Bipolar disorder rates are not lower in countries outside of the United States.
 People with bipolar have increased activation of left hemisphere ventral limbic areaswhich mediate emotional experiences and generation of emotional responsesand decreased activation of right hemisphere cortical structures related to cognitionstructures associated with the regulation of emotions
=== Comorbid conditions ===People with bipolar disorder often have other co-existing psychiatric conditions such as anxiety (present in about 71% of people with bipolar disorder), substance abuse (56%), personality disorders (36%) and attention deficit hyperactivity disorder (1020%) which can add to the burden of illness and worsen the prognosis

