Dyslexia and attention deficit hyperactivity disorder (ADHD) are two neurological conditions that can make learning more difficult. The former affects 11%, and the latter affects between 5 to 20%, but it’s difficult to estimate precisely. Sometimes, the symptoms of ADHD and dyslexia can be hard to tell apart — as both can cause trouble with reading and writing. But even though the symptoms can appear similar, the underlying reasons for the symptoms are very different.