According to the National Institutes of Health, people have used marijuana or cannabis to treat diseases for at least 3000 years. However, although cannabidiol, a substance present in marijuana, was approved in June 2018 and can be used to treat certain types of epilepsy.
Over the years, research has yielded results to suggest that marijuana may be of benefit in the treatment of some conditions. These are listed below.
Last year, a large review from the National Academies of Sciences, Engineering, and Medicine assessed more than 10,000 scientific studies on the medical benefits and adverse effects of marijuana.
One area that the report looked closely at was the use of medical marijuana to treat chronic pain. Chronic pain is a leading cause of disability, affecting more than 25 million adultsTrusted Source in the U.S.
The review found that marijuana, or products containing cannabinoids — which are the active ingredients in marijuana, or other compounds that act on the same receptors in the brain as marijuana — are effective at relieving chronic pain.
The review published in Clinical Psychology Review assessed all published scientific literature that investigated the use of marijuana to treat symptoms of mental illness.
Its authors found some evidence supporting the use of marijuana to relieve depression and post-traumatic stress disorder symptoms.
That being said, they caution that marijuana is not an appropriate treatment for some other mental health conditions, such as bipolar disorder and psychosis.
The review indicates that there is some evidence to suggest that marijuana might alleviate symptoms of social anxiety, but again, this is contradicted by the National Academies of Sciences, Engineering, and Medicine review, which instead found that regular users of marijuana may actually be at increased risk of social anxiety.
In June 2018, the Food and Drug Administration (FDA) approved the useTrusted Source of a medication containing cannabidiol (CBD) to treat two rare, severe, and specific types of epilepsy — called Lennox-Gastaut syndrome and Dravet syndrome — that are difficult to control with other types of medication. This CBD-based drug is known as Epidiolex.
CBD is one of many substances that occurs in cannabis. It is not psychoactive. The drug for treating these conditions involves a purified form of CBD. The approval was based on the findings of research and clinical trials.
A study published in 2017 found that the use of CBD resulted in far fewer seizures among children with Dravet syndrome, compared with a placebo.
Dravet syndrome seizures are prolonged, repetitive, and potentially lethal. In fact, 1 in 5 children with Dravet syndrome do not reach the age of 20 years.
In the study, 120 children and teenagers with Dravet syndrome, all of whom were aged between 2 and 18, were randomly assigned to receive an oral CBD solution or a placebo for 14 weeks, along with their usual medication.
The researchers found that the children who received the CBD solution went from having around 12 seizures per month to an average of six seizures per month. Three children receiving CBD did not experience any seizures at all.
Children who received the placebo also saw a reduction in seizures, but this was slight — their average number of seizures went down from 15 each month before the study to 14 seizures per month during the study.
The researchers say that this 39 percent reduction in seizure occurrence provides strong evidence that the compound can help people living with Dravet syndrome, and that their paper has the first rigorous scientific data to demonstrate this.
However, the study also found a high rate of side effects linked to CBD. More than 9 in 10 of the children treated with CBD experienced side effects — most commonly vomiting, fatigue, and fever.
The patient information leaflet for Epidiolex warns of side effects such as liver damage, sedation, and thoughts of suicide.