Attention deficit hyperactivity disorder (ADHD ) is a condition that affects behavior or development in children. The subtypes of ADHD include combined , inattentive , and hyperactive/impulsive.

The exact cause of ADHD is not clear, but many factors may increase the risk of developing  ADHD including gender, genetics, environmental factors, substance abuse during pregnancy, and neurophysiology.

The exact pathophysiology of attention deficit hyperactivity disorder (ADHD) is still unclear. Abnormalities in the functioning of neurotransmitters, brain structure and cognitive function are suggested mechanisms that promote ADHD.

In children with ADHD, each type has its own distinctive symptoms such as short attention span and being easily distracted for the inattentive type. The hyperactive/impulsive shows symptoms such as being unable to sit still, being unable to concentrate on tasks , little or no sense of danger, and being unable to wait their turn.

Diagnosis for ADHD includes physical exam, information gathering, and ADHD rating scales .

The standard treatments for ADHD are medications such as amphetamines and methylphenidates, behavior therapy such as psychotherapy and parenting skills training, and alternative medicine such as special diets. These treatments may relieve many of ADHD symptoms.

If untreated, ADHD may lead to several complications such as struggling in the classroom,  more tendency for accidents and injuries than other children, learning disabilities , anxiety disorders , depression , and disruptive mood dysregulation disorder.

Avoiding anything that could harm fetal development during pregnancy, protecting child from exposure to pollutants and toxins, and avoiding children of excessive exposure to TV and video games in the first five years of child life may prevent ADHD.

However, some may find adaptive ways to cope with ADHD as they mature, children with the disorder seldom outgrow it. Early treatment does help reduce the long-term impact of ADHD.

According to a published review in the, Pediatrics journal, 7.2% of children with ADHD in ages 18 and under, from a meta-analysis of 175 research studies worldwide.

Attention deficit hyperactivity disorder in children (ADHD), is one of the most common neurodevelopmental disorders of childhood that is diagnosed in childhood and persists into adulthood.

There are three types of ADHD including:

• ADHD combined type

 This is the most common type of ADHD where children have trouble concentrating, are fidgety or restless, and are always hyperactive. Acting without thinking often happens in this type. (2,3)

• ADHD inattentive type or attention deficit disorder (ADD)

 This type is accompanied by concentration problems, remembering instructions, paying attention and finishing tasks. However, impulsivity or hyperactivity are not normal in this type, which is sometimes known as attention-deficit disorder (ADD). 

• ADHD hyperactive/impulsive type

 Hyperactivity, an urge of constant moving and impulse control difficulties are seen in this type.

The exact cause of ADHD is unknown but there are many factors that may increase the risk of developing  ADHD. 

Risk factors that may be involved in the development of ADHD include:

• Gender

Attention deficit hyperactivity disorder is more common in males than females. The combined type of ADHD is predominant in males, whereas the inattentive type is in females. 

•             Genetics

Attention deficit hyperactivity disorder can run in families, so genetics may play a role of increasing the risk of developing ADHD. 

•             Environmental factors

Certain environmental factors may increase the risk of ADHD, such as the exposure to lead or pesticides during pregnancy or at a young age. 

•             Substance abuse during pregnancy

Women using substances such as nicotine, cocaine, and alcohol during pregnancy may increase the risk of developing ADHD in the baby.

•             Neurophysiology

Electrical activity and metabolism , in addition to  altered brain structure or function and

improper central nervous system development may increase risk of development of ADHD. 

•             Adverse childhood experiences

Inattention and hyperactivity could go back to several reasons such as the lack of early attachment for the baby with their parent or caregiver, or when the baby has traumatic experiences related to the attachment .

•             Birth problems.

Birth problems such as premature delivery and low birth weight may increase the risk of developing  ADHD. 

• Dietary factors

Although dietary factors as risk factors are not well established, several  factors may increase the risk of developing  ADHD such as sensitivities to certain food chemicals, deficiencies in fatty acids and zinc, and sensitivity to sugar. 

Although the exact pathophysiology of (ADHD) is not clear, abnormalities such as functioning of neurotransmitters, brain structure and cognitive function have been suggested to be in relation with ADHD. 

• Neurotransmitters

Dopamine and noradrenaline could play a major role in the pathophysiology of ADHD since certain drugs such as psychostimulants and noradrenergic tricyclics have proved to be very effective in treating ADHD.  These drugs are able to minimize symptoms by aiding the release and function of dopamine or noradrenaline neurotransmitters. Therefore, deficient neural transmission could be related to symptoms and pathophysiology of ADHD.

• Brain Structure

Structural areas of the brain such as the frontal and prefrontal regions, parietal lobe, and cerebellum have been linked to ADHD. Altered activation of the brain when certain activities are being done have been recorded by magnetic resonance imaging (MRI) in children with ADHD.

Children with ADHD can be associated with deformations of the basal ganglia nuclei which is a  group of subcortical nuclei .These deformations may be decreased by the efficiency of stimulant drugs in treating ADHD . Moreover, further research has shown a slower rate of cortical thinning in the brain, most present in the prefrontal regions of the brain, for more hyperactive or impulsive children. 

• Cognitive function

Neurophysiological deficits and abnormalities in the cognitive function are associated with ADHD. Such deficits can be usually seen in the resting brain. This results in  difficulties  regulating and maintaining attention in people affected. 

Cognitive function abnormalities may be observed in patients with ADHD leading to symptoms specific to  ADHD. This is manifested in symptoms such as reaction times that are slow or variable during a task and  an increased number of errors. 

Symptoms can be detected as early as 3 years old with a range from mild to severe and with a possible continuation into adulthood. Signs and symptoms for the types of ADHD include:

Inattentive type  

• Having a short attention span and being easily distracted.
• Making careless mistakes.
• Appearing forgetful or losing things.
• Being unable to stick to tasks that are tedious or time-consuming.
• Appearing to be unable to listen to or carry out instructions.
• Constantly changing activity or task.
• Having difficulty organizing tasks.

Hyperactive/impulsive type

• Constantly fidgeting and squirming with inability of sitting still.
• Being unable to concentrate on tasks. 
• Excessive physical movement and talking.
• Being unable to wait their turn.
• Acting without thinking and interrupting or introducing conversation or other activities of other people.
• Little or no sense of danger.
• May have a quick temper. 
• Guesses, rather than taking time to solve a problem or blurts out answers in class.

Such symptoms significantly affect a child’s life such as underachievement at school, poor social interaction with other children and adults, and discipline problems.

No single test can confirm the diagnosis. ADHD may diagnosed by these ways :  

• Physical exam

Physical examination in this case helps rule out other possible causes for symptoms.

• Information gathering

Information gathering such as any current medical issues, personal and family medical history, and school records, in addition to interviews and filling out questionnaires by family members, child's teachers or other people who know the child well.

• ADHD criteria from the Diagnostic and Statistical Manual of Mental Disorders

This book is published by the American Psychiatric Association and helps in diagnosis.

• ADHD rating scales

ADHD rating scales to help collect and evaluate information about the child.

Combining medication, education, training and psychological counseling is often the most effective treatment of ADHD for relieving symptoms despite the fact that they do not cure ADHD. 

Treatment for ADHD in children includes:

• Medication

Types of medications used to treat ADHD include:

• Stimulant medications

Stimulant medications appear to boost and balance levels of brain chemicals called neurotransmitters, such as products that include methylphenidate or amphetamine. They could also improve signs and symptoms of inattention and hyperactivity in an efficient way and within a short time.

• Other medications

These are used when stimulants can’t be used , cause severe side effects, or a history  of substance abuse is present. Medications that are used to treat ADHD include the nonstimulant atomoxetine and certain antidepressants such as tricyclics, and  bupropion, which work slower than stimulants do. 

• ADHD behavior therapy

Behavior therapy can benefit children with ADHD, there are many examples of therapy, including:

• Behavior therapy

Learning behavior-changing strategies, such as token reward systems and timeouts, for dealing with difficult situations. 

• Psychotherapy

Allowing older children with ADHD to talk about troublesome issues, exploring negative behavioral patterns and learning ways to deal with their symptoms.

• Parenting skills training

This involves helping parents understand and guide their child's behavior.

• Family therapy

This teaches parents and siblings coping with the stress of living with someone who has ADHD.

• Social skills training.

Social skills training can help children learn appropriate social behaviors. 

• Alternative medicine

Consulting a doctor is advised before taking any of these alternative medicine treatments  into consideration. These treatments have been tried, but are not yet fully proved scientifically including:

• Special diets

Studies have not found a consistent link between diet and improved symptoms of ADHD, though some anecdotal evidence suggests diet changes might make a difference. The majority of diets suggested for ADHD involve eliminating foods thought to increase hyperactivity, such as sugar, and common allergens such as wheat, milk and eggs. 

• Vitamin or mineral supplements

There is no evidence that supplemental vitamins or minerals can reduce symptoms of ADHD. Certain vitamins and minerals from foods are necessary for good health. 

• Essential fatty acids

Fatty acids, which include omega-3 oils, are necessary for proper functioning of the brain. It is still debated whether these may improve ADHD symptoms.

• Neurofeedback training

Neurofeedback training used to focus on certain tasks while using a machine that shows brain wave patterns and also called as electroencephalographic (EEG) biofeedback. More research is needed to see if this is efficient.

• Exercise

Regular exercise may have a positive effect on behavior in children with ADHD , when added to treatment. 

Children with attention deficit hyperactivity disorder do not have an easy life. Complications of Children with ADHD including:

• Classroom struggles that are reflected as academic failure and judgment by other children and adults.
• Accidents and injuries of all kinds have higher incidences in children with ADHD than in children who do not.
• Tending to have poor self-esteem.
• Interacting with and acceptance by peers and adults problems.
• Alcohol and drug abuse and other criminal behavior are higher in children with ADHD. 

Although ADHD is not responsible for causing other conditions, the following are more likely to occur in children with ADHD:

• Learning disabilities.
• Anxiety disorders.
• Depression.
• Disruptive mood dysregulation disorder.
• Oppositional defiant disorder (ODD)
• Conduct disorder.
• Bipolar disorder.
• Tourette syndrome, a neurological disorder .

Several ways to reduce risk of development of ADHD include: 

• Avoiding anything that could harm fetal development during pregnancy, such as abstaining from alcohol, or smoking cigarettes.
• Exposure to pollutants and toxins, including cigarette smoking and lead paint, should be avoided with children.
• Avoiding excessive exposure to TV and video games in the first five years of a child’s life. 

There is no treatment for ADHD and only rare cases have gone away with age. Adapting to the condition with age is helpful for some people.

Children with attention deficit hyperactivity disorder are up to 100 times more likely to be excluded from school, without treatment. Children with ADHD are likely to face adult problems such as unemployment, relationship difficulties, substance misuse and involvement in crime.

Early treatment does help reduce the long-term impact of ADHD.

According to published review in the American journal, Pediatrics, 7.2% of children with ADHD in aged 18 and under, from a meta-analysis of 175 research studies worldwide. Thus, 7.2% of this total population is 129 million—a rough estimate of the number of children worldwide who have ADHD.