Bipolar disorder is a mental health condition that affects 2.1% of the global population.
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”There seems to be a bidirectional relationship between migraine and bipolar disorder. Patients suffering from migraine with aura are three times more likely to suffer from bipolar disorder than the general population. Conversely, about one-third of patients with bipolar disorder have migraine.”5 A study found the prevalence of migraine was 32.7% in individuals with type 1 bipolar disorder and 54.17% in those with type 2.
So while 2.1% of the population has bipolar disorder, roughly 6.3% of people who have migraines with aura has bipolar disorder.
For some reason the article doesn’t state the prevalence of migraine with aura in the general population. Google tells me it’s around 8%, which would mean people with bipolar disorder are about 4x as likely to suffer from migraines with aura as the general population.