Attention Deficit Hyperactivity Disorder (ADHD) is the most common neurodevelopment disorder among children and teens. ADHD used to be called Attention Deficit Disorder (ADD) but this is now outdated terminology. 

ADHD is very common.  It is estimated that ADHD affects about 3.4% of children worldwide.  However the prevalence ranges across studies anywhere from 2-18% depending on the population and diagnostic criteria used. 

Children with ADHD will often experience behaviour symptoms of inattention, hyperactivity, or impulsivity.  They may not have all of the symptoms – they may only have symptoms of inattention.  Symptoms are present in more than one setting, meaning that they occur at both school and at home.  

Symptoms of inattention include:

  • making careless mistakes at school
  • difficulty staying focused at school or while playing
  • seem unable to listen when spoken to
  • difficulty following through with instructions or finishing schoolwork
  • difficulty organizing tasks
  • often losing things or forgetfulness

Children who have challenges with hyperactivity or impulse control may: 

  • fidget or tap
  • have difficulty staying seated or squirm in their seat
  • run or climb in inappropriate situations
  • have difficulty being quiet
  • talk excessively or blurt things out
  • have difficulty waiting their turn or often interrupt others

Neurotransmitter Imbalance

Chemicals in our brains are called neurotransmitters.  It appears that a genetic imbalance of neurotransmitters, specifically dopamine, in the brain is the cause of ADHD symptoms. The imbalance seems to occur in specific parts of the brain that are responsible for sustaining attention and reducing impulsive behaviour.

The symptoms of ADHD often start in childhood and can persist into adulthood.

Every person is on a “spectrum” of behaviour – naturally some people are more inattentive or impulsive than others, which can be normal. However, ADHD serves as an important diagnosis for children when these symptoms impair a child’s ability to participate in school, home, or play activities.

This post was co-authored by  Stephanie Liu, MD, MSc, CCFP, BHSc , Suzanne Black, MD, BSc and Erin Manchuk, BScPharm, BCGP.

References:

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.

Shaw P, Eckstrand K, Sharp W, et al. Attention-deficit/hyperactivity disorder is characterized by a delay in cortical maturation. Proc Natl Acad Sci U S A 2007;104:19649-54.