"The public health burden of cannabis use is probably modest compared with that of alcohol, tobacco, and other illicit drugs. A recent Australian study96 estimated that cannabis use caused 0·2% of total disease burden in Australia—a country with one of the highest reported rates of cannabis use. Cannabis accounted for 10% of the burden attributable to all illicit drugs (including heroin, cocaine, and amphetamines). It also accounted for around 10% of the proportion of disease burden attributed to alcohol (2·3%), but only 2·5% of that attributable to tobacco (7·8%)."
"Tetrahydrocannabinol is a very safe drug. Laboratory animals (rats, mice, dogs, monkeys) can tolerate doses of up to 1,000 mg/kg (milligrams per kilogram). This would be equivalent to a 70 kg person swallowing 70 grams of the drug—about 5,000 times more than is required to produce a high. Despite the widespread illicit use of cannabis there are very few if any instances of people dying from an overdose.
"The gateway effect, if it exists, has at least two potential and quite different sources (MacCoun, 1998). One interpretation is that it is an effect of the drug use itself (e.g., trying marijuana increases the taste for other drugs or leads users to believe that other substances are more pleasurable or less risky than previously supposed). A second interpretation stresses peer groups and social interactions. Acquiring and using marijuana regularly may lead to differentially associating with peers who have attitudes and behaviors that are prodrug generally, not only with respect to marijuana.
"Our results indicate a moderate relation between early teen marijuana use and young adult abuse of other illicit substances; however, this association fades from statistical significance with adjustments for stress and life-course variables. Likewise, our findings show that any causal influence of teen marijuana use on other illicit substance use is contingent upon employment status and is short-term, subsiding entirely by the age of 21. In light of these findings, we urge U.S.
THC Potency of Tested Cannabis from Federal Seizure and State and Local Eradication Samples, by Type, 1985-2014
Thirty-Day Prevalence of Daily Marijuana, Alcohol, and Tobacco Use Among 19-30 Year Olds in the US
"Synthetic marijuana, so named because it contains synthetic versions of some of the cannabinoids found in marijuana, is a recent and important addition to the smorgasbord of drugs available to young people in the US. These designer chemicals are sprayed onto herbal materials that are then sold in small packets under such brand names as Spice and K-2. They have been readily available as over-the-counter drugs on the Internet and in venues like head shops and gas stations.
Cannabis and Lung Cancer: "Despite several lines of evidence suggesting the biological plausibility of marijuana use being carcinogenic (1), it is possible that marijuana use does not increase cancer risk, as suggested in the recent commentary by Melamede (26). Although the adjusted ORs <1 may be chance findings, they were observed for all non-reference exposure categories with all outcomes except oral cancer. Although purely speculative, it is possible that such inverse associations may reflect a protective effect of marijuana.
"In the current study, we demonstrated that chronic cannabis smokers had relative visceral adiposity and adipose tissue insulin resistance but not hepatic steatosis, glucose insulin insensitivity, impaired pancreatic b-cell function, glucose intolerance, or dyslipidemia compared with age-, sex-, ethnicity-, and BMI-matched control individuals.
Times for THC Absorption, Bioavailability, and Excretion: "Absorption is slower following the oral route of administration with lower, more delayed peak THC levels. Bioavailability is reduced following oral ingestion due to extensive first pass metabolism. Smoking marijuana results in rapid absorption with peak THC plasma concentrations occurring prior to the end of smoking. Concentrations vary depending on the potency of marijuana and the manner in which the drug is smoked, however, peak plasma concentrations of 100-200 ng/mL are routinely encountered.