Attention-Deficit/Hyperactivity Disorder (ADHD)

Overview

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition affecting the nervous system – including the brain – from childhood to adulthood. People with ADHD can experience impulsivity, hyperactivity, distractedness, and difficulty following instructions and completing tasks.

Since 1994, experts have used the term Attention-Deficit/Hyperactivity Disorder to refer to neurodivergence that affects attention and concentration. However, some people do not experience hyperactivity and associated traits such as lower risk aversion or impulsivity.

It’s a common misperception that ADHD only affects young boys. Approximately 10 million adults have attention-deficit/hyperactivity disorder (ADHD). In early adulthood, ADHD may be associated with depression, mood or conduct disorders and substance abuse.

Adults with ADHD often suffer from difficulties at work and in their personal and family lives related to ADHD symptoms. Many have inconsistent performance at work or in their careers, have difficulties with day-to-day responsibilities, experience relationship problems, and may have chronic feelings of frustration, guilt or blame.

Individuals with ADHD may also have difficulties with maintaining attention, executive function and working memory. Recently, deficits in executive function have emerged as key factors affecting academic and career success. Executive function is the brain’s ability to prioritise and manage thoughts and actions. This ability permits individuals to consider the long-term consequences of their actions and guide their behaviour over time more effectively. Individuals who have issues with executive functioning may have difficulties completing tasks or may forget important things.

How common is ADHD?

A meta-analysis of 175 research studies worldwide on ADHD prevalence in children aged 18 and under found an overall pooled estimate of 7.2% (Thomas et al. 2015). The US Census Bureau estimates 1,795,734,009 people aged 5-19 worldwide in 2013. Thus, 7.2% of this total population is 129 million – a rough estimate of the number of children worldwide who have ADHD.

Based on DSM-IV screening of 11,422 adults for ADHD in 10 countries in the Americas, Europe and the Middle East, the estimates of worldwide adult ADHD prevalence averaged 3.4% (Fayyad et al. 2007).

Symptoms and causes

Symptoms of ADHD

ADHD is diagnosed by a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development.

The name Attention-Deficit/Hyperactivity Disorder includes the forward slash (/) between Attention-Deficit and Hyperactivity. This means that people diagnosed with ADHD could have either or both presentations (inattentive or hyperactive-impulsive). The presentations are:

• Attention-deficit/hyperactivity: combined presentation
• Attention-deficit/hyperactivity: predominantly inattentive presentation
• Attention-deficit/hyperactivity: predominantly hyperactive-impulsive presentation

Inattention

To meet the diagnostic criteria for inattention, 6 or more of the following symptoms from each must have persisted for at least 6 months to a degree that is inconsistent with developmental level and that negatively impacts the person directly on social and academic/occupational activities.

The symptoms should not be solely a manifestation of oppositional behaviour, defiance, hostility, or failure to understand tasks or instructions. For older adolescents and adults (age 17 and older), at least 5 symptoms are required.

• Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or during other activities (e.g., overlooks or misses details, work is inaccurate).
• Often has difficulty sustaining attention in tasks or play activities (e.g., has difficulty remaining focused during lectures, conversations, or lengthy reading).
• Often does not seem to listen when spoken to directly (e.g., mind seems elsewhere, even in the absence of any obvious distraction).
• Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (e.g., starts tasks but quickly loses focus and is easily sidetracked).
• Often has difficulty organising tasks and activities (e.g., difficulty managing sequential tasks; difficulty keeping materials and belongings in order; messy, disorganised work; has poor time management; fails to meet deadlines).
• Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (e.g., schoolwork or homework; for older adolescents and adults, preparing reports, completing forms, reviewing lengthy papers).
• Often loses things necessary for tasks or activities (e.g., school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).
• Is often easily distracted by extraneous stimuli (for older adolescents and adults, may include unrelated thoughts).
• Is often forgetful in daily activities (e.g., doing chores, running errands; for older adolescents and adults, returning calls, paying bills, keeping appointments).

Hyperactivity

To meet the diagnostic criteria for hyperactivity, 6 or more of the following symptoms from each must have persisted for at least 6 months to a degree that is inconsistent with developmental level and that negatively impacts the person directly on social and academic/occupational activities.

The symptoms should not be solely a manifestation of oppositional behaviour, defiance, hostility, or failure to understand tasks or instructions. For older adolescents and adults (age 17 and older), at least 5 symptoms are required.

• Often fidgets with or taps hands or feet or squirms in their seat.
• Often leaves their seat in situations when remaining seated is expected (e.g., leaves his or her place in the classroom, in the office or other workplace, or in other situations that require remaining in place).
• Often runs about or climbs in situations where it is inappropriate. (Note: In adolescents or adults, may be limited to feeling restless.)
• Often unable to play or engage in leisure activities quietly.
• Is often “on the go,” acting as if “driven by a motor” (e.g., is unable to be or uncomfortable being still for extended time, as in restaurants, meetings; may be experienced by others as being restless or difficult to keep up with).
• Often talks excessively.
• Often blurts out an answer before a question has been completed (e.g., completes people’s sentences; cannot wait for their turn in conversation).
• Often has difficulty waiting his or her turn (e.g., while waiting in line).
• Often interrupts or intrudes on others (e.g., butts into conversations, games, or activities; may start using other people’s things without asking or receiving permission; for adolescents and adults, may intrude into or take over what others are doing).

In addition

• Several inattentive or hyperactive-impulsive symptoms were present prior to age 12 years.
• Several inattentive or hyperactive-impulsive symptoms are present in two or more settings (e.g., at home, school, or work; with friends or relatives; in other activities).
• There is clear evidence that the symptoms interfere with, or reduce the quality of, social, academic, or occupational functioning.
• The symptoms do not occur exclusively during the course of schizophrenia or another psychotic disorder and are not better explained by another mental disorder (e.g., mood disorder, anxiety disorder, dissociative disorder, personality disorder, substance intoxication or withdrawal).

Causes of ADHD

While there are still sceptics out there with ill-informed opinions that ADHD isn’t a real diagnosis, some of the most prestigious scientific-based organisations in the world conclude that ADHD is, in fact, a real disorder. Experts have also stated that there are potentially devastating consequences when ADHD is not properly identified, diagnosed and treated.

Research has demonstrated that ADHD has a very strong neurobiological basis.

Although precise causes have not yet been identified, there is little question that heredity makes the largest contribution to the expression of the disorder in the population.

Dr. Gabor Maté – a renowned speaker and bestselling author – suggests that it’s a common mistake to think that everything that’s biological is genetically caused. Biology is greatly affected by what happens in a person’s life, in their family and in the society around them, and so on.

He says that for the most part, genes don’t predetermine or “cause” anything that happens, they just lay out a set of potentials that might happen, given the right (or wrong) environmental inputs.

Particularly in early childhood, our brains are very much affected by social and psychological relationships. Over the lifetime, the brain is in constant interaction with the environment, so something can absolutely be biological without therefore being written in genetic stone.

In addition to neurobiology, 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. These things may 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 and treatment

How is ADHD diagnosed?

ADHD is typically diagnosed by mental health providers or primary care providers. A psychiatric evaluation will normally include a description of symptoms, completion of scales and questionnaires, gaining an understanding of psychiatric and medical history, family history, and information regarding education, environment, and upbringing. It may also include a referral for medical evaluation to rule out other medical conditions.

It is important to note that several conditions can mimic ADHD such as learning disorders, mood disorders, anxiety, substance use, head injuries, thyroid conditions, and use of some medications such as steroids (Austerman, 2015). ADHD may also co-exist with other mental health conditions, such as oppositional defiant disorder or conduct disorder, anxiety disorders, and learning disorders (Austerman, 2015). Thus, a full psychiatric evaluation is very important. There are no specific blood tests or routine imaging for ADHD diagnosis. Sometimes, patients may be referred for additional psychological testing (such as neuropsychological or psychoeducational testing) or may undergo computer-based tests to assess the severity of symptoms.

Healthcare providers use the guidelines in the American Psychiatric Association’s Diagnostic and Statistical Manual, Fifth edition (DSM-5), to help diagnose ADHD. This diagnostic standard helps ensure that people are appropriately diagnosed and treated for ADHD. Using the same standard across communities can also help determine how many children have ADHD, and how public health is impacted by this condition.

Only trained healthcare providers can diagnose or treat ADHD.

Differential diagnosis for ADHD

Differential diagnosis can include:

• A specific learning disorder: Children with specific learning disorder may appear inattentive because of frustration, lack of interest, or limited ability. However, inattention in individuals with a specific learning disorder who do not have ADHD is not impairing outside of academic work.
• Anxiety disorders: ADHD shares symptoms of inattention with anxiety disorders. Individuals with ADHD are inattentive because of their attraction to external stimuli, new activities, or preoccupation with enjoyable activities. This is distinguished from the inattention due to worry and rumination seen in anxiety disorders. Restlessness might be seen in anxiety disorders. However, in ADHD, the symptom is not associated with worry and rumination.
• Autism spectrum disorder: Individuals with ADHD and those with autism spectrum disorder exhibit inattention, social dysfunction, and difficult-to-manage behaviour. The social dysfunction and peer rejection seen in individuals with ADHD must be distinguished from the social disengagement, isolation, and indifference to facial and tonal communication cues seen in individuals with autism spectrum disorder. Children with autism spectrum disorder may display tantrums because of an inability to tolerate a change from their expected course of events. In contrast, children with ADHD may misbehave or have a tantrum during a major transition because of impulsivity or poor self-control.
• Bipolar disorder: Individuals with bipolar disorder may have increased activity, poor concentration, and increased impulsivity, but these features are episodic, occurring several days at a time. In bipolar disorder, increased impulsivity or inattention is accompanied by elevated mood, grandiosity, and other specific bipolar features. Children with ADHD may show significant changes in mood within the same day; such lability is distinct from a manic episode, which must last 4 or more days to be a clinical indicator of bipolar disorder, even in children. Bipolar disorder is rare in preadolescents, even when severe irritability and anger are prominent, whereas ADHD is common among children and adolescents who display excessive anger and irritability.
• Depressive disorders: Individuals with depressive disorders may present with inability to concentrate. However, poor concentration in mood disorders becomes prominent only during a depressive episode.
• Disruptive mood dysregulation disorder: Disruptive mood dysregulation disorder is characterised by pervasive irritability, and intolerance of frustration, but impulsiveness and disorganised attention are not essential features. However, most children and adolescents with the disorder have symptoms that also meet criteria for ADHD, which is diagnosed separately.
• Intellectual disability (intellectual developmental disorder): Symptoms of ADHD are common among children placed in academic settings that are inappropriate to their intellectual ability. In such cases, the symptoms are not evident during non-academic tasks. A diagnosis of ADHD in intellectual disability requires that inattention or hyperactivity be excessive for mental age.
• Intermittent explosive disorder: ADHD and intermittent explosive disorder share high levels of impulsive behaviour. However, individuals with intermittent explosive disorder show serious aggression toward others, which is not characteristic of ADHD, and they do not experience problems with sustaining attention as seen in ADHD. In addition, intermittent explosive disorder is rare in childhood. Intermittent explosive disorder may be diagnosed in the presence of ADHD.
• Medication-induced symptoms of ADHD: Symptoms of inattention, hyperactivity, or impulsivity attributable to the use of medication (e.g., bronchodilators, isoniazid, neuroleptics [resulting in akathisia], thyroid replacement medication) are diagnosed as other specified or unspecified other (or unknown) substance–related disorders.
• Neurocognitive disorders: Early major neurocognitive disorder (dementia) and/or mild neurocognitive disorder are not known to be associated with ADHD but may present with similar clinical features. These conditions are distinguished from ADHD by their late onset.
• Oppositional defiant disorder: Individuals with oppositional defiant disorder may resist work or school tasks that require self-application because they resist conforming to others’ demands. Their behaviour is characterised by negativity, hostility, and defiance. These symptoms must be differentiated from aversion to school or mentally demanding tasks due to difficulty in sustaining mental effort, forgetting instructions, and impulsivity in individuals with ADHD. Complicating the differential diagnosis is the fact that some individuals with ADHD may develop secondary oppositional attitudes toward such tasks and devalue their importance.
• Other neurodevelopmental disorders: The increased motoric activity that may occur in ADHD must be distinguished from the repetitive motor behaviour that characterises stereotypic movement disorder and some cases of autism spectrum disorder. In stereotypic movement disorder, the motoric behaviour is generally fixed and repetitive (e.g., body rocking, self-biting), whereas the fidgetiness and restlessness in ADHD are typically generalised and not characterised by repetitive stereotypic movements. In Tourette’s disorder, 64 Neurodevelopmental Disorders frequent multiple tics can be mistaken for the generalised fidgetiness of ADHD. Prolonged observation may be needed to differentiate fidgetiness from bouts of multiple tics.
• Personality disorders: In adolescents and adults, it may be difficult to distinguish ADHD from borderline, narcissistic, and other personality disorders. All these disorders tend to share the features of disorganisation, social intrusiveness, emotional dysregulation, and cognitive dysregulation. However, ADHD is not characterised by fear of abandonment, self-injury, extreme ambivalence, or other features of personality disorder. It may take extended clinical observation, informant interview, or detailed history to distinguish impulsive, socially intrusive, or inappropriate behaviour from narcissistic, aggressive, or domineering behaviour to make this differential diagnosis.
• Psychotic disorders: ADHD is not diagnosed if the symptoms of inattention and hyperactivity occur exclusively during the course of a psychotic disorder.
• Reactive attachment disorder: Children with reactive attachment disorder may show social disinhibition, but not the full ADHD symptom cluster, and display other features such as a lack of enduring relationships that are not characteristic of ADHD.
• Substance use disorders: Differentiating ADHD from substance use disorders may be problematic if the first presentation of ADHD symptoms follows the onset of abuse or frequent use. Clear evidence of ADHD before substance misuse from informants or previous records may be essential for differential diagnosis.

Treatment for ADHD

Types of treatment for adult ADHD usually includes a combination of medication and psychotherapy.

Therapy options may include:

• Behavioural therapy
• Cognitive behaviour therapy (CBT)
• Education
• Social skills training
• If the patient is a child, family therapy and parental skills training may also be recommended

Medication may include:

• Stimulants
  • Methylphenidate (brand names Artige, Concerta, Ritalin)
  • Lisdexamfetamine (brand name Vyvanse)
  • Dexamfetamine
• Non-stimulants
  • Atomoxetine (brand names include Atomerra and Strattera)
  • Guanfacine (brand name Intuniv)

Comorbidity

In clinical settings, comorbid disorders are frequent in individuals whose symptoms meet criteria for ADHD. In the general population, oppositional defiant disorder co-occurs with ADHD in approximately half of children with the combined presentation and about a quarter with the predominantly inattentive presentation.

• Antisocial or other personality disorders: In adults, antisocial and other personality disorders may co-occur with ADHD. Other disorders that may co-occur with ADHD include obsessive-compulsive disorder, tic disorders, and autism spectrum disorder.
• Anxiety disorders: Anxiety disorders and major depressive disorder occur in a minority of individuals with ADHD but more often than in the general population.
• Conduct disorder: Conduct disorder co-occurs in about a quarter of children or adolescents with the combined presentation, depending on age and setting.
• Disruptive mood dysregulation disorder: Most children and adolescents with disruptive mood dysregulation disorder have symptoms that also meet criteria for ADHD; a lesser percentage of children with ADHD have symptoms that meet criteria for disruptive mood dysregulation disorder.
• Intermittent explosive disorder: Intermittent explosive disorder occurs in a minority of adults with ADHD, but at rates above population levels.
• Specific learning disorder: Specific learning disorders commonly co-occurs with ADHD.
• Substance use disorders: Although substance use disorders are relatively more frequent among adults with ADHD in the general population, the disorders are present in only a minority of adults with ADHD.

Outlook and prognosis

With the right treatment and help, ADHD is a condition that is easily managed. Through the administration of the correct medication and with education and support, those with the condition can live normal, productive and successful lives.

If you believe you have ADHD, it’s essential to seek professional, medical treatment.