Marijuana

    Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant Cannabis sativa , which contains the psychoactive (mind- altering) chemical delta-9-tetrahydrocannabinol (THC), as well as other related compounds. This plant material can also be concentrated in a resin called hashish or a sticky black liquid called hash oil .
    Marijuana is the most common illicit drug used in the United States. After a period of decline in the last decade, its use has been increasing among young people since 2007, corresponding to a diminishing perception of the drug’s risks that may be associated with increased public debate over the drug’s legal status. Although the federal government considers marijuana a
Schedule I substance (having no medicinal uses and high risk for abuse), two states have legalized marijuana for adult recreational use,
and 21 states have passed laws allowing its use as a treatment for certain medical conditions

How is Marijuana used?
    Marijuana is usually smoked in hand-rolled cigarettes (joints) or in pipes or water pipes (bongs). It is also smoked in blunts—cigars that have been emptied of tobacco and refilled with a mixture of marijuana and tobacco. Marijuana smoke has a pungent and distinctive, usually sweet-and-sour, odor. Marijuana can also be mixed in food or brewed as a tea.

How does Marijuana affect the brain?
    When marijuana is smoked, THC rapidly passes from the lungs into the bloodstream, which carries the chemical to the brain and other organs throughout the body. It is absorbed more slowly when ingested in food or drink. However it is ingested, THC acts on specific molecular targets on brain cells, called cannabinoid receptors. These receptors are ordinarily activated by chemicals similar to THC that naturally occur in the body (such as
anandamide; see picture, above) and are part of a neural communication network called the endocannabinoid system. This system plays an important role in normal brain development and function.
    The highest density of cannabinoid receptors is found in parts of the brain that influence pleasure, memory, thinking, concentration, sensory and time perception, and coordinated movement. Marijuana overactivates the endocannabinoid system, causing the “high” and other effects that users experience. These effects include altered perceptions and mood, impaired coordination, difficulty with thinking and problem solving, and disrupted learning and memory.
    Marijuana also affects brain development, and when it is used heavily by young people, it's effects on thinking and memory may last a long time or even be permanent. A recent study of marijuana users who began using in adolescence revealed substantially reduced connectivity
among brain areas responsible for learning and memory. And a large long-term study in New Zealand showed that people who began smoking marijuana heavily in their teens lost an average of 8 points in IQ between age 13 and age 38.
Importantly, the lost cognitive abilities were not fully restored in those who quit smoking marijuana as adults. Those who started smoking marijuana in adulthood did not show significant IQ declines.

What are the health effects of Marijuana?
    Marijuana use may have a wide range of effects, particularly on cardiopulmonary and mental health.
Marijuana smoke is an irritant to the lungs, and frequent marijuana smokers can have many of the same respiratory problems experienced by tobacco smokers, such as daily cough and phlegm production, more frequent acute chest illness, and a heightened risk of lung infections.
    One study found that people who smoke marijuana frequently but do not smoke tobacco have more health problems and miss more days of work than those who don’t smoke marijuana, mainly because of respiratory illnesses. It is not yet known whether marijuana smoking
contributes to risk for lung cancer.
Marijuana also raises heart rate by 20-100 percent shortly after smoking; this effect can last up to 3 hours. In one study, it was estimated
that marijuana users have a 4.8-fold increase in the risk of heart attack in the first hour after smoking the drug. This risk may be greater in older individuals or in those with cardiac
vulnerabilities.
    A number of studies have linked chronic marijuana use and mental illness. High doses of marijuana can produce a temporary psychotic reaction (involving hallucinations and paranoia) in some users, and using marijuana can worsen the course of illness in patients with schizophrenia. A series of large studies following users across time also showed a link between marijuana use and later development of psychosis. This relationship was influenced by
genetic variables as well as the amount of drug used, drug potency, and the age at which it was first taken—those who start young are at
increased risk for later problems.
Additionally, because it seriously impairs judgment and motor coordination, marijuana contributes to risk of injury or death while driving
a car. A recent analysis of data from several studies found that marijuana use more than doubles a driver’s risk of being in an accident.
The combination of marijuana and alcohol is worse than either substance alone with respect to driving impairment

Is Marijuana medicinal?
    Marijuana has been proven helpful for treating the symptoms of a variety of medical conditions. The body's endocannabinoid system may explain why.
    For many seriously ill people, medical marijuana is the only medicine that relieves their pain and
suffering, or treats symptoms of their medical condition, without debilitating side effects.
    Marijuana’s medicinal benefits are
incontrovertible, now proven by decades of peer-reviewed, controlled studies published in highly respected medical journals. Marijuana has been shown to alleviate symptoms of wide range of debilitating medical conditions including cancer, HIV/AIDS, multiple sclerosis, Alzheimer’s
Disease, post-traumatic stress disorder (PTSD).