Cannabis, also known as marijuana among several other names,[n 1] is a preparation of the Cannabis plant intended for use as a psychoactive drug or medicine.[12][13][14] The main psychoactive part of cannabis is tetrahydrocannabinol (THC); one of 483 known compounds in the plant,[15] including at least 65 other cannabinoids.[16] Cannabis can be used by smoking, vaporization, within food, or as an extract.[17]
Cannabis is often used for its mental and physical effects, such as a “high” or “stoned” feeling, a general change in perception, euphoria (heightened mood), and an increase in appetite.[17][18] Short term side effects may include a decrease in short-term memory, dry mouth, impaired motor skills, red eyes, and feelings of paranoia or anxiety.[17][19][20] Long term side effects may include addiction, decreased mental ability in those who started as teenagers, and behavioral problems in children whose mothers used cannabis during pregnancy.[17] Onset of effects is within minutes when smoked and about 30 to 60 minutes when cooked and eaten.[17][21] They last for between two and six hours.[21]
Cannabis is mostly used recreationally or as a medicinal drug. It may also be used for religious or spiritual purposes. In 2013, between 128 and 232 million people used cannabis (2.7% to 4.9% of the global population between the ages of 15 and 65).[22] In 2015, 43% of Americans had used cannabis, which increased to 51% in 2016.[23] About 12% have used it in the past year, and 7.3% have used it in the past month.[24] This makes it the most commonly used illegal drug both in the world and the United States.[17][22]
The earliest recorded uses date from the 3rd millennium BC.[25] Since the early 20th century, cannabis has been subject to legal restrictions. The possession, use, and sale of cannabis is illegal in most countries of the world.[26][27] Medical cannabis refers to the physician-recommended use of cannabis, which is taking place in Canada, Belgium, Australia, the Netherlands, Spain, and 23 U.S. states.[28] Cannabis use started to become popular in the US in the 1970s.[29] Support for legalization has increased in the United States and several US states have legalized recreational or medical use.[30]