Attention Deficit Hyperactivity Disorder (ADHD) Part 1 [Diagnosis, Prevalence, and Neurobiology]

ADHD is one of the most common neurodevelopmental disorders of childhood. It is usually first diagnosed in childhood and often lasts into adulthood. Children with ADHD may have trouble paying attention, controlling impulsive behaviors (may act without thinking about what the result will be), or be overly active.

Signs and Symptoms It is normal for children to have trouble focusing and behaving at one time or another. However, children with ADHD do not just grow out of these behaviors. The symptoms continue, can be severe, and can cause difficulty at school, at home, or with friends.

A child with ADHD might:

daydream a lot
forget or lose things a lot
squirm or fidget
talk too much
make careless mistakes or take unnecessary risks
have a hard time resisting temptation
have trouble taking turns
have difficulty getting along with others

Types
There are three different ways ADHD presents itself, depending on which types of symptoms are strongest in the individual:

1. Predominantly Inattentive Presentation: It is hard for the individual to organize or finish a task, to pay attention to details, or to follow instructions or conversations. The person is easily distracted or forgets details of daily routines.

2. Predominantly HyperactiveImpulsive Presentation: The person fidgets and talks a lot. It is hard to sit still for long (e.g., for a meal or while doing homework). Smaller children may run, jump or climb constantly. The individual feels restless and has trouble with impulsivity. Someone who is impulsive may interrupt others a lot, grab things from people, or speak at inappropriate times. It is hard for the person to wait their turn or listen to directions. A person with impulsiveness may have more accidents and injuries than others.

3. Combined Presentation: Symptoms of the above two types are equally present in the person.
Because symptoms can change over time, the presentation may change over time as well.

Causes of ADHD

Scientists are studying cause(s) and risk factors in an effort to find better ways to manage and reduce the chances of a person having ADHD. The cause(s) and risk factors for ADHD are unknown, but current research shows that genetics plays an important role. Recent studies link genetic factors with ADHD.1

In addition to genetics, scientists are studying other possible causes and risk factors including:

Brain injury
Exposure to environmental risks (e.g., lead) during pregnancy or at a young age
Alcohol and tobacco use during pregnancy
Premature delivery
Low birth weight

Research does not support the popularly held views that ADHD is caused by eating too much sugar, watching too much television, parenting, or social and environmental factors such as poverty or family chaos. Of course, many things, including these, might make symptoms worse, especially in certain people. But the evidence is not strong enough to conclude that they are the main causes of ADHD.

Diagnosis of ADHD as per DSM V

Typically, ADHD symptoms arise in early childhood. According to the DSM5, several symptoms are required to be present before the age of 12. Many parents report excessive motor activity during the toddler years, but ADHD symptoms can be hard to distinguish from the impulsivity, inattentiveness and active behavior that is typical for kids under the age of four. In making the diagnosis, children should have six or more symptoms of the disorder present; adolescents 17 and older and adults should have at least five of the symptoms present. The DSM5 lists three presentations of ADHD—Predominantly Inattentive, HyperactiveImpulsive and Combined.

1. ADHD predominantly inattentive presentation

Fails to give close attention to details or makes careless mistakes
Has difficulty sustaining attention
Does not appear to listen
Struggles to follow through with instructions
Has difficulty with organization
Avoids or dislikes tasks requiring sustained mental effort
Loses things
Is easily distracted
Is forgetful in daily activities



2. ADHD predominantly hyperactiveimpulsive presentation

Fidgets with hands or feet or squirms in chair
Has difficulty remaining seated
Runs about or climbs excessively in children; extreme restlessness in adults
Difficulty engaging in activities quietly
Acts as if driven by a motor; adults will often feel inside as if they are driven by a motor
Talks excessively
Blurts out answers before questions have been completed
Difficulty waiting or taking turns
Interrupts or intrudes upon others

ADHD combined presentation

The individual meets the criteria for both inattention and hyperactiveimpulsive ADHD presentations.