Attention-deficit/hyperactivity disorder (ADHD)



Attention deficit hyperactivity disorder (ADHD) is a disorder that affects behavior. It can cause hyperactive, impulsive behavior, and/or make it difficult to pay attention. These behavioral problems continue over a long period of time. ADHD can affect people of all ages. Though ADHD is present throughout the lifetime, it may not be diagnosed until adulthood.

There are 3 types of ADHD:

  • Inattentive (classic 'ADD')
  • Hyperactive-impulsive
  • Combined inattentive and hyperactive—the most common type


The cause of ADHD is unknown. It most likely is caused by a chemical imbalance in the brain. The change may happen while the brain is developing. Genes and environmental factors may both play a role.

Child's Brain
Child Brain
A chemical imbalance in the brain may be responsible for ADHD.
Copyright © Nucleus Medical Media, Inc.

Risk Factors

Factors that may increase your chances of ADHD:

  • Premature birth
  • Having a parent or sibling (especially an identical twin) with ADHD
  • Having a mother who smoked cigarettes and/or drank alcohol, had a urinary tract infection, or had preterm labor during pregnancy
  • Having a parent with certain conditions such as alcohol use disorder and conversion disorder
  • Head injury at a young age—less than 2 years old
  • Exposure to lead or certain pesticides

Parenting styles may influence the symptoms of ADHD but do not cause it.



These symptoms are common in all children at some point in childhood. Children with ADHD have symptoms that are more severe and occur more often. These children also often have difficulty in school and connecting with their family and peers.

ADHD can in adults can cause problems with relationships, job performance, and job retention. Symptoms can vary according to the type of ADHD:

  • Inattentive (classic 'ADD')
    • Easily distracted by sights and sounds
    • Does not pay attention to detail
    • Does not seem to listen when spoken to
    • Makes careless mistakes
    • Does not follow through on instructions or tasks
    • Avoids or dislikes activities that require longer periods of mental effort
    • Loses or forgets items necessary for tasks
    • Is forgetful in day-to-day activities
  • Hyperactive-Impulsive
    • Is restless, fidgets, and squirms
    • Runs and climbs, and is not able to stay seated
    • Blurts out answers before hearing the entire question
    • Has difficulty playing quietly
    • Talks excessively
    • Interrupts others
    • Has difficulty waiting in line or waiting for a turn
  • Combined ADHD—Combination of the symptoms above.

Certain mental health or behavior challenges are more common in those with ADHD. This may be because of changes in the brain or challenges because of ADHD symptoms. Common issues include:

  • Depression
  • Anxiety
  • Seizures
  • Conduct disorder —difficulty following social rules
  • Oppositional defiant disorder —negative, angry, and defiant behaviors
  • Learning and language disorders
  • Physical conditions such as sleep apnea
  • Trouble sleeping
  • Substance abuse
  • Cigarette use


There is no standard test to diagnose ADHD. It is done by a trained health professional who observes the patient and collects information from the patient, family, caregivers, and teachers.

During diagnosis, the following information may be gathered:

  • Behavior and symptoms of ADHD in different settings—home, recreation/sports, and school
  • Age at which symptoms started
  • How much the behavior affects the child's ability to function



The goal is to improve the child's ability to grow, learn, and develop relationships. Doctors should work together with parents and school staff. Together, they can set realistic goals and keep an eye on the child's response. Proper treatment can prevent problems later in life.

Treatments include:


Children who do not sleep enough may suffer from worse behavioral problems. A key part of treatment is to ensure that children with ADHD get plenty of sleep.


Medications can help control behavior and increase attention span. They are generally the first line of treatment for children aged 6 years and older, and adolescents. For preschool children who do not respond to behavior therapy, medications may be added to their treatment plan. Stimulants are the most common choice for ADHD. They increase activity in parts of the brain that appear to be less active in children with ADHD. Some of these medications have an increased risk of heart or psychiatric problems. The medical team will work to find medication with the most benefit and least risk for each child.

Other medications include:

  • Selective norepinephrine reuptake inhibitors—to promote attention and decrease impulsiveness and hyperactivity
  • Antidepressants—to manage depression symptoms
  • Antipsychotics—to treat aggressive behavior
  • Alpha-agonist hypotensive agents—to treat impulsivity

Behavior Therapy

Children who take medication and go to therapy do better than those who just use medication. Young children may respond to therapy alone. Therapy sessions focus on practicing social and problem-solving skills. Counselors will also teach parents and teachers techniques that may help help. This could involve changes in the classroom, as well as in parenting style. For example, an inflated cushion on a child's seat at school may help their attention span.

ADHD coaching can also be helpful. These coaches work with individuals to help them organize and create strategies for efficiency and success.

Neurofeedback is a treatment that has shown some promise but is still being studied. This treatment shows brain wave patterns with images on a screen. It gives people a visual cue when their attention starts to wander. Over several sessions, people can retrain their brain to use the good brain patterns and avoid patterns that result in inattention.


There are no current guidelines to prevent ADHD because the cause is unknown.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.

a (ADHD and ADD; Hyperkinetic Syndrome; Hyperkinetic Impulse Disorder)


Attention Deficit Disorder Association 

Children and Adults with Attention-Deficit/Hyperactivity Disorder 


About Kids Health—The Hospital for Sick Children 

Canadian Psychiatric Association 


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