The onset of bipolar symptoms can happen at almost any age. In nearly two-thirds of patients, symptoms leading to a Bipolar I diagnosis appear between the ages of 20-35, tapering off after that. Patients diagnosed with Bipolar II were found to have their first symptoms spread over a wide age range, with more than 10% appearing after age 50.
Since the publication of The Bipolar Child by Papolos and Papolos more than ten years ago, it's almost been forgotten that children can have symptoms very much like adult bipolar disorder. Indeed, I believe I started showing those symptoms at a young age. When I was excited, I was VERY excited, and I was depressed often and severely enough for the school to recommend having me evaluated by a child psychologist.
Depression symptoms in particular grew worse and worse as I got older, but I wasn't diagnosed with Bipolar II until age 49. Just think what my life could have been like if I'd been treated 10 years, 20 years earlier!
So what about you? When did your symptoms surface? Share in the comments.
Baldessarini, M. J. ,. E. A. (2010). Onset-age of bipolar disorders at six international sites. Journal of Affective Disorders, 121(1-2), 143-146. Retrieved from http://www.sciencedirect.com/science/article/pii/S0165032709002535