Attention deficit hyperactivity disorder (ADHD) typically manifests in an inability for a child to consistently pay attention coupled with hyperactive and impulsive behavior. The first symptoms are likely to appear between the ages of four and six (sometimes as early as age three), although in many cases it is not apparent until the child begins school. Symptoms of hyperactivity and impulsiveness typically precede inattention by up to a year or more.

Hyperactive children may fidget excessively or squirm in their seats. They may run or climb a lot and have difficulty playing quietly. Excessive talking and interrupting of others also are typical signs of hyperactivity. Children who are impulsive may act before thinking or blurt out responses to questions before the questioner is finished. In games or any activity that requires turn-taking, they may have difficulty waiting their turn.

Inattention may become evident in careless mistakes and significant errors during schoolwork or an inability to listen closely or process directions. Children with ADHD frequently struggle to finish tasks and are often forgetful. They may not follow through on multiple steps in a task, such as forgetting a homework assignment and also forgetting the books needed for the assignment. Rather than appearing hyperactive, children who struggle predominantly with inattention may appear sluggish, passive and unmotivated. struggle to finish tasks and are often forgetful. Rather than appearing hyperactive, children who struggle predominantly with inattention may appear sluggish, passive and unmotivated.

A child with ADHD is unlikely to display all of the symptoms associated with the disorder. Gender may also play a role in which symptoms are exhibited. For example, boys are more likely to be hyperactive whereas girls are more likely to be inattentive. In regard to inattentiveness, girls are more likely to daydream whereas boys are more likely to play aimlessly.

Children with ADHD are often more sensitive to various sights, sounds and textures than those without the disorder. When a child with ADHD becomes overstimulated, they may lose control in a way that manifests as aggressive behavior or giddiness. Children with ADHD may have difficulty making friends and developing other meaningful relationships. This is at least partially because they have difficulty following rules and waiting their turn, and may talk excessively. These qualities may be off-putting to peers.

Many of the behaviors associated with ADHD are common in young children. They may indicate a child at a different developmental stage or another problem. For example, inattention can also be a symptom of a child with hearing or vision problems.

Children with ADHD are at much higher risk of academic difficulty than other children. Between 40 and 60 percent of children with ADHD have major learning difficulties, according to Mental Health America. Hyperactivity, poor organizational skills and difficulty paying attention may all contribute to this lack of school success.