More childhood onset bipolar disorder in the United States than Canada or Europe: Implications for treatment and prevention

- In the US, two-thirds of bipolar disorder begins before age 19, and only1/3 in Europe.
- High risk and epidemiological studies are consistent with this increased incidence.
- More psychiatric illness is present across 4 generations of family members in the US versus Europe.
- In the US bipolar illness is more severe and associated with longer treatment delays.
- These data emphasize the need for new efforts to ameliorate this high illness burden.

Evidence of a high or increasing incidence of childhood onset bipolar disorder in the United States (US) has been viewed skeptically. Here we review evidence that childhood onsets of bipolar disorder are more common in the US than in Europe, treatment delays are longer, and illness course is more adverse and difficult. Epidemiological data and studies of offspring at high risk also support these findings.In our cohort of outpatients with bipolar disorder, two of the major vulnerability factors for early onset − genetics and environmental adversity in childhood − were also greater in the US than in Europe. An increased familial loading for multiple psychiatric disorders was apparent in 4 generations of the family members of the patients from the US, and that familial burden was linked to early onset bipolar disorder. Since both early onset and treatment delay are risk factors for a poor outcome in adulthood, new clinical, research, and public health initiatives are needed to begin to address and ameliorate this ongoing and potentially devastating clinical situation.