There are two main treatments for ADHD: Medication or Behavior modification. 

Medications  

There are a lot of medications, but the most common are: Ritalin and Dexedrine. 

When the child or adult takes the medication, there are two sides: good and bad.

The good is that it decreases the symptoms (e.g. pays more attention). The medication is considered safe if used properly, and works for 90% of kids.

The bad side is that the long term effect of the medication is unknown, and sometimes the medications don't even work! Also, when the children take the medication, their parents are  sometimes worried about the fact that their children are taking medication. You should also know that the medication doesn't teach good behavior. When the medications lose their effect, sometimes the child gets angry. Sometimes, the medication is not as effective, so the  child/adult needs to take more and more medication.

You should also know that the medications have side effects. Such as: the child/adult doesn't want to eat, can't sleep well, there is a possibility of raising their heartbeat and blood pressure. They can also have stomach aches, head aches and they can sometimes feel depressed or nervous.

Behavior Modification

The research about behavior modification isn't as studied as the medications. But, it does teach good behavior and it doesn't have any side effects. YAY!