Attention-Deficit/Hyperactivity Disorder is characterized by a persistent, long-standing pattern of attentional issues, marked by hyperactivity-impulsivity, inattention, or both.

Symptomology - Symptoms are present for a minimum of 6 months, and several symptoms would have been evident prior to age 12. The individual must experience issues in at least two unique settings, such as school and home, and additional informants may be required to accurately attest to the behavior, such as a parent, teacher, or supervisor. Symptoms cluster into inattentiveness, such as: failing to attend to details, difficulty focusing on activities requiring sustained attention, lack of follow through on tasks, disorganization of belongings and time, frequently losing things needed for essential tasks, and forgetfulness; and hyperactive-impulsivity, such as: fidgeting, difficulty being quiet, feeling a constant need to be in motion, talking to excess, interrupting others, and restlessness.