Essay by EssaySwap ContributorCollege, Undergraduate February 2008

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Marijuana, although the single most common drug in the US, may be the one people know least about. This may be because marijuana does not have many proven long-term effects. Marijuana is also not proven to be chemically addictive, (although it may be psychologically). The effects of marijuana lack much scientific evidence. Following are some of the known facts on marijuana.

Drugs such as cocaine and heroin affect the neurotransmitter dopamine. Dopamine is the neurotransmitter that triggers the body's pleasure sensations. Cocaine and heroin interfere with its production, causing too much to be produced. The result may be extremely pleasurable and this may lead to severe abuse and addiction. It has recently been proven that marijuana is not a drug that affects the production of dopamine.

Over 400 chemicals are found in the average marijuana plant; many more are formed once vaporized. When smoked, nerve cell receptors of the brain sense these chemicals.

The chemical in marijuana that has the biggest impact on the brain is THC (tetrahydrocannabinol).

THC receptors are found throughout the brain but are concentrated in certain areas. One area of the brain where THC receptors are very concentrated is the hippocampus. The hippocampus processes memory. When THC attaches to the receptors in the hippocampus, it weakens short-term memory. The hippocampus also communicates with other areas of the brain in turn process new information into long-term memory. Under the influence of marijuana, new information may never be stored and could be completely lost from memory.

There is also a dense concentration of THC receptors in the basal ganglia and the cerebellum. These areas both help control the body's movement and coordination. These functions, in turn, are affected when marijuana is smoked.

One area of the brain that does not contain any THC receptors at all is the...