ADHD The Facts


Overview of ADHD

Most people have difficulty sitting still, paying attention or controlling impulsive behaviour occasionally. For some people, however, the problems are so pervasive and persistent that they interfere with every aspect of their life: home, academic, social and work.

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder affecting 11 percent of school-age children (Visser, et al., 2014.) Symptoms continue into adulthood in more than three-quarters of cases (Brown, 2013.)

ADHD is characterized by developmentally inappropriate levels of inattention, impulsivity and hyperactivity. Individuals with ADHD can be very successful in life. However, without identification and proper treatment, ADHD may have serious consequences, including school failure, family stress and disruption, depression, problems with relationships, substance abuse, delinquency, accidental injuries and job failure. Early identification and treatment are extremely important.

Medical science first documented children exhibiting inattentiveness, impulsivity and hyperactivity in 1902. Since that time, the disorder has been given numerous names, including minimal brain dysfunction, hyperkinetic reaction of childhood, and attention-deficit disorder with or without hyperactivity. With the Diagnostic and Statistical Manual, Fifth Edition (DSM-5) classification system, the disorder has been renamed Attention-Deficit/Hyperactivity Disorder.

The current name reflects the importance of the inattention aspect of the disorder as well as the other characteristics of the disorder such as hyperactivity and impulsivity. Symptoms Typically, arise in early childhood. According to the DSM-5, several symptoms are required to be present before the age of 12. Many parents report excessive motor activity during the toddler years, but ADHD symptoms can be hard to distinguish from the impulsivity, inattentiveness and active behaviour that is typical for kids under the age of 4.

In making the diagnosis, children should have six or more symptoms of the disorder present; adolescents 17 and older and adults should have at least five of the symptoms present.

More than 75 percent of children with ADHD continue to experience significant symptoms in adulthood. In early adulthood, ADHD may be associated with depression, mood or conduct disorders and substance abuse.

The DSM-5 lists three types of ADHD:

– Predominantly Inattentive
– Predominantly Hyperactive – Impulsive
– Combined (both of the above)

The symptoms for each are adapted and summarized below:

ADHD predominantly inattentive presentation

  • Fails to give close attention to details or makes careless mistakes
  • Has difficulty sustaining attention
  • Does not appear to listen
  • Struggles to follow through with instructions
  • Has difficulty with organization
  • Avoids or dislikes tasks requiring sustained mental effort
  • Loses things
  • Is easily distracted
  • Is forgetful in daily activities

ADHD predominantly Hyperactive-Impulsive presentation

  • Fidgets with hands or feet or squirms in chair
  • Has difficulty remaining seated
  • Runs about or climbs excessively in children; extreme restlessness in adults
  • Difficulty engaging in activities quietly
  • Acts as if driven by a motor; adults will often feel inside as if they are driven by a motor
  • Talks excessively
  • Blurts out answers before questions have been completed
  • Difficulty waiting or taking turns
  • Interrupts or intrudes upon others ADHD combined presentation

ADHD combined presentation

The individual meets the criteria for both inattention and hyperactive-impulsive ADHD presentations.

These symptoms can change over time, so children may fit different presentations as they get older.

Is it ADHD or ADD?

In 1994, the name of the disorder was changed in a way that is confusing for many people. Since that time all forms of attention deficit disorder are officially called “Attention-Deficit/ Hyperactivity Disorder,” regardless of whether the individual has symptoms of hyperactivity or not. Even though these are the official labels, a lot of professionals and lay people still use both terms: ADD and ADHD. Some use those terms to designate the old subtypes; others use ADD just as a shorter way to refer to any presentation.

Severity of symptoms:

As ADHD symptoms affect each person to varying degrees, the DSM-5 now requires professionals diagnosing ADHD to include the severity of the disorder. Clinicians can designate the severity of ADHD as “mild,” “moderate” or “severe” under the criteria in the DSM-5.

Mild: Few symptoms beyond the required number for diagnosis are present, and symptoms result in minor impairment in social, school or work settings.

 Moderate: Symptoms or functional impairment between “mild” and “severe” are present.

Severe: Many symptoms are present beyond the number needed to make a diagnosis; several symptoms are particularly severe; or symptoms result in marked impairment in social, school or work settings. As individuals age, their symptoms may lessen, change or take different forms.

How severe the disorder is can change with the presentation during a person’s lifetime.

ADHD throughout the lifespan

Children with ADHD often experience delays in independent functioning and may behave younger than their peers. Many children effected by ADHD can also have mild delays in language, motor skills or social development that are not part of ADHD but often co-exist. They tend to have low frustration tolerance, difficulty controlling their emotions and often experience mood swings. Children with ADHD are at risk for potentially serious problems in adolescence and adulthood:

  • academic failure or delays,
  • driving problems,
  • difficulties with peers and social situations,
  • risky sexual behaviour,
  • substance abuse.

There may be more severe negative behaviours with co- existing conditions such as oppositional defiant disorder or conduct disorder.

Adolescent girls with ADHD are prone to eating disorders.

Teens with ADHD present a special challenge. During these years, academic and life demands increase. At the same time, these kids face typical adolescent issues such as emerging sexuality, establishing independence, dealing with peer pressure and the challenges of driving. In early adulthood, ADHD may be associated with depression, mood or conduct disorders and substance abuse. Adults with ADHD often cope with difficulties at work and in their personal and family lives related to ADHD symptoms. Many have inconsistent performance at work; have difficulties with day-to-day responsibilities; experience relationship problems; and may have chronic feelings of frustration, guilt or blame.

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

Co-occurring Disorders

More than two-thirds of children with ADHD have at least one other co-existing condition. Any disorder can co-exist with ADHD, but certain disorders seem to occur more often. These disorders include:

  • oppositional defiant,
  • conduct disorders,
  • anxiety,
  • depression,
  • tic disorders or Tourette syndrome,
  • substance abuse,
  • sleep disorders,
  • learning disabilities.

When co-existing conditions are present, academic and behavioural problems, as well as emotional issues, may be more complex. These co-occurring disorders can continue throughout a person’s life. A thorough diagnosis and treatment plan that considers all the symptoms present is essential.


Despite multiple studies, researchers have yet to determine the exact causes of ADHD.  However, scientists have discovered a strong genetic link since ADHD can run in families. More than 20 genetic studies have shown evidence that ADHD is strongly inherited.

ADHD is a complex disorder, which is the result of multiple interacting genes. (Cortese, 2012.) Other factors in the environment may increase the likelihood of having ADHD:

  • exposure to lead or pesticides in early childhood
  • premature birth or low birth weight
  • brain injury

Scientists continue to study the exact relationship of ADHD to environmental factors but point out that there is no single cause that explains all cases of ADHD and that many factors may play a part. Previously, scientists believed that maternal stress and smoking during pregnancy could increase the risk for ADHD, but emerging evidence is starting to question this belief (Thapar, 2013.) However, further research is needed to determine if there is a link or not.

The following factors are NOT known causes, but can make ADHD symptoms worse for some children:

  • watching too much television
  • diet
  • family stress (poverty, family conflict)
  • traumatic experiences

ADHD symptoms, themselves, may contribute to family conflict. Even though family stress does not cause ADHD, it can change the way the ADHD presents itself and result in additional problems such as antisocial behaviour (Langley, Fowler et al., 2010.) Problems in parenting or parenting styles may make ADHD better or worse, but these do not cause the disorder. ADHD is clearly a neurodevelopmental disorder. Currently research is underway to better define the areas and pathways that are involved.


There is no single test to diagnose ADHD.  Therefore, a comprehensive evaluation is necessary to establish a diagnosis, rule out other causes, and determine the presence or absence of co-existing conditions. Such an evaluation requires time and effort and should include a careful history and a clinical assessment of the individual’s academic, social, and emotional functioning and developmental level. There are several types of professionals who can screen for ADHD, however in Australia, only psychiatrists and paediatricians can make an official diagnosis and prescribe medication.  Regardless of who does the evaluation, the use of the DSM-5 diagnostic criteria for ADHD is necessary.

Determining if a child has ADHD is a complex process. Many biological and psychological problems can contribute to symptoms like those exhibited by children with ADHD. For example, anxiety, depression and certain types of learning disabilities may cause similar symptoms. In some cases, these other conditions may be the primary diagnosis; in others, these conditions may co-exist with ADHD. A thorough history should be taken from the parents and teachers, and when appropriate, from the child. Checklists for rating ADHD symptoms and ruling out other disabilities are often used by clinicians; these instruments factor in age-appropriate behaviours and show when symptoms are extreme for the child’s developmental level.

For adults, diagnosis also involves gathering information from multiple sources, which can include ADHD symptom checklists, standardized behaviour rating scales, a detailed history of past and current functioning, and information obtained from family members or significant others who know the person well. ADHD cannot be diagnosed accurately just from brief office observations or just by talking to the person. The person may not always exhibit the symptoms of ADHD in the office, and the diagnostician needs to take a thorough history of the individual’s life. A diagnosis of ADHD must include consideration of the possible presence of co-occurring conditions. As part of the evaluation, a physician should conduct a thorough examination, including assessment of hearing and vision to rule out other medical problems that may be causing symptoms like ADHD.   In rare cases, persons with ADHD may also have a thyroid.

Diagnosing ADHD in an adult requires an evaluation of the history of childhood problems in behaviour and academic domains, as well as examination of current symptoms and coping strategies.


American Psychiatric Association: Diagnostic and Statistical Manual of Mental Health Disorders, Fifth Edition. Arlington, VA, American Psychiatric Association, 2013.

Da Camara, G. (2018). Fridays with Tristan: Understanding ADHD from a Mentoring Perspective

Hinshaw, S.P. & Arnold, L.E. for the MTA Cooperative Group (2015 Jan–Feb).  Attention deficit hyperactivity disorder, multimodal treatment, and longitudinal outcome:  Evidence, paradox, and challenge. WIREs Cognitive Science, 6(1):39-52.

MTA Cooperative Group. (1999). A 14-month randomized clinical trial of treatment strategies for attention deficit hyperactivity disorder.  Archives of General Psychiatry, 56, 12.

Brown, T.E. (2013). A New Understanding of ADHD in Children and Adults: Executive Function. Routledge.

Smith, B.H. & Shapiro, C.J. (2015). Combined treatments for ADHD in Barkley, R.A. (Ed), (2015). Attention-Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment (4th ed.), (pp. 686–704). New York, NY: Guilford Press.

Thapar, Anita; Cooper, Miriam; et al. (January 2013). Practitioner Review: What have we learnt about the causes of ADHD? Journal of Child  Psychology and Psychiatry, 54(1):3-16.

Visser, S.N., Danielson, M.L., Bitsko, R.H., et al. (2014). Trends in the Parent-Report of Health Care Provider-Diagnosis and Medication Treatment for ADHD disorder: United States, 2003–2011. Journal of the American Academy of Child & Adolescent Psychiatry, 53(1):34–46. e2.

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