Most experts in the field believe that ADHD has a strong inheritance component. So you will often find one or both parents with some variation of ADHD. However, since ADHD is usually related to some kind of brain physiology problem, it can also come from birth trauma or early head injury. These latter two scenarios are somewhat less likely.

Another way to look at where ADHD comes from is that it has to do with the way the brain is functioning. Recent electrophysiological studies have found that about 95% of the time, a person with ADHD has one of five types of brain wave patterns, according to Quantitative Electroencephalogram (QEEG) studies. Even though there may be a definable brain physiology for most people with ADHD, there is a tendency for people to inherit their parents' brains. But in the lives of most parents of present day adults, ADHD was not well known. Therefore, parents had no perspective on the likelihood that their child had this disorder. As a result, the parents probably behaved in an ordianary way towards their children, disciplining the child for the distractibility as if it could be changed at will. But for a child who truly has ADHD, such training at home and at school may have had little effect. What resulted, far too many times, was a low self-esteem.

Have you had a head injury? If you have had a head injury, you may experience symptoms similar to ADHD. Technically, such a person might not qualify for ADHD because this injury was not something you were born with. It is also sometimes possible people do not connect their head injury with the symptoms associated with ADHD, and therefore go from therapist to therapist, doctor to doctor, without getting the right treatment. Diagnosis and treatment of a head injury is similar to the procedure of diagnosing and treating a learning disability. Many discussions found in this site may apply.