Cannabis FAQs

Medical Cannabis


What is Cannabis?

Cannabis (also known as marijuana or marihuana) is a common name for the Cannabis plant. There are two major types of Cannabis plant, Cannabis sativa and Cannabis indica. The chemical substances that provide the effects of cannabis are known as cannabinoids. There are hundreds of cannabinoids in the plant.

Two of the most common and best-studied cannabinoids are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), which are responsible for the majority of effects that cannabis has on the body. THC is known for producing the "high" effect people associate with cannabis use. CBD, on the other hand, does not produce the "high" or euphoria that THC does. There are many factors that affect the ratio of THC to CBD in a particular plant, including the strain and the growing conditions.

How can cannabis be consumed?

There are a variety of ways cannabis can be consumed, including smoking, vaping, dabbing, as well as drinking or eating (e.g., teas, cannabis oil, baked goods, etc.). How it's consumed can affect when its effects start and how long they will last. Smoking and oral ingestion are the two most popular ways of consuming cannabis. With smoking or vaporizing, effects can be felt within minutes and can last up to 24 hours, whereas with oral ingestion (eating or drinking) effects may take as long as 2 hours to be felt and can last up to 24 hours.

What are the medical uses of cannabis?

The effects of cannabis in the body are regulated through the endocannabinoid system. This system is involved in many processes in our body such as pain sensation, mood, sleep, energy balance, and memory. Medical cannabis has been studied for several uses, including:

  • improving quality of life in a palliative care setting (for people with terminal diseases)
  • chronic pain involving cancer
  • nausea and vomiting during chemotherapy
  • loss of appetite by cancer patients
  • neurological problems including multiple sclerosis, amyotrophic lateral sclerosis, and spinal cord injury
  • epilepsy and other seizure disorders
  • HIV/AIDS-related weight loss
  • anorexia nervosa
  • musculoskeletal disorders including osteoarthritis, rheumatoid arthritis, and fibromyalgia
  • sleep disorders
  • headache and migraine
  • movement disorders including Huntington's disease, Parkinson's disease, and Tourette's syndrome
  • glaucoma
  • neuropathic pain
  • psychiatric disorders including anxiety, depression, post-traumatic stress disorder, and schizophrenia
  • asthma
  • high blood pressure
  • alcohol and opioid withdrawal symptoms
  • inflammatory skin disease such as dermatitis and psoriasis
  • irritable bowel syndrome

However, the evidence supporting its effectiveness for these uses are limited – many studies showed conflicting results and most studies were done with a small number of participants. This makes it difficult to draw any definitive conclusions on its effectiveness. Another issue is that the dosage used in these studies varied, making it hard to determine the proper dosage for medical use. Currently, there are many ongoing trials to try and understand more about cannabis and its possible medical uses.

Commercially available prescription products that use or closely imitate THC include nabilone (Cesamet®) and THC-cannabidiol (Sativex®).

What are the short-term health risks of cannabis?

Because the endocannabinoid system plays a role in many processes in our body, there are lots of potential side effects of cannabis use. Some of the short-term health risks of cannabis include:

  • breathing problems
  • change in mood
  • disorientation and confusion
  • dizziness or lightheadedness
  • dry mouth
  • hallucinations, delusions, and paranoia
  • impaired decision-making ability
  • increased heart rate
  • loss of physical coordination
  • loss of short-term memory
  • low blood pressure
  • poor reaction time
  • red eyes

What are the long-term health risks of cannabis?

Some of the long-term health risks of cannabis include:

  • addiction
  • anxiety
  • bronchitis
  • chronic cough
  • decrease in intelligent quotient (IQ)
  • depression
  • greater risk of lung infection
  • increased buildup of mucus in the chest
  • increased risk of stroke
  • loss of memory
  • mental illness
  • pregnancy complication
  • suicidal thoughts
  • cannabinoid hyperemesis syndrome (recurrent nausea, vomiting, and cramping abdominal pain)

These health risks develop over longer periods of time, with continued cannabis use. Some of these side effects are more likely to affect people who start using cannabis as teenagers, as this is an important time for brain development. Long-term negative health effects appear to be worse for those who've used cannabis more frequently or for longer periods of time.

Does cannabis interact with other drugs?

Cannabis may increase the risk of bleeding when used with drugs that have anticoagulating or antiplatelet effects, for example NSAIDs such as ASA (Aspirin®) and ibuprofen (Advil®, Motrin®), warfarin (Coumadin®), clopidogrel (Plavix®), heparin, and others.

Cannabis may affect the activity of liver enzymes and therefore the metabolism of some drugs such as acetaminophen (Tylenol®), clarithromycin (Biaxin®), lovastatin (Mevacor®), and others.

In addition, cannabis may affect blood sugar levels and blood pressure. You should be cautious about using it if you are using any medications to treat diabetes or blood pressure. You should also be careful if you're using any medication that affects the brain or are drinking alcohol, as cannabis can increase their effects.

Since cannabis affects many different functions in the body and interacts with various medications, it is important to speak to your health care professional first, especially if you have a medical condition or are on medication.

Is cannabis addictive?

Cannabis can be addictive. It's important to know that inappropriate use of cannabis can lead to physical dependence and addiction, especially with long-term, heavy use, particularly among people who started as adolescents. Physical dependence means that when a person stops using the substance, they develop withdrawal symptoms. Medical trials have shown dependence after taking high doses of cannabis. Withdrawal symptoms typically begin about 12 hours after the last use and last up to 1 to 2 weeks. Some of the symptoms include anger, aggression, anxiety, headache, disturbed sleep, decreased appetite, restlessness, irritability, and sweating. Physical dependence is not the same as addiction.

Addiction is characterized by  an inability to control the need to use the drug despite the harm it may cause. Whether or not someone becomes addicted to cannabis will depend on a variety of factors, such as genetics. Teenagers are more likely to become addicted because their brains are still developing. Addiction is also more likely for those who use it more often. For example, it is estimated that the risk of addiction is between 25% to 50% for those who smoke cannabis every day.

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