Cannabis (Marijuana, Weed)

Cannabis, also known as marijuana among other names, is a preparation of the Cannabis plant intended for use as a psychoactive drug or medicine. The main psychoactive part of cannabis is tetrahedron (THC); one of 483 known compounds in the plant, including at least 65 other cannabis. Cannabis can be used by smoking, vaporization, within food, or as an extract.

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. 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. 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. Onset of effects is within minutes when smoked and about 30 to 60 minutes when cooked and eaten. They last for between two and six hours.

Cannabis is mostly used recreational 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). In 2015, 43% of Americans had used cannabis which increased to 51% in 2016. About 12% have used it in the past year, and 7.3% have used it in the past month. This makes it the most commonly used illegal drug both in the world and the United States.

Medical cannabis, or medical marijuana can refer to the use of cannabis and its cannabis to treat disease or improve symptoms; however, there is no single agreed upon definition. The use of cannabis as a medicine has not been rigorously scientifically tested, often due to production restrictions and other federal regulations. There is limited evidence suggesting cannabis can be used to reduce nausea and vomiting during chemotherapy, to improve appetite in people with HIV/AIDS, and to treat chronic pain and muscle spasms. Its use for other medical applications is insufficient for conclusions about safety or efficacy. Short-term use increases the risk of both minor and major adverse effects. Common side effects include dizziness, feeling tired, vomiting, and hallucinations. Long-term effects of cannabis are not clear. Concerns include memory and cognition problems, risk of addiction, schizophrenia in young people, and the risk of children taking it by accident.

THC, the principal psychoactive constituent of the cannabis plant, has low toxicity. The dose of THC needed to kill 50% of tested rodents is extremely high. Acute effects may include anxiety and panic, impaired attention, and memory (while intoxicated), an increased risk of psychotic symptoms, and possibly an increased risk of accidents if a person drives a motor vehicle while intoxicated. Short-term cannabis intoxication can hinder the mental processes of organizing and collecting thoughts. This condition is known as temporal disintegration. Psychotic episodes are well-documented and typically resolve within minutes or hours. There have been few reports of symptoms lasting longer. Cannabis has not been reported to cause fatal overdose. Studies have found that cannabis use during adolescence is associated with impairments in memory that persist beyond short-term intoxication.

Cannabis smoke contains thousands of organic and inorganic chemical compounds. This tar is chemically similar to that found in tobacco smoke, and over fifty known carcinogens have been identified in cannabis smoke, including; minestrone, reactive formaldehyde, and polyclinic hydrocarbons, including Benz pyre. Cannabis smoke is also inhaled more deeply than is tobacco smoke. As of 2015, there is no consensus regarding whether cannabis smoking is associated with an increased risk of cancer. Light and moderate use of cannabis is not believed to increase risk of lung or upper airway cancer. Evidence for causing these cancers is mixed concerning heavy, long-term use. In general there are far lower risks of pulmonary complications for regular cannabis smokers when compared with those of tobacco. A 2015 review found an association between cannabis use and the development of testicular germ cell tumors (TGCTs), particularly non-Seminole TGCTs. Combustion products are not present when using a vaporizer, consuming THC in pill form, or consuming cannabis foods.