Quick Facts on the Linkages Between Dyslexia and ADHD
According to the Mayo Clinic, Attention-deficit/hyperactivity disorder is:
"A chronic condition that affects millions of children and often persists into adulthood. ADHD includes a combination of problems, such as difficulty sustaining attention, hyperactivity and impulsive behavior."
There are successful strategies and accommodations to deal with it, and the symptoms often decrease with age, but may never completely disappear.
Subtypes of ADHD include: predominantly hyperactive-impulsive, predominantly
inattentive and combined hyperactive-impulsive and inattentive. (See pie chart below).
The exact cause of ADHD isn't known, but like dyslexia it is not
the result of laziness, low intelligence, disobedience, poor parents,
diet or too much television. This can't be emphasized enough.
Research has shown that both genetic and environmental factors are involved. In identical twins, if one has it, there is a high probability both will. A genetic predisposition to ADHD may be 'activated' by certain environmental factors before or after birth.
For example, use of drugs and alcohol during pregnancy has been linked to higher rates of ADHD in children. Pre-school exposure to high levels of lead has also been implicated in ADHD research.
ADHD seems to reside in the frontal areas of the brain associated with executive functioning, regulation of behaviour, organization, and planning. The specific issue in those areas may be an imbalance in the levels of various neurotransmitters (particularly norepinephrine and dopamine), explaining why common ADHD medications (Ritalin + others) inhibit the uptake of neurotransmitters, leaving more in the bloodstream.
Finally, some recent brain imaging studies have found
that in children with ADHD the brain
matures in a normal pattern but is simply delayed by about 3 years. This
may explain why a significant portion of children seem to outgrow the
Like dyslexia, ADHD can't be cured though treatment, but it can be managed. Every child requires a personal plan which should be developed in consultation with your family doctor and a specialist, usually a clinical psychologist. Treatment may include a combination of:
Common Forms of ADHD Medications
The most common type of medication used is a stimulant called methylphenidate. It's used in many drugs such as Concerta, Ritalin and Daytrana. Its purpose is to improve a child's ability to pay attention and reduce hyperactivity and impulsiveness.
The ability to sustain focused attention is critical for reading and for any task of long duration or with multiple steps - precisely the kinds of tasks those with both dyslexia and ADHD have a lot of trouble performing.
Focus is also important for keeping things neat and organized. Focused
attention is essential for noticing that you just threw your shirt on the floor instead
of the hamper or left the textbook and your pen on the table when running off to play
Common side effects from methylphenidate include include loss of appetite and difficulty sleeping. These can be major problems, but research shows that these side effects diminish after several weeks of use. If they didn't, ADHD drugs would be the hotest diet pills around, but they are not, because appetite returns for most users. Sleep cycles too improve with time.
Alternative therapies such as healthier diets, exercise, meditation and so forth may hold some benefit and are certainly unlikely to do much harm, but there are no alternative therapies we are aware of with a body of research evidence behind them.
They are so commonly found together that some mistake dyslexia and ADHD for the same thing, but, to be clear, dyslexia and ADHD are two different disorders one to do with attention and behavior and the other specifically to do with reading. Still, the significant overlap (co-morbidity) suggests some related cause.
You may be concerned that your child is struggling to read, but at the same time unable to distinguish whether this is because she can't focus attention or because she has a problem processing sounds, letters and words.
There is no one test to determine which it may be, or if both conditions are present. If at times your child can read fluently then it may be more likely to be an ADHD problem, but the only certain way to find out is through a separate professional assessment for each condition. Ask your school about reading assessment and your family doctor about assessment for ADHD.
Dyslexia and ADHD are distinct and separate conditions but they often occur together, suggesting some shared underlying causes, likely hereditary and neurological in origin.
Without professional assessment it may be difficult to tease the two problems apart with ADHD possibly accounting for some reading disability. For more information on reading assessment try our page on dyslexia testing. For assessment of ADHD, consult with your family doctor.
Return to the top of Dyslexia and ADHD
Corkboard: ©Thinglass. www.dreamstime.com
ADHD Subtypes Piechart: By Psyc3330 w11 (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Methylphenidate Pills: By Alfie↑↓© (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons