Facts about Marijuana:

  • Marijuana comes from the leaves of the Cannabis sativa plant.  The leaves are dried and crushed, than generally rolled into a “joint”, cigar (aka blunt), or put into a pipe to be smoked. The leaves can also be eaten, and are sometimes mixed into baked goods, such as brownies.


  • The Cannabis sativa plant, as are most plants, is sensitive to the environment in which it grows.  The conditions of the soil, weather, and other factors, can affect the amount of chemicals inside the plant.  In other words, a plant grown in Hawaii, might have a somewhat different chemical make up, than a plant grown in someplace like Mexico.
  • The most common slang terms for Marijuana include: pot, weed, grass, ganja, skunk, green, Mary Jane, chronic, and several others.  The “slang” changes a bit with new generations.
  • There are over 400 chemicals in the average marijuana plant.  When the leaves are smoked, heat produces an even larger variety of chemicals.
  • Hashish is made from the resin and is usually smoked in a pipe.  In this form, it is approximately 5 times stronger than marijuana.
  • The chemicals in the marijuana plant can have different affects on different people.  For example, some people become less focused, others may have a heightened awareness of physical sensations in the body, some become paranoid, still others break out into fits of laughter.  General effects also include: increased appetite, impaired coordination, slowed perception of time, reddening of the eyes, and an increased heart rate.

How marijuana affects the brain:

  • When the drug enters the body, the chemicals enter the bloodstream.  When the chemicals reach the brain, the chemicals from the drug attach to specific places on the brain’s nerve cells, called receptors.  Receptors receive information.  When a receptor in the brain “receives information” it causes changes inside the nerve cell.
  • THC (or tetrahydrocannabinol) is the main chemical found in marijuana that has the strongest effect in the brain.  There are certain areas in the brain that have a lot of receptors for THC.  So when the chemical THC attaches to these receptors, it causes the nerve cells to make changes.
  • The chemical THC can cause some of the nerve cells in the brain to become off balance, and perform functions differently than they normally would.  Generally, the drug affects the areas of the brain that govern emotions, judgement and memory.
  • One particular area of the brain, that has many receptors for the chemical THC, is the hippocampus. One of the jobs of the hippocampus is to process memory.  This is why people who use marijuana often frequently admit that it affects their short hippocampusterm memory.  If a person is under the influence of marijuana, new information received, such as someone giving you a new phone number, may not be processed normally. Therefore it doesn’t become a part of the long term memory.  In summary, people who frequently smoke marijuana may have a difficult time learning new information.
  • THC also acts on an area of the brain that influences emotions.  This may explain why, in some cases, a person using the drug may find things to be funnier than usual.  And in other instances, a person may become afraid, and have feelings of paranoia. The reaction a person has can be influenced by the environment or mood of the individual.  For example, someone who is already feeling anxious about something, and than smokes marijuana, the drug intensifies the already anxious mood possibly resulting in an acute anxiety attack.
  • Marijuana also appears to affect motivation.  Some users experience “anti-motivational syndrome”, which is characterized by apathy, lack of ambition, and difficulty concentrating (Maugh, 1982).
  • Remember: Because the drug can affect judgement, and reaction time, it should NEVER be used when driving a car, or doing any activity that requires a person to be alert.
  • Marijuana also effect different parts of the body, such as the heart.  Using the drug often increases the heart rate.  It can increase the heart rate up to 160 beats per minute, which is obviously not good for your heart, considering your normal heart rate ranges  from 60 to 100 beats per minute.
  • The chemicals in marijuana smoke are also damaging to the lungs, causing similar affects as tobacco smoke.  Smoke is an irritant to the throat and lungs and cause a heavy cough.  Those who smoke marijuana regularly, report more symptoms of chronic bronchitis, than those who do not smoke (Tashkin, 2013).  In addition, because people who smoke marijuana inhale deeply, and hold the smoke in the lungs, marijuana smoking leads to up to four times the deposition of tar when compared with cigarette smoking (Hancox, Poulton, & Ely, 2010).

Medical Marijuana:

  • Some of the effects of THC have proved to be useful for certain medical conditions.  For example, it’s ability to increase appetite and prevent nausea.  This can be especially helpful for people going through chemotherapy, and other conditions in which it’s hard for a person to eat, due to severe nausea. In addition, THC can help to block pain.  These are just a couple of the most commonly cited medical benefits.
  • The trick is for researchers to find a way to get the positive results from the drug, while at the same time minimize, or remove, the harmful effects.
  • Researchers have come a long way in realizing the beneficial effects of THC and working to find solutions.  For example, scientists have found that the brain makes a chemical called anandamide, that attaches to the THC receptors in the brain.  Discoveries like this one are helpful in developing medications that are similar to THC, but less harmful.

Resources for Help:

If you or a loved one is struggling with drug addiction.  Please reach out for help.



Hancox, R., Poulton, R. Ely, M. (2010). Effects of cannabis on lung function: a population-based cohort study. European Respiratory Journal; 35(1):42-47. doi:10.1183/09031936.00065009.

National Institute of Health [NIH]. (2006). The brain’s response to marijuana. Publication No. 063859.

Tashkin, D. (2013). Effects of marijuana smoking on the lung. American Thoracic Society; 10(3):239-247. doi:10.1513/AnnalsATS.201212-127FR.