Early functional impairment in bipolar youth: a nested population-based case-control study

The objective of this report is to evaluate functioning in bipolar disorder in a population-based sample of young adults (18 to 24 years old). To this end, people with bipolar disorder were compared with matched participants with only depressive episodes and control subjects without a history of mood episodes.

Case-control study nested in a population-based sample. Caseness was confirmed with the Structured Clinical Interview for DSM-IV. The Functioning Assessment Short Test was used as a measure of general functioning. A multivariate model was elaborated to account for potential confounders.

The sample consisted of 231 subjects. Both bipolar disorder (coef=0.60, SE=0.14, p<0.001) and major depression (coef=0.44, SE=0.14, p=0.001) were associated with functioning in the multivariate model. Current depressive symptoms appeared to influence functioning in those with major depression (Z=2.05, p=0.04), but not in those with bipolar disorder (Z=0.78, p=0.43).

Neuropsychological testing was not performed and we see it as an important limitation of this study.

This population-based study further reinforces the notion that functional impairment is a fundamental characteristic of bipolar illness. It is present from early stages and is not completely explained by mood symptoms.