Is cannabis safe after a concussion?

A concussion is a type of traumatic brain injury (TBI) that happens when the brain moves inside the skull. It can be caused by a bump, jolt, or blow to the head.

Common concussion symptoms include neck pain, headache, confusion, brain fog, and nausea or vomiting.

While recovering from a concussion, your doctor may advise you to get lots of rest and take over-the-counter medications to help ease symptoms.

If you have a concussion and also use cannabis, it’s important to know how cannabis may affect your recovery.

The research on weed and concussions

Compounds in cannabis called cannabinoids, including cannabidiol (CBD) and tetrahydrocannabinol (THC), may help ease certain concussion symptoms, including pain, nausea, and inflammation.

These cannabinoids work on your body’s endocannabinoid system, which helps regulate certain functions, such as:

• Memory
• Stress response
• Pain
• Mood
• Inflammation
• Nausea

Research suggests that CBD may protect the brain following a concussion by helping to improve blood flow, reduce inflammation, and protect brain cells. But clinical trials are needed to confirm these benefits.

Other small studies have demonstrated the benefits of cannabis for chronic symptoms that can result from a concussion. One study found that cannabis use led to significant improvements in some chronic symptoms, including headache, poor sleep, and negative mood.

In another study, cannabis users reported milder symptoms in the weeks after a concussion compared to non-users.

Cannabis might even be helpful when a person’s head injury is not quite as severe as a concussion. In a small study of soccer players, those who used cannabis experienced less impairment and inflammation after heading the ball compared to those who didn’t use cannabis.

Potential benefits

Cannabis may offer some benefits after a concussion, such as:

• Lower pain: Cannabis may help lower pain levels following a concussion, including headache pain.
• Reduced nausea and vomiting: Cannabis may help ease nausea and vomiting.
• Decreased brain swelling: Cannabis may help reduce brain swelling following a concussion.
• Brain-protecting effects: CBD may help protect brain cells that are affected by a concussion.
• Improved mood and sleep: Cannabis, especially CBD, may help improve sleep and mood.

Potential risks and side effects

There’s no evidence currently suggesting that cannabis can complicate or slow healing following a concussion.

That said, while using cannabis is generally considered safe, it can still cause some side effects, especially if you consume products that are high in THC.

These side effects include:

• Dry mouth
• Drowsiness
• Dizziness
• Headache
• Confusion
• Anxiety or paranoia
• Nausea
• Fast heartbeat

Some of these side effects, like dizziness and confusion, may negate the positive effects of cannabis for a concussion. Opting for low doses of THC may help to minimize these side effects.

Cannabis can also interact with certain medications, including some that are used to treat concussion-related pain. Ask your doctor if it’s safe to use cannabis with the medications you’re taking.

Clinical trials on cannabis and CBD for concussions

There’s growing interest in the use of cannabis to help treat concussions, and researchers are conducting several ongoing clinical trials.

For example, a clinical trial led by the University of Miami is exploring how CBD may help improve brain function following a concussion.

If you’re interested in participating in a clinical trial regarding cannabis for concussions, resources are available. ClinicalTrials.gov is a searchable database and registry that allows you to sign up for clinical trials based on your health condition.

Can you smoke weed with a concussion?

No research suggests that it’s dangerous to smoke cannabis with a concussion, but it’s best to speak with your doctor before doing so.

Keep in mind that smoking or vaping high-THC cannabis products may increase your risk of certain side effects and negate some of the plant’s potential benefits.

Consider smoking low-THC varieties to avoid side effects, including:

• Dizziness
• Drowsiness
• Confusion

When smoked, cannabis can take effect within 15 minutes. This may be helpful for acute symptoms, like headache or nausea.

Can you take an edible with a concussion?

Edibles are cannabis-infused products that are ingested, like gummies and brownies. They can produce powerful effects that last for several hours, but may not take effect for 1 to 2 hours after consumption.

There’s no evidence that it’s dangerous to consume edibles when you have a concussion. However, their powerful effects may increase your risk of certain side effects, such as drowsiness or dizziness.

To help minimize these side effects, consider taking edibles with only a low dose of THC, like 3 to 5 milligrams (mg) or less.

The bottom line: Cannabis may offer some benefits after a concussion

Limited research suggests that cannabis may help with certain concussion symptoms, including headache, nausea, and inflammation. Cannabis might also help protect brain health following a concussion.

These early positive results have led to growing interest in cannabis as a potential treatment for concussions, with clinical trials ongoing.

If you’re considering cannabis for a concussion, it’s important to speak with a health professional, especially if you’re taking any medications. A Leafwell telepharmacist can offer guidance on using cannabis to help ease your symptoms.

Resources

• Cannabidiol in anxiety and sleep: A large case series. https://www.thepermanentejournal.org/doi/10.7812/TPP/18-041
• Cannabinoid regulation of acute and anticipatory nausea. https://www.liebertpub.com/doi/full/10.1089/can.2016.0006
• Cannabinoids in traumatic brain injury and related neuropathologies: preclinical and clinical research on endogenous, plant-derived, and synthetic compounds. https://jneuroinflammation.biomedcentral.com/articles/10.1186/s12974-023-02734-9
• Cannabis, alcohol, and cigarette use during the acute post-concussion period. https://www.tandfonline.com/doi/full/10.1080/02699052.2019.1679885
• Cannabis for addressing physical pain. https://www.liebertpub.com/doi/abs/10.1089/ict.2024.29115.bca
• ‘Concussion pill’ shows promise in pre-clinical pilot study. https://news.med.miami.edu/concussion-pill-shows-promise-in-pre-clinical-pilot-study/
• Medical cannabis, headaches, and migraines: A review of the current literature. https://assets.cureus.com/uploads/review_article/pdf/67643/20210923-14469-2ab93m.pdf
• Neuroprotection following concussion: The potential role for cannabidiol. https://pubmed.ncbi.nlm.nih.gov/32029015/

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