In many cases, ADHD can be difficult to diagnose because many people exhibit the principal ADHD symptoms of hyperactivity, inattention, and impulsivity. Because everyone shows some of these behaviors at times, making a diagnosis requires that such behavior be demonstrated to a degree that is inappropriate for the person's age. The specific guidelines for diagnosing this condition also require a person's symptoms to meet certain criteria.
Not everyone who is overly hyperactive, inattentive, or impulsive has ADHD. Since most people sometimes blurt out things they didn't mean to say, or jump from one task to another, or become disorganized and forgetful, how can specialists be sure if the problem is ADHD?
Because everyone shows some of these behaviors at times, diagnosing ADHD requires that such behavior be demonstrated to a degree that is inappropriate for the person's age. The diagnostic guidelines also contain specific requirements for determining when the symptoms indicate ADHD.
Some parents see signs of inattention, hyperactivity, and impulsivity in their toddler long before the child enters school. The child may lose interest in playing a game or watching a TV show, or may run around completely out of control. Because children mature at different rates and are very different in personality, temperament, and energy levels, it's useful to get an expert's opinion of whether the behavior is appropriate for the child's age. Parents can ask their child's pediatrician, or a child psychologist or psychiatrist, to assess whether their toddler has an attention deficit hyperactivity disorder or is (more likely at this age) just immature or unusually exuberant.
ADHD may be suspected by a parent or caretaker or may go unnoticed until the child runs into problems at school. Given that ADHD tends to affect functioning most strongly in school, sometimes the teacher is the first to recognize that a child is hyperactive or inattentive and may point it out to the parents and/or consult with the school psychologist. Because teachers work with many children, they come to know how "average" children behave in learning situations that require attention and self-control. However, teachers sometimes fail to notice the needs of children who may be more inattentive and passive, yet who are quiet and cooperative, such as those with the predominantly inattentive form of ADHD.