What is Marijuana?

Cannabis is a naturally occurring plant that is used for a variety of purposes in the world, including paints, textiles, animal feed.  One if its more well-known uses is in the substance we refer to as marijuana.  Often called pot, weed, grass, reefer, or herb, Marijuana is a greenish-gray mixture of the dried, shredded leaves, stems, and seeds and flowers of the cannabis plant.  

The active ingredient in marijuana, tetrahydrocannabinol (THC), creates a "high" in users after it is inhaled or ingested.  When inhaled, most users smoke marijuana in hand-rolled cigarettes (called joints, among other names) or using a pipe or water pipe called a bong. Marijuana can also be combined with tobacco to create a marijuana cigar, or blunt.  Marijuana can also be vaporized.

When ingested, the oil from marijuana can be cooked into certain foods (brownies, cookies, etc.)  This gives the product the effect of creating a potent high.  It can sometimes take users 90 minutes to 2 hours to feel the affects of this high.

Marijuana is a depressant, which means that it slows down messages traveling between your brain and your body.  In some cases, though not all, using marijuana can result in hallucinogenic effects like intense paranoia or seeing things that aren’t there.  These experiences may cause people to act erratically.

What are the effects of marijuana?

The human brain continues to develop until around the age of 25.  In the teen years, the brain is not growing, but actually eliminating unnecessary connections (synapses) it feels it does not need.  In addition, the brain is producing myelin, which can be thought of like the insulation around an electrical wire.  This insulation helps signals move more quickly in the brain.

While not fully understood, some research suggestions that marijuana can affect both these processes.  Marijuana seems to negatively influence the production of myelin, which could result in long-term cognitive deficiencies  for individuals who use in their teens.  Additionally, using marijuana in your teens can affect certain neurotransmitters produced in the brain.  As the brain strives to become more efficient, it could prune away synapses which produce these neurotransmitters, resulting in a  deficit in adulthood.

Is Marijuana Addictive?

While marijuana may not be physically addictive, like we might think of alcohol or heroin, marijuana is still mentally addictive.  In the section above it was mentioned that marijuana can affect certain neurotransmitters being produced in your brain.  One of them is actually a chemical very similar to THC, called an endocannabinoid.  These neurotransmitters are responsible for helping you to calm down, or to fall asleep, or deal with stress.  If a teen is using marijuana to help them with stress or anxiety, research suggests that their brains may prune away it’s ability to produce endocannabinoids as efficiently, meaning that without marijuana the teen will have a harder time coping, which would continue into adulthood.  Its easy to see how this situation could develop into dependence.

What about medical marijuana?

The medicinal properties of marijuana have been confirmed to contain active ingredients with therapeutic potential for relieving pain, controlling nausea, and stimulating appetite. As a result, an Institute of Medicine report concluded that further research on cannabinoid drugs (marijuana) and safe delivery systems was warranted.  It is important to remember that marijuana is not a cure for any illness or condition, but a treatment to help manage certain symptoms.

With the recent passage of the Massachusetts Medical Marijuana Law, it is important to note that, as well as with all medicine prescribed by a doctor, the prescription should only be taken by the person to whom it was prescribed, as prescribed, and any unused marijuana should be properly disposed of.  

For more information visit NIDA Marijuana Facts for Teens, or The White House Marijuana Resource Center.

Source: NIDA Research Report Series – Marijuana Abuse