Jump to content
  • Sign Up
  • 0

Physiological Effects of Cannabis Consumption

Guest Urbanhog


Guest Urbanhog

Physiological Effects of Cannabis Consumption


The effects of marijuana have been disputed ever since its ban in 1937. Harry J. Anslinger, the head of the Federal Bureau of Narcotics and Dangerous Drugs (FBNDD) from 1931 to 1962, and his associates like William Randolph Hearst used what has since been termed "yellow journalism" to spread news of marijuana's ill effects. There were claims that marijuana was addictive, caused psychosis and induced violent behavior.


As time progressed, people that wanted to see marijuana remain illegal came up with an ever-increasing list of marijuana's supposed ill effects. This section of my page will follow cannabis through the body from its initial entry into the lungs, to the effects on the lungs themselves, then to the effects on the heart and finally the diverse effects on the brain. Within these sections, I will also address the issues of tolerance and addiction potential, cancer and anti-motivational syndrome.






Methods of Ingestion

Smoked marijuana has been shown to be a more effective medicine for a number of ailments, when compared to orally ingested THC capsules. There are a number of methods of smoking marijuana, some of which can help to reduce the inherent perils of inhaling hot vapors containing particulate matter. Common methods include a rolled cigarette or joint, a pipe similar to a tobacco pipe, and various types of water pipes.


Most studies concerning the physiological effects of smoking marijuana have used joints to administer the smoke. This method is commonly used with lower grades of marijuana by casual users, as it is fairly inefficient. Studies have shown that only about 10% to 20% of the THC contained in the original marijuana is converted into main stream smoke that enters the smoker's body, and not all of this is absorbed by the smoker's lungs. (cite Research Findings on Smoking of Abused Substances) Pipes are a more efficient method of smoking, but still allow for less than 45% of the THC to be available to the smoker.


So far the most efficient means of smoking has been through a water pipe. These devices have a couple of advantages over conventional pipes. First of all, virtually none of the smoke is lost to the surroundings, or "side-stream smoke." This is achieved by loading the bowl with only as much marijuana as can be inhaled in one breath. The smoker draws all of the smoke into the chamber of the water pipe, combusting all of the marijuana, then "clears" the chamber in one breath. (cite Research Findings on Smoking of Abused Substances p. 45) Another advantage is that the hot smoke is passed through cool water before it reaches the smoker's throat. The advantages to this are twofold. First the smoke is cooled, which makes it easier for the smoker to inhale without coughing and reduces the damage done to the throat. Secondly, as the smoke passes through the water, some of the particulate matter that is suspended in it is filtered into the water. The THC molecule is not water soluble, so very little of it is lost to the water.


A study is currently under way at the Institute for Smoking and Health in New York. Headed by Dr. Hoffman, this study's aim is to determine the harm-reduction potential of smoking marijuana through a water pipe as opposed to other methods. Funded by the Multidisciplinary Association for Psychedelic Studies (MAPS), this study will attempt to determine the most effective type of water pipe, then compare the constituents of the smoke that it provides the smoker with the smoke from a standard unfiltered joint. To determine the most effective water pipe, the researchers will measure the proportions of THC delivered to the amount of tar in the smoke.


This study will also look at the feasibility and effectiveness of a vaporizer. This device is fundamentally different from other types of smoking in that it is not actually smoking at all. The vaporizer heats the marijuana to a point that is hot enough to activate the THC and release it in the form of steam, but not hot enough to actually burn the plant material. This form of ingestion holds great potential for a high THC/tar ratio, but is at this point a tedious process. Information about vaporization of cannabis versus smoking it is still fairly scant, but it is growing.







Effects of Marijuana Smoking on the Lungs


One of the major arguments that has been presented opponents of legalization of medicinal marijuana is that smoking anything is unsafe and marijuana smoke is even more harmful than tobacco. These people claim that there are over 400 chemicals in "crude" marijuana and no one should allow sick people to be exposed to them. (There are over 800 chemicals present in "crude" broccoli.) They also claim that there are twice as many carcinogens present in marijuana smoke than in tobacco smoke. One of the major opponents of rescheduling marijuana is Dr. Gabriel Nahas, who says medical marijuana is a cruel hoax.


The National Institute on Drug Abuse said in its 1990 report on marijuana's pulmonary effects, that they found, "No difference in prevalence of chronic cough, sputum production or wheeze was noted between the marijuana and tobacco smokers (included within their study), nor were additive effects of combined smoking of tobacco and marijuana on the prevalence of acute or chronic respiratory symptoms apparent." (NIDA book, p. 65)

The study also found that marijuana smoke and that of tobacco affected the lungs in different ways. Tobacco smoke predominantly caused degeneration of the peripheral airways and alveolated regions of the lung, while marijuana smoke affected mainly the large pathways. Because these two drugs affect different parts of the pulmonary system, their damaging effects can be additive. (NIDA book, p. 72)

Another study, this time conducted by the National Center for Toxicological Research, used 62 male rhesus monkeys to test various effects of regular (heavy exposure twice weekly) and chronic (heavy, regular smoking) use of marijuana. After a year of smoking, then seven months without exposure, some of the monkeys were sacrificed and autopsies were performed on them. The results were very encouraging as they said, "The data presented here suggest that seven months after the last smoke exposure, there is not evidence of increased marijuana smoke-induced carcinogen-DNA adducts in the lungs of exposed monkeys."


Furthermore, the report concluded in saying, "The general health of the monkeys was not compromised by a year of marijuana smoke exposure as indicated by weight gain, carboxyhemoglobin and clinical chemistry/hematology (studies of the oxygen-carrying capacity of red blood cells) values."


There are inherent risks in inhaling hot vapors, especially those that contain particulate matter such as tar found in smoke. This is an undisputed fact, but the dangers associated with marijuana smoke are not as drastic as some people would have you believe, and the risks involved can be greatly reduced by utilizing alternative methods of ingestion.




Effects of Marijuana Smoking on the Heart


The primary effect of marijuana smoking on the heart is tachycardia (a brisk increase in rate), which can be accompanied by an increase in blood pressure. The stroke volume of a normal heart remains the same throughout exposure, so the net effect on the heart is an increase of work performed. These effects are similar to those induced by stress and are not deleterious to the workings of a normal, healthy heart.

People with ailments affecting the circulatory system, such as arteriosclerosis or propensity to heart failure, may have some complications when smoking marijuana. These difficulties would be similar to those induced by stress, which can vary in severity. More studies need to be done to assess the risks for people with heart and circulatory difficulties, but one very promising fact is that nowhere in medical history has anyone died from marijuana-induced heart failure.




Effects of Marijuana Smoking on the Brain


The effects of marijuana on the human brain are numerous and complex. The psychoactive constituent of cannabis, delta-9 THC, affects the brain in a fundamentally different way than many other drugs, such as cocaine and opiates. These drugs are associated with the dopamine pathways within the brain and are subject to high rates of abuse, as seen with self-administration experiments done with animals.

Early research on cannabis' effects on the brain was limited by the technology of the time and was thus subject to influence by observations of behavior, rather than neuropharmacology. This lack of concrete knowledge about THC's effects allowed cultural biases to maintain fallacy that marijuana acted similarly to heroin. Research done during the past decade, since the discovery of a THC receptor in the brain, has refuted such claims. The congressional Office of Technology Assessment found that recent research findings, especially those done by Dr. Miles Herkenham of the National Institute of Mental Health (NIMH), have proved that marijuana has no effect on the dopamine-related brain systems.


Dopamine is a neurotransmitter in the brain that is associated with pleasure. The neural systems that are associated with dopamine are known as the "brain reward system." These systems are intimately involved with limbic system, an area of the brain which is associated with the control of emotions and behavior. Highly addictive drugs, such as cocaine, affect these pathways and cause an effective increase in the amount of dopamine in the brain. Cocaine and amphetamines block the reabsorbtion of dopamine, thus prolonging and intensifying the effects. Opiates activate production of dopamine by blocking the inhibitory signal, gamma-aminobutyric acid, which would ordinarily slow or stop dopamine production.


Research on animals and observations of addicts in our population has shown that animals will forsake their own personal good, whether it be refusing food and water or exposing themselves to extreme risk of contracting HIV, in order to stimulate the brain's reward system. Whether or not a drug stimulates the dopamine-associated pathways, is a large determining factor of whether or not the drug will prove to be addictive.


As coined by the Office of Technological Assessment, "The capacity to produce reinforcing effects is essential to any drug with significant abuse potential."


The OTA continued to say, "Animals will not self-administer THC in controlled studies... Cannabinoids generally do not lower the threshold needed to get animals to self-stimulate the brain reward system, as do other drugs of abuse."


Another signal that a drug has a high potential for addiction and abuse is its ability to induce tolerance. Many drugs, such as cocaine and opiates, create a tolerance by wearing out the dopamine receptors in the brain. With a percentage of the receptors being worn out with each exposure, the consumer must progressively increase the dosage to achieve the same effects. This is not the case with THC.


The mammalian brain creates an equilibrium by manipulating the number of active THC receptors to effectively put a ceiling on the drug's effectiveness. The more marijuana a person smokes, fewer THC receptors remain active. If a person rarely smokes, or only does so occasionally, the receptors will stay functioning and the "high" can be achieved with a relatively small dose.


The psychological effects of marijuana are not solely due to THC. While THC is the major psychoactive ingredient that is responsible for the altered sense of reality and euphoric feelings, another constituent of the smoke, cannabinol (CBN), produces only the depressant effects. Tolerance does not develop to this chemical. The paradoxical situation this sets up is this: to maximize the desired effects, a smoker must maintain moderate use. This will keep the THC receptors active, but minimize the proportional amount of CBN ingested. For more information on the specifics of marijuana tolerance, look at Jon Gettman's Marijuana and the Brain, Part II: The Tolerance Factor


The neural toxicity of acute marijuana ingestion was tested by NIDH when they administered a 10 mg/kg dose (a dose that is frequently used in clinical research) of THC to a group of rats. This amount of THC was proportionately more than a very heavy smoker would consume in a week (the approximate equivalent of 670 inhalations from a waterpipe or 100 joints of high-quality {7.5% THC} marijuana for a 165 lb. person).


The chronic (heavy, regular use) effects of marijuana consumption on the brain are disputed and the evidence available makes it difficult to draw any certain conclusions. R.G. Heath et al found, in their 1979 study of rhesus monkeys, anatomic changes in brain tissue. These changes included widening of the synaptic cleft, clumping of synaptic vesicles and other unspecified changes in morphology of brain cells. These changes were observed 6 months after cessation of 6 months of heavy exposure to marijuana smoke. The report is unclear as to its methods for morphology evaluation and controls that were used. Regardless of slight changes in brain tissue morphology, the behavior and performance levels of the monkeys returned to normal with in 8 months of cessation.




for more information check out the website where I copied/pasted the information:


The Medical Feasibility of Marijuana - By Blue Miner Young



Link to comment
Share on other sites

0 answers to this question

Recommended Posts

There have been no answers to this question yet

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Answer this question...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

By using the community in any way you agree to our Terms of Use and We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.