Cannabis has been with us for millennia, some of the earliest records of cannabis use come from ancient Chinese texts, 2700 years before Christ, where it was used for medicinal purposes. In fact, the Chinese had been growing and using the hemp plant, which is one of the strains of cannabis sativa that has a very low amount of THC and doesn't make you feel high, to make clothing, rope and paper. Also from 2000 BC onwards there is evidence of the plant's use for medicinal purposes in ancient India, by Scythian nomads in modern day Siberia and it is also believed that some Native American tribes used it for medicine and rituals (yes, there were varieties of the cannabis plant in America before colonization). The use of cannabis to treat pain, anesthetize patients for surgery, treat rheumatism, constipation and many other ailments spread around the world to the Middle East, Africa and Europe. So we can be sure that mankind has always known the health benefits of the plant, but chose to forget about it at a certain point in history.
How did it become illegal?
The answer is not pretty. Until the 1900s, cannabis was prescribed by doctors and was readily available in general stores and people traded the plant all over the world. Beyond certain regulations imposed by the British to control the use of narcotics due to the opium and alcohol abuse that was taking place, cannabis was still legal in most parts of the world. And here the problems begin: the practice of smoking marijuana for recreational purposes was particularly common in Mexico, and the millions of Mexicans who flooded the U.S. border as a result of the Mexican Revolution brought the habit with them. They called it "marijuana." The substance became strongly associated with Mexicans and American xenophobia led them to dislike or fear the herb because of this association. Soon after, the U.S. Federal Bureau of Narcotics launched a campaign to fight this "foreign narcotic that had a Spanish name" which from then on they started calling themselves Marijuana, and based their prejudice purely on racist ideas, saying that most of the people who used the substance were people of color and immigrants and that their satanic music, such as jazz and swing, were a product of marijuana use. Cannabis was vile according to them and "could make a white woman want to have sex with a colored man." Despite objections from some physicians who claimed that cannabis prohibition could be an obstacle in future research into its health benefits, white congressmen issued a ban against "Marihuana" (and consolidated the name change to make a complete allusion to Mexicans).
As unusual as it sounds, this did not happen that long ago and it is important to understand where most of the prejudice against marijuana comes from in order to fight it. This happened in the 1940s, remember that back then the United States was on top of the world, so they used their Hollywood movies and all the political propaganda to make the world believe that marijuana caused violence and insanity, and all the other countries followed suit and banned the substance as well. During the 1960s, because of its psychoactive effects, but mostly because it was an act of rebellion to use cannabis, hippies became greedy for its use and the U.S. government conveniently found a cause to redouble their persecution of the substance. They issued stricter laws that increased prison sentences and treated marijuana as a highly dangerous narcotic like heroin or cocaine, issuing up to 20 years in prison to someone found in possession of cannabis. I'm still trying to figure it out, twenty years, a third or a quarter of your life is going away for carrying a plant in your pocket.
How did decriminalization begin?
It wasn't until the late 1990s and early 2000s that people and doctors began to call for the decriminalization of marijuana, at least for medicinal use. In 2009, Barack Obama admitted to smoking marijuana as a student and that helped the movements that wanted the decriminalization of recreational marijuana use gain momentum. In 2012, Colorado and Washington were the first states to legalize cannabis use and Uruguay was said to be the first country to completely legalize marijuana use nationwide during 2013, but as we already know, that's not true because marijuana has been legal worldwide for most of its history. It was just a small speck, a speck of dust on the timeline of Earth and cannabis, that conservative parties managed to create when they tried to ban marijuana for purely xenophobic reasons.
Cannabis in Barcelona
We are fortunate to live in Barcelona, where you can have access to weed clubs and cannabis associations and consume excellent products within the framework of the law, but when you think about it, there is still a long way to go. Marijuana consumption is decriminalized in Spain, but you can't say it's legal. You still need an invitation to be part of a cannabis club and you can't legally buy it (or sell it) like you can do with so many narcotics in a pharmacy, you can only grow it or consume it on the premises of these clubs or in the privacy of your own home or car (and by the latter I mean consume it, I doubt you are growing the plant inside your car). But we are grateful for what we have, and looking to the future, I am sure that in a few years most of the world will have fully legalized cannabis consumption.