there are many different symptoms. diagnosis with add and depression could be one of them. same with personality disorders. teenaged angst could also be a sign. it can often times be a subtle condition that is hard to diagnose and not worth treating with medication, but talk therapy can help.
there are different types of bipolar disorder, and people experience it differently. it is often diagnosed later on in life or after being diagnosed with something else.
ultimately i would go to 2 different doctors and see what each of them thinks.
I can't vouch for the accuracy of these statements, but many of them do correlate with other things I have read. This is a post from a person with experience in both worlds. Let me know how you feel about it.
The link is -
http://www.medhelp.org/private_messages/show/1075639