How Does Marijuana Effect Humans?

2009.05.05

A mild hallucinogen, marijuana has some of alcohol’s depressant and disinheriting properties. User reaction, however, is heavily influenced by expectations and past experience, and many first-time users feel nothing at all. 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 (making it dangerous to operate machinery, drive a car or boat, or ride a bicycle). Stronger doses prompt more intense and often disturbing reactions including paranoia and hallucinations.

Most of marijuana’s short-term effects wear off within two or three hours. The drug itself, however, tends to linger on. THC is a fat-soluble substance and will accumulate in fatty tissues in the liver, lungs, testes, and other organs. Two days after smoking marijuana, one-quarter of the THC content may still be retained. It will show up in urine tests three days after use, and traces may be picked up by sensitive blood tests two to four weeks later.

The Impact on the Mind

Marijuana use reduces learning ability. Research has been piling up of late demonstrating clearly that marijuana limits the capacity to absorb and retain information. A 1995 study of college students discovered that the inability of heavy marijuana users to focus, sustain attention, and organize data persists for as long as 24 hours after their last use of the drug. Earlier research, comparing cognitive abilities of adult marijuana users with non-using adults, found that users fall short on memory as well as math and verbal skills. Although it has yet to be proven conclusively that heavy marijuana use can cause irreversible loss of intellectual capacity, animal studies have shown marijuana-induced structural damage to portions of the brain essential to memory and learning.

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.

The Impact on 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.