what age does bipolar disorder show up
1 The median age of onset for bipolar disorder is 25 years (National Institue of Mental Health), although the illness can start in early childhood or as late as the 40's and 50's. Bipolar disorder affects approximately 5.7 million adult Americans, or about 2.6% of the U.S. population age 18 and older every year. ( 2 National Institute of Mental Health).