According to the National Institute of Mental Health approximately 2.6% of Americans 18 years or older have bipolar disorder. Significantly, there is now further evidence that it is a brain chemistry disorder.
A study in Molecular Psychiatry reports that specific chemical abnormalities can be demonstrated, unfortunately at this point that testing seems to be confined to post-mortem. It would seem that in the future this may yield some sort of testing for diagnosis of bipolar disorder. That would be a great step forward. Those same researchers were also able to demonstrate improvement in the chemical milieu with treatment, documenting that these drugs do provide benefit. These results may also point the way for new, innovative treatments.