Let me add something here. I am for the legalization of personal use Marijuana when the authorities can tell if someone is under the influence of it while driving (like they can with drinking and driving… similar to a breathalyzer).
For those interested, I have read books that are pro-Marijuana such as The Emperor Wears No Clothes: The Authoritative Historical Record of Cannabis and the Conspiracy Against Marijuana, and, Marijuana Myths Marijuana Facts: A Review Of The Scientific Evidence. Granted, these books may be a bit dated, but I guarantee you I have read more on the topic than any pastor I know. Which leads me to mention, I doubt any reading this — that are fighting/arguing for its legalization — have read books like, No Need for Weed: Understanding and Breaking Cannabis Dependency, or, The Truth About Pot: Ten Recovering Marijuana Users Share Their Personal Stories. Reasoned balance in thinking on topics is the idea here.
So what are some positions to discourage use of marijuana by individuals? Here are just a few reasons and links to a quick synopsis or studies regarding the topic.
Health and Perception
The short-term effects of marijuana include:
- Distorted perception (sights, sounds, time, touch)
- Problems with memory and learning
- Loss of coordination
- Trouble with thinking and problem-solving
- Increased heart rate, reduced blood pressure
Effects on the Brain
The active ingredient in marijuana, delta-9 tetrahydrocannabinol or THC, acts on cannabinoid receptors on nerve cells and influences the activity of those cells. Some brain areas have many cannabinoid receptors, but other areas of the brain have few or none at all. Many cannabinoid receptors are found in the parts of the brain that influence pleasure, memory, thought, concentration, sensory and time perception, and coordinated movement.
When high doses of marijuana are used, usually when eaten in food rather than smoked, users can experience the following symptoms:
Effects on the Heart
Within a few minutes after smoking marijuana, the heart begins beating more rapidly and the blood pressure drops. Marijuana can cause the heart beat to increase by 20 to 50 beats per minute, and can increase even more if other drugs are used at the same time.
Because of the lower blood pressure and higher heart rate, researchers found that users’ risk for a heart attack is four times higher within the first hour after smoking marijuana, compared to their general risk of heart attack when not smoking.
Effects on the Lungs
Smoking marijuana, even infrequently, can cause burning and stinging of the mouth and throat, and cause heavy coughing. Scientists have found that regular marijuana smokers can experience the same respiratory problems as tobacco smokers do, including:
- Daily cough and phlegm production
- More frequent acute chest illnesses
- Increased risk of lung infections
- Obstructed airways
Most marijuana smokers consume a lot less cannabis than cigarette smokers consume tobacco, however the harmful effects of smoking marijuana should not be ignored. Marijuana contains more carcinogenic hydrocarbons than tobacco smoke and because marijuana smokers typically inhale deeper and hold the smoke in their lungs longer than tobacco smokers, their lungs are exposed to those carcinogenic properties longer, when smoking.
What About Cancer?
Although one study found that marijuana smokers were three times more likely to develop cancer of the head or neck than non-smokers, that study could not be confirmed by further analysis.
Because marijuana smoke contains three times the amount of tar found in tobacco smoke and 50 percent more carcinogens, it would seem logical to deduce that there is an increased risk of lung cancer for marijuana smokers. However, researchers have not been able to definitively prove such a link because their studies have not been able to adjust for tobacco smoking and other factors that might also increase the risk.
Studies linking marijuana smoking to lung cancer have also been limited by selection bias and small sample size. For example, the participants in those studies may have been too young to have developed lung cancer yet. Even though researchers have yet to “prove” a link between smoking pot and lung cancer, regular smokers may want to consider the risk.
Other Health Effects
Research indicates that THC impairs the body’s immune system from fighting disease, which can cause a wide variety of health problems. One study found that marijuana actually inhibited the disease-preventing actions of key immune cells. Another study found that THC increased the risk of developing bacterial infections and tumors.[….]
See Also: NIDA InfoFacts: Marijuana
Early Onset of Schizophrenia
Overview: Use of street drugs (including LSD,methamphetamine,marijuana/hash/cannabis) and alcohol have been linked with significantly increased probability of developing psychosis and schizophrenia. This link has been documented in over 30 different scientific studies (studies done mostly in the UK, Australia and Sweden) over the past 20 years. In one example, a study interviewed 50,000 members of the Swedish Army about their drug consumption and followed up with them later in life. Those who were heavy consumers of cannabis at age 18 were over 600% more likely to be diagnosed with schizophrenia over the next 15 years than those did not take it. (see diagram below). Experts estimate that between 8% and 13% of all schizophrenia cases are linked to marijuna / cannabis use during teen years.
Many of these research studies indicate that the risk is higher when the drugs are used by people under the age of 21, a time when the human brain is developing rapidly and is particularly vulnerable.
People with any biological predisposition towards schizophrenia are at the highest risk — unfortunately its impossible to accurately identify this predisposition beforehand ( a family history of mental illness is just one indicator of such a predisposition). [see causes and prevention of schizophrenia for more information on all risk factors linked to a person developing schizophrenia]
Researchers in New Zealand found that those who used cannabis by the age of 15 were more than three times (300%) more likely to develop illnesses such as schizophrenia. Other research has backed this up, showing that cannabis use increases the risk of psychosis by up to 700% for heavy users, and that the risk increases in proportion to the amount of cannabis used (smoked or consumed). Additionally, the younger a person smokes/uses cannabis, the higher the risk for schizophrenia, and the worse the schizophrenia is when the person does develop it. Research by psychiatrists in inner-city areas speak of cannabis being a factor in up to 80 percent of schizophrenia cases.
Professor Robin Murray (London Institute of Psychiatry) has recently (2005) completed a 15-year study of more than 750 adolescents in conjunction with colleagues at King’s College London and the University of Otago in New Zealand.
Overall people were 4.5 times more likely to be schizophrenic at 26 if they were regular cannabis smokers at 15, compared to 1.65 times for those who did not report regular use until age 18.