What Are the Side Effects of Secondhand Marijuana Smoke?
Marijuana smoke is created whenever someone burns the leaves, flowers, stems, or seeds of the cannabis plant. Marijuana is used by an average of 26 million Americans per month. It’s been studied for some medical uses.
But despite marijuana’s prevalence, its safety is sometimes in dispute. Smoking it, or being near someone else who is smoking it, does cause side effects.
Marijuana contains a chemical called THC, which can block pain and bring on a feeling of relaxation to people who breathe it in or consume it. Smoking weed has depressant, hallucinogenic, and stimulant effects. Inhaling THC can also impair your ability to concentrate and to operate a car.
Whenever you’re breathing in THC, it’s possible to get high. Effects of THC vary from person to person, as well as how much of the chemical you’re exposed to.
Drug test results can differ for people who are exposed to secondhand marijuana smoke and people who smoked marijuana.
In 2015, a small study of six smokers and six nonsmokers showed that marijuana smoked in highly concentrated quantities could trigger a positive urine drug test among people who were simply exposed to the smoke in an unventilated room.
However, ventilation during marijuana exposure, as well as how often exposure occurred, were critical factors in what the drug test result would be.
For example, smelling marijuana smoke in passing once in a while is a lot different from living with a habitual marijuana smoker who uses marijuana in your presence regularly.
Another small study attempted to mimic a more true-to-life example.
Rather than stick nonsmokers in a closed, unventilated room for long smoking sessions, these study participants spent three hours in a coffee shop where other patrons were smoking marijuana cigarettes.
After their exposure to secondhand marijuana smoke, participants were tested for THC. While a trace amount of THC did show up in their blood and urine, it wasn’t enough to trigger a positive drug test result.
It was unlikely that any contact high was passed during this study.
With that being said, getting a contact high is possible.
Being near marijuana smoke often and in poorly ventilated areas (like a car with the windows rolled up or a small bedroom without a fan) may result in feeling a limited amount of the effects that the person smoking experiences.
But catching a whiff of marijuana fragrance through your apartment window or entering a room where people were smoking several hours ago is very unlikely (maybe even impossible) to affect you at all.
There isn’t much by way of clinical data to understand if secondhand marijuana smoke is as bad for your health as tobacco smoke.
According to the American Lung Association, regularly smoking marijuana yourself can damage your lungs and weaken your immune system.
And a 2016 study on rats showed that just one minute of secondhand marijuana smoke impaired lung function for at least 90 minutes — which is longer than the lungs are affected by tobacco secondhand smoke.
Secondhand marijuana smoke exposes you to many of the same toxic chemicals as smoking it directly does. Because of this, the American Lung association recommends that people avoid exposure to secondhand marijuana smoke.
Contact high may be less common than we think, but it’s possible. Here are some of the other side effects and symptoms of secondhand marijuana smoke exposure.
Smoking weed can slow your reaction time when you’re on the road. If you have high levels of THC in your blood from secondhand marijuana smoke, it might have the same effect.
If you’re around marijuana smoke for a long period of time, you may begin to feel lightheaded or dizzy.
One effect of the THC in marijuana is the feeling of calmness it gives some users. For others, this calmness can take the form of feeling tired or lethargic.
Researchers are still trying to understand the connection between excessive marijuana exposure and mental health. It appears that marijuana use can trigger or worsen some mental health conditions, including depression.
No link has been established between secondhand smoke marijuana exposure and depression.
The legal and medical use of marijuana is changing rapidly, but that doesn't mean it's safe for everyone to be exposed to it. Here's what you need to know.
How marijuana affects the body
Marijuana is the dried and ground up or shredded parts of the cannabis plant. Nearly all parts of the plant make up marijuana, including the leaves, stem, flowers, and seeds. As with other medications and procedures, marijuana use can potentially bring both positive and negative effects.
Many of marijuana’s effects are short-term, meaning that they last for only a short period. Other effects are long-term and may not show up immediately.
There is not much research into the effects of secondhand marijuana smoke. It is possible that secondhand smoke exposure may be enough to cause some of the temporary effects, as well as some of the long-term effects, in some people. More research is necessary to examine the effects of secondhand marijuana smoke.
Often, a person will smoke marijuana to feel its effects. However, a person could also:
- vape it
- cook it into food
- use it as part of an oil
- brew it with teas
- use other topical or oral marijuana products
The following article discusses some of the potential benefits and side effects that marijuana has on the body.
Some of the most common effects on physical health from marijuana use include:
- a higher likelihood of developing bronchitis, when a person smokes it
- more phlegm, when a person smokes it
- lung irritation from irritants including some carcinogens, such as accidentally burning the mouth or throat when smoking
- a weakened immune system due to the effects of tetrahydrocannabinol, which is the main psychoactive chemical in marijuana
- pain relief
- reduction in vomiting and nausea
- faster heart rate by 20–50 beats per minute
- red eyes from the increase in blood flow
- relief from the symptoms of glaucoma, for short periods
- aggravation of existing lung conditions, such as asthma, when a person smokes it
- potential interference with tumor growth
- interference with fetal development during pregnancy
- interference with brain development among teenagers
When people use it medically, marijuana is often useful for the following:
- reducing pain associated with certain medical conditions
- reducing inflammation
- helping with glaucoma
- reducing nausea in people undergoing chemotherapy
Some of the most common effects a person may experience include:
- increased appetite and thirst
- increased or decreased depression symptoms, depending on the user
- increased or decreased anxiety symptoms, depending on the user
- impaired judgment, making it harder for people to think clearly
- problems with memory
- the release of dopamine, which causes the feeling of being high
- symptoms of withdrawal after long-term use
- delayed reactions to stimuli
- temporary paranoia and hallucinations
- addiction, in some cases
Marijuana has many potential psychological effects, and it is worth noting that this is not a comprehensive list.
Marijuana is only potentially safe for use by adults.
Children and teenagers are susceptible to potential ill effects. When a mother uses marijuana while pregnant, the baby may develop memory and concentration issues as they grow.
Breastfeeding mothers who also use marijuana may be exposing their baby to its potentially harmful effects. Women should avoid using marijuana while pregnant and breastfeeding.
Marijuana may affect the brain development of older children and teenagers. This can lead to memory loss, concentration issues, and impaired problem-solving skills.
Research strongly suggests that for those under 25 years of age, marijuana use can impair memory and learning ability.
Long-term effects depend on several factors, including:
- how a person uses marijuana
- how often they use it
- the age of the person using it
- how much a person uses at any given time
Some of the potential long-term effects include the following:
- memory loss
- concentration and memory issues from exposure while in the womb
- lung irritation
- possibly lung cancer, although research does not fully support this
- development of cannabinoid hyperemesis syndrome, which causes nausea and vomiting
Marijuana has many potential short- and long-term effects on the body. Although many proponents believe that marijuana is a modern day cure-all, others believe that its negative effects outweigh its potential medicinal benefits.
People have used marijuana recreationally for many years. As of 2019, 34 states in the United States have some form of legal cannabis. A few states have also legalized its recreational use.
In states where recreational use is still not legal, people should consider other approaches and speak to their healthcare provider about what is best for them.
Marijuana has several potential physical and psychological effects on the body, such as lung irritation and increased appetite. Learn more about the effects of marijuana on the body here.