Adhd is a medical condition, it's like saying you are going to treat diabetes with therapy. You may learn behaviors to avoid sugar but in the end the only thing that will help is medication.
actually I would disagree--or rather, agree that adhd is, in some ways, like diabetes. For while medication might solve some issues, the best diabetes patients are the ones who commit to serious, albeit difficult, lifestyle changes: radical changes in diet, exercise, and the like. For a family just starting to deal with ADHD, it is definitely worthwhile to address things like: behavioral modification, diet, exercise, sleep, accommodations, etc. This does not mean that medication is terrible or unnecessary, but it is my opinion that kids with adhd, whether they are medicated or not, also need other kinds of 'medication'--healthy lifestyles. As a parent, it is much harder--the constant reinforcement of social and emotional skills, the contact with the school/teachers, planning activities/exercise, regulating sleep, helping your child understand his/her impulses, etc--but it is as important as medication.