"Of the many masks that ADD wears, substance abuse is one of the most difficult to see behind because the substance abuse itself causes such problems. Whens omeone is alcoholic, is abusing cocaine, or is dependent on marijuana, we often become so preoccupied with the problems the drug use creates that we fail to consider what purpose the drug must have been serving for the user. ADD is one of the underlying causes of substance abuse that is particularly important to look for, because it can be treated." (Hallowell and Ratey 2011)