Bipolar Disorders (BD) can have highly detrimental effects on the lives of people with the diagnosis and those who care about them. However, growing evidence suggests that aspects of bipolar experiences are also greatly valued by some people (Jamison, ref review on positives of mental illnesses).
BD is diagnosed in around two in a hundred people, but is also a hidden disorder with an average of eight years passing between onset and diagnosis (Hirschfeld, Angst). Furthermore, population studies (or: epidemiological research?) shows that up to half all individuals who meet diagnostic criteria never receive a diagnosis (Morgan, ). What can say about this undiagnosed but symptomatic population? We can say that we have little to no data, due to sampling biases where researchers recruit from clinical settings. Evidence is therefore biased toward only the half who are formally diagnosed.