(shamelessly stolen from a speaker at a morning teaching conference)

With regards to adherence to medication regimens: Rewards and prizes for staying on their insulin/inhaled corticosteroid/Coumadin/phosphate binder/anti-hypertensive/methadone are much more effective than threats of death.

The chance of winning one of those cheapo clock radios or walkmen makes patients more likely to adhere to their meds than the fact that they will significantly shorten their lives and possibly catastrophically kill themselves if they don’t listen to you.