ADHD, also called attention-deficit disorder, is a behavior disorder, usually first diagnosed in childhood, that is characterized by inattention, impulsivity, and, in some cases, hyperactivity. These symptoms usually occur together; however, one may occur without the other(s).⁠ ⁠ The symptoms of hyperactivity, when present, are almost always apparent by the age of 7 and may be present in very young preschoolers. Inattention or attention-deficit may not be evident until a child faces the expectations of elementary school.⁠ ⁠ _____⁠ ⁠ There are three major types of ADHD:⁠ ⁠ - ADHD, combined type. This, the most common type of ADHD, is characterized by impulsive and hyperactive behaviors as well as inattention and distractibility.⁠ - ADHD, impulsive/hyperactive type. This, the least common type of ADHD, is characterized by impulsive and hyperactive behaviors without inattention and distractibility.⁠ - ADHD, inattentive and distractible type. This type of ADHD is characterized predominantl...