The Diagnostic and Statistical Manual of Mental Disorders breaks down the symptoms of attention deficit hyperactivity disorder (ADHD) into three general categories: inattentive behavior, above-normal energy levels (hyperactivity), and lack of impulse control. Diagnosing a child can be difficult because nearly all children—especially those under six years of age—tend to be inattentive, hyper, and impulsive at some point. These behaviors move from normal conduct to a disorder when a child is so overactive, inattentive, or impulsive that he or she endangers oneself—or someone else—or can't complete daily activities such as eating, dressing, or playing with friends. As of July 2010, a revision to update these criteria is under review. Below is a list of red-flag behaviors, divided into the three main categories, as it currently exists.

Inattentive behavior

  • Has trouble paying attention to details
  • Makes careless mistakes
  • Gets distracted from work and play
  • Doesn’t seem to listen when being spoken to
  • Often doesn’t follow through on instructions and not because he or she didn’t understand or is opposed to them
  • Can’t stay organized
  • Loses things that are necessary for the completion of tasks or activities
  • Avoids anything that requires sustained mental engagement
  • Forgets aspects of daily activities

Hyperactivity

  • Can’t sit still or fidgets with hands and feet
  • Younger children will run around and jump in inappropriate situations.  Older children will complain of feelings of restlessness.
  • Will get up and leave a classroom, waiting room, or other situation where he or she is expected to stay seated
  • Talks excessively
  • Has nonstop energy
  • Cannot play or engage in activities quietly

Lack of impulse control

  • Has difficulty waiting for his or her turn
  • Will blurt out the answer to a question before the question has been finished
  • Will interrupt others in conversations or activities

One clue that a child has something other than ADHD is if the behaviors only come up in a single situation. For example, if you have a child who only acts up in school but not at home, with one teacher but not all teachers, or during a certain activity (while playing soccer, for example) but not all activities, then he or she may have a learning disability, personality conflict, or aversion to an activity. A child with ADHD would likely struggle in all of those situations.