CBD and THC: what's the difference?

CBD and THC are the best-known cannabinoids in Cannabis sativa, and also the most studied. Although they come from the same plant, their effects, uses and precautions are quite different. Understanding these differences is one of the first steps toward feeling more confident about treatment.

CBD (cannabidiol)

CBD does not cause the intoxicating effect associated with recreational use. It acts broadly in the body, modulating a range of receptors and systems. The effects being studied include:

• an anticonvulsant (anti-seizure) effect, the use with the strongest evidence;
• a possible anti-anxiety effect;
• anti-inflammatory action;
• effects on sleep and pain.

It is usually well tolerated, but it can cause drowsiness and changes in bowel habits and appetite. It also interacts with other medications, something that requires a doctor's attention.

THC (tetrahydrocannabinol)

THC binds directly to the CB1 receptor, which is abundant in the brain, and it is responsible for the plant's psychoactive effects. In medical use, however, it is given in low, controlled doses, which considerably changes its effect profile. The effects being studied include:

• pain relief, especially for nerve (neuropathic) pain;
• reduced nausea and vomiting;
• increased appetite;
• reduced muscle spasticity;
• help with sleep.

The most common side effects include dizziness, dry mouth, drowsiness and a faster heart rate. At higher doses, it can cause anxiety, confusion or changes in perception, which is why the dose is adjusted carefully.

Why the two are sometimes used together

Some studies suggest that CBD and THC may work in complementary ways. CBD, for example, may soften some of THC's unwanted effects. That's why, for conditions such as chronic pain and spasticity, formulations that combine the two in defined ratios are used.

Some researchers call the idea that the plant's compounds work together the entourage effect. It is still being researched and should not be taken as a rule.

Types of product

• Isolate: contains a single purified cannabinoid, usually CBD.
• Broad spectrum: combines several compounds from the plant, with the THC removed or present only in trace amounts.
• Full spectrum: keeps a range of the plant's compounds, including small amounts of THC.

The choice between them depends on the treatment goal, the condition, the patient's age, other medications and even the patient's daily life, such as needing to drive or take drug tests.

Which one is best for me?

There is no single answer. The ratio of CBD to THC, the dose and the way the product is taken are decided during the consultation, based on your medical history. What matters most is that the choice is made with care, good information and follow-up, and adjusted according to how you respond.

In summary

• CBD is not intoxicating; THC is psychoactive, but it is used in low, controlled doses.
• The two have different uses and side effects.
• They can be combined in specific ratios for some conditions.
• The choice is always individual and made during a consultation.