Long-term prognosis of bipolar I disorder.

This study examined the contribution of demographic, syndromal and longitudinal course variables to the long-term prognosis of 165 bipolar patients prospectively observed over 10 years as part of the National Institute of Mental Health Collaborative Study of Depression. Although most baseline clinical and demographic variables were not strong prognostic indicators, switching polarity within episodes was. Most episodes among the poor-prognosis patients were polyphasic, while most episodes among the comparison group with a better prognosis were monophasic. There was no evidence of shortening of cycle lengths over follow-up for either the poor-prognosis group or the entire sample. The relevance of these findings to the 'kindling' model is discussed.