What Is Marijuana?

Marijuana is a green or gray mixture of dried, shredded flowers and leaves of the hemp plant Cannabis sativa. It has been around for a long while. Its source, the hemp plant (cannabis sativa), was being cultivated for psychoactive properties more than 2,000 years ago. There are over 200 slang terms for marijuana including "pot," "herb," "weed," "boom," "kush," and countless others. It is usually smoked as a cigarette, in a pipe or bong (a type of water-cooled pipe). Marijuana can also be mixed into foods or brewed into tea.

The main active chemical in marijuana is THC (delta-9-tetrahydrocannabinol). This chemical kicks off a series of cellular reactions that produces the high that users experience. Perceived positive effects include euphoria, heightening of the senses, i.e. smell, hearing and taste and an increase in appetite. The short term negative effects of marijuana use may involve problems with memory and learning; distorted perception; difficulty in thinking and problem-solving; loss of coordination; and increased heart rate, anxiety, and, in some instances, panic attacks.

Effects of smoking are generally felt within a few minutes and peak in 10 to 30 minutes. They include dry mouth and throat, increased heart rate, impaired coordination and balance, delayed reaction time, and diminished short-term memory. Moderate doses tend to induce a sense of well-being and a dreamy state of relaxation that encourages fantasies, renders some users highly suggestible, and distorts perception (sometimes making it dangerous to operate machinery, drive a car or boat, or ride a bicycle).

Health Hazards

Effects of Marijuana on the Brain

Researchers have found that THC changes the way in which sensory information gets into and is acted on by the hippocampus. This is a component of the brain's limbic system that is crucial for learning, memory, and the integration of sensory experiences with emotions and motivations. Investigations have shown that neurons in the information processing system of the hippocampus and the activity of the nerve fibers are suppressed by THC. In addition, researchers have discovered that learned behaviors, which depend on the hippocampus, also deteriorate.

Recent research findings also indicate that long-term use of marijuana produces changes in the brain similar to those seen after long-term use of other major drugs of abuse. “Teens using marijuana before age 18 are two to four times more likely to develop psychosis as young adults compared to those who do not.” (http://www.ednewscolorado.org/2012/02/22/33516-research-shows-adverse-effects-of-marijuana-on-teens-as-drug-use-among-students-appears-to-be-rising)

Effects on the Lungs

Someone who smokes marijuana regularly may have many of the same respiratory problems that tobacco smokers have. These individuals may have daily cough and phlegm, symptoms of chronic bronchitis, and more frequent chest colds. Continuing to smoke marijuana can lead to abnormal functioning of lung tissue injured or destroyed by marijuana smoke.

Regardless of the THC content, the amount of tar inhaled by marijuana smokers and the level of carbon monoxide absorbed are three to five times greater than among tobacco smokers. This may be due to the marijuana users inhaling more deeply and holding the smoke in the lungs.

“Habitual marijuana use may lead to the following effects on the lung:

• acute and chronic bronchitis;
• extensive microscopic abnormalities in the cells lining the bronchial passages (bronchial epithelium), some of which may be premalignant;
• overexpression of genetic markers of progression to lung cancer in bronchial tissue;
• abnormally increased accumulation of inflammatory cells (alveolar macrophages) in the lung; and
• impairment in the function of these immune-effector cells (reduced ability to kill microorganisms and tumor cells) and in their ability to produce protective inflammatory cytokines.” (http://www.ukcia.org/research/EffectsOfMarijuanaOnLungAndImmuneDefenses.php)

Effects of Heavy Marijuana Use on Learning and Social Behavior

A study of college students has shown that critical skills related to attention, memory, and learning are impaired among people who use marijuana heavily, even after discontinuing its use for at least 24 hours. Researchers compared 65 "heavy users," who had smoked marijuana a median of 29 of the past 30 days, and 64 "light users," who had smoked a median of 1 of the past 30 days. After a closely monitored 19- to 24-hour period of abstinence from marijuana and other illicit drugs and alcohol, the undergraduates were given several standard tests measuring aspects of attention, memory, and learning. Compared to the light users, heavy marijuana users made more errors and had more difficulty sustaining attention, shifting attention to meet the demands of changes in the environment, and in registering, processing, and using information. The findings suggest that the greater impairment among heavy users is likely due to an alteration of brain activity produced by marijuana.

Longitudinal research on marijuana use among young people below college age indicates those who used have lower achievement than the non-users, more acceptance of deviant behavior, more delinquent behavior and aggression, greater rebelliousness, poorer relationships with parents, and more associations with delinquent and drug-using friends.

Research also shows more anger and more regressive behavior (thumb sucking, temper tantrums) in toddlers whose parents use marijuana than among the toddlers of non-using parents.

The Impact on the Body

Chronic marijuana smokers are prey to chest colds, bronchitis, emphysema, and bronchial asthma. Persistent use will damage lungs and airways and raise the risk of cancer. There is just as much exposure to cancer-causing chemicals from smoking one marijuana joint as smoking five tobacco cigarettes. And there is evidence that marijuana may limit the ability of the immune system to fight infection and disease.

Marijuana also affects hormones. Regular use can delay the onset of puberty in young men and reduce sperm production. For women, regular use may disrupt normal monthly menstrual cycles and inhibit ovulation. When pregnant women use marijuana, they run the risk of having smaller babies with lower birth weights, who are more likely than other babies to develop health problems. Some studies have also found indications of developmental delays in children exposed to marijuana before birth.

Marijuana as Medicine

Although U.S. Federal law classifies marijuana as a Schedule I controlled substance (which means it has no acceptable medical use), a number of patients claim that smoking pot has helped them deal with pain or relieved the symptoms of glaucoma, the loss of appetite that accompanies AIDS, or nausea caused by cancer chemotherapy. Numerous states have, in recent years, authorized the medical use of the drug and  this past election, 2012, it was legalized for personal recreational use in the states of Washington and Colorado.