For anyone who knows about 1960’s marijuana, the idea that it could be addictive might sound ridiculous — in the 1960’s addiction was something that only happened to people who abused heroin, cocaine or speed.

That view is bolstered by today’s media portrayals of marijuana that never even imply it could be addictive. The closest thing to a portrait of a THC addict are the bemused Cheech and Chong character types.

But the Substance Abuse and Mental Health Services Administration’s (SAMHSA) most recent study from 2014 tells us that more than 2 million people nationwide are addicted to THC substances and that more than 300,000 of those are aged 12-17. To those numbers, add another 1.5 million who have THC abuse issues but who are not yet addicted.

THC and CBD Levels in marijuana 1960-2011

Let’s put those numbers in a state context and move all those THC addicts to Florida. If that happened the next time you visited Jacksonville, Miami, Tampa, St. Petersburg and Orlando, Florida’s top most populated cities, every single resident you see would be a THC/marijuana addict.

Then, if we moved in the other 1.5 million with THC abuse problems, we’d fill up the next nine most populated Florida cities — in total all 14 of the largest Florida cities would be populated with nothing but THC addicts or those who have THC abuse issues. In short, THC abuse and addiction are serious, widespread problems.

But, if marijuana addiction wasn’t seen as a widespread problem in the 1960s and 1970s, when did THC/marijuana addiction begin?

Remarkably, we can be reasonably sure about when THC addition began: experts say that marijuana addiction began afflicting users when common marijuana THC levels went above about 5%.

In the 1960s, marijuana THC levels were somewhere around 1%. Since then, thanks to advancing cultivation techniques, that percentage has steadily risen to 14% – 20%, or more than 15X as strong, with peaks as high as 32% THC.

That means that smoking a single joint today is like smoking 15 or more joints in the 1960s and 70s. Addiction is one result but many other issues are showing up too, issues we’ll cover in other articles, but it’s safe to say that whenever anyone talks about addiction and marijuana today, they really need to be talking about THC.