The genetic key to bipolar disorder (med.uio.no)

>There are approximately 160,000 individuals living with bipolar disorder in Norway, and globally, around 40 to 50 million people are affected.

Does Norway have an unusually high prevalence? That is 2% of Norway's population and 0.6% of the global population

Perhaps it is not a disorder if it contributes to fitness (in a biological sense). Classifying "normal", albeit very distressing and obnoxious, human behavior as disordered is a misunderstanding.