Are there developmentally limited forms of bipolar disorder?

Bipolar spectrum disorders have traditionally been thought to be chronic in course. However, recent epidemiologic research suggests that there may be developmentally limited forms of bipolar disorder. Two large, nationally representative studies reveal a strikingly high prevalence of bipolar disorders in emerging adulthood (5.5%-6.2% among 18-24-year-olds) that appear to resolve substantially during the latter half of the 3rd decade of life (3.1%-3.4% among 25-29-year-olds). Although ascertainment bias due to early mortality, institutionalization, incarceration, and homelessness may account for some of this reduction, the prevalence distribution suggests a high incidence in late adolescence and emerging adulthood that appears to resolve spontaneously in most cases. There were very few differences across age groups in symptom endorsement and comorbid diagnoses, suggesting that 18-24-year-olds that meet criteria for bipolar diagnoses experience clinically significant impairment and associated consequences of the disorder. More fine-grained longitudinal research is needed to determine whether developmentally limited forms of bipolar disorder exist and, if so, what markers might distinguish these forms of the disorder from more chronic courses.