I remember on some documentary, thinking John Stossel or 60 minutes, was talking about the "war on drugs" and had mentioned that the marijuana now is stronger due to specific breeding practices on the grower to maximize effect whereas the farmers that grew it didn't grow it with that in mind. Also showed people were going to Amsterdam to buy the seeds for specific plants and then bringing it back to the States and grow in basements using hydroponics and elaborate lights and feeding/watering of the plants. It also stated that the LSD is weaker now than during Woodstock era. But now you have folks on meth and makes the rest of it look like candy cigs.