Attention Deficit Hyperactivity Disorder (ADHD)

Article Author:
Warren Magnus
Article Editor:
Steve Bhimji
Updated:
9/12/2018 5:54:05 PM
PubMed Link:
Attention Deficit Hyperactivity Disorder (ADHD)

Introduction

Attention-Deficit/Hyperactivity Disorder (ADHD) has been a diagnosis of some controversy over the last century in psychiatric and psychological circles. Over the past 30 years, however, a consensus has come about regarding both the existence and clarity of the symptoms that make up the ADHD phenomenon, and more recently, how these manifest as the condition persists into adulthood. There has increased understanding both of the neurochemical and physiologic causation of ADHD and the techniques for effective management of the condition.

ADHD is a developmental disorder of executive functioning that impairs the ability to focus, increases impulsivity, and increases motor activity.  The condition is usually diagnosed between the ages of 6 to 12, but symptoms can persist into adulthood. Treatment of adults with persistent symptoms is becoming increasingly common.[1][2][3]

Etiology

ADHD has developmental components of both genetic and environmental factors. No single cause has been identified. Recent studies suggest that ADHD is polygenic, and a variety of genes contribute to the development of the disorder. At the neurochemical level, both dopamine and norepinephrine are implicated with pharmaceutical intervention targeting these neurotransmitters.[4]

Epidemiology

Current estimates put the incidence of ADHD at 3% to 5% of school-age children. The primary age of diagnosis is between 6 and 12. The persistence of symptoms that plague children throughout their academic career and into adulthood is becoming increasingly recognized. For people who suffered clear ADHD symptomatology as children, 50% to 80% have persistent symptoms in adulthood even though the core symptoms change to reflect adult behaviors. For high functioning individuals, diagnosis is often delayed until late adolescence or adulthood as academic functioning may have been minimally impaired during developmental years.[5][6]

Pathophysiology

Executive function occurs in the prefrontal cortex. Dopamine plays an essential role in the cortex in maintaining executive functioning. Dopaminergic neurons participate in the in the regulation of systems expectation, memory, activity, attention, reward, emotional state, and motivation. Neuroimaging techniques such as PET and functional MRI have demonstrated the poor functioning of the frontal and frontocortical pathways. In ADHD the dysfunctions fall mainly into activity, memory, reward and motivational areas. These functional issues create the hallmarks of ADHD, hyperkinesis, and distractibility. [7][8]

History and Physical

There are no specific physical findings for ADHD. Neuropsychological testing can document the degree of impulsivity and determine attentional and executive functioning deficiencies that suggest ADHD. Some authorities suggest that some behaviors are nearly pathognomonic, such as frequent speeding tickets being strong indicators in adult patients. Patients with ADHD demonstrate a high level of difficulties with time management and prioritization of tasks. They have difficulty initiating and completing tasks promptly. Often patients demonstrate difficulty changing tasks once a task set has begun. Additionally, symptoms of hyperkinesis and poor working memory are often present. Hyperkinetic behaviors, while most obvious in children, can be seen in adult patients often in more muted forms such as visible fidgeting on observation.

Evaluation

The diagnosis of ADHD is largely clinical though recently some neuropsychological tests have come about to test attention and focus. There is no imaging that confirms the diagnosis of ADHD, though when imaged the right prefrontal cortex, caudate nucleus, and globus pallidus are often smaller in patients with ADHD. Adults with ADHD symptomatology often have comorbid conditions such as depression or obsessive-compulsive disorder that developed in response to the ADHD-related dysfunctionality.

Treatment / Management

Treatment of ADHD is historical and still relies heavily on stimulant medications as they act both on the dopaminergic and noradrenergic pathways. Mainstays of treatment remain methylphenidate (MPH) and dextroamphetamine (D-AMP). Longer acting and extended release formulations are becoming more commonly prescribed as the potential for abuse and diversion are lower. Newer non-stimulant medications act on a mix of pathways and offer another clinical option. Alpha-adrenergic blocking agents can be used alone or in concert with stimulant medications and provide some attentional benefit. These medications can also be used adjunctively to treat side effects of stimulant medications. Non-pharmacologic therapy includes parental training, cognitive behavioral therapy, and contingency training. [9][10][11]

In addition to the medical management of ADHD, often there is a need for significant psychological and emotional support. The cognitive and emotional differences that ADHD patients experience make interpersonal relationships more difficult and in children often impact their social and interpersonal functioning. As academic performance improves with pharmacotherapy, it may be necessary for outside counseling to provide the bridge to improving their social functioning. In adults, the functional differences have often resulted in significant adaptive responses and behaviors to make up or cover for the neuro-cognitive deficits. As the cognitive deficits improve, coaching to readapt patients to improved motivation, activity completion and prioritization may be necessary to help the patient fully integrate their new-found capabilities into their daily life. In some cases, vocational or academic skills retraining may be necessary as well. For adults diagnosed later in life, there may be a significant adaptive reaction that requires clinical support.

An exercise prescription for regular moderate to high-intensity cardiovascular exercise can positively impact cognition, confusion, and fatigue as well as improve self-motivation and short term memory. While transient, integrating exercise into the daily routine of an ADHD patient can significantly improve functioning for many patients. 

Dietary interventions that have shown some benefit include reducing simple dietary sugars and increasing dietary protein. Adding L-tyrosine rich foods such as soy products, milk, cheese, chicken, fish, turkey, avocados, chickpeas, pumpkin seeds, and the like can increase dopamine precursors but to date has shown little direct benefit to ADHD.

Omega-3 supplementation has been shown to be effective at improving academic measures of ADHD as the fractions of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) increase. DHA alone was found to be ineffective at improving ADHD symptomatology.[12][13]

Postoperative and Rehabilitation Care

For optimal results, the patient needs long-term follow up. ADHD is not an illness where one can just prescribe pills and assume a cure. These patients and their families are also extremely anti-healthcare and medications- so one has to be patient and develop a trusting relationship. Individuals who show evidence of self-harm usually require admission.

Pearls and Other Issues

ADHD can be associated with a number of comorbidities including dyslexia, dyspraxia, Tourette Syndrome, major depression, oppositional defiant disorder, obsessive-compulsive disorder, and anxiety disorders.

The comorbid conditions can exist as a result of ADHD functional deficits and the impact on daily life such as obsessive behaviors that began as coping mechanisms to short-term memory or prioritization issues or depression that has roots in social functioning issues.

Comorbid learning disorders are common in the ADHD population and patients should be screened for these as well. Further, these patients need regular screening for substance abuse.

Enhancing Healthcare Team Outcomes

Childhood ADHD is not a benign disorder - later in life, there is also a risk of substance abuse and conduct disorders. Several studies indicate that with age these individuals have marital and interpersonal difficulties, become antisocial, have poor education performance, and are unable to hold on to jobs. Thus, long-term monitoring of these individuals is important.

ADHD carries significant morbidity and some evidence suggest that it may be a precursor later in life to schizophrenia or bipolar disorder. In addition, in children, ADHD also carries a risk of depression and self-harm behaviors. [14] [15] (Level V)

Evidence-based Approach

The one positive feature of ADHD is that it is treatable but the education of the patient and family is critical. The role of the nurse and pharmacist are indispensable. The key feature is that the family is also very demanding and suspicious of healthcare workers and their motives-thus it is vital to establish a relationship based on trust and honesty.

Both the nurse and pharmacist need to encourage the use of medications, improvement of social skills, structure time, control behavior, and direct positive cognitive behavior. Further, these individuals need to be screened for substance abuse and other behavior problems. There are many educational resources that can be given to the patients and their families. In addition, there is also a hotline - the National Resource Center (1-800 233 4050) that parents can call and speak to a health information specialist.

Evidence indicates that an integrated approach with a team of professionals dedicated to ADHD may help reduce the barriers to treating these patients. It is important to set endpoints in treatment because the disease can be treated but is not curable. [1][16](level V)