Bipolar at-risk criteria: an examination of which clinical features have optimal utility for identifying youth at risk of early transition from depression to bipolar disorders

Background: A clinical and research challenge is to identify which depressed youth are at risk of "early transition to bipolar disorders (ET-BD)." This 2-part study (1) examines the clinical utility of previously reported BD at-risk (BAR) criteria in differentiating ET-BD cases from unipolar depression (UP) controls; and (2) estimates the Number Needed to Screen (NNS) for research and general psychiatry settings.

Methods: Fifty cases with reliably ascertained, ET-BD I and II cases were matched for gender and birth year with 50 UP controls who did not develop BD over 2 years. We estimated the clinical utility for finding true cases and screening out non-cases for selected risk factors and their NNS. Using a convenience sample (N = 80), we estimated the NNS when adjustments were made to account for data missing from clinical case notes.

Results: Sub-threshold mania, cyclothymia, family history of BD, atypical depression symptoms and probable antidepressant-emergent elation, occurred significantly more frequently in ET-BD youth. Each of these "BAR-Depression" criteria demonstrated clinical utility for screening out non-cases. Only cyclothymia demonstrated good utility for case finding in research settings; sub-threshold mania showed moderate utility. In the convenience sample, the NNS for each criterion ranged from ~4 to 7.

Conclusions: Cyclothymia showed the optimum profile for case finding, screening and NNS in research settings. However, its presence or absence was only reported in 50% of case notes. Future studies of ET-BD instruments should distinguish which criteria have clinical utility for case finding vs screening.