The main features of attention deficit hyperactivity disorder (or ADHD) are inattention, hyperactivity, and/or impulsivity. But because most young children and even teenagers may display these behaviors from time to time, it is important not to assume that every child or teen you see with these symptoms has ADHD.

Symptoms of attention hyperactivity deficit disorder usually develop over several months. In general, impulsiveness and hyperactivity are observed before one notices the lack of attention, which often appears later.

It also may go unnoticed because the “inattentive daydreamer” may be overlooked when the person who “can’t sit still” at school or work or is otherwise disruptive will be noticed first. The observable symptoms of ADHD will therefore vary a great deal depending on the situation and the specific demands it makes on an individual’s self-control.

Different forms of ADHD may result in a person being labeled differently — especially in children. For example, an impulsive child may be labeled a “discipline problem.” A passive child may be described as “unmotivated.” But ADHD could be the cause of both behavior patterns. It may only be suspected once the child’s hyperactivity, distractibility, lack of concentration, or impulsivity start affecting school performance, friendships, or behavior at home.

There are three subtypes of ADHD generally recognized by professionals, now called “presentations” in the DSM-5:

  • Predominantly Hyperactive-Impulsive Presentation — If symptoms of hyperactivity-impulsivity but not symptoms of inattention have been shown for at least 6 months.
  • Predominantly Inattentive Presentation — If symptoms of inattention but not symptoms of hyperactivity-impulsivity have been shown for at least 6 months.
  • Combined Presentation — If symptoms of both inattention and hyperactivity-impulsivity have been shown for at least 6 months.

A person must have symptoms of ADHD present before age 12 in order to be diagnosed.

There must also be evidence that the ADHD behaviors are present in two or more settings — e.g., at home and at school; with friends and family; and in other activities. Someone who can pay attention at school but is inattentive only at home usually wouldn’t qualify for a diagnosis of ADHD.

Hyperactive/Impulsive Type of ADHD

A person who is hyperactive always seem to be “on the go” or constantly in motion. The person may dash around touching or playing with whatever is in sight, or talk incessantly. Sitting still at dinner or during a class at school can be nearly impossible. They squirm and fidget in their seats or roam around the room. Or they may wiggle their feet, touch everything, or noisily tap their pencil.

Hyperactive teenagers may also feel internally restless. They often feel the need to stay busy and may try to do several things at once.

People who are impulsive seem unable to control their immediate reactions or think before they act. They will often blurt out inappropriate comments, show their emotions without restraint, and act without considering the consequences. They may find it hard to wait for things they want, or to take their turn in games. They may grab a toy from another child or hit or even act out when upset.

As teenagers, impulsive people may choose to do things that have an instant reward instead of seeing through activities which take more effort but would lead to greater but delayed rewards.

Specific diagnostic symptoms of hyperactivity-impulsivity are:

  • Often fidgets with or taps hands or feet, or squirms in seat.
  • Often leaves seat in situations when remaining seated is expected (e.g., leaving seat in classroom or in their workplace)
  • Running or climbing in situations where it is inappropriate
  • Blurting out answers before hearing the whole question
  • Talking excessively
  • Interrupting or intruding on others
  • Having difficulty waiting in line or taking turns
  • Unable to play or engage in leisure activities quietly
  • Feeling very restless, as if “driven by a motor”, and talk excessively.

A child or teen must meet 6 or more of the above symptoms for at least 6 months to qualify for this component of the ADHD diagnosis. As with all diagnoses, these behaviors must also have a direct, negative impact on the person’s social and academic functioning.

Inattentive Type of ADHD

A person diagnosed with the Predominantly Inattentive type of ADHD have trouble focusing on any one thing and may get bored with a task after only a few minutes. However, if they are doing something they really enjoy, they usually have no trouble paying attention. But focusing deliberate, conscious attention to organizing and completing a task or learning something new is difficult.

Homework is particularly hard. They will forget to write down an assignment, or leave it at school. They will forget to bring a book home, or bring home the wrong one. The homework, when finally finished, will be full of mistakes. It is often accompanied by frustration for the child and their parents.

Inattentive people are rarely impulsive or hyperactive, but have a significant problem paying attention. They often appear to be daydreaming, “spacey,” easily confused, slow moving, and lethargic. They may process information more slowly and less accurately than others. A child with inattention has a hard time understanding what he or she is supposed to do when a teacher gives oral or even written instructions. Mistakes are frequent. The person may sit quietly and appear to be working, but in reality is not fully attending to or understanding the task and the instructions.

People with this form of ADHD often get along better with others than the more impulsive and hyperactive forms, as they may not have the same sorts of social problems common with the other forms of ADHD. Because of this, the problems with inattention are often overlooked.

Diagnostic symptoms of inattention are:

  • Not giving close attention to details or making careless mistakes in schoolwork, work, or other activities
  • Often has difficulty sustaining attention in tasks or play activities
  • Often does not seem to listen when spoken to directly
  • Often has trouble organizing tasks and activities, often skipping from one uncompleted activity to another (e.g., fails to meet deadlines; messy, disorganized work; difficulty keeping organized)
  • Becomes easily distracted by irrelevant stimuli, like sights and sounds (or unrelated thoughts)
  • Fails to pay attention to instructions and makes careless mistakes, not finishing work, chores, or duties
  • Loses or forgets things needed for a task, like pencils, books, assignments, or tools
  • Avoids, dislikes, or is reluctant to engage in things that take a lot of mental effort for a long period of time
  • Is often forgetful in daily activities (e.g., doing chores, running errands; returning calls, paying bills; keeping appointments)

A child or teen must meet 6 or more of the above symptoms for at least 6 months to qualify for this component of the ADHD diagnosis. As with all diagnoses, these behaviors must also have a direct, negative impact on the person’s social and academic functioning.

Combined Type of ADHD

A person exhibiting hyperactivity, impulsivity, and inattention are considered to have the Combined Presentation of ADHD, which combines all of the above symptoms.