Can Cannabis Help Traumatic Brain Injury?
Jan 14, 2020
Traumatic brain injury is a major cause of death, disability, and long-term cognitive impairment. As with many other conditions, researchers have been exploring whether cannabis can help. Cannabinoids are known to be neuroprotective and this has prompted research exploring how cannabinoids may decrease the adverse outcomes of traumatic brain injury.
Endocannabinoids are naturally released as part of the body’s protective response to brain injury. Consuming tetrahydrocannabinol (THC) and cannabidiol (CBD) may help mimic the neuroprotective properties of endocannabinoids naturally released as a response to brain trauma.
There are some promising observational studies and preclinical research on the efficacy of cannabis for traumatic brain injury. However, the available data from clinical trials is less conclusive and has limitations.
As legal medical cannabinoids become more prevalent, further clinical trials should help to determine just how effective cannabis is for traumatic brain injury.
How Cannabis Works on Concussions and Brain Trauma
The endocannabinoid system exists in all vertebrates and helps regulate crucial functions such as sleep, pain, and appetite. The human body produces its own cannabinoids, which modulate and activate its various functions, but as its name suggests, the endocannabinoid system can also be modulated and activated by cannabinoids found in the cannabis plant. Because the entire system was only discovered in the past 30 years, scientists still have much to learn about the myriad ways cannabis affects the human body.
Preclinical studies have focused on how to manipulate the endocannabinoid system to improve outcomes of traumatic brain injury. These studies have given us insights into how the endocannabinoid system is associated with the pathology of traumatic brain injury.
- A recent review of preclinical data on endocannabinoids and traumatic brain injury suggests that the endocannabinoids anandamide and 2-Arachidonoylglycerol (2-AG) naturally increase in response to brain injury.
- Research on rats and mice shows that when anandamide and 2-AG are administered after traumatic brain injury, this reduces brain damage and improves recovery.
- Data from test-tube and animal studies suggest that anandamide and 2-AG reduce the production of factors that promote brain damage like reactive oxygen species (ROS).
Based on these studies, it appears that the endocannabinoid system is involved in the recovery process after traumatic brain injuries in animal models.
Medical Studies on Traumatic Brain Injury and Cannabis
A three-year review found that THC was associated with a lower chance of death as a result of traumatic brain injury; mortality in the THC group was 2.4% and mortality in the non-THC group was 11.5%.
In one study on mice, THC reduced the release of glutamate, which is a common neurotransmitter in the brain. Excessive glutamate signaling is known to be one of the primary contributors to cell death following brain injury.
While data from reviews and preclinical trials show promise for cannabis, the results from clinical trials are mixed and also have limitations such as the exclusive use of synthetic cannabinoids.
In one randomized, double-blind clinical trial, researchers tested the effectiveness of the synthetic cannabinoid dexanabinol on patients with severe traumatic brain injury aged between 16-65. Both groups experienced similar adverse events that were typical of traumatic brain injury. The group treated with dexanabinol experienced 31% and 14% higher ‘good neurological outcomes’ after three to six months, respectively.
Another randomized placebo-controlled clinical trial also explored the effects of dexanabinol on severe traumatic brain injury. Results after six months showed no significant differences between both groups, and mortality rates did not differ significantly.
In yet another randomized controlled trial, researchers looked at the effects of the synthetic cannabinoid KN 38-7271 on the outcomes of early survival comatose patients after experiencing a severe traumatic brain injury. Survival rates were higher in the group given KN 38-7271 compared to placebo.
Overall, there is more positive than negative evidence regarding cannabis’s ability to decrease adverse outcomes of traumatic brain injury. However, more clinical trials are definitely needed before researchers can come to a concrete conclusion. Unfortunately, no ongoing or upcoming clinical trials looking at cannabis and traumatic brain injury can be found on ClinicalTrials.gov.
In the majority of people, cannabis is well-tolerated. Common side effects of cannabis include drowsiness, fatigue, dry mouth, and appetite changes.
While cannabis has now become established as an effective medicine for many conditions, there are downsides worth mentioning.
- The psychoactive effects of THC can cause side effects such as memory impairment, anxiety, and euphoria.
- The development of psychosis is not unheard of, especially in genetically vulnerable individuals.
- Chronic and heavy cannabis use in one’s adolescent years has been associated with long-term cognitive deficits.
Cannabis addiction (also known as cannabis use disorder) occurs in approximately one in ten users. Heavy cannabis users who start young seem to be particularly susceptible to addiction, due to the plasticity of the developing brain.
The Cannigma content is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Always consult with an experienced medical professional with a background in cannabis before beginning treatment.
About Concussion and Brain Trauma
Traumatic brain injury, or TBI, is when your brain is bounced or twisted around inside your skull after a sudden, sharp blow to the head or body. This damages brain cells in many ways which are usually temporary but can also be permanent, depending on the severity of the injury.
A “concussion” is a diagnosis used to describe a mild form of TBI, when the brain cells are affected temporarily. Most people recover completely from a concussion, although it is still a significant injury that can have serious effects.
Moderate and severe TBI cause physical damage to the brain cells which can lead to long-term complications like personality changes, permanent disability, seizures and irreversible coma, or can even result in death.
People who play a lot of contact sports are at high risk of getting a concussion, while moderate and severe TBI tends to result from serious accidents like car crashes, violent crime, or from gunshot wounds to the head. Worldwide, 69 million people experience a TBI every year, with far more occurring in low-to-middle income countries than in high-income countries. In Asia and Africa, TBI is mostly caused by road traffic accidents, but in North America, falls account for almost half of all TBI-related emergency department visits.
The symptoms of traumatic brain injury can vary widely and may take a few days or even a few weeks to show up. Some people who have mild TBI (that is, a concussion) don’t even realize it.
The symptoms of a concussion include:
- A headache that won’t go away, and doesn’t get better when you take pain relief
- Dizziness or “seeing stars”
- Temporarily losing consciousness
- Nausea and/or vomiting
- Feeling confused or dazed
- Amnesia, usually forgetting what caused the concussion
- Slurred speech
- Double vision or blurred vision
- Moving clumsily and having trouble with balance
You might also have difficulty sleeping and focusing, get irritated more easily than normal, have some personality changes, and feel sensory disorders like strange tastes and smells. These symptoms often take longer to develop, appearing a few days or weeks later.
It’s particularly difficult to spot the symptoms of a concussion in babies and young children, so look out for:
- A change in their normal behavior
- Unusual crying
- Changes in concentration and sleeping habits
- Losing interest in people and/or objects
Moderate and severe brain trauma can include all the symptoms of a concussion, as well as:
- Losing consciousness for longer periods of time
- Difficulty waking up or staying awake
- Repeated vomiting
- Blood or clear fluid draining from the nose or ears
- Dilation of the pupils in one or both of the eyes
- Swelling or bruising around the eyes or behind the ears
- Trouble walking
- Weakness or numbness in the fingers and/or toes
- Extreme confusion, agitation or aggression
Importantly, symptoms of mild concussions can be mild and subtle but can persist for a prolonged period of time untreated. That is why it is important to recognize the symptoms and patterns.
Any severe blow to the head is serious and needs medical attention. Even a mild concussion or mild TBI can have serious effects. If someone shows the symptoms of moderate to severe TBI, they need urgent care.
If you go to your doctor with a possible concussion or mild TBI, the doctor will usually ask about your symptoms and the incident that caused it. Your doctor will also do a neurological examination, checking your vision, hearing, balance, reflexes, and coordination.
You might also do cognitive tests to check your memory, concentration and ability to recall information.
Depending on your symptoms, you might have an MRI or CT scan to check for bleeding and damage within your brain. Doctors sometimes use an intracranial pressure monitor to check whether your brain tissue is swelling and increasing the pressure within your skull, since that can cause further damage.
If you’re unconscious, doctors will use the Glasgow Coma Scale to test how severe your TBI is. This assigns points on a scale of three to 15, checking things like the ability to move eyes and limbs, verbal responses, and response to pressure or pain. Higher scores mean the injury is less severe.
Your brain is soft and jelly-like, cushioned by cerebrospinal fluid and protected by your skull. However, if you get a hard blow to the head or body, that can make your brain slide around and bump against the bony walls of the skull.
The most common causes of all types of TBI are:
- Road traffic accidents, including car crashes, bike accidents, or getting hit by a vehicle can make your body whip back and forth in a way that shakes the brain inside the skull.
- Sports injuries, especially from football and boxing, but soccer, lacrosse, baseball, and any high-impact or extreme sports can cause TBI.
- Falls are a common cause of TBI in babies and young children, and in older adults.
- Violence, like gunshot wounds to the head, domestic violence, assault, and child abuse. “Shaken baby syndrome” is another cause of TBI in babies and infants.
- Explosive blasts can cause TBI, although it’s not clear how or why.
Treating a concussion and mild TBI generally involves getting plenty of rest. Your brain recovers on its own, but you may be kept under observation in the hospital for a few days to check that your symptoms don’t get worse. You can expect to have to wait a while before you go back to work or school, and long before you’re allowed to resume sports.
Emergency treatment for TBI involves giving oxygen when needed and preventing any additional damage to the head and neck.
If you’ve just had a severe TBI injury that is life-threatening, you might be given medication to limit any further damage to your brain. These include:
- Diuretics, which reduce the amount of fluid in your tissues. These can help reduce pressure in the brain.
- Anti-seizure drugs, because people who have moderate or severe TBI are at risk of seizures during the first week after injury.
- Coma-inducing drugs that put you into a temporary coma, because that way your brain needs less oxygen and can recover faster.
- Surgery to relieve pressure in the skull, remove hematomas (bleeds), and/or repairing bone fracture
After severe TBI, you’ll probably need rehabilitation to help you relearn how to walk, talk, and/or carry out basic daily activities.
Your rehabilitation team can include physical therapists, occupational therapists, speech therapists, a rehabilitation nurse, and a neuropsychologist. It might begin as an inpatient in the hospital, but it will continue and be completed as an outpatient once you leave the hospital.