Impulsivity is the tendency to act on impulse -- that is, without forethought about the appropriateness or consequences of the action. A certain degree of impulsivity is common in children and even some young adults often display impulsivity of behavior. Only when present to excess and accompanied by problems with normal function is impulsivity considered abnormal in young children. Impulsivity can be manifested in an action or in interrupting a discussion, blurting out answers, or the inability to wait one's turn at an activity. Impulsivity is often observed in those who suffer from attention deficit hyperactivity disorder (ADHD), which can affect adults as well as children and teens. Impulsivity is often accompanied by symptoms such as restlessness, hyperactivity, inattention, problems doing quiet activities, problems with executive function, talking excessively, and fidgeting. Impulsivity can, less commonly, be related to medical problems that interfere with an individual's cognitive function, such as stroke or dementia.