title: Admixture analysis of age at first suicide attempt.
abstract: OBJECTIVE
  Clinical and familial studies have suggested that age at first suicide attempt (SA) is a marker for different subtypes of suicidal behaviors. However, none of the various thresholds used to define subgroups according to the age at first suicide attempt have been validated. The aim of this study was to try to define different subgroups according to age at first SA subtypes using admixture analysis.
  
  
  METHODS
  In a sample of 368 consecutively recruited patients from Sept. 2001 to Sept. 2005 with a personal history of suicide attempt, admixture analysis was used to determine the best-fitting model for the observed distribution of age at first SA.
  
  
  RESULTS
  The theoretical model that best explains the observed distribution of age at first SA was a mixture of two Gaussian distributions with mean ages (+/-SD) of 19.5 +/- 4.3 and 38.5 +/- 12.4 years with a cut-off point of 26 years for the two subgroups. In multivariate analyses, the early onset subgroup was characterized by more frequent comorbid anxiety disorders, cannabis misuse and personal history of emotional and sexual abuse. Patients belonging to the late onset subgroup were more likely to suffer from major depressive disorders (single or recurrent).
  
  
  CONCLUSIONS
  This study provides a mathematical modelisation suggesting the existence of two age at onset subgroups in suicidal behaviors with different clinical picture and history of childhood trauma. Given the heterogeneity of suicidal behavior, these results suggest that the age at first SA may represent a valid 'candidate symptom' for future investigations of vulnerability factors.
authors.affiliation: INSERM, U955, IMRB, Department of Genetics, Psychiatry Genetics Team, Créteil, France. slama.frederic@wanadoo.fr
authors.forename: Frédéric
authors.initials: F
authors.lastname: Slama
authors.forename: Philippe
authors.initials: P
authors.lastname: Courtet
authors.forename: Jean Louis
authors.initials: JL
authors.lastname: Golmard
authors.forename: Flavie
authors.initials: F
authors.lastname: Mathieu
authors.forename: Sébastien
authors.initials: S
authors.lastname: Guillaume
authors.forename: Liova
authors.initials: L
authors.lastname: Yon
authors.forename: Fabrice
authors.initials: F
authors.lastname: Jollant
authors.forename: Helene
authors.initials: H
authors.lastname: Misson
authors.forename: Isabelle
authors.initials: I
authors.lastname: Jaussent
authors.forename: Marion
authors.initials: M
authors.lastname: Leboyer
authors.forename: Frank
authors.initials: F
authors.lastname: Bellivier
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D017668:Age of Onset; D001499:Bayes Theorem; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012189:Retrospective Studies; D013406:Suicide, Attempted / Q000523:psychology* / Q000706:statistics & numerical data*; D055815:Young Adult