In a ground-breaking move, patients in Victoria will be able to access medical cannabis in exceptional circumstances after the Access To Medical Cannabis Bill passed through Parliament.
The announcement reignites a smouldering debate among scientists, activists, and lawmakers about how to leverage marijuana's medical benefits while minimising its potential for abuse.
Learn more about the controversial plant that has our society divided.
The drug-like effects experienced by cannabis users are caused by cannabinoids, the active chemicals that are present in the plant. The main active cannabinoid in cannabis is delta-9-tetrahydrocannabinol, more simply known as THC.
THC affects specific parts of the brain with cannabinoid receptors, triggering a series of cellular reactions that leads to the "high" experienced by users.
Some areas of the brain have many cannabinoid receptors, and others have few or none at all. The most can be found in areas of the brain that influence sensory and time perception, pleasure, concentrating, memory, and coordinated movement.
Besides THC, another active cannabinoid is cannabidiol, a compound that may decrease inflammation and relieve pain without the "high" that comes from THC.
According to the National Institute of Drug Abuse, the acute effects and health risks of marijuana use include: slowed reaction time, distorted sensory perception, impaired balance and coordination, increased heart rate and appetite, impaired learning and memory, anxiety, panic attacks, psychosis, cough, frequent respiratory infections, possible mental health decline, and addiction.
Shortly after smoking marijuana, a user may experience a 20 to 100 percent increase in the heart rate, which can last up to three hours. In one study, it was estimated that marijuana users have a 4.8-fold increased risk of heart attack in the first hour after smoking.
Marijuana smoke contains 50 to 70 percent more carcinogenic hydrocarbons than tobacco smoke.
Cannabinoids may be useful in the treatment of cancer and the side effects of cancer treatment.
Possible effects of treatment with cannabinoids include: a decrease in pain and inflammation, blockage of cell growth, the prevention of blood vessel growth that supplies tumours, and anti-viral activity.
The medicinal use of cannabis dates back at least 3,000 years. It was introduced to Western medicine in the 19th century, as it was believed that the drug could be a useful pain reliever, anti-inflammatory, anti-spasmodic, and anti-convulsant.
In Colorado, USA, two percent of registered medical marijuana patients are using marijuana due to cancer. More than 90 percent use the drug for the management of "severe pain." Nearly 20 percent use the drug for "muscle spasms," the second-most reported ailment the drug is used to treat.