Attention Deficit Hyperactivity Disorder, or ADHD,  is the most common neurodevelopmental disorder among children in North America. As a physician that sees ADHD in my practice, I wonder how common ADHD is and the effects of undiagnosed ADHD.

How common is ADHD? 

It is estimated that nearly 10% of all American children between 4 to 17 years old are affected by ADHD.  The reported rates vary depending on the diagnostic criteria used as well as the populations included in the studies. 

ADHD is more common in boys than girls.  Boys are more than twice as likely to have a diagnosis of ADHD than girls.  

Children with ADHD are also more likely to have other psychiatric disorders along with ADHD.  These may include oppositional defiant disorder, anxiety, depression, among others.    

Why is the diagnosis of ADHD important?

ADHD serves as an important diagnosis for children.  Effective treatment is available for ADHD.  Undiagnosed or untreated can have serious, lifelong complications.  ADHD can interfere with a child’s ability to participate in school, trouble learning, and put them in physician danger due to impulsivity.  As adults, they may experience problems with the law, poor relationships, and even difficulty holding down a job.

Compared to children without ADHD, children with ADHD are at greater risk of:

• Self-injury: Children with ADHD are more likely to engage in intentional, or unintentional self-harm.  This can include things like burning themselves or cutting themselves.  
• Car Crashes: Are almost twice as likely to have motor vehicle accidents when they begin to drive.
• Worse School Performance: Children with ADHD are more likely to drop out of school, have lower academic achievement scores, and fail more courses.  This impairment persists even if the child no longer meets criteria for an ADHD diagnosis into adolescence or adulthood.  
• Less likely to attend college or university: Data shows only 15-19% of adolescents with ADHD complete a bachelor’s degree, compared to 50-64% of adolescents without ADHD.
• Drug use: Children with ADHD are over 2.5 times more likely to use substances like nicotine, alcohol, marijuana and cocaine in adolescence and adulthood.  

Perhaps it is unclear if the prevalence of ADHD is increasing or if we are just getting better at detecting it.  What is clear is that the timely diagnosis and treatment of ADHD is important for your child’s growth and development.  

If you think your child may have ADHD, please speak to your child’s doctor. 

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

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