Teenagers believe that they have absolute power and control over their world. When they work with you to develop a contract, they generally sign it out of a sincere belief that they are in control of their chemical use.

A formal contract helps to clearly define your mutual expectations for abstinence from illegal substances, and outlines consequences for chemical use.

Once the contract is initiated, any chemical use brings your child into violation of the contract and into conflict with their choice to use an illegal substance.         

If they are able to refrain from chemical use, the contract has worked.

If they are unable to refrain from chemical use, then the contract works by revealing their denial about chemical use.