[SeeSharp]

This is absolutely 100% predictable and completely the result of prohibition. Heroin was invented in Hong Kong shortly after the British made opium illegal and morphine restricted. You couldn't buy 100 proof whiskey in this country until they made whiskey illegal. Marijuana is now more than twenty times more powerful than the stuff we had when I was in High school back in the 70's.

There is a economist at Mises.org who has studied the potency phenomenon. Here's an interview: The Potency of Marijuana

[SoCal Pubbie]

You really believe that potency would not have increased without drug prohibition? Like how engine horsepower has gone way up because of government restrictions..oh, wait!

[RedStateRocker]

Shhhhh
You’ll rile up the jack boot lickers and drug warrior types. They are incapable of learning that prohibition is never the answer.

[CommerceComet]

Marijuana is now more than twenty times more powerful than the stuff we had when I was in High school back in the 70's.

I would expect the potency to go up with time whether marijuana was legal or not. Consumers are always seeking a better product and suppliers respond. Why would I expect any difference whether the product is prohibited or not?

[T-Bone Texan]

"...Marijuana is now more than twenty times more powerful than the stuff we had when I was in High school ..."

Actually, it is 3 to 5 times as strong, and no one has ever overdosed on cannabis. The accepted upper limit to THC in cannabis is approximately 20 to 25%.

The thing that has increased is the terpenes and other non-psychoactive components.