Signs, Symptoms, & Causes of ADHD

The first step to getting help is recognizing the problem. If you’re concerned your child or teenager may be suffering from ADHD, learn more about the signs and symptoms to watch for.

Understanding ADHD

Learn about ADHD

Attention-deficit/hyperactivity disorder (ADHD) is an ongoing pattern of inattention and/or hyperactivity and impulsivity that interferes with daily functioning or development that begins in childhood with at least several symptoms appearing before age 12. While this disorder is characterized by hyperactivity, impulsivity, and inattention, not all those who have ADHD have symptoms in all three categories. There are three subtypes of ADHD based upon the presenting symptoms: predominately inattentive, predominately hyperactive and impulsive, and combined. While once believed to be a disorder outgrown by adulthood, recent studies suggest that children who have ADHD will continue to have symptoms throughout life that lead to challenges in both social and occupational functioning. Several of the behaviors seen in children who have ADHD may persist into the teen and adult years, however these symptoms are often subtle due to the more mature coping mechanisms and need to adapt to the expected behaviors demanded by society at increasing ages. While ADHD can cause significant disruption for children and teens with this common disorder, with suitable therapeutic interventions, lifestyle changes, and medications, most cases can be properly managed.


ADHD statistics

In the United States, research indicates that 8% to 10% of children meet the diagnostic criteria for ADHD, making it one of the most common disorders of childhood. ADHD occurs two to four times more often in boys, male to female ration is 4:1 for the predominately hyperactive subtype and 2:1 for the predominately inattentive subtype. Some researchers into the subject believe that about 60% to 80% of ADHD-hyperactive children will have (generally non-hyperactive) symptoms that persist into adolescence and adulthood.

Causes and Risk Factors

Causes and risk factors for ADHD in children and teens

While the precise cause for ADHD is not clear, researchers continue to study the reasons in which a child or teen may develop the disorder. It’s widely believed that ADHD is caused by multiple genetic, environmental, and physical risk factors working together. The most commonly cited causes and risk factors for ADHD include:

Genetic: While the exact genes responsible for ADHD have yet to be identified, it is clear that ADHD has a familial component. Children and teens who have a close relative with the disorder are at greater risk for developing the disorder than others without a similar family history. However, many children and teens without a family history do go on to develop the disorder.

Physical: Functional imaging of the brain (CT scans and MRIs) have suggested that there are differences in the brains of those affected by ADHD. In addition, differences in the chemistry of neurotransmitters involved in impulse control, judgment, planning, alertness, and mental flexibility have been demonstrated in affected individuals.

Environmental: Exposure to certain environmental toxins including lead found in the paint and pipes of older buildings may lead to the development of ADHD. Additionally very low birthweight (less than 1,500 grams) increases the risk for the disorder.

Risk Factors:

  • Temperamental differences such as reduced behavioral inhibition, effortful control or constraint, negative emotionality, and/or novelty-seeking
  • Maternal smoking
  • History of child abuse including neglect
  • Multiple foster placements
  • Prenatal neurotoxin exposure
  • Being male

Signs and Symptoms

Signs and symptoms of ADHD in children and teens

ADHD includes a number of problems that can impact virtually every area of a child or teen’s life and causes problems at work, in school, at home, and with friends. While no two children or teens will have the same symptomatology, the most common classes of symptoms follow and must be present for six or more months to a degree inconsistent with developmental level:

Inattentive symptoms: These symptoms are often observed between ages 8 and 9 and may persist throughout adulthood.

  • Easily distracted
  • Fails to finish tasks, chores, or schoolwork
  • Does not appear to be listening while someone is speaking
  • Has challenges sustaining attention in tasks or during play activities
  • Does not pay attention to details, as a result, makes careless mistakes in schoolwork or other activities
  • Forgetfulness about daily activities
  • Problems organizing tasks and activities
  • Avoids or dislikes activities that require sitting still
  • Attempts to avoid or dislikes activities that require sustained mental effort
  • Often loses things that are needed for tasks or activities
  • Tendency toward daydreaming
  • Hyperfocus – intense focus upon certain activities (in adolescents and teens)

Hyperactivity symptoms: These symptoms of excessive motor activity are often noted by age 5 and peak in severity between the ages of 7 and 8. Often with maturation, these symptoms have been “outgrown” by adolescence.

  • Often fidgets with his hands or feet or squirms in his or her chair
  • Often leaves his or her seat in the classroom during situations in which staying seated is expected
  • Often has challenges in playing or engaging in leisure activities quietly
  • Often runs around or climbs excessively in inappropriate situations

Impulsivity symptoms: These symptoms are often linked to hyperactivity and generally peak between ages 7 and 8 and often remain throughout adulthood.

  • Often blurts out answers before questions have been completed
  • Has challenges waiting his or her turn
  • Often interrupts or intrudes on others
  • High-risk behaviors (in adolescents and teens)
  • Financial mismanagement such as shopping sprees (in adolescents and teens)

Other symptoms:

  • Irritability and/or extreme changes in mood
  • Poor self-image
  • Lack of motivation, procrastination, poor organizational skills (in adolescents and teens)
  • Chronic boredom (in teens and adolescents)
  • Interpersonal relationship problems; difficulties making friends
  • Substance abuse or addiction (in teens and adolescents)
  • Employment problems (in teens and adolescents)
  • Chronic tardiness and lateness


Effects of ADHD in children and teens

Left untreated, ADHD can cause lasting problems in the life of a child or teen. Long-term complications will vary based upon severity of symptoms and presence of co-occurring disorders. Common effects of untreated ADHD may include:

  • Delinquent behaviors
  • Academic failure and subsequent judgment from peers and adults
  • Increased risks for accidents and injuries
  • Lifelong struggles with self-esteem
  • Problems being accepted by peers and adults

Co-Occurring Disorders

ADHD and co-occurring disorders

While ADHD does not cause other development or psychological conditions, children and teens who have ADHD are more likely than others to have comorbid, co-occurring disorders, including:

  • Anxiety disorders
  • Learning disabilities
  • Disruptive behavior disorders
  • Depression
  • Bipolar disorder
  • Oppositional defiant disorder (ODD)
  • Conduct disorder
  • Tourette syndrome
  • Autism spectrum disorder
  • Tic disorders
  • Obsessive-compulsive disorder (OCD)