What is marijuana?

Marijuana is a green or gray mixture of dried, shredded flowers and leaves of the hemp plant cannabis sativa. There are numerous slang terms for marijuana including “pot”, “herb”, “weed”, “boom”, “Mary Jane”, “gangster”, and “chronic”. It is usually smoked as a cigarette – called a joint or a nail – or in a pipe or bong. In recent years, it has appeared in blunts. These are cigars that have been emptied of tobacco and refilled with marijuana, often in combination with another drug, such as crack. Some users also mix marijuana into foods or use it to brew tea.

Marijuana´s active chemical ingredient

The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). In 1988, it was discovered that the membranes of certain nerve cells contain protein receptors that bind THC. Once securely in place, THC kicks off a series of cellular reactions that ultimately lead to the high that users experience when they smoke marijuana.

The short-term effects of marijuana use include problems with memory and learning; distorted perception; difficulty in thinking and problem solving; loss of coordination, and increased heart rate, anxiety, and panic attacks.

Scientists have found that whether an individual has positive or negative sensations after smoking marijuana can be influenced by heredity. A recent study demonstrated that identical twins were more likely than non identical male twins to report similar responses to marijuana use, indicating a genetic basis for their sensations. Identical twins share all of their genes, and fraternal twins share about half.

Environmental factors such as the availability of marijuana, expectations about how the drug would affect them, the influence of friends and social contacts, and other factors that would be different even for identical twins also were found to have an important effect. However, it also was discovered that the twin´s shared or family environment before age 18 had no detectable influence on their response to marijuana.