Most people, study after study shows, don’t take the medicines prescribed for them. It doesn’t matter what they are — statins, high blood pressure drugs, drugs to lower blood sugar, asthma drugs. Either patients never start taking them, or they stop. It’s a problem that doctors call nonadherence — the common human tendency to resist medical treatment — and it leads to countless deaths and billions of dollars of preventable medical costs each year. But that resistance may be overcome by the block