I think what Simcha posted is good. I just want to add that you are in control of your treatment. My first GP was my physician for many years, but his response to me regarding ADHD was unacceptable. I need to know that my doctor will listen to me and my concerns. I found a new GP physician who listen to my concerns, took them seriously, and although he was unwilling to Rx medication, he did make arrangements to connect me with another MD. Although the neurologist is treating me for ADHD, my GP is very interested and is keeping close tabs on my overall health.

Your treatment options should no be limited by what other family members have,IMO. One assessment done by a T who saw you once and just gave you a computer-based test, provides just one piece to a very complex puzzle. If you really think you may have ADHD, and want to see if medication will help...be persistent. I would recommend finding another health care professional who has experience dx and treating ADHD. I would not lie but I would have this person assess you without disclosing a lot of the family baggage.