I went 10 years stable also. Totally stable, I refused to believe I had bipolar.

Then I went through an extremely stressful year, and it triggered an epic manic episode that climaxed with me thinking I was literally GOD, I had to be restrained with a straight-jacket and knocked out with thorazine in the emergency room.

Anyway, the point of this story is that YES, you can go years without symptoms, and still have bipolar disorder....I was stable and didn't have ANY bipolar symptoms for 10 years, and then BAM! I had a manic episode so extreme, it was manic type 1, psychotic super-mania. After I was released from the mental hospital, I went into a depression for two ****ing years. Now I am medicated and stable again.

I hope this helps.