Given the fuzzy character of the disorder, the symptoms of ADHD are not clear-cut. There are many possible symptoms and whichever ones occur must be persistent to be considered diagnostically relevant. They must also be unusual given a child's developmental stage, since a child might display some symptoms simply because they are typical for his or her age group.
To qualify as symptoms of ADHD, they must also create significant impairment of functioning in school or home.
For an adult to be diagnosed with ADHD, he or she must have had some of these symptoms during childhood.
The symptoms of ADHD fall into two distinct categories: inattention and hyperactivity/impulsivity. Those whose symptoms are restricted to inattention aren't usually as disruptive and therefore often go undiagnosed.
Symptoms of Inattention:
Symptoms of hyperactivity/impulsivity:
Dig Deeper in the Diagnosis Dictionary