Cannabis is a plant. People use the dried leaves, seed oil, and other parts of the cannabis plant for recreational and medicinal purposes. It can have a pleasurable effect and may soothe the symptoms of various conditions, such as chronic pain.

Ways of using it include:

• smoking or vaping it
• brewing it as a tea
• consuming it in the form of edibles, such as brownies or candies
• eating it raw
• applying it as a topical treatment
• taking it as capsules or supplements

Some of the ingredients in cannabis are psychoactive (mind-altering), but others are not. The potency and balance of the ingredients vary, depending on how the manufacturer grows and processes the plant.

Cannabis contains at least 120Trusted Source active ingredients, or cannabinoids. The most abundant ones are cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC).

Some cannabinoids can have euphoric or psychoactive effects. THC produces both effects.

CBD is present in various forms, including:

• oils for applying to the skin
• capsules, to take as a supplement
• gummy candies

So far, most studies have focused on CBD and THC, but scientists are looking into the effects of other cannabinoids, too.

Is CBD legal?The 2018 Farm Bill removed hemp from the legal definition of marijuana in the Controlled Substances Act. This made some hemp-derived CBD products with less than 0.3 percent THC federally legal. However, CBD products containing more than 0.3 percent THC still fall under the legal definition of marijuana, making them federally illegal but legal under some state laws. Be sure to check state laws, especially when traveling. Also, keep in mind that the FDA has not approved nonprescription CBD products, and some products may be inaccurately labeled.

Medical uses

According to the National Academies of Sciences, Engineering, and Medicine, there is conclusive evidence that cannabis or cannabinoids can help manage:

• chronic pain in adults
• nausea and vomiting resulting from chemotherapy treatment
• some symptoms of multiple sclerosis (MS)

There is moderate evidence that it can help with sleep problems relating to sleep apnea, fibromyalgia, chronic pain, and MS.

Other conditions that it may be helpful for include:

• low appetite
• Tourette’s syndrome
• anxiety, in some individuals

In 2018, the Food and Drug Administration (FDA)Trusted Source approved Epidiolex, a medication that derives from cannabis, to treat two rare and severe types of epilepsy that do not respond well to other treatments. Epidiolex is a purified form of CBD that does not contain THC.

Three drugs that contain synthetic substances with a structure similar to that of THC have received FDA approval. Marinol, Syndros, and Cesamet are treatment options for some kinds of anorexia.

Effects

There are different ways of using cannabis, and the method can determine the effects of the drug.

Smoking or inhaling: A sense of elation can start within minutes and peak after 10–30 minutes. The feeling will typically wear off after about 2 hours.

Ingesting: If a person consumes products containing cannabis by mouth, they will usually feel the effects within 1 hour, and the sensations will peak after 2.5–3.5 hours. One study suggests that the type of edible affects the time it takes to feel the effect, with hard candies kicking in quicker.

Topical: Transdermal patches allow the ingredients to enter the body over a prolonged periodTrusted Source. This steady infusion can benefit people who are using cannabis to treat pain and inflammation.

What are the effects of secondhand cannabis smoke?

How do cannabinoids work?

The human body naturally produces some cannabinoids through the endocannabinoid system. They act in a similar way to neurotransmitters, sending messages throughout the nervous system.

These neurotransmitters affect brain areas that play a role in memory, thinking, concentration, movement, coordination, sensory and time perception, and pleasure.

The receptors that respond to these cannabinoids also react to THC and other cannabinoids. In this way, cannabinoids from an outside source can change and disrupt normal brain function.

THC appears to affect areas of the brain that control:

• memory and attention
• balance,Trusted Source posture, and coordination
• reaction time

Due to these effects, a person should not drive a car, operate heavy machinery, or engage in risky physical activities after using cannabis.

THC stimulates specific cannabinoid receptors that increase the release of dopamine. Dopamine is a neurotransmitter that relates to feelings of pleasure.

THC can also affect sensory perception. Colors may seem brighter, music more vivid, and emotions more profound.

Do the benefits of cannabis outweigh the risks? Find out here.

What does a person feel?

When people use cannabis, they may notice the following effects:

• a feeling of elation or euphoria, known as a high
• relaxation
• changes in perception, for example, of color, time, and space
• an increase in appetite
• feeling more talkative

Learn more about how cannabis affects the body.

Risks

Using cannabis can also entail some risks. These include:

• Impairment of judgment: A 2012 studyTrusted Source reported a higher chance of having a road traffic accident when driving within 3 hours of smoking cannabis.
• Immune response: A 2019 studyTrusted Source showed that frequent cannabis use may affect the immune system, but more studies are necessary to confirm this.
• Gum disease: According to the American Dental Association, there may be a link between cannabis use and gum disease
• Memory loss: One studyTrusted Source found that smokers of potent cannabis strains (skunk, for instance) may have a higher risk of acute memory loss.
• Testicular cancer: A 2018 reviewTrusted Source concluded that using cannabis more than 50 times in a lifetime may increase the risk of testicular cancer.

People have modified some types of cannabis, such as skunk, to maximize the potency of certain components. From the 1990s to 2018, the average THC content in confiscated cannabis rose from 4% to over 15%Trusted Source.

One problem with using unregulated or recreational drugs is that people cannot know exactly what they contain or how strong the effect will be. There may also be contaminants.

Can cannabis use kill you? Find out here.

Addiction

With long-term use, changes in the brain can occur that lead to problematic use, or cannabis use disorder. This disorder, in which a person experiences withdrawal symptoms when not taking the drug, may affect about 30% of people who use cannabis, according to the National Institute on Drug Abuse (NIDA)Trusted Source.

Of these individuals, about 9% may develop an addiction. A person has an addiction when they cannot stop using a substance.

The NIDA add that up to 17% of those who start using cannabis in their teens may become dependent on it.

Cannabis withdrawal

Quitting cannabis, after becoming dependent, is not life threatening, but it can be uncomfortable.

Symptoms may include:

• irritability
• mood changes
• insomnia
• cravings
• restlessness
• decreased appetite
• general discomfort

Symptoms tend to peak within the first week after stopping and last up to 2 weeks.

Experts do not know exactly how frequent and long-term cannabis use affects a person’s health. Both the short- and long-term effects may vary among individuals.

Takeaway

Cannabis contains chemicals that can have various effects on the human body. It is a popular recreational drug with some medicinal uses.

Anyone who is considering using cannabis for any purpose should first check that it is legal to use in their state. They should also consider its possible effects on their mental and physical health.

A doctor can be a good person to ask for advice.

Best cannabis strains for chronic pain

Cannabis may help relieve certain types of chronic pain.

How does cannabis work for pain?

Cannabis contains compounds that may relieve pain, nausea, and other symptoms. The components of cannabis that most studies focus on for pain relief are cannabidiol (CBD) and tetrahydrocannabinol (THC).

THC vs. CBD

THC resembles the cannabinoid chemicals that occur naturally in the body. When people ingest or inhale THC, it stimulatesTrusted Source the brain’s cannabinoid receptors.

This activates the brain’s reward system and reduces pain levels. THC is a psychoactive compound as it binds to cannabinoid receptors and produces an elevated state of mind, known as a high.

CBD does not cause a high, although it does interact with pain receptors in the brain to exert pain-relieving and anti-inflammatory effects.

What the research says

In recent years, many studies have looked at the effects of cannabis for chronic pain. Some studies used parts of the cannabis plant and some have used the entire plant so more research is needed. Using parts of the cannabis plant (like CBD oil) helps study specific actions of that ingredient, but when the whole plant is used there is what is called an entourage effect, where the parts work together to have more effect.

A 2015 reviewTrusted Source of research on the use of cannabis and cannabinoids for various chronic pain conditions reports that several trials had positive results. The researchers suggest that cannabis or cannabinoids may be effective for treating some types of chronic pain including neuropathy (nerve pain).

A research paper from 2016 found that cannabis use for cancer pain led to a 64-percent reduction in opioid use, improved quality of life, and caused fewer medication side effects. It also led to participants using fewer medications.

Smaller studies have reported benefits for other types of chronic pain. For example:

• Of about 17,000 people with cancer, 70 percent reportedly experienced an improvement in pain and general well-being after cannabis use.
• People with chronic migraines experiencedTrusted Source a decrease in migraine episodes after using the drug.

However, there is still a need for more research into the area of cannabis use for chronic pain, especially into the use of different strains, dosages, and methods of delivery.

An Australian studyTrusted Source, published in July 2018, concluded that cannabis use did not reduce the symptoms of pain or the need to use opioid medications. However, the findings were mostly based on reports from people who used the drug recreationally.

Using cannabis specifically for medicinal purposes might yield different results.

Synthetic and medicinal cannabis

Medical cannabis refers to the whole, unprocessed plant or its extracts.

Medical cannabis only has approval from the U.S. Food and Drug Administration (FDA)Trusted Source as a safe or effective treatment for two conditions. These are rare and severe forms of epilepsy that involve seizures that other drugs have not been able to control.

The name of the drug is Epidiolex. It contains a purified form of CBD, and the FDA gave approval in June 2018.

The FDA have also approved medications containing synthetic THC cannabinoids called dronabinol (Marinol) and nabilone (Cesamet). These drugs reduce nausea in people undergoing cancer treatments and increase appetite in people living with HIV.

The FDA have not yet approved the use of any cannabis drugs for pain relief.

Synthetic cannabis is also the name given to drugs such as K2 or Spice. The National Institute on Drug Abuse (NIDA)Trusted Source point out that these are not cannabis, they are not safe, and they are not recommended for any purpose. The adverse effects of these drugs can be fatal.

Synthetic cannabis attempts to duplicate the effects of the ingredients in the plant. There is theory that the entire plant has a more profound effect with the different ingredients working together to have an entourage effect.

Risks and side effects

Cannabis use can cause some side effects, including:

• dependence
• breathing problems
• dizziness
• addiction, which occurs in 9 percent of people who begin use in adulthood
• impaired reaction times
• interactions with medication
• loss of concentration
• memory issues
• mental health issues in those predisposed to them
• rapid heart rate
• withdrawal symptoms

Cannabis is available in several different forms, including:

Oil

A popular way of consuming cannabis is through edibles.

Cannabis vs. opioids for pain relief

Opioids are powerful medications that relieve pain by acting on the nervous system. They are highly addictive, and withdrawal symptoms are not uncommon.

In 2016, approximately 116 people died every day in the U.S. from opioid-related drug overdoses, and 11.5 million people misuse prescription opioids every year.

Is cannabis better than opioids?

Medical cannabis may offer an alternative to addictive opioids. When researchers surveyed almost 3,000 medical cannabis users, they found that 30 percent had used opioids in the last 6 months.

Of those respondents, 81 percent agreed or strongly agreed that cannabis was more effective alone than in combination with opioids.

In addition, 97 percent said they agreed or strongly agreed that they could decrease their opioid usage when taking cannabis.

Takeaway

Some research has suggested that cannabis is as effective as opioids for chronic pain relief.

What are the medical benefits of cannabis?

Over the years, research has yielded results to suggest that cannabis may be of benefit in the treatment of some conditions. These are listed below.

Chronic pain

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 cannabis.

One area that the report looked closely at was the use of medical cannabis 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 cannabis, or products containing cannabinoids — which are the active ingredients in cannabis, or other compounds that act on the same receptors in the brain as cannabis— are effective at relieving chronic pain.

Alcoholism and drug addiction

Another comprehensive review of evidence, published last year in the journal Clinical Psychology Review, revealed that using cannabis may help people with alcohol or opioid dependencies to fight their addictions.

But this finding may be contentious; the National Academies of Sciences review suggests that cannabis use actually drives increased risk for abusing, and becoming dependent on, other substances.

Also, the more that someone uses cannabis, the more likely they are to develop a problem with using cannabis. Individuals who began using the drug at a young age are also known to be at increased risk of developing a problem with cannabis use.

Depression, post-traumatic stress disorder, and social anxiety

The review published in Clinical Psychology Review assessed all published scientific literature that investigated the use of cannabis to treat symptoms of mental illness.

Evidence to date suggests that cannabis could help to treat some mental health conditions.

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.

What are the health risks of cannabis?

At the other end of the spectrum is the plethora of studies that have found negative associations between cannabis use and health. They are listed below.

Mental health problems

Daily cannabis use is believed to exacerbate existing symptoms of bipolar disorder among people who have this mental health problem. However, the National Academies of Sciences, Engineering, and Medicine report suggests that among people with no history of the condition, there is only limited evidence of a link between cannabis use and developing bipolar disorder.

Moderate evidence suggests that regular cannabis users are more likely to experience suicidal thoughts, and there is a small increased risk of depression among cannabis users.

Cannabis use is likely to increase risk of psychosis, including schizophrenia. But a curious finding among people with schizophrenia and other psychoses is that a history of cannabis use is linked with improved performance on tests assessing learning and memory.

Testicular cancer

Although there is no evidence to suggest any link between using cannabis and an increased risk for most cancers, the National Academies of Sciences did find some evidence to suggest an increased risk for the slow-growing seminoma subtype of testicular cancer.

Respiratory disease

Regular cannabis smoking is linked to increased risk of chronic cough, but “it is unclear” whether smoking cannabis worsens lung function or increases the risk of chronic obstructive pulmonary disease or asthma.

A 2014 studyTrusted Source that explored the relationship between cannabis use and lung disease suggested that it was plausible that smoking cannabis could contribute to lung cancer, though it has been difficult to conclusively link the two.

The authors of that study — published in the journal Current Opinion in Pulmonary Medicine — conclude:

“There is unequivocal evidence that habitual or regular cannabis smoking is not harmless. A caution against regular heavy cannabis usage is prudent.”

“The medicinal use of cannabis is likely not harmful to lungs in low cumulative doses,” they add, “but the dose limit needs to be defined. Recreational use is not the same as medicinal use and should be discouraged.”

So, is cannabis good or bad for your health?

There is evidence that demonstrates both the harms and health benefits of cannabis. Yet despite the emergence over the past couple of years of very comprehensive, up-to-date reviews of the scientific studies evaluating the benefits and harms of the drug, it’s clear that more research is needed to fully determine the public health implications of rising cannabis use.

More research is needed to confirm the harms and benefits of cannabis use.