This question has one claim in the title and four others in the body
1. The black market in Colorado has increased since legalization
Possible. There are claims many places including here that legalization has created an environment where illegal and quasi-legal growers can grow and export to other states.
But that's unlikely to be correlated with ...
The answer is yes, in laboratory experiments, and perhaps in a clinical setting as well.
Let me emphasize: the proof exists in controlled laboratory experiments. It has not been demonstrated to be true in human trials. So don't smoke up in the expectation that it's a better cancer treatment than a doctor's recommendations (generally chemotherapy, ...
Yes, it does, approximately 3 times that amount by weight, but that's not the whole story. You should consider other factors too in determining whether this means it is more harmful:
Firstly, when people smoke cannabis leaves or buds, they smoke them in a rolled cigarette which is usually larger than a tobacco cigarette. This would suggest that not only ...
This is a thorny question, both because it is a politicized issue, and because the effects of cannabis use while driving are less well studied than the effects of alcohol, and appear to include a number of confounding factors.
Overall, my survey of the literature suggests that there are two questions, which have (surprisingly) different answers:
Since the original article wasn't mentioned in the question, here's a link with abstract:
MEIER MH, et. al. Persistent cannabis users show neuropsychological decline from childhood to midlife. Proc Natl Acad Sci U S A. 2012 Oct 2;109(40):E2657-64. doi: 10.1073/pnas.1206820109. Epub 2012 Aug 27.
The purpose of the study, published in Proceedings of the ...
There is some truth to this claim although I would not rate the study which I source here as high-quality evidence.
Chen AL, Chen TJ, Braverman ER, Acuri V, Kemer M, Varshavskiy M, Braverman D, Downs WB, Blum SH, Cassel K, Blum K., Hypothesizing that marijuana smokers are at a significantly lower risk of carcinogenicity relative to tobacco-non-marijuana ...
I had to dig a little, but I believe I have an answer for you, and the answer is: Yes, but how quickly depends on the user.
I'm drawing from this study from the British Journal of Anesthesia. According to the study, your average modern joint is going to have between 60mg and 150mg of THC (which mirrors information gathered by the National Highway Traffic ...
Yes, this was studied in Medical Marijuana Laws Reduce Prescription Medication Use In Medicare Part D Health Affairs July 2016 vol. 35 pages 1230-1236 :
In states with medical marijuana laws, pain medication was reduced by 1,826 daily doses filled per physician per year.
Ultimately, we estimated that nationally the Medicare program and its enrollees ...
This claim ultimately traces back to a May 30, 2000, article published by AlterNet, Pot Shrinks Tumors; Government Knew in '74, and a book first published in 1985.
The AlterNet story claims that:
In 1974 researchers at the Medical College of Virginia, who had been funded by the National Institute of Health to find evidence that marijuana damages the ...
The USC webpage states
MARIJUANA USE CONSEQUENCES
The well-confirmed danger of smoking marijuana is lung damage and lung cancer. As examples:
1 joint = 5 cigarettes in terms of amount of carbon monoxide (CO) intake.
1 joint = 4 cigarettes in terms of amount of tar intake.
2 joints = 20 cigarettes in terms of microscopic damage to ...
The last paragraph does appear to be true, at least in the first couple of years. It is based on a study by the Colorado Department of Health.
The report found a huge gap in numbers in relation to how adolescents,
ages 10-17 were being in arrested, which apparently was contingent
upon their race. While there was an eight percent decrease in arrest
It appears marijuana leaves about 3x the tar as cigarettes.
As compared with smoking tobacco, smoking marijuana was associated with .. an approximately threefold increase in the amount of tar inhaled, and retention in the respiratory tract of one third more inhaled tar
What about the difference in smoking styles?
Significant differences were also ...
To complement Yisela's answer:
There is a more recent study (from 2016) that contradicts the results of the 2012 study by Meier MH et. al:
Impact of adolescent marijuana use on intelligence: Results from two longitudinal twin studies, January 2016, Proceedings of the National Academy of Sciences of the United States of America
From the abstract:
Yes, some doctors do recommend smoking marijuana in certain cases.
In this article in Virtual Mentor, Dr. Igor Grant, MD, says that smoked marijuana can be useful in cases of painful sensory neuropathy, and specifically describes inhalation as superior to oral administration.
Grant is chair of the Department of Psychiatry at the University of California, ...
The Bible records the Israelites as using kaneh-bosm as anointing oil, specifically in the Old Testament. The exact composition of the oil is unclear as kaneh-bosm is an Aramaic word, although most scholars believe that it was made from Calamus, a kind of palm.
Various sources which discuss the issue:
Although the ...
We don't know.
The study cited for all the articles about the statistics for the state of Washington was one produced by the AAA Foundation for Traffic Safety.
Prevalence of Marijuana Involvement in Fatal Crashes: Washington, 2010-2014
The paper, itself, is quick to point out that it is not attributing cause, just looking at the incidence levels.
Because you say, "I thought marijuana was legal in some Arab countries", therefore I assume you're asking about the contemporary world:
I hope it goes without saying that cannabis has been known and used since prehistoric times.
The first (that I know of) wide-spread international treaty outlawing cannabis was "the second Opium Law" introduced on 12 May ...
The article you quoted is must be very old. It refers to a recent reclassification of cannabis to a class-C drug in UK law, which happened in 2001 (and was reclassified as Class-B in 2009). It also refers to a BMJ article published "today", which I assume is Comparing cannabis with tobacco.. This article attempts to correlate the severity of ...
Mexico outlawed marijuana 10 years before the United States did because they viewed it as a problem there. The Dupont and Hearst bit makes for good conspiracy theory though.
The name marijuana (Mexican Spanish marihuana, mariguana) is associated almost exclusively with the plant's psychoactive use. ...
As @LangLangC found, there is a more recent study also reported by Nationwide Children’s Hospital:
Study results showed from January 2000 through June 2017 there were 2,968 ingestions of marijuana by children younger than six years old reported to U.S. poison centers. The majority (72.4%) of exposures were in children younger than three years old. More ...
Cannabis is not without dangers. But these are really small in the bigger perspective. And with all drugs, dosis facit venenum. High as a kite all day and every day leads to behaviour that is unlikely to maintain the training of the brain "as a muscle". Especially THC alone in high concentrations can be quite nasty.
First, many studies were specially ...
This psychology today article suggest that combining both can lead to severe effects and even death.
Consuming too much alcohol usually leads to vomiting, as the body is getting rid of the toxins, but since marijuana prevents vomiting the outcome can be death.
Medicinal Use of Marijuana — Polling Results (from a 2013 poll in the New England Journal of Medicine) says,
We were surprised by the outcome of polling and comments, with 76% of all votes in favor of the use of marijuana for medicinal purposes ... In sum, the majority of clinicians would recommend the use of medicinal marijuana in certain circumstances.
There are details, with a list of more than 250 references/citations, at Information for Health Care Professionals: Marihuana (marijuana, cannabis) [Health Canada, 2010] (hyperlink).
It talks about the following clinical uses:
4.1 Nausea and vomiting
4.2 Wasting syndrome and loss of appetite in AIDS and cancer patients
4.2.1 To stimulate appetite and ...
The National Institute on Drug Abuse (NIDA) admits that cannabis is not physically addictive, it is not a gateway to drugs, it does not cause cancer or emphysema, there is no evidence it negatively affects driving, there is no evidence it causes an early onset of psychosis, and there is no evidence it negatively affects teen IQ.
The most important of these ...
According to the American Lung Association:
when equal amounts of marijuana and tobacco are smoked, marijuana deposits four times as much tar into the lungs. This is because marijuana joints are un-filtered and often more deeply inhaled than cigarettes.