I started having my suspicions after I read what I consider the best book about the bipolar experience called "The Loony Bin Trip" by the late Kate Millet. She got more manic than I but eventually I got more depressed than she. Interviews with psychiatrists are where it was diagnosed. It's helpful before those interviews to think back about periods of childhood when you felt really disconnected and out of it and then the times you had long periods of a really good mood. Then relay those experiences to the pdoc honestly and let them tell you what they think. It's important not to tell them what you think they want to hear or bend the truth so you get a "trendy" diagnosis. Even if you think you're story is boring and you feel you have to punch it up, resist that urge. Just tell them like it is and they might surprise you with a correct diagnosis that you never heard of or never expected. You can't get treated right until you get honest, and this includes about drug and alcohol consumption.