Explain what ADHD is and what the three types are. Put it in paragraph form, no more than 200 words. 

ADHD is Attention Deficit Hyperactivity Disorder. It is a behavior disorder that includes hyperactivity, inattention, and impulsivity. There are three types of ADHD. The combined type, which is the most common, includes impulsive and hyperactive behaviors, along with inattention and distractibility. Inattentive and distractable type includes inattentive and distractable behaviors without hyperactivity. The impulsive/hyperactive type is the least common and includes impulsive and hyperactive behaviors without distractibility and inattention.