title: Heterogeneity of the risk of suicidal behavior in bipolar-spectrum disorders.
abstract: OBJECTIVE
  The risk of suicidal behavior is substantially elevated in major affective disorders (AD). In bipolar disorder (BD), as many as 15% of patients may commit suicide and family history of suicide is recognized as one of the most important risk factors. Lithium reduces the rates of suicidal behavior in BD, especially in patients who achieve full mood stabilization. Yet even patients who continue experiencing mood episodes do benefit from anti-suicidal properties of lithium. These observations raise questions about the nature of the relationship between the neurobiological mechanisms of BD and suicide, namely whether they are shared or independent.
  
  
  METHODS
  We studied the distribution of suicides and suicide attempts in 539 subjects from 78 families of probands with major AD, all responders to lithium prophylaxis. A Cox proportional hazard regression model was used to assess the contribution of several independent variables to the risks of AD, BD, and suicidal behavior.
  
  
  RESULTS
  The lifetime prevalence of BD was significantly greater among first-degree relatives of suicide than non-suicide probands (22% versus 11%) and the prevalence of BD in families was associated with an increased risk of developing mood disorder and subsequently committing or attempting suicide (p = 0.003). Families fell into 1 of 3 groups, corresponding to a low (<0.1%), intermediate (17.8%), and high (87.8%) risk for suicide in affectively ill subjects.
  
  
  CONCLUSIONS
  Suicidal behavior is distributed unevenly in families of probands with BD, aggregating in a subset of families. Our results also suggest that partially overlapping sets of genetic factors may underlie BD and suicide.
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Cavazzoni
authors.forename: Paul
authors.initials: P
authors.lastname: Grof
authors.forename: Anne
authors.initials: A
authors.lastname: Duffy
authors.forename: Eva
authors.initials: E
authors.lastname: Grof
authors.forename: Bruno
authors.initials: B
authors.lastname: Müller-Oerlinghausen
authors.forename: Anne
authors.initials: A
authors.lastname: Berghöfer
authors.forename: Bernd
authors.initials: B
authors.lastname: Ahrens
authors.forename: Petr
authors.initials: P
authors.lastname: Zvolsky
authors.forename: Carrie
authors.initials: C
authors.lastname: Robertson
authors.forename: Alison
authors.initials: A
authors.lastname: Davis
authors.forename: Tomas
authors.initials: T
authors.lastname: Hajek
authors.forename: Martin
authors.initials: M
authors.lastname: Alda
mesh_terms: D000328:Adult; D018692:Antimanic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy / Q000453:epidemiology* / Q000235:genetics / Q000523:psychology; D003865:Major Depressive Disorder / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D018020:Lithium Compounds / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics / Q000523:psychology; D012307:Risk Factors; D013405:Suicide / Q000523:psychology / Q000706:statistics & numerical data*; D013406:Suicide, Attempted / Q000517:prevention & control / Q000523:psychology / Q000706:statistics & numerical data*; D000092864:Suicide Prevention
chemical_list: D018692:Antimanic Agents; D018020:Lithium Compounds