The next page advises, "If you suspect that your child is using drugs, question everything. Make sure you monitor what your child is doing as much as possible."
This is what the "protectors" of our communities have been telling our parents: If your child begins to experience any changes, invest a sudden interest in their activities. Pay attention not because you care about your kids, but because you care if they're using drugs. Also, since "these signs may indicate a problem other than drug use" (for example, "a lack of concern for appearance or hygeine" may actually indicate being a communist, practicing witchcraft, or having an unhealthy obsession with the conservation of spotted owls), "drugs, traces of drugs, and drug paraphernalia are more direct evidence of drug use." So in other words, look for direct evidence. Perhaps try drug testing. It's perfectly legal for parents to find the evidence without a warrant. However, "Be prepared that your child will probably lie, and you may have to seek outside help." So please feel free to invite your friends from the police department over.
You know what, Officer What's-Your-Name? Don't you talk about my mother that way. (Of course it comes as no surprise that there wasn't any harm reduction literature.)