fier “with rapid cycling.” 
Risk and Prognostic Factors
Environmental. Bipolar disorder is mo re common in high-income than in low-income
countries (1.4 vs. 0.7%). Separated, divorced,  or widowed individuals have higher rates of
bipolar I disorder than do individuals who ar e married or have neve r been married, but
the direction of the association is unclear. 
Genetic and physiological. A family history of bipolar diso rder is one of the strongest and
most consistent risk factors for bipolar disord ers. There is an average 10-fold increased risk
among adult relatives of individuals with bipo lar I and bipolar II disorders. Magnitude of
risk increases with degree of kinship. Schizophrenia and bipolar disorder likely share a ge-
netic origin, reflected in familial co-aggregat ion of schizophrenia and bipolar disorder. 
Course modifiers. After an individual has a manic episode with psychotic features, subse-
quent manic episodes are more likely to in clude psychotic featur es. Incomplete inter-
episode recovery is more common when th e current episode is accompanied by mood-
incongruent psychotic features.
Culture-Related Diagnostic Issues
Little information exists on specific cultural differences in the expression of bipolar I dis-
order. One possible explanation for this ma y be that diagnostic instruments are often
translated and applied in diff erent cultures with no transcultural validation. In one U.S.
study, 12-month prevalence of bipolar I diso rder was significantly lower for Afro-Carib-
beans than for African Americans or whites. 
Gender-Related Diagnostic Issues
Females are more likely to experience rapid cycling and mixed states, and to have patterns of
comorbidity that differ from th ose of males, including higher rates of lifetime eating disor-