Marijuana and its effects on humans
Marijuana and its effects on humansThe Health Effects of Marijuana on Humans Tim Murphy Introduction Marijuana has been used as a drug since the beginning of time, yet there are still many mysteries about its health effects on humans. Marijuana, or cannabis sativa, is a preparation of the crushed flowers and buds of female hemp plant. The existence of the plant has been reported as early as 1500-1200 BC. in China, and cannabis has been described as an analgesic as early as 200 AD . Since then, an overwhelming number of studies have attempted to explain the physical and psychological effects of cannabis on humans. Physical Effects Physically, cannabis is relatively harmless. Studies have observed interesting results, including that it causes structural changes in the brain, depresses male sperm counts, causes chromosome damage, lowers testosterone levels, and damages the lungs. Most of these claims, however, have been unreplicated in humans or have been contradicted by other work. This section will address each of these reported negative side-effects. Various studies have claimed that cannabis destroys brain cells. However, several other studies found no structural or neurochemical atrophy in the brain at all. Furthermore, it should be noted that Heath's work was sharply criticized for avoiding safeguards of bias and reporting "changes" that occur normally in the mammalian brain. Wu et al. found a correlation between cannabis use and low sperm counts in human males. This is misleading because a decrease in sperm count has not been shown to have a negative effect on fertility and because the sperm count returns to normal after cannabis use has stopped.. Another claim made was that cannabis causes chromosome breakage. The primary source for this are studies that were conducted by Dr. Gabriel Nahas in the early 1980s. Nahas observed abnormalities in somatic (not sex) cells of rhesus monkeys in vitro (i.e., in test tubes and petri dishes) and then made the unjustified conclusion that these changes would occur in human bodies in vivo (in the body). Nahas' work was criticized by his colleagues and, in 1983, he backed away from his own conclusions. A widely held claim has also been that cannabis lowers male testosterone levels. This theory has been challenged by several studies that found no correlation at all. Marijuana and Health, also, after reviewing literature at that time, concluded that "Due to conflicting and incomplete evidence, it is not possible to conclude at the present time whether marijuana smoking has a significant effect upon gonadotropic and testosterone concentrations in humans." The most serious physical danger of using cannabis is in smoking it. Inhaling any sort of burnt plant matter is not very good for the lungs. Tashkin et al. reports decreased gas exchange capacity and the existence of particle residue in the lungs of marijuana smokers several times greater than for tobacco smokers. Wu noted that marijuana is several times more carcinogenic than tobacco. These findings, though, must be interpreted with caution. In both studies, smoked marijuana was not filtered, while...
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