What are the effects of marijuana?

By Dana Byerly 04/02/14

The effects of marijuana vary by method of ingestion—either by smoking, vaping or eating—and each method comes with its own short and long term effects and risks.


Liquid, solid or vapor?  It’s a choice all marijuana users make, and an important one that determines both short-term and long-term side effects on the body.   

While marijuana-related deaths and overdoses are generally lower in frequency compared to other Schedule 1 drugs, there are still many risks and side effects to using marijuana.  

The method of ingestion a marijuana user chooses, for example, can have major effects on immediate responses or actions, as well as long-term health issues.  Just how serious those effects are varies by individual and depends on the quantity and frequency of use. 

Smoking marijuana

The first hour after ingestion is when the drug starts inflicting its damage on the body.  This is when users are four times more likely to experience effects to both the cardiopulmonary and nervous systems.  Many describe symptoms that include enhanced visual, auditory and taste perceptions, increased appetite, irrational or paranoid thoughts, poor memory and an inability to concentrate.

As with any drug, there are multiple side effects to each method of marijuana consumption, but smoking remains the most common practice of ingestion and has proved to be the most harmful means available.  Many administer the drug through the use of a rolled cigarette, or “joint,” but many others consume it through a glass or water pipe. 

By absorbing deep breaths of smoke and holding them in the lungs, users experience the effects quickly -- usually within a few seconds of consumption – and can stop when they reach the desired “high” they are looking for.  Since there are 50 to 70 percent more toxic hydrocarbons in marijuana than tobacco smoke, users also run a higher risk of developing chest colds, chronic coughs and lung infections due to the prolonged exposure of smoke to the lungs. All of these factors contribute to an increased likelihood of long-term respiratory issues, particularly since the lungs are subjected to an unsafe amount of chemicals over time.  

In addition to respiratory problems, smoking marijuana also can cause serious damage to the heart.  Studies show smoking the drug increases a user’s heartbeat 25 to 100 times its normal rate when consumed and can cause some to experience an uncontrollable shaking, arrhythmia or even a heart attack. 

Vaping marijuana

Vaporization -- a safer method of ingestion that eliminates the toxic byproducts of combustion by placing the marijuana plant into a vaporizer and heating it to approximately 350 F – allows essential oils to form a vapor before being collected then inhaled.  As a result, these vapors lack the tars, hydrocarbons, benzene, carbon monoxide and other toxic gases and have fewer long-term respiratory effects on users.  

Eating marijuana

Other, less common, forms of ingestion include trickling liquid drops orally from tinctures, using sprays or capsules, and swallowing with food.  Some users will actually eat the herb in its natural state, but most users to choose to mix marijuana with a solid form of food before ingesting it. Candies, cookies and popcorn are the most popular edible options of choice. 

No matter which method of ingestion users choose, frequent use of any kind has proved to be the main cause of dependence, according to studies by the National Institute on Drug Abuse.  Most industry professionals believe marijuana addiction is determined more by habitual behaviors than by a chemical need.  It’s these physical and emotional symptoms that indicate someone is abusing marijuana.  

The emotional side effects of marijuana use include a heightened sense of awareness or altered perceptions, intense hunger, reduced motivation, extreme anxiety and mood swings – particularly to a more relaxed, often drowsy or sedated, state. 

There are also several physical indicators of marijuana use: dilated pupils or bloodshot eyes, dry mouth, depression, reduced coordination, impaired short-term memory, inappropriate laughing spells and strong, pungent smells on clothing or in a car or room. 

Prolonged use, however, is generally believed to be the cause of marijuana abuse or dependence.   If all the signs of use mentioned earlier are missed, there are final, withdrawal indicators of marijuana addiction.  Frequent users will experience the following physical symptoms when they stop using abruptly: agitated mood, aggression, insomnia, intense perspiration and loss of appetite.


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Dana Byerly is on staff at The Fix, and has written for the San Antonio Express-News and The Oklahoman among others. She last wrote about federal classification of marijuana. She can be found on Twitter.