INTRODUCTION:

Attention-Deficit Hyperactivity Disorder is generally considered to be a developmental disorder, largely neurological in nature, affecting about 5% of the world's population.^1,2The disorder typically presents itself during childhood, and is characterized by a persistent pattern of inattention and/or hyperactivity, as well as forgetfulness, poor impulse control or impulsivity, and distractibility.³ADHD is currently considered to be a persistent and chronic condition for which no medical cure is available. ADHD is most commonly diagnosed in children and, over the past decade, has been increasingly diagnosed in adults. About 60% of children diagnosed with ADHD retain the disorder as adults.⁴

CLASSIFICATION:

ADHD was first described by Dr. Heinrich Hoffman in 1845, a physician who wrote books on medicine and psychiatry. Since then, extensive research on the disorder has been done, providing information on its nature, course, causes, impairments, and treatments.

ADHD is a developmental disorder that is often said to be neurological in nature. The term "developmental" means that certain traits such as impulse control significantly lag in development when compared to the general population.

This developmental lag has been estimated to range between 30-40 percent in ADHD sufferers in comparison to their peers; consequently these delayed attributes are considered impairment. ADHD has also been classified as a behavior disorder and a neurological disorder or combinations of these classifications such as neurobehavioural or neurodevelopmental disorders. These compounded terms are now more frequently used in the field to describe the disorder. The behavioral classification for ADHD is not completely accurate in that those with Predominately Inattentive ADHD often display few or no overt behaviors.

SYMPTOMS:

The principal characteristics of ADHD are inattention, hyperactivity, and impulsivity. These symptoms appear early in a child’s life. Symptoms of ADHD will appear over the course of many months, often with the symptoms of impulsiveness and hyperactivity preceding those of inattention, which may not emerge for a year or more. Different symptoms may appear in different settings, depending on the demands the situation may pose for the child’s self-control. A child who “can’t sit still” or is otherwise disruptive will be noticeable in school, but the inattentive daydreamer may be overlooked. The impulsive child who acts before thinking may be considered just a “discipline problem,” while the child who is passive or sluggish may be viewed as merely unmotivated. Yet both may have different types of ADHD. All children are sometimes restless, sometimes act without thinking, sometimes daydream the time away. When the child’s hyperactivity, distractibility, poor concentration, or impulsivity begin to affect performance in school, social relationships with other children, or behavior at home, ADHD may be suspected. But because the symptoms vary so much across settings, ADHD is not easy to diagnose. This is especially true when inattentiveness is the primary symptom.

Based on these symptoms, three types of ADHD have been found⁵:

· Inattentive type, where the person can’t seem to get focused or stay focused on a task or activity;

· Hyperactive-impulsive type, where the person is very active and often acts without thinking; and

· Combined type, where the person is inattentive, impulsive, and too active.

Inattentive type: Many children with ADHD have problems paying attention. Children with the inattentive type of ADHD often:

· Do not pay close attention to details;

· Can’t stay focused on play or school work;

· Don’t follow through on instructions or finish school work or chores;

· Can’t seem to organize tasks and activities;

· Get distracted easily; and

· Lose things such as toys, school work, and books.

Hyperactive-impulsive type: Being too active is probably the most visible sign of ADHD. The hyperactive child is “always on the go.” (As he or she gets older, the level of activity may go down.) These children also act before thinking (called impulsivity). For example, they may run across the road without looking or climb to the top of very tall trees.

Hyperactivity and impulsivity tend to go together. Children with the hyperactive-impulsive type of ADHD often may:

· fidget and squirm;

· get out of their chairs when they’re not supposed to;

· run around or climb constantly;

· have trouble playing quietly;

· talk too much;

· blurt out answers before questions have been completed;

· have trouble waiting their turn;

· interrupt others when they’re talking; and

· butt in on the games others are playing.

Combined type: Children with the combined type of ADHD have symptoms of both of the types described above. They have problems with paying attention, with hyperactivity, and with controlling their impulses.
Of course, from time to time, all children are inattentive, impulsive, and too active. With children who have ADHD, these behaviors are the rule, not the exception.

These behaviors can cause a child to have real problems at home, at school, and with friends. As a result, many children with ADHD will feel anxious, unsure of themselves, and depressed. These feelings are not symptoms of ADHD. They come from having problems again and again at home and in school.

CAUSES:

There is little compelling evidence at this time that ADHD can arise purely from social factors or child-rearing methods. Most substantiated causes appear to fall in the realm of neurobiology and genetics⁶. This is not to say that environmental factors may not influence the severity of the disorder, and especially the degree of impairment and suffering the child may experience, but that such factors do not seem to give rise to the condition by themselves.

The exact cause of ADHD remains unknown and in all probability ADHD is a heterogeneous disorder, meaning that several causes could create very similar symptomology. Still, there is a wide body of evidence which indicates that the overriding cause of ADHD is genetics. Research suggests that a large majority of ADHD arises from a combination of various genes, many of which affect dopamine transporters.⁷ Suspect genes include the 10-repeat allele of the DAT1 gene, the 7-repeat allele of the DRD4 gene, and the dopamine beta hydroxylase gene (DBH TaqI). Additionally, Single Photon Emission Computed Tomography (SPECT) scans found people with ADHD to have reduced blood circulation,and a significantly higher concentration of dopamine transporters in the striatum which is in charge of planning ahead.

An early Positron Emission Tomography (PET) scan study found that global cerebral glucose metabolism was 8.1% lower in medication-naive adults who had been diagnosed as ADHD while children. Additionally, the regions with the greatest deficit of activity in the ADHD patients (relative to the controls) included the premotor cortex and the superior prefrontal cortex. A second study in adolescents failed to find statistically significant differences in global glucose metabolism between ADHD patients and controls, but did find statistically significant deficits in 6 specific regions of the brains of the ADHD patients (relative to the controls). Most notably, lower metabolic activity in one specific region of the left anterior frontal lobe was significantly inversely correlated with symptom severity.⁸ These findings strongly imply that lowered activity in specific regions of the brain, rather than a broad global deficit, is involved in ADHD symptoms. The estimated contribution of non genetic factors to the contribution of all cases of ADHD is 20 percent.⁹

Over the last few decades, scientists have come up with possible theories about what causes ADHD.

Genetics:

Attention disorders often run in families, so there are likely to be genetic influences. Studies indicate that 25 percent of the close relatives in the families of ADHD children also have ADHD, whereas the rate is about 5 percent in the general population.¹⁰Studies of twins suggest a genetic link to ADHD. In 80-90 per cent of identical twins where one has ADHD so does the other. Recent research also suggests there is a greater chance of inheriting the condition from male relatives such as grandfathers and uncles.

Environmental Agents:

Studies have shown a possible correlation between the use of cigarettes and alcohol during pregnancy and risk for ADHD in the offspring of that pregnancy. As a precaution, it is best during pregnancy to refrain from both cigarette and alcohol use.

Another environmental agent that may be associated with a higher risk of ADHD is high levels of lead in the bodies of young preschool children. Since lead is no longer allowed in paint and is usually found only in older buildings, exposure to toxic levels is not as prevalent as it once was. Children who live in old buildings in which lead still exists in the plumbing or in lead paint that has been painted over may be at risk.^11]

Brain Injury:

One early theory was that attention disorders were caused by brain injury. Some children who have suffered accidents leading to brain injury may show some signs of behavior similar to that of ADHD, but only a small percentage of children with ADHD have been found to have suffered a traumatic brain injury.

Despite the lack of evidence that nutrition causes ADHD, studies have found that malnutrition is correlated with attention deficits.¹²Recent studies indicate that culture and lifestyle may also count on the chances of children to develop ADHD.

Pathophysiology:

The pathology of ADHD is not clear. Findings indicating that psychostimulants (which facilitate dopamine release) and noradrenergic tricyclics treat this condition have led to speculation that certain brain areas related to attention are deficient in neural transmission. The neurotransmitters dopamine and norepinephrine have been associated with ADHD.

The underlying brain regions predominantly thought to be involved are frontal and prefrontal; the parietal lobe and cerebellum may also be involved. In one functional MRI study, children with ADHD who performed response-inhibition tasks were reported to have differing activation in frontal-striatal areas compared to healthy controls. Adults with ADHD also have been reported to have deficits in anterior cingulate activation while performing similar tasks.

Diagnosis:

When a child shows signs of ADHD, he or she needs to be evaluated by a trained professional. A complete evaluation is the only way to know for sure if the child has ADHD. It is also important to:

· Rule out other reasons for the child’s behavior, and

· Find out if the child has other disabilities along with ADHD.

Among possible causes of ADHD-like behavior are the following:

· A sudden change in the child’s life—the death of a parent or grandparent; parents’ divorce; a parent’s job loss

· Undetected seizures, such as in petit mal or temporal lobe seizures

· A middle ear infection that causes intermittent hearing problems

· Medical disorders that may affect brain functioning

· Underachievement caused by learning disability

· Anxiety or depression.

The American Academy of Pediatrics Clinical Practice Guideline for children with ADHD emphasizes that a reliable diagnosis is dependent upon the fulfillment of three criteria:

· The use of explicit criteria for the diagnosis using the DSM-IV (The American Psychiatric Association's Diagnostic and Statistical Manual, Vol. IV)

· The importance of obtaining information about the child’s symptoms in more than one setting.

· The search for coexisting conditions that may make the diagnosis more difficult or complicate treatment planning.

The first criterion can be satisfied by using an ADHD-specific instrument such as the Conners' Rating Scale.¹³ The second criterion is best fulfilled by examining the individual's history. This history can be obtained from parents and teachers, or a patient's memory.¹⁴ The requirement that symptoms be present in more than one setting is very important because the problem may not be with the child, but instead with teachers or parents who are too demanding. The use of intelligence testing, psychological testing, and neuropsychological testing (to satisfy the third criterion) is essential in order to find or rule out other factors that might be causing or complicating the problems experienced by the patient.¹⁵

Ideally, in ruling out other causes, the specialist checks the child’s school and medical records. Next the specialist gathers information on the child’s ongoing behavior which also involves talking with the child and, if possible, observing the child in class and other settings.

The child’s teachers, past and present, are asked to rate their observations of the child’s behavior on standardized evaluation forms, known as behavior rating scales, to compare the child’s behavior to that of other children the same age.

In looking at the results of these various sources of information, the specialist pays special attention to the child’s behavior during situations that are the most demanding of self-control, as well as noisy or unstructured situations such as parties, or during tasks that require sustained attention, like reading, working math problems, or playing a board game. Behavior during free play or while getting individual attention is given less importance in the evaluation. The specialist then takes into account the entire profile of the child and decides if the child is really suffering from ADHD.

TREATMENT:

Treatment of ADHD is done by multimodal therapy which includes medication management, behavioral treatment or a combination of both; or routine community care.¹⁶ Generally speaking, long-term combination treatments and the medication-management alone are superior to intensive behavioral treatment and routine community treatment. And in some areas—anxiety, academic performance, oppositionality, parent-child relations, and social skills—the combined treatment is usually superior. Another advantage of combined treatment is that children could be successfully treated with lower doses of medicine, compared with the medication-only group.

For children with ADHD, no single treatment is the answer for every child. A child may sometimes have undesirable side effects to a medication that would make that particular treatment unacceptable. And if a child with ADHD also has anxiety or depression, a treatment combining medication and behavioral therapy might be best. Each child’s needs and personal history must be carefully considered.

Medications:

The medications that seem to be the most effective are a class of drugs known as stimulants. Following is a list of the stimulants that are commonly used in ADHD. “Approved age” means that the drug has been tested and found safe and effective in children of that age.

The U.S. Food and Drug Administration (FDA) recently approved a medication for ADHD that is not a stimulant. The medication, Strattera®, or atomoxetine, works on the neurotransmitter norepinephrine, whereas the stimulants primarily work on dopamine. Both of theses neurotransmitters are believed to play a role in ADHD.¹⁷

Some people get better results from one medication, some from another. For many people, the stimulants dramatically reduce their hyperactivity and impulsivity and improve their ability to focus, work, and learn. The medications may also improve physical coordination, such as that needed in handwriting and in sports.

The stimulant drugs, when used with medical supervision, are usually considered quite safe. About one out of ten children is not helped by a stimulant medication. Other types of medication may be used if stimulants don’t work or if the ADHD occurs with another disorder. Antidepressants and other medications can help control accompanying depression or anxiety.

Sometimes the doctor may prescribe for a young child a medication that has been approved by the FDA for use in adults or older children. This use of the medication is called “off label.”

Side Effects of the Medications:

Most side effects of the stimulant medications are minor and are usually related to the dosage of the medication being taken. Higher doses produce more side effects. The most common side effects are decreased appetite, insomnia, increased anxiety, and/or irritability. Some children report mild stomach aches or headaches. A very few children cannot tolerate any stimulant, no matter how low the dosage. In such cases, the child is often given an antidepressant instead of the stimulant.

But medications don’t cure ADHD; they only control the symptoms on the day they are taken. Although the medications help the child pay better attention and complete school work, they can’t increase knowledge or improve academic skills. The medications help the child to use those skills he or she already possesses.

Behavioral therapy, emotional counseling, and practical support will help ADHD children cope with everyday problems and feel better about themselves.¹⁸

Behavioral Treatment for ADHD:

Despite the well documented benefits of stimulant medication for treating ADHD, medication is no panacea. An important non-medical approach used in treating children with ADHD is known as Behavior Therapy. It is based on several simple and sensible notions about what leads children to behave in socially appropriate ways. The goal of behavior therapy, therefore, is to increase the frequency of desirable behavior by increasing the child's interest in pleasing parents and by providing positive consequences when the child behaves. Inappropriate behavior is reduced by consistently providing negative consequences when such behavior occurs. While Behavioral treatment, one should take care of the following points:

· Be very clear about what behavior is expected of your child in order to earn the reward and make sure your child's understands this.

· Make sure that the expectation you have for your child is reasonable - do not set you and your child up for failure by having expectations that are not appropriate for your child's age.

· Don't try to work on too many different things at one time. It is generally better to focus on a couple of things that are really important rather than taking on everything at once.

· Let the child participate in choosing the types of rewards he or she can earn.

· Design the program in such a way that the child has a good chance to experience some initial success.

· Be sure to provide lots of social rewards (e.g. praise) in addition to the more tangible rewards that can be earned.

· Be consistent. Using the program one day but not the next, or failing to provide rewards when they are earned, is a sure fire way to keep this from being helpful.

In addition to using positive reinforcement to encourage good behavior, behavioral treatment also relies on negative consequences or punishment to reduce undesirable behavior. But one should try hard not to overdo the negative consequences. Children tend to get discouraged if they are used too frequently and can lose interest in the program as a result. Plan out, in advance, a graded series of punishments for persistent misbehavior. Virtually any type of behavior can be targeted using a behavioral treatment approach.

Psychotherapy:

Works to help people with ADHD to like and accept themselves despite their disorder. It does not address the symptoms or underlying causes of the disorder. In psychotherapy, patients talk with the therapist about upsetting thoughts and feelings, explore self-defeating patterns of behavior, and learn alternative ways to handle their emotions. As they talk, the therapist tries to help them understand how they can change or better cope with their disorder.

Social skills training:

Can also help children learn new behaviors. In social skills training, the therapist discusses and models appropriate behaviors important in developing and maintaining social relationships, like waiting for a turn, sharing toys, asking for help, or responding to teasing, then gives children a chance to practice.

Parenting skills training:

Offered by therapists gives parents tools and techniques for managing their child’s behavior. One such technique is the use of token or point systems for immediately rewarding good behavior or work. Another is the use of “time-out” or isolation to a chair or bedroom when the child becomes too unruly or out of control. During time-outs, the child is removed from the agitating situation and sits alone quietly for a short time to calm down. Parents may also be taught to give the child “quality time” each day, in which they share a pleasurable or relaxing activity.

PREVENTION:

There is no known way to prevent ADHD. Some studies indicate an association between mothers who smoke during pregnancy and a higher rate of ADHD in their children.¹⁹ Avoiding smoking, alcohol, and drugs during pregnancy may help prevent a higher risk of developing ADHD or similar behaviour in offspring.

DISORDERS THAT SOMETIMES ACCOMPANY ADHD:

Learning Disabilities:

Many children with ADHD—approximately 20 to 30 percent—also have a specific learning disability (LD).²⁰ In preschool years, these disabilities include difficulty in understanding certain sounds or words and/or difficulty in expressing oneself in words. A type of reading disorder, dyslexia, is quite widespread.

Tourette Syndrome:

A very small proportion of people with ADHD have a neurological disorder called Tourette syndrome. People with Tourette syndrome have various nervous tics and repetitive mannerisms, such as eye blinks, facial twitches, or grimacing. Others may clear their throats frequently, snort, sniff, or bark out words.

Oppositional Defiant Disorder:

As many as one-third to one-half of all children with ADHD—mostly boys—have another condition, known as oppositional defiant disorder (ODD). These children are often defiant, stubborn, non-compliant, have outbursts of temper, or become belligerent. They argue with adults and refuse to obey.

Conduct Disorder:

About 20 to 40 percent of ADHD children may eventually develop conduct disorder, a more serious pattern of antisocial behavior. These children frequently lie or steal, fight with or bully others, and are at a real risk of getting into trouble at school or with the police. They violate the basic rights of other people, are aggressive toward people and/or animals, destroy property, break into people’s homes, commit thefts, carry or use weapons, or engage in vandalism. These children or teens are at greater risk for substance use experimentation, and later dependence and abuse. They need immediate help.

Anxiety and Depression:

Some children with ADHD often have co-occurring anxiety or depression. If the anxiety or depression is recognized and treated, the child will be better able to handle the problems that accompany ADHD. Conversely, effective treatment of ADHD can have a positive impact on anxiety as the child is better able to master academic tasks.

Bipolar Disorder:

There are no accurate statistics on how many children with ADHD also have bipolar disorder. Differentiating between ADHD and bipolar disorder in childhood can be difficult. In children, bipolar disorder often seems to be a rather chronic mood dysregulation with a mixture of elation, depression, and irritability. Furthermore, there are some symptoms that can be present both in ADHD and bipolar disorder, such as a high level of energy and a reduced need for sleep. Of the symptoms differentiating children with ADHD from those with bipolar disorder, elated mood and grandiosity of the bipolar child are distinguishing characteristics.²¹

ADHD: FACT SHEET:

· Incidence in school-age children is estimated to be 3-7%.

· In children, ADHD is 3-5 times more common in boys than in girls.

· The predominantly inattentive type of ADHD is found more commonly in girls than in boys.

· ADHD is a developmental disorder that requires an onset of symptoms before age 7 years. After childhood, symptoms may persist into adolescence and adulthood, or they may ameliorate or disappear.

· Concordance of ADHD in monozygotic twins is greater than in dizygotic twins, suggesting some contribution of genetics.

· The mean heritability of ADHD is about 76%, indicating that ADHD is one of the most heritable psychiatric disorders.

· Children with ADHD do better with short term goals than long term goals.

· Children with ADHD require more frequent reminders about what is expected of them and what they can earn for meeting those expectations.

· Children with ADHD often require frequent changes in the program to remain interested in it.

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Received on 17.06.2008 Modified on 11.07.2008

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