Cannabis, Glutamate, and the Vulnerable Brain

For years, many people have believed that cannabis is a harmless natural treatment for seizures. While some highly purified, prescription CBD medications have been shown to help certain rare forms of epilepsy under medical supervision, that does not mean that smoked or recreational cannabis is safe for everyone with epilepsy. In fact, many people living with epilepsy report exactly the opposite - they find that cannabis makes their seizures more frequent or more severe and new neuroscience research may help explain why.

Researchers are beginning to look beyond the traditional focus on dopamine and how it works in Epilepsy and are studying another important brain chemical called glutamate, which is the brain's primary excitatory neurotransmitter. Think of it as the brain's "go" signal. Every time one nerve cell tells another to fire, glutamate is often involved. A lot of glutamate can make the brain very jumpy, or excitable.

Balancing glutamate is another neurotransmitter called GABA, which acts like the brain's braking system. While glutamate tells neurons to become active, GABA tells them to calm down. Healthy brain function depends on keeping these two systems in balance.

One way to imagine this is as an orchestra - Glutamate is the musicians playing their instruments, GABA is the conductor making sure everyone stays in rhythm. When the balance is maintained, the music is beautiful… but when too many instruments begin playing at once without enough control, the performance becomes chaotic. The brain works much the same way.

People with epilepsy already have a nervous system that is more susceptible to abnormal and excitable electrical activity. Their neurons can become overactive more easily than those of someone without epilepsy. Because glutamate plays such an important role in exciting the nerve cells, scientists are interested in whether changes in glutamate signaling could make some brains even more vulnerable.

A recent study at the at the University of Pennsylvania Perelman School of Medicine found that cannabis users who had altered glutamate levels in an area of the brain called the anterior cingulate cortex tended to have more severe psychotic symptoms than non-users. The researchers aren’t sure that cannabis causes psychosis in everyone, but they suggest that changes in glutamate levels may be one biological pathway that explains why certain people appear to be more vulnerable than others. Although this particular study focused on psychosis rather than epilepsy, the findings are still important because glutamate is deeply involved in both seizure activity and many other brain disorders.

The temporal lobes, where many focal seizures begin, communicate constantly with the anterior cingulate cortex. These brain regions rely heavily on glutamate and GABA to regulate normal brain activity. If those chemical signals become disrupted, a brain that is already sensitive may react very differently than a healthy brain, and this may help explain why cannabis affects different people in such different ways. One person may experience less seizure activity, while another person may experience worsening or an increase of seizure frequency or severity.

This is why personal experience matters. If you consistently notice that cannabis makes your seizures worse, that experience should not be dismissed simply because someone else reports that cannabis helped them. One man’s medicine might be another man’s poison.

It is also important to understand that CBD and THC are not the same thing. Prescription CBD medications used for specific severe childhood epilepsies are purified pharmaceutical products that contain little or no THC and are carefully dosed under medical supervision. Recreational cannabis products often contain much higher concentrations of THC which can have very different effects on the brain. They also might contain other things like pesticides or molds.

Scientists are still learning exactly how THC influences glutamate and other neurotransmitters, but research is now suggesting that changes in these systems may help explain why some people experience worsening seizures after using cannabis. The takeaway is not that cannabis is dangerous for everyone, but that brains are different. The brain is a complex organ and seizures may start in one part of the brain for one person, and locate in a different part of the brain for another. Not all seizures are the same and not everyone has the same reason for having seizures. One person might have seizures because of scar tissue in the brain caused by brain damage from a concussion or a stroke. Another person might have genetic epilepsy… there are many types of epilepsy and not every medication or treatment works for all of them. Like there are many types of bacterial infections, so there are many kinds of antibiotics to treat those infections. One epilepsy medication might help one kind of seizure while another one won’t work at all, or make it worse. Epilepsy is not a “one size fits all” disease.

People with epilepsy already have a nervous system that is more electrically sensitive than the average person’s. As our understanding of glutamate grows, researchers are beginning to uncover biological reasons why cannabis may affect people with epilepsy very differently than the general population. If cannabis consistently worsens your seizures, please pay attention. Your experience is real, and emerging neuroscience may finally be able to explain why. Just because someone said that cannabis would make seizures better doesn’t mean that it actually does for everyone. For example, taking the antibiotic bactrim will cure an intestinal infection, where penicillin might not touch it. Corporate Pot just wants to sell you their latest snake oil, they don’t care if it helps you or not, they are in it for the payoff. Be attuned to your body and observe your symptoms, and talk to your doctor about what works best for you, or what doesn’t. You only get one brain… take care of it.