They have genetically altered it, so that it is thousands of times stronger than natural. Many have died from it.
The Dutch are doing a billion business with it for years. Decades. You can't even imagine how many "tourists" are going to Amsterdam for a "joint" annually.
The general opinion of all Doctors used to be that Marijuana caused Schizophrenia. As a young adult, I knew somebody who had smoked Marijuana/Cannabis when he was in his teens. Apparently, by the time he was a young adult in his 20's, he was diagnosed with Schizophrenia. The Doctors said that it had probably been caused by smoking Cannabis when he was younger.
It was only legalized for the tax revenue, which is not a good reason to legalize anything.