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Attention Deficit Hyperactivity Disorder

Fact Sheet

What is Attention Deficit Hyperactivity Disorder?

Attention Deficit Hyperactivity Disorder (ADHD) is a neurobiological condition that is characterized by three main symptoms: inattention, hyperactivity and impulsivity.  It is the most prevalent childhood psychiatric disorder in Canada.  ADHD is not a learning disability but a person with ADHD can have an accompanying learning disability.  Children with ADHD are often labeled as having behaviour problems rather than a medical problem. 

Although it’s not clear what causes ADHD neurological (brain structure and functioning), genetic, and environmental factors play a role.  It is a chronic disorder that persists across the lifespan although symptoms can change over time. Teens may grow out of their hyperactivity or learn to channel it into appropriate physical activities while symptoms of inattention may increase in adulthood.

How is it Manifested?

ADHD effects mood regulation and executive functioning which is responsible for problem solving, organizing and planning things out.  This combination can impact the ability of a child with ADHD to self-regulate.  

Although hyperactivity is one of the main symptoms of ADHD some children may not demonstrate hyperactivity and may appear to lack energy and seem quiet and reserved.  While lack of focus and difficulty attending to task is another symptom of ADHD, when engaged in high interest activities children with ADHD can become hyper focused and may have difficulty moving on from the activity. 

Children with ADHD can have difficulty picking up on the social cues of others and may behave in socially inappropriate ways appearing to act without thinking.  They may interrupt other’s conversations or activities and can have difficulty listening or waiting for a turn in a conversation. 

Children with ADHD can have a short attention span which can lead to difficulty paying attention to long instructions or teaching sessions.  They are likely to daydream or begin to move and fidget when they are expected to sit quietly for long periods. 

Children with ADHD can experience mental health challenges such as anxiety or depression.  Low self-esteem is also a concern as some of the behaviours associated with ADHD can result in strained relationships with educators, and caregivers as well as isolation from peers and siblings.  

Who is Affected?

Boys are up to three times more likely to be diagnosed with ADHD than girls, but this can be attributed to the fact that girls are more prone to inattentive type ADHD which is marked by disorganized and unfocused behaviour.  Impulsiveness in girls with ADHD may be expressed as excessive talking rather than the disruptive, impulsive physical behaviours typically seen in boys.  Because symptoms appear so differently between boys and girls, girls usually go undiagnosed until later in adolescence or even adulthood. 

The general prevalence of ADHD is estimated at between 5-9% for children and adolescents, however, because girls are typically diagnosed so much later this statistic is likely low.  Up to approximately half of children diagnosed with ADHD also have another neurological disorder such as autism or mental health condition such as anxiety or depression.

How is ADHD Diagnosed or Detected?

The first step in diagnosing ADHD is for the family to discuss their concerns with their family doctor or pediatrician.  If the doctor does not have specific training regarding ADHD they will make a referral to a medical professional that is able to assess the child.  A diagnosis is made based on family history, the professional’s observations of the child and questionnaires filled out by the family and the child’s teachers.

ADHD is categorized into one of three categories, depending on the presence or absence the three core symptoms: inattention, hyperactivity and impulsivity.

  • Predominantly inattentive presentation (used to be referred to as ADD)
  • Predominantly hyperactive-impulsive presentation (very rare)
  • Combined presentation (most prevalent)

ADHD can be diagnosed in children as early as age four however, some professionals may hesitate to provide a diagnosis at such a young age. 


The Centre for ADHD Awareness Canada 

The CADDAC website is a comprehensive source of information about ADHD.  They are a “Canadian national charitable organization dedicated to improving the lives of those with ADHD through ADHD awareness, education and advocacy.”

They provide a series of 3 videos explaining ADHD to children: Me and My ADHD: A series of animated videos helping children understand ADHD

Regroupment Des Associations Panda Du Québec

French language ADHD information and resources.

ADHD & You

A comprehensive website with downloadable stories, practical tips and resources designed for parents of children with ADHD as well as teens and adults who have ADHD.


The content contained in this document is for general information purposes. It is not the intention to diagnose or treat a child.

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