even extreme vomiting (cannabis hyperemesis syndrome).

Long-Term Effects

The long term effects of using cannabis tend to develop gradually when a person uses cannabis frequently for weeks, months, or years. Health Canada has advised that the brain does not stop developing until around age 25. The younger you are when you begin cannabis use and the more often and the longer you use it, the more likely it is to have a larger impact on your brain. Some of the long term effects include problems with memory or concentration, impaired cognition and decision-making, and even reductions in IQ, according to Health Canada.

Other effects include bronchitis, chronic cough, and lung infections, although these typically only occur when it is smoked. Addiction is another potential long term effect. Men and women who are trying to conceive a child are advised to avoid using cannabis, Health Canada warns. This is because cannabis may affect a person’s fertility.

The long-term effects can last for days to months after a person stops using cannabis. Some effects may not be fully reversed upon cessation, Health Canada warns. Importantly, studies are still ongoing to evaluate the long term side effects of cannabis use, and it is possible that not all risks have been identified.

Summary

• THC and CBD are two of the most abundant and most well-understood cannabinoids in the cannabis plant.
• THC is psychoactive, meaning it affects the mind, while CBD is non-psychoactive.
• The concentration of THC found in cannabis has increased between fivefold and tenfold since the 1980s. This may increase the risk of serious side-effects.
• Cannabis has different effects in the short-term and the long-term. The short-term effects include relaxation, euphoria, and heightened senses, as well as anxiety and confusion, while the long-term effects may include problems with memory and concentration, impaired cognition, and lung problems like bronchitis.

Please note that the content of this article is provided for general informational purposes only and should not be taken as medical advice. Contact your healthcare provider with any questions about your condition or treatment.