Continuity and cascade in offspring of bipolar parents: a longitudinal study of externalizing, internalizing, and thought problems.

There is growing evidence that many offspring of bipolar parents will develop moderate to severe forms of psychopathology during childhood and adolescence. The purpose of this study was to apply growth curve models to evaluate developmental progression with regard to continuity and cascades representative within the context of a family risk study of bipolar disorder (BD). Repeated assessments of externalizing, internalizing, and thought problems, spanning more than a decade, were examined in a total of 94 offspring of parents with BD (O-BD), major depressive disorder (O-UNI), or no significant psychiatric or medical problems (O-WELL). Continuity was defined by the growth curve of the O-WELL group who exhibited low levels of problems from early childhood through late adolescence. Discontinuity, as evidenced by greater complexity of growth curves relative to the O-WELL group, was exhibited in the at- risk offspring groups for internalizing problems. Different patterns of developmental cascades were supported for the at-risk group with O-UNI showing a robust cascade from self-regulatory deficits (externalizing problems) to internalizing problems. There was also support for a cascade from self-regulatory deficits to thought problems across the entire group (with some support that this pattern was accounted for primarily by O-BD). This study not only serves to advance our understanding of the risks associated with a family history of BD, but also provides a novel approach to examining developmental cascades.