Attention-deficit hyperactivity disorder overview

# Overview
Attention-deficit hyperactivity disorder (ADHD) is a neurobehavioral brain disorder marked by an ongoing pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development. It may negatively impact the patients academic or professional performance and/or social interactions. ADHD has a strong component of heritability. ADHD is more commonly diagnosed in boys than in girls, though this may be because the symptoms of the disorder are less easily recognized in girls.

# Historical Perspective
- ADHD symptoms have been recognized in children and described in medical texts since the nineteenth century, though the formal diagnosis had not yet been devised.
- ADHD was first included in some form in the DSM in its second edition, when it was referred to as hyperkinetic reaction of childhood. It was not until the third edition of the DSM was released in 1980 that the disorder was formally identified as ADD (Attention-Deficit Disorder) with or without hyperactivity.
- In 1937, Rhode Island physician Dr. Charles Bradley pioneered the use of medications to treat ADHD. The prescription of stimulants has since become a first-line treatment for ADHD.

# Classification
ADHD may be classified according to the DSM V criteria into three subgroups:
- predominantly inattentive type;
- predominantly hyperactive-impulsive type; and
- combined type.

# Pathophysiology
- ADHD is highly heritable, although one-fifth of all cases are estimated to be caused by trauma or exposure to toxins.
- ADHD is a heterogeneous disorder, meaning that several causes could create very similar symptomology.
- Although there is evidence for dopamine abnormalities in ADHD, it is not clear whether abnormalities of the dopamine system are a molecular abnormality of ADHD or a secondary consequence of ADHD.

# Causes
There are no established causes of ADHD. Studies suggest that ADHD results from a complex interaction between genetic and environmental factors.

# Differentiating Attention Deficit Hyperactivity Disorder from other Diseases
- ADHD must be differentiated from other diseases that cause behavioral issues and anxiety such as anxiety disorder, dissociative disorder, conduct disorder, and oppositional defiant disorder.
- ADHD must also be differentiated from the other psychiatric disorders with which it shares common genetic roots, including autism, bipolar disorder, major depression, and schizophrenia.

# Epidemiology and Demographics
- The prevalence of attention-deficit hyperactivity disorder (ADHD) is estimated to be 5,000 per 100,000 (5%) children and 2,500 per 100,000 (2.5%) adults.
- Boys are more commonly affected by ADHD than girls. The male to female ratio is 2 to 1.

# Risk Factors
Common risk factors in the development of attention-deficit hyperactivity disorder (ADHD) are:
- child abuse
- infections of the CNS
- epilepsy
- traumatic brain injury

# Natural History, Complications and Prognosis
If left untreated, patients with ADHD may experience negative social consequences, such as isolation from and difficulty communicating with friends and loved ones. Patients are unlikely to experience any physical problems as a direct result of ADHD.

# Diagnosis
The diagnosis of ADHD is made based on the DSM V criteria, which can be found on the Attention-deficit hyperactivity disorder diagnostic criteria page.

## History and Symptoms
- The most common symptoms of ADHD include chronic and long-lasting hyperactivity, impulsivity, and inattention.
- It is particularly important to collect a family history with regard to psychiatric disorders, as ADHD has a strong genetic component.
- It is also vital to understand how long the patient has been experiencing symptoms of ADHD, as the DSM V stipulates that symptoms must have been present for at least 6 months in order for a diagnosis of ADHD to be made. Similarly, an adult cannot be diagnosed with ADHD unless his/her symptoms were present prior to the age of 12 years.

## Physical Examination
- A psychiatric evaluation of a patient who may be suffering from ADHD consists of a behavioral assessment.
- It is common practice for clinicians to administer rating scales to those who have frequent contact with the patient, often including parents and teachers. It is important that rating scales be completed by people who observe the patient in different settings, such as at home and at school, since ADHD symptoms can be situation-specific.
- Commonly used rating scales include the Vanderbilt Rating Scale, the Brown Rating Scale, and the Wender Utah Rating Scale.
- These rating scales are subjective, and informants regularly differ in their reports.

## Laboratory Findings
- There are no laboratory findings associated with ADHD.

## Electrocardiogram
- There are no ECG findings associated with ADHD.

## Chest X Ray
- There are no chest x-ray findings associated with ADHD.

## CT Scan
- There are no CT scan findings associated with ADHD.

## Electrocardiography or Ultrasound
- There are no echocardiography or ultrasound findings associated with ADHD.

## Other Imaging Findings
- Though the brains of ADHD patients follow a normal pattern of development, imaging findings indicative of ADHD may include delayed physical development of the brain. This may help explain why some adolescent ADHD patients do not experience symptoms into adulthood.

# Treatment
The mainstay of therapy for ADHD is the administration of such stimulants as Ritalin and Adderall. While there is no cure for ADHD, currently available treatments can help reduce symptoms and improve functioning. Other treatment options include psychotherapy, education and training, or a combination of therapies.

## Medical Therapy
- Stimulants such as Ritalin and Adderall are used to increase the patients supply of the brain chemicals dopamine and norepinephrine, which play essential roles in thinking and attention.
- Behavioral therapy aims to help a patient monitor and change his or her conduct.
- Support groups, stress management training, and education about living with psychiatric disorders are often recommended for both the patient and his or her loved ones and family members.

## Surgery
Surgical intervention is not recommended for the management of ADHD.

## Prevention
- There is no established method for the prevention of ADHD. Although there is no proven way to prevent ADHD, early identification and treatment can prevent many of the problems associated with ADHD.
- Secondary prevention strategies following a diagnosis of ADHD include the administration of stimulants, cognitive behavioral therapy, regular psychiatric evaluations, and the maintenance of a healthy diet.

## Psychotherapy
- Many psychological interventions can be used to manage symptoms of attention-deficit hyperactivity disorder.

## Brain Stimulation Therapy
- There is no brain stimulation therapy associated with attention-deficit hyperactivity disorder.