Why is P2P meth producing such pronounced symptoms of mental illness in so many people? No one I spoke with knew for sure. One theory is that much of the meth contains residue of toxic chemicals used in its production, or other contaminants. Even traces of certain chemicals, in a relatively pure drug, might be devastating. The sheer number of users is up, too, and the abundance and low price of P2P meth may enable more continual use among them. That, combined with the drug’s potency today, might accelerate the mental deterioration that ephedrine-based meth can also produce, though usually over a period of months or years, not weeks. Meth and opioids (or other drugs) might also interact in particularly toxic ways. I don’t know of any study comparing the behavior of users—or rats for that matter—on meth made with ephedrine versus meth made with P2P. This now seems a crucial national question.