How Does Marijuana Use Affect Health?

It’s also difficult to know how marijuana will affect a specific person at any given time, because its effects vary based on individual factors: a person’s genetics, whether they’ve used marijuana or any other drugs before, how much marijuana is used, and how strong it is. Effects can also be unpredictable when marijuana is used in combination with other drugs.

Researchers have found marijuana can affect your body in the following ways:



  • Affects short-term memory, you could fail to remember things you just learned or recall recent events—short-term memory can be affected up to 28 days after smoking marijuana.
  • Impairs judgment and decision-making, using it can cause you to do things you might not do when you are thinking straight which can result in getting in a car with someone who’s been drinking or is high on marijuana.
  • Alters perception and slows reaction time—affecting ability to drive
  • May lead to an inability to focus or pay attention
  • May affect mental health. Marijuana has been associated with Psychosis (mental disorder in which there is a loss of contact with reality, including false ideas about what is happening and seeing or hearing things that aren’t there) depression and anxiety, but more research is necessary to confirm and better understand that relationship.


  • Raises blood pressure
  • The heart rate, normally 70 to 80 beats per minute, may increase by 20 to 50 beats per minute. This effect can be greater if other drugs are taken with marijuana.
  • Regular use- can cause weight gain and that adds stress to the heart


  • Smoking with no filter, inhaling deeply and holding in marijuana smoke can result in a greater exposure to tar and respiratory irritants.
  • Can lead to asthma attack for people with asthma
  • Can cause coughing
  • People who smoke marijuana have some of the same breathing problems as those who smoke tobacco—they are more susceptible to chest colds, coughs, and bronchitis than people who do not smoke


  • May lower testosterone levels causing mood swings, low sperm production, or problems having an erection
  • Linked to irregular periods and fertility problems
  • Also, since marijuana can affect judgment and decision making, such as engaging in risky sexual behavior, which can result in exposure to sexually transmitted infections



Many people don’t think of marijuana as addictive—they are wrong. About 9 percent of people who use marijuana become dependent on it. The number increases to about one in six among those who start using it at a young age, and to 25 to 50 percent among daily users. Marijuana increases dopamine, which creates the good feelings or “high” associated with its use. A user may feel the urge to smoke marijuana again, and again, and again to re-create that experience. Repeated use could lead to addiction—a disease where people continue to do something, even when they are aware of the severe negative consequences at the personal, social, academic, and professional levels.

People who use marijuana may also experience a withdrawal symptoms when they stop using the drug. It is similar to what happens to tobacco smokers when they quit—people report being irritable, having sleep problems, and weight loss—effects which can last for several days to a few weeks after drug use is stopped. Relapse is common during this period, as users also crave the drug to relieve these symptoms.