It’s true! You’re not just imagining things: Weed is a hell of a lot stronger now than it was during the 1960s, according to an AMA session by marijuana researcher Dr. Kevin Hill in Reddit’s Science community.

Interestingly, from the 1960s through the 1980s, the average THC content—a psychoactive property—in weed was a mere three to four percent. Nowadays, weed’s normal THC content is around 13 percent. But in some strains, THC levels are at a whopping 20 to 30 percent.

This is most likely due to legal dispensaries meeting the demands of their customers to “grow stronger stuff.” But higher THC level-strains can lead to more consequences: It may increase paranoia.

Hill also shares that “most people who use marijuana don’t become addicted.” Only nine percent—out of the 20 million Americans who smoked weed last year—are addicted to marijuana.

And if you’re trying to pass a drug test, Hill says that usually marijuana stays in your system for about a week (if you’re NOT a habitual user, that is):

“Generally, marijuana will cause a positive urine test about 4 hours after use. People are also interested in the length of time mj can be detected. It depends on whether the user is a regular user or not, and also the cut-off, or sensitivity of the test. New users, single use, about 2-5 days at 50 ng/ml, the standard drug test. Chronic users—longer because mj is stored in the fat.”

Check out Kevin Hill’s entire AMA here.