More pernicious course of bipolar disorder in the United States than in many European countries: implications for policy and treatment.

BACKGROUND

There is some controversy but growing evidence that childhood onset bipolar disorder may be more prevalent and run a more difficult course in the United States than some European countries.

METHODS

We update and synthesize course of illness data from more than 960 outpatients with bipolar disorder (average age 40) from 4 sites in the U.S. and 3 sites in Netherlands and Germany. After giving informed consent, patients reported on parental history, childhood and lifetime stressors, comorbidities, and illness characteristics.

RESULTS

Almost all aspects of bipolar disorder were more adverse in patients from the US compared with Europe, including a significantly higher prevalence of: bipolar disorder in one parent and a mood disorder in both parents; childhood verbal, physical, or sexual abuse; stressors in the year prior to illness onset and the last episode; childhood onsets of bipolar illness; delay to first treatment; anxiety disorder, substance abuse, and medical comorbidity; mood episodes and rapid cycling; and nonresponse to prospective naturalistic treatment.

LIMITATIONS

Selection bias in the recruit of patients cannot be ruled out, but convergent data in the literature suggest that this does not account for the findings. Potential mechanisms for the early onset and more adverse course in the U.S. have not been adequately delineated and require further investigation.

CONCLUSIONS

The data suggest the need for earlier and more effective long-term treatment intervention in an attempt to ameliorate this adverse course and its associated heavy burden of psychiatric and medical morbidity.