Misdiagnoses happen quite often, as many symptoms of one disorder are sometimes closely related to another. For example, bipolar disorder is often mixed up with depression or anxiety disorders, causing bi-polar disorder to be under-diagnosed. The same goes for ADHD.
Individuals who were previously diagnosed with an anxiety disorder are often diagnosed with ADHD later on. This mistake can often confuse the patient, as they did not previously receive the correct treatment.
Unfortunately, these mix-ups occur quite often, as symptoms of one illness tend to overlap with others. This common mistake doesn’t mean that ADHD doesn’t exist at all. Yes, there are several misdiagnoses, and while many could argue that the disorder is under or over-diagnosed, the same could be right for several different conditions.