Commingling analysis of age-of-onset in bipolar I disorder and the morbid risk for major psychoses in first degree relatives of bipolar I probands

摘要

Background: Age-of-onset (AO) is increasingly used in molecular genetics of bipolar 1 disorder (BP-I) as a phenotypic specifier with the goal of reducing genetic heterogeneity. However, questions regarding the cut-off age for defining early onset (EO), as well as the number of onset groups characterizing BP-I have emerged over the last decade with no definite conclusion. The aims of this paper are: 1) to see whether a mixture of three distributions better describes the AO of BP-I than a mixture of two distributions in different independent samples; 2) to compare the morbid risk (MR) for BP-1 and for major affective disorders and schizophrenia in first degree relatives of BP-I probands by proband onset group derived from commingling analysis, since the MR to relatives is a trait with strong genetic background.