A 2012 review found that the THC content in marijuana had increased worldwide from 1970 to 2009. It is unclear, however, whether the increase in THC content has caused people to consume more THC or if users adjust based on the potency of the cannabis. It is likely that the higher THC content allows people to ingest less tar. At the same time, CBD levels in seized samples have lowered, in part because of the desire to produce higher THC levels and because more illegal growers cultivate indoors using artificial lights. This helps avoid detection but reduces the CBD production of the plant.
In the United States, cannabis is overall the number four value crop, and is number one or two in many states including California, New York and Florida, averaging $3,000 per pound ($6,600/kg). Some believe it generates an estimated $36 billion market. Some have argued that this estimate is methodologically flawed, and makes unrealistic assumptions about the level of marijuana consumption. Other estimates claiming to correct for this flaw claim that the market is between $2.1-$4.3 billion. The United Nations Office on Drugs and Crime claims in its 2008 World Drug Report that typical U.S. retail prices are $10–15 per gram (approximately $280–420 per ounce). Street prices in North America are known to range from about $40–$400 per ounce ($1.4–$14/g), depending on quality.
Over the ages, countless innovations have attempted to improve on the basic experience of inhaling the smoke of combusted cannabis. As a result, there are numerous ways to smoke marijuana. The rolling technique is at the root of joints, blunts, and spliffs. On the other hand, glassware and other devices are essential for smoking weed out of a pipe, bong, or bubbler.
Cannabis has an ancient history of ritual use and is found in pharmacological cults around the world. Hemp seeds discovered by archaeologists at Pazyryk suggest early ceremonial practices like eating by the Scythians occurred during the 5th to 2nd century BC, confirming previous historical reports by Herodotus. It was used by Muslims in various Sufi orders as early as the Mamluk period, for example by the Qalandars. Smoking pipes uncovered in Ethiopia and carbon-dated to around c. AD 1320 were found to have traces of cannabis.
“The plan? Whip the public into a frenzy over ill effects of marijuana, the psychoactive leaves and flowers of the hemp plant; the reputation of the fibers and seeds used by industry would be posing little threat to society emerged as the ‘assassin of youth.’ The strategy worked. In 1937, with virtually no warning, Congress announced a prohibitive tax on hemp, effectively ending the production and sale of the plant in the United States.
But he wasn’t finished. In February of 1980, Dr. Mechoulam teamed up with South American researchers to publish a study regarding cannabis and epilepsy. This study is seen as one of the earliest double-blind studies of CBD on clinical subjects. The study Dr. Mechoulam and his team conducted included 16 people, many of whom were children, who all suffered from severe epilepsy. The results were startling: Every subject who received CBD experienced improvement in their condition with little to no side effects. This anticonvulsant study has since proven to be an integral milestone in the world of clinical marijuana research, but largely went unnoticed at the time.
The Duquenois–Levine test is commonly used as a screening test in the field, but it cannot definitively confirm the presence of cannabis, as a large range of substances have been shown to give false positives. Despite this, it is common in the United States for prosecutors to seek plea bargains on the basis of positive D–L tests, claiming them to be conclusive, or even to seek conviction without the use of gas chromatography confirmation, which can only be done in the lab. In 2011, researchers at John Jay College of Criminal Justice reported that dietary zinc supplements can mask the presence of THC and other drugs in urine. However, a 2013 study conducted by researchers at the University of Utah School of Medicine refute the possibility of self-administered zinc producing false-negative urine drug tests.
The question of whether heteromorphic sex chromosomes are indeed present is most conveniently answered if such chromosomes were clearly visible in a karyotype. Cannabis was one of the first plant species to be karyotyped; however, this was in a period when karyotype preparation was primitive by modern standards (see History of Cytogenetics). Heteromorphic sex chromosomes were reported to occur in staminate individuals of dioecious "Kentucky" hemp, but were not found in pistillate individuals of the same variety. Dioecious "Kentucky" hemp was assumed to use an XY mechanism. Heterosomes were not observed in analyzed individuals of monoecious "Kentucky" hemp, nor in an unidentified German cultivar. These varieties were assumed to have sex chromosome composition XX. According to other researchers, no modern karyotype of Cannabis had been published as of 1996. Proponents of the XY system state that Y chromosome is slightly larger than the X, but difficult to differentiate cytologically.
Because C. sativa has been a neglected crop for so long in North America, there are only negligible genetic resources available on this continent. Most germplasm stocks of hemp are in Europe, and the largest and most important collection is the Vavilov Institute gene bank in Leningrad. Figure 11 shows THC concentrations in the Vavilov collection, as well as in our own collection, largely of European germplasm. A disturbingly high percentage of the collections have THC levels higher than 0.3%, making it difficult to incorporate these into breeding programs.
Hemp is not the same as marijuana. One really has nothing to do with the other. Hemp was made illegal back in the days when cotton was king in the south and southern cotton plantation owners did not want the competition. They lobbied for, and got a law against hemp being grown nationwide. It never had to do with drugs at that time, and still doesn’t. As always, money and government go hand in hand. Now, recently, South Carolina has legalized growing hemp again, which is the only state in 50 to do so. We will hope for more enlightened agri-business legislation across the nation, soon.
The document gives a cursory breakdown of cannabis, cannabinoids like THC and CBD, concentrates and high-CBD/low-THC hemp plants, but only provides recommendations based on results from cases where animals came in to the vet from a toxic reaction. The evidence shows your animal will typically experience effects within 1-3 hours of exposure, but that they can “manifest in as little as 5 minutes or as long as 96 hours.” The AVMA notice also explains that most toxic cases have occurred in young puppies, and that most cases with dogs involved other toxicities such as chocolate, raisins, xylitol or wrapping.
It's a little more uniform when the product is absorbed by smoking or vaping the oil, Ward said. But, "there are obvious concerns about smoking something." A 2007 review published in the journal JAMA Internal Medicine found that smoking marijuana resulted in similar declines in respiratory system health as smoking tobacco. A similar review published in 2014 in The American Journal of Cardiology found that marijuana smoke inhalation can increase the chances of heart attack or stroke. Neither review analyzed the effects of vaping cannabis oil alone, so it's unclear if it has the same health risks as smoking other marijuana products.