Physical Effects of Marijua
na Use(完整版)
Marijuana(Cannabis sativa) is one of man’s oldest and most widely used drugs. It has been consumed in various ways as long as medical history has been recorded and is currently used throughout the world by hundreds of millions of people. A fairly consistent picture of its short-term effects on users is presented in many publications. There are, however, strongly contradictory opinions about whether the ultimate effects are harmful, harmless, or beneficial to human functioning. Many of the old reports suffered from multiple problems such as biased sampling, lack of control groups, and use of substances of unknown potency.1However, recent scientific literature presents a clear, well-documented case.
Several factors have to be taken into consideration in order to evaluate some of the research.The first aspect is the amount of the dose of tetrahydrocannabinol (THC), the major ingredient in marijuana.Another factor is the kind of person using marijuana. Also, the non-drug factor of setting must be considered in evaluating the results of experimental studies. These points are not going to be detailed or discussed although they have a very strong influence on an individual who smokes “pot.”
Our study may be divided into two categories; (a) at the beginning of use, and (b) when a user is into the situation. It could also be divided with reference to the level of the physical effects in man. In order to study physical effects rather than how they are produced, this paper proposes a third classification based on the duration and intensity of marijuana’s effects. Therefore, short-term and long-term or chronic effects are chosen as divisions. Short-Term Effects
The most consistent physiological sign is an increase of pulse rate.For example, doses of 14 mg.THC have resulted in higher than average pulse rates immediately after smoking.Another symptom found by Berke and Hernton is reddening of the eyes.Other researchers support these findings but find no evidence for claims that pupils dilate.Littlerunning no effect on respiratory rates,lung vital capacity ,or basal metabolic rate is noted .
Other symptos frequently reported are dryness of the mouth and throat and increasing frequency of urination .
Short-term biochemical effects are also an important consideration .Reports of increased hunger especially for sweets during Cannabis intoxication have focused attention on possible changes in blood sugar level.Many of Berke’s subjects experienced appetite stimulating and general hunger . Neurological experiments have not revealed major abnormalites during marijuana intoxication .Muscle strength and performance of simple motor tasks do appear to be affected .Cannabis users often report increased auditory sensibility ,visual acuity ,and aesthetic appreciation of music .
Berke divides short-term physical effects reported by subjects into two groups:the major symptoms are nausea ,vomiting ,and dizziness;less enduring ones are headaches,exhaustion ,feeling faint ,cold,and sweating.In his interviews he found that in general
these effects last from fifteen minutes to an hour .One of his interviewees said:
I have been ill physically about four times ,when I attributed it to hash or pot smoking .I became very dizzy,hot flushes,sweating,and vomiting in 3 of the occasions .It lasted once 10 minutes ,once about 2 hours or so ,and the other time about half an hour .When the illness left ,I was perfectly fit and was left very stoned indeed.On one occasion ,it occurred after the first smoke of the day ,and on the other after three or four smokes,so I deduce no connection with quantity .
To summarize what Berke tries to explain with this example ,the physical effects of Cannabis depend upon the experience which an individual has with it,and that is the point which people have to consider when they talk about physical effects .He makes this point strongly in an explanatory list of physical symptoms versus frequency in 257 people: From 257 People Nausea 95 Vomiting 62 Sick,Sickness 92 Dizziness,Giddiness 59 Headache 25 Sleepiness,Sleep 5 Exhaustion 20 Buzz In Head 2 Feel Faint,Faint 8 Discoordination 9 Heaviness 15 Gastric Distress 2 Feel Cold 4 Head Feel Bad 2 Sweating 11 Other 14 Long-term Effects
After having dealt with short-term effects we must discuss long-term effects. Long-term effects are not classified according to their frequency but according to their duration and intensity .It is difficult to find a chronic symptom caused by marijuana .
Silverstein and Lessin stated that smoking marijuana does not produce any impairment of cellular immunity .Nothing was found in the application of standard skin tests of an antigen to 22 chronic marijuana users .In contrast ,Nahas concluded from a study of 51 subjects that cellular immunity of an individual can be diminished or weakened by the chronic use of marijuana .
More recent experiments performed by Nahas on long-term “pot” smokers ,show that THC interferes with the body’s production of DNA, which is the genetic material that causes cell division and hereditary characteristics. Nahas uses the slowing down of the DNA process in order to explain that the weakness caused by marijuana stimulates the production of virus-fighting white blood cells /
Dr. Morton A. Stenchever and his associates discovered that a high percentage of marijuana users develop a significant increase in chromosome breaks, compared to nonusers.
At the Reproductive Biology Research Foundation in St. Louis, Dr. Robert C. Kolodny has found that men smoking at least ten marijuana cigarettes a week had a lower level of testosterone (principal male sex hormone) than nonsmokers. In thirty percent of the users (6 of 20),sperm counts were relatively low.
Experiments carried out by Dr. Forest S. Tenant, Jr.,in the U.S,Army’S drug program in Europe,found in teenage smokers up to their 20’s (a) a type of acute bronchitis,and (b) tissue changes in lung biopsies ,abnormalities which were the same as those associated with lung cancer.
There are other suspected or reported effects which are produced when the smoker is unstable
physiologically or psychologically. Nutrition, sanitation and climate ,potency ,drug dose level and frequency of use, and use of other drugs are conditions which influence the body .Consequently , it would be easier for marijuana to cause disorders which are not really attributed to it. Conclusion
While much has already been learned about the acute physiological effects of Cannabis, much remains to be learned. It is also important to understand the possible influence of other constituents of Cannabis which may not in themselves be psycho-or physical-active but may nevertheless influence the action of those constituents which are.
In spite of the increase of marijuana research papers in the last 10 years, some actions of marijuana are incompletely understood and their possible significance for health cannot at present be evaluated. These areas are discussed under the classical organ systems approach commonly used in medicine. Cardiovascular systems, gastrointestinal function, liver function, neuroendocrine effects of marijuana, and lung function are, from my point of view, the main areas to be investigated.
Physical Effects of Marijuana Use(学术英语)
