Also known as Blunt, dope, ganja, grass, herb, joint, bud, Mary Jane, pot, reefer, green, trees, smoke, skunk, weed, hash, tea, chronic, loud. Marijuana  is a green and brown mix of dried flowers, stems, seeds and leaves from the hemp plant Cannabis sativa. The main active chemical is THC (tetrahydrocannabinol), which moves quickly through the bloodstream to the brain and other organs throughout the body.

THC acts on specific targets in the brain, called cannabinoid receptors. Ordinarily, these receptors are activated by brain chemicals similar to THC that are part of a neural communication system, and play an important role in brain development and function. Marijuana over activates this system, causing impaired coordination, difficulty with thinking and problem solving, and disrupted learning and memory.

Because it impairs coordination and judgment, marijuana use can more than double a driver’s risk of being in an accident. And when used in conjunction with alcohol, the combined result is worse than either substance alone.

There is also an association between chronic marijuana use and mental illness. A link has been demonstrated with later development of psychosis, and the risk increases for those who start young. Associations have also been found with other mental health problems such as depression, anxiety, and suicidal thoughts among adolescents, although more research is needed to better understand these connections. In addition to the possible effects on your cognitive development and mental health, marijuana smoke is an irritant to the lungs, and frequent marijuana smokers can develop many of the same respiratory problems as tobacco smokers, such as daily cough and phlegm production, more frequent acute chest illness, and a greater risk of chest infections.

Marijuana can be addictive – it affects the brain’s reward centers in similar ways as all other addictive substances. When marijuana use becomes daily, or nearly daily, alterations to the brain can lead to an inability to perceive any negative impact.40

Marijuana has the potential to cause problems in your daily life, or make existing problems worse. It limits your brain's effectiveness, slows down thinking, and impairs coordination and judgment. And while you're young and still maturing, marijuana can have a long-lasting, negative impact on your developing brain. Marijuana can also be laced with different drugs so there is very high risk when buying and smoking it.

Also known as K2, fake marijuana, Blaze, Yucatan Fire, Skunk, Moon Rocks.

Spice is a mildly hallucinogenic mix of dried plant material that is laced with synthetic cannabinoids (chemicals similar to THC, the active ingredient in marijuana). But because the chemical composition of many products sold as spice is unknown, it can contain substances that could cause dramatically different effects than the user might expect.

The inconsistency and variability of ingredients can lead to unexpected harm to your body and brain. People taken to emergency rooms or Poison Control Centers (1-800-222-1222) have symptoms that include rapid heart rate, vomiting, agitation, confusion and hallucinations. The drug has also been linked to acute kidney injuries, which can lead the kidneys to shut down.

Filling your body with unknown substances can have severe consequences. New risks have continued to emerge – including signs of withdrawal and addiction – however, it’s not yet known how the synthetic cannabinoids and other ingredients in spice may affect you down the line.