Smoking lots of pot really can rob you of your ambition, and cannabis-use disorder—CUD, or pot addiction—is a real thing that can take away years of your productive life, if you belong to the roughly one-tenth of pot smokers who smoke too much and let cannabis get in the way of other things, like work, study, or family. Problem smokers keep smoking too much for 44 months, on average—“not a small chunk to take out a lifetime, especially a young lifetime,” Kleiman wrote. For that reason, Kleiman thought states should legalize pot in ways that would minimize excessive use. First, don’t let distributors advertise or otherwise encourage their customers’ habits. I once lived two blocks from a legal cannabis dispensary, and it took me a year to realize what it sold, so subtly did it market its product. Second, keep prices very high, far higher than the few pennies it would cost to grow and sell a joint. Make pot expensive enough that occasional users barely notice the cost but addicts do and feel spurred to cut back as their bank accounts decline.

Hallucinogens do not seem to have comparable addictive effects. Taking them is not like being a kid on a roller coaster who runs back into the line to ride again as soon as the train coasts to its terminus. The explorer Wade Davis compares the experience of a nose powder used ritually by the Yanomami to being “being shot out of a rifle barrel lined with baroque paintings and landing on a sea of electricity.” I have no idea what this means, but I am certain that the experience is so intense that no normal person would want to get out of the electricity sea, towel off, and stuff himself right back into the rifle barrel. Take enough cannabis, cocaine, or opium, and you’ll sharpen your craving for more. Hallucinogens, however, typically kill off any craving for more hallucinogens for a good amount of time. (Ketamine is an exception, both addictive and able to kill you, if you take too much and choke.)