The cannabis plant produces hundreds of different compounds, many of which have differing effects in the body. Tetrahydrocannabinol, or THC, is the substance that is most known for its psychoactive effects, or the “high” associated with marijuana.
However, there are many other substances from the cannabis plant that also produce effects in the body. Many of these differ from THC in that they are not psychoactive – and they do not produce a “high.” Cannabidiol, or CBD, is one of those substances.
Cannabidiol is a complex molecule that is produced by the cannabis plant. Cannabis has been proposed for centuries as a medicinal plant. Only recently has CBD been studied scientifically for various disorders.
Compared to THC, CBD works at different receptors in the brain and other parts of the body. In this way, CBD is very different from THC and may offer new mechanisms of treatment. For this reason, CBD has received a great amount of attention as a possible treatment for many different disorders.
CBD has been proposed as a cure or treatment for many disorders and diseases, including epilepsy, chronic pain, anxiety, multiple sclerosis, amyotropic lateral sclerosis (ALS or Lou Gehrig’s disease) and insomnia. Some of these uses are based on science, but others are proposed by advocates of CBD and medical marijuana. Several anecdotal reports, case reports, case series and small studies have reported on CBD for many of these disorders. Information from these reports is conflicting. Case reports, case series and small studies are considered insufficient evidence to prove or disprove the safety and efficacy of a drug or treatment. This is because these studies are usually unable to distinguish between the effect of a drug and a placebo effect, the patient thinking the drug is working when it really is not providing benefit.
However, there are two well-designed, large studies that indicate CBD is effective in the two different epilepsy syndromes. In these studies, about 40 percent of patients taking CBD had a significant reduction in specific types of seizures.
Epilepsy is the only disorder where there is solid scientific evidence demonstrating that CBD is safe and effective. This does not mean that CBD will not work for other disorders, but epilepsy is the only one where we have clear, well-documented evidence that CBD helps.
Results from these studies show that CBD does have side effects. The most common ones are drowsiness, nausea, intestinal cramping, bloating and diarrhea. More serious side effects can occur. In one of the studies in epilepsy, about 10 percent of patients taking CBD had an increase in laboratory tests of liver function. These tests commonly indicate damage to the liver. About 2-3 percent of patients taking CBD had to discontinue it due to large increases in certain liver enzymes in laboratory tests, showing possible liver damage.
We are also learning about drug interactions that occur with CBD. In these studies, CBD slowed the metabolism of several drugs that are commonly given to individuals with epilepsy. The interactions between CBD and other drugs patients were taking caused side effects. It is unclear if these side effects were due to CBD, the other drugs, or a combination. Doses of the other drugs were reduced, due to the interactions.
The mechanism for these interactions indicate that there are likely several other interactions between CBD and other common medications. Cannabidiol needs to be used cautiously in combination with other medications.