Attention-Deficit / Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized as a persistent pattern of inattention and/or hyperactivity-impulsivity, affecting individuals throughout their lifetime.1

ADHD is a complex, heterogeneous disorder affecting individuals over the course of their lifetime.1 Symptoms of ADHD begin before age 12 and interfere with functioning or development.


ADHD affects approximately 11% of school-aged children in the U.S., based on the 2011 National Survey of Children’s Health, in which parents were asked if a healthcare practitioner had ever told them their child had ADD or ADHD.2

The estimated prevalence of adult ADHD in the U.S. is 4.4%.3 This is based on results from semi-structured clinical interviews conducted in 3,199 respondents aged 18-44 in the National Comorbidity Survey Replication (from 2001 to 2003).

Estimates of the prevalence of ADHD vary due to different research methodologies, varying age groups in epidemiological studies, and changes in the diagnostic criteria over time.4

Screening and Diagnosis

The American Academy of Child and Adolescent Psychiatry recommends that screening for ADHD should be a part of every patient’s mental health assessment, and the American Academy of Pediatrics recommends initiating an evaluation for ADHD in school-aged children who present with academic or behavioral problems and symptoms of inattention and/or hyperactivity-impulsivity.4,5

For a diagnosis of ADHD, individuals must meet the DSM-5 criteria.1 According to the DSM-5, an individual must show at least 6 symptoms of inattention and/or at least 6 symptoms of hyperactivity-impulsivity that must have persisted for at least 6 months to a degree that is inconsistent with the developmental level and negatively impacts social, academic, and/or occupational activities. In individuals 17 years or older, at least 5 symptoms of inattention and/or at least 5 symptoms of hyperactivity-impulsivity must be present.

DSM-5 Symptoms of Inattention
Symptoms must occur often
DSM-5 Symptoms of Hyperactivity and Impulsivity
Symptoms must occur often
Fails to give close attention to detail, or makes careless mistakesFidgets, squirms, or taps hands or feet
Has difficulty sustaining attention in tasks or playLeaves seat when sitting is expected
Does not seem to listen when spoken to directlyRuns around or climbs when it is not appropriate
Does not follow through on instructions and fails to finish chores, homework, or work dutiesUnable to play or engage in leisure activities quietly
Shows difficulty in organizing tasksActs “as if driven by a motor” / is "on the go"
Avoids, dislikes, or is reluctant to engage in activities that require sustained mental effortTalks excessively
Loses things needed for tasks or activitiesAnswers questions before the question is fully asked
Is easily distractedHas difficulty waiting for a turn or waiting in lines
Is forgetful in daily activitiesInterrupts or intrudes on others

Additionally, to meet the DSM-5 diagnostic criteria, several of the symptoms must have been present prior to age 12, must be present in two or more settings, must have clear evidence that they interfere with, or reduce the quality of, social, academic or occupational functioning, and must not occur exclusively within the course of schizophrenia or another psychiatric disorder.1

These are not the complete diagnostic criteria.

Diagnosis should be based on a complete history and evaluation of the patient.


While its exact cause is unknown, ADHD is thought to be the result of interactions between genetics, neurobiology, and the environment.6,7

The idea that an individual’s unique mix of genetic and environmental pressures influences disease pathology has given rise to a theory that an individual will manifest signs and symptoms of ADHD if and when their cumulative vulnerability exceeds a certain threshold.7 Based on numerous studies of twins, the mean heritability of ADHD has been estimated to be 77%, suggesting it to be among the most heritable of psychiatric disorders.6

Perinatal factors such as preterm birth, smoking and alcohol exposure during pregnancy, and low birth weight have been proposed as risk factors for ADHD.8,9 While the neurobiology of ADHD is not completely understood, it is thought that neurotransmitter dysfunction and dysregulation of various regions in the prefrontal cortex, as well as other areas of the brain, may be associated with symptoms of ADHD.10,11

Navigating ADHD

As there is no cure for ADHD, the primary goal of ADHD management is to help address the core symptoms of inattention and/or hyperactivity-impulsivity.4

Each treatment plan should be individualized, comprehensive, and multimodal, taking into account available pharmacological and non-pharmacological therapies, education, and patient support resources.5 Periodic reassessments should be performed in order to monitor or assess the efficacy and safety of the treatment plan. Evaluation and management of ADHD should continue as long as symptoms are present and cause impairment of daily activities.