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Attention Deficit Hyperactivity Disorder (ADHD)

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Last Update: July 17, 2019.

Introduction

Attention Deficit-Hyperactivity Disorder (ADHD) is a psychiatric condition that has long been recognized as affecting children's ability to function. Individuals suffering from this disorder show patterns of developmentally inappropriate levels of inattentiveness, hyperactivity, or impulsivity. Although there used to be two different diagnoses of Attention Deficit Disorder vs Attention Deficit Hyperactivity Disorder, the DSM IV combined this into one disorder with three subtypes: predominantly inattentive, predominantly hyperactive, or combined type. 

The symptoms begin at a young age and usually include lack of attention, lack of concentration, disorganization, difficulty completing tasks, being forgetful, and losing things. These symptoms should be present before the age of 12, have lasted six months, and interfere with daily life activities in order to be labeled as 'ADHD'. This must be present in more than one setting (ie at home and at school, or at school and at afterschool activities). It can have large consequences including social interactions, increased risky behaviors, loss of jobs, and difficulty achieving in school. 

ADHD must be considered within the context of what is developmentally and culturally appropriate for a person. It is considered a dysfunction of executive functioning, predominantly a frontal lobe activity. Therefore, patients with ADHD show disability not only in attention and focus but also in decision making and emotional regulation. Children with ADHD can have difficulty with social interactions, can be easily frustrated, and can be impulsive. They are often labeled as "trouble makers." 

ADHD is not a new condition and has been called different names throughout history. It was labeled as 'minimal brain dysfunction' in the 1930s and has ever since changed names to ADD and ADHD respectively.[1] Its prevalence has increased over time, with a seeming spike in the 1950s as school became more standardized for children. 

It is important to diagnose and treat the disorder at a young age so that the symptoms do not persist into adulthood and cause other comorbid conditions. The treatment for the disorder is mostly related to stimulants and psychotherapy.[2] This review would further shed light upon the causal factors, pathophysiology, and management of ADHD.

Etiology

The etiology of ADHD is related to a variety of factors that include both a genetic and an environmental component. It is one of the most heritable condition in terms of psychiatric disorders. There is a much greater concordance in monozygotic twins than dizygotic. Siblings have twice the risk of having ADHD than the general population. Similarly, viral infections, smoking during pregnancy, nutritional deficiency and alcohol exposure in the fetus have also been explored as possible causes of the disorder. There are no consistent findings on brain imaging of patients with ADHD. The number of dopaminergic receptors has also been implicated in the development of the disorder whereby research has shown that the receptors are decreased in the frontal lobes in individuals with ADHD.[3][1] There is also evidence for the role of noradrenergic receptor involvement in ADHD. 

Epidemiology

The subtypes of attention deficit disorders are found to have a different rate of prevalence in a group of individuals suffering from the disorders. It is found that the inattentive subtype is prevalent in about 18.3% of the total patients while hyperactive/impulsive and combined represent 8.3% and 70% respectively. It is also found that the inattentive subtype is more common amongst the female population. The disorders (collectively) are found in a 2:1 male to female ratio as per different researches.[4] It is prevalent in around 3%-6% of the adult population.[5] It is one of the most prevalent disorders found in childhood. There is some evidence that ADHD is more prevalent in the United States than in other developed countries. 

Pathophysiology

ADHD is associated with cognitive and functional deficits that relate to diffuse abnormalities in the brain. The anterior cingulate gyrus and dorsolateral prefrontal cortex (DLFPC) are found to be small in individuals who are suffering from ADHD. It is thought that these changes account for the deficits in goal-directed behavior. Moreover, activity in the frontostriatal region is also reduced in these individuals as measured by fMRI. It is important to understand these pathophysiological mechanisms so that the pharmacotherapy is directed onto them.[6] It is important to remember that ADHD is a clinical diagnosis. There are no standard laboratory or imaging results among patients with ADHD. 

History and Physical

In order to diagnose ADHD, it is very important to take a relevant history of the concerned individual.  ADHD is diagnosed in children based upon their history where the children face difficulty in at least 6 of the 9 symptoms as mentioned in DSM V. Inattentive symptoms include: not paying close attention to tasks, missing small details, rushing through tasks, not seeming to listen when spoken two, difficulty organizing things, not finishing work, dislikes or avoids tasks that take sustained mental effort, losing thins, or being forgetful. Hyperactive symptoms include: fidgeting, feeling like an "internal motor" is always going, leaving their seat, climbing on things, being loud, blurting out answers, talking excessively or out of turn, having trouble waiting their turn, interrupts or intrudes on others. These symptoms must be present in multiple settings.

In adults, however, these core symptoms may be missing and they may manifest as other problems such as procrastination, mood instability, and low self-esteem. They will likely be more impulsive in nature, or inattentive, as the hyperactivity symptoms can be better controlled. The symptoms of inattention or hyperactivity will likely be elicited when doing a proper history of childhood but may have been missed. 

ADHD interferes with functioning and development. This can be included in adults who do not work and is often dismissed in this population. For example, a stay at home mom may have difficulty getting her children to school on time, organizing her home, paying attention while driving, etc, that affect her functioning and daily life even though she is not at work or at school. It is important to take this into consideration when making a diagnosis. 

Different scales are used to measure the problems that patients with ADHD are suffering from. One such example is of the Brown Attention Deficit Disorder Scale which includes common areas that these individuals face difficulty in and can be used in adults to identify the disorder. For children, the Vanderbilt ADHD scale is often used as it has both a teacher and parent component. A physical examination, on the other hand, is not as useful in the diagnosis of ADHD but it can still be used to exclude medical causes such as thyroid problems. It could also help to identify any medical issue that could thereby direct the treatment options. For example, individuals with hypertension may not opt for stimulants as a treatment option.[7][8][9]

Evaluation

ADHD is a disorder that is diagnosed clinically and does not have any specific laboratory or radiologic tests. The neuropsychological tests are not as sensitive for diagnosing the disorder and hence the disorder should be diagnosed based upon the history of the patient.[7] The evaluation of the patient with ADHD is usually done with different rating scales and multiple informants which may include the teachers and parents. It is necessary for a clinician to look for other disorders as they may be a cause for the symptoms that a child is exhibiting. It should not be diagnosed in the context of symptoms from another disorder, for example, a psychotic episode or manic episode.

DSM V: types of ADHD

  1. Predominantly inattentive
  2. Predominantly impulsive or hyperactive
  3. Combination of the above
  • The onset is usually before age 12
  • Symptoms present at school, work or home
  • The disturbance causes significant impairment in social, occupational and academic functioning
  • The disorder is not accounted for by any other behavior disorder

Treatment / Management

Pharmacological therapy remains the mainstay of treatment for patients suffering from ADHD. It is divided into two major categories which fall into stimulants or non-stimulants. Stimulants are further broken into amphetamines and methylphenidates. Both types of stimulants block the reuptake of dopamine at the presynaptic membranes and postsynaptic membranes. Amphetamines also directly release dopamine. Stimulants are the mainstay of treatment for ADHD. They are effective in about 70% of patients. There is a number needed to treat of 2. There are multiple formulations of each subtype of stimulants including immediate release and extended release, long-acting, or sustained release. Side effects of stimulants include changes in blood pressure, decreasing appetite and sleep, and risk of dependency. However, there is an increased risk of substance use in patients with ADHD and studies show treating with a stimulant decreases their overall lifetime risk of substance abuse. Because stimulants are controlled substances, providers often are hesitant to use them. However, repeated evidence has shown how imperative it is to try stimulants in ADHD. 

Of the non-stimulant option, there are also two types: antidepressants and alpha agonists. Within the antidepressant category, atomoxetine is is the best known, and works as a selective norepinephrine reuptake inhibitor. It is known to be effective in many trials as a treatment option for ADHD, though not nearly as effective as stimulants. It also has minimal antidepressant effects. It is often used in children who don't tolerate stimulants or have anxiety. Other antidepressants include bupropion, which targets dopamine and serotonin, and TCAs which are the last choice options. These work by targeting norepinephrine.

Lastly, alpha agonists such as clonidine and guanfacine can be used as an effective treatment for ADHD. However, these are associated with multiple cardiovascular effects like lowering blood pressure, sedation (clonidine more than guanfacine), weight gain, dizziness, etc. They are found to be more effective in younger children than adults.[6] 

Psychosocial treatment is the other form of treatment that is used for individuals suffering from the disorder. This form of treatment includes psycho-education for the family and patient and cognitive behavioral training programs designed specifically for the patient to achieve short and long term goals. Research has found that these training programs prove to be very effective when used along with the pharmacotherapy. However, unlike other psychiatric disorder, there is strong evidence for medication management without therapy as being the most efficacious. [10][11][12]

The FDA has just approved the trigeminal nerve stimulation system for children not on medications. The device generates a low-level electrical pulse which suppresses hyperactivity.

There is no diet that has been found to improve ADHD

Differential Diagnosis

It is important to differentiate ADHD from other clinical disorders as it can have symptoms that may overlap with them. Mood disorders such as depression and anxiety can be misdiagnosed in a patient with ADHD as these symptoms (inattention and poor focus, memory loss, distractibility, etc) generally persist in individuals with the disorder. Substance abuse disorders should also be carefully examined as children with ADHD are prone to substance abuse. It is important to rule out hearing disorders, learning disorder, and developmental disorders from ADHD. [6]

Prognosis

The prognosis of ADHD is variable depending upon the age of the individual who is experiencing the symptoms. It is seen that the symptoms of ADHD persist into the teenage years and may involve the social and academic domains of life. Two-fifths of the patients continue experiencing the symptoms in the teenage years whereas a quarter of them are also diagnosed with a concurrent antisocial disorder. However, an important trend in the long term was also noted whereby the symptoms of the patients with ADD decreased in adulthood by about 50%. The general rule of thumb is that 50% of patients "grow out of" ADHD, especially with treatment, and another 25% do not need treatment into adulthood. This is theorized twofold; first that stimulants help improve the development of the frontal lobe over time, and second that adults often choose careers that don't require sustained attention. In adulthood, these patients are able to achieve their educational and vocational goals.[13]

Treatment of ADHD has also been shown to improve symptoms of the oppositional defiant disorder and conduct disorder. It has shown a decreased risk of substance use. 

However, untreated ADHD can cause persisting dysfunction and devastating consequences included but not limited to long term inability to work, increased car accidents, and increased substance abuse. [14][15]

Deterrence and Patient Education

It is important that patients with ADHD are followed up regularly to check upon their symptoms and comorbidities. In order to achieve treatment goals, the role of patient education cannot be emphasized enough. For children who suffer from ADHD, the parents should be formally educated about the disorder so that they understand the concept behind the diagnosis. Medication treatment can only be optimized if there is ongoing interaction between the primary caregiver and the family.[16]

Pearls and Other Issues

ADHD is often a very easily treated disorder that is highly stigmatized in society. Proper diagnosis and treatment can change the lives of patients who suffer from these

Providers should not be hesitant to try stimulant medications. They are highly effective and can be very safe when properly prescribed

ADHD has multiple comorbidities including anxiety, depression, and conduct disorder. Treatment of ADHD can improve the symptoms of these other disorders

Enhancing Healthcare Team Outcomes

ADHD is a condition that can be managed but the protocols for managing it must be followed effectively in order to achieve a fruitful result. The management involves an interprofessional team that includes the specialist psychiatrist, pediatrician, pharmacist, and other health care professionals including nurse practitioners who help in diagnosing the disorder. The collaboration on part of the family and the health care team becomes important so as to know the exact history of the events that the patient has gone through.

The team should then make up a management plan that may include a pharmacologic treatment, a psychosocial intervention or both. The comorbid disorders of ADHD would have to be analyzed by the team as depression and anxiety disorders are much more common in this set of population.  In order to make a diagnosis of ADHD, regular follow-ups with the primary caregiver of the child should be scheduled along with the child. The clinician can then ascertain and evaluate the child himself and clinically co-relate it to the findings as provided by the caregiver. This can further be taken to a specialist psychiatrist whereby a confirmatory diagnosis can be made. This would then involve a set of other health-care professionals such as a psychologist or a trained psychotherapist along with the psychiatrist. The treatment plan is then formulated by the team and the caregiver himself is given an important role along with the healthcare team. The caregiver has to observe the patient and help in noticing the changes that the child may exhibit. It can be hence concluded that an integrated healthcare plan should be followed for the diagnosis and treatment of ADHD so that the long term goals of the treatment can be achieved. (I) [17]

Open communication between the interprofessional team is the key to improve outcomes. The team should have a conference as that everyone knows what message is to be sent to the caregiver, who often get upset with mixed messages.

Outcomes

Despite decades of research, the outcomes for patients with ADHD are guarded. Noncompliance with medications is common and follow is difficult as many patients seek alternative treatments. Many parents do not trust the drugs and often seek alternative care. There is no question that currently available treatments do help some patients improve functionally but without treatment, the individuals continue to deteriorate and eventually end up in financial, legal and social difficulties.[4][18][19]

Questions

To access free multiple choice questions on this topic, click here.

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