Which condition characterized by inattention and hyperactivity is diagnosed in children?

The condition characterized by inattention and hyperactivity that is diagnosed in children is Attention Deficit Hyperactivity Disorder (ADHD). ADHD is recognized as a neurodevelopmental disorder that affects a child's ability to focus, control impulses, and manage their activity levels. Children with ADHD typically experience challenges in maintaining attention on tasks, may appear restless, and often act without fully considering the consequences of their actions.

This condition is diagnosed based on specific behavioral criteria that highlight patterns of inattention and hyperactivity-impulsivity that are inconsistent with the developmental level of the child. The diagnosis is crucial because it allows for targeted interventions and support, which can help children manage their symptoms and improve their functioning at home, in school, and in social situations.

In contrast, Autism Spectrum Disorder involves a different set of symptoms primarily affecting communication and social interaction. Narcissistic Personality Disorder is a condition that pertains to adult personality traits and is not diagnosed in children. Oppositional Defiant Disorder involves patterns of angry, irritable mood, argumentative behavior, or vindictiveness but does not specifically center on hyperactivity and inattention as in ADHD. Thus, ADHD stands out as the correct answer due to its direct association with the symptoms outlined in the question.