All definitional requirements for Transtorno de déficit de atenção e hiperatividade are met. Both inattentive and hyperactive-impulsive symptoms are clinically significant, com neither predominating in the clinical presentation. Inattention refers to significant difficulty in sustaining attention to tasks that do not provide a high level of stimulation or frequent rewards, distractibility and problems com organisation. Hyperactivity refers to excessive motor activity and difficulties com remaining still, most evident in structured situations that require behavioural self-control. Impulsivity is a tendency to act in response to immediate stimuli, sem deliberation or consideration of the risks and consequences.