If all you listen to is conservatives and proponents of America’s war on drugs, you may believe that marijuana came from the devil himself. Like video games and music, politicians like to say that weed can alter behavior to the point that it could make someone violent—and that is reason enough that it shouldn’t be legalized. Crazy, right?

Well, it’s not that simple. Researchers have debated for decades whether or not marijuana can have negative effects such as making someone violent, and it’s proven a little difficult to reach a conclusion. One study that looked into marijuana and its effects on behavior lasted 50 years(!) and followed more than 400 people.

Let’s explore what scientists have said, and decide whether or not you should take extra care the next time you toke up.