CRF Blog

Marijuana: The High and the Low

by Bill Hayes

In Marijuana: The High and the Low for the New York Review of Books, Jerome Groopman reviews A New Leaf: The End of Cannabis Prohibition by Alyson Martin and Nushin Rashidian.

Cannabis is one of the oldest psychotropic drugs in continuous use. Archaeologists have discovered it in digs in Asia that date to the Neolithic period, around 4000 BCE. The most common species of the plant is Cannabis sativa

, found in both tropical and temperate climates. Marijuana is a Mexican term that first referred to cheap tobacco and now denotes the dried leaves and flowers of the hemp plant. Hashish is Arabic for Indian hemp and refers to its viscous resin. An emperor of China, Shen Nung, also the discoverer of tea and ephedrine, is held to be among the first to report on therapeutic uses of cannabis in a medicinal compendium that dates to 2737 BCE. In 1839, William O’Shaughnessy, a British doctor working in India, published a paper on cannabis as an analgesic and appetite stimulant that also tempered nausea, relaxed muscles, and might ameliorate epileptic seizures. His observations led to widespread medical use of cannabis in the United Kingdom; it was prescribed to Queen Victoria for relief of menstrual discomfort.

The cannabis plant contains some 460 compounds, including more than 60 cannabinoids. THC, the key psychoactive substance in marijuana, has increased from about 1–5 percent to as much as 10–15 percent in cultivated plants since the 1960s. When herbal cannabis is smoked, some 20 to 50 percent of the THC is absorbed via the lungs. When herbal cannabis is eaten, less THC reaches the brain because it is metabolized as it passes from the gut through the liver. THC accumulates in fatty tissues, from which it is slowly released, and acts primarily on CB1 receptors in the brain’s mesolimbic dopamine system, which is believed to contribute to the positive reinforcing and rewarding effects of the drug.

While smoking or eating cannabis typically results in the user’s feeling “high,” with a relaxed, euphoric sense as anxiety and alertness decrease, some first-time users, as well as individuals who have psychological problems, can experience dysphoria, fear, and panic. Typically, when high on marijuana, there is an increased sense of sociability, although among those who have a dysphoric reaction, there can be sharp social withdrawal. Perception of time is altered, generally with perceived time faster than clock time; spatial perception also may change, and colors may seem brighter and music more resonant. High doses of cannabis can result in hallucinations, which may account for its religious use in some cultures. Yet unlike opioids, there are no reported cases of death due to a THC overdose, probably because cannabinoids do not inhibit our respiratory drive, which would result in asphyxiation. Among regular users, abstinence from marijuana can cause an uncomfortable or distressing withdrawal syndrome.

In 2008 the World Health Organization published a Mental Health Survey of 54,068 persons age sixteen and older in seventeen nations. On the basis of this survey, cannabis was found to have been used at least once by some 160 million people between the ages of fifteen and sixty-five; reported use was lowest in the People’s Republic of China, 0.3 percent, and highest in the United States, 42.4 percent, with New Zealand close behind. [more]