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Objective: Preliminary data suggested that there are three subgroups of bipolar affective disorder based on age at onset. The authors sought to replicate those findings and determine the cut-off age of each subgroup. Method: Admixture analysis was used to determine the bestfitting model for the observed ages at onset of 368 consecutively admitted patients. The results obtained were compared with those of the previously described model. The authors also investigated whether affected siblings are more likely to belong to the same theoretical age-at-onset subgroup as identified by admixture analysis. Results: The existence of three subgroups defined by age at onset was confirmed. The mean ages estimated in this model were 17.4 years (SD = 2.3), 25.1 years (SD = 6.2), and 40.4 years (SD = 11.3). Affected siblings were more likely to belong to the same theoretical subgroup. Conclusions: There are three age-at-onset subgroups of bipolar patients, and specific familial vulnerability factors might underlie each subgroup. [ABSTRACT FROM AUTHOR]

Objective: Family and twin studies suggest that liability for suicide attempts is heritable and distinct from mood disorder susceptibility. The authors therefore examined the association between common genomewide variation and lifetime suicide attempts. Method: The authors analyzed data on lifetime suicide attempts from genomewide association studies of bipolar I and II disorder as well as major depressive disorder. Bipolar disorder subjects were drawn from the Systematic Treatment Enhancement Program for Bipolar Disorder cohort, the Wellcome Trust Case Control Consortium bipolar cohort, and the University College London cohort. Replication was pursued in the NIMH Genetic Association Information Network bipolar disorder project and a German clinical cohort. Depression subjects were drawn from the Sequential Treatment Alternatives to Relieve Depression cohort, with replication in the Netherlands Study of Depression and Anxiety/Netherlands Twin Register depression cohort. Results: Strongest evidence of association for suicide attempt in bipolar disorder was observed in a region without identified genes (rs1466846); five loci also showed suggestive evidence of association. In major depression, strongest evidence of association was observed for a single nucleotide polymorphism in ABI3BP, with six loci also showing suggestive association. Replication cohorts did not provide further support for these loci. However, meta-analysis incorporating approximately 8,700 mood disorder subjects identified four additional regions that met the threshold for suggestive association, including the locus containing the gene coding for protein kinase C-epsilon, previously implicated in models of mood and anxiety. Conclusions: The results suggest that inherited risk for suicide among mood disorder patients is unlikely to be the result of individual common variants of large effect. They nonetheless provide suggestive evidence for multiple loci, which merit further investigation. [ABSTRACT FROM AUTHOR]