title: The specificity of the familial aggregation of early-onset bipolar disorder: A controlled 10-year follow-up study of offspring of parents with mood disorders.
abstract: BACKGROUND
  Two major sources of heterogeneity of mood disorders that have been demonstrated in clinical, family and genetic studies are the mood disorder subtype (i.e. bipolar (BPD) and major depressive disorder (MDD)) and age of onset of mood episodes. Using a prospective high-risk study design, our aims were to test the specificity of the parent-child transmission of BPD and MDD and to establish the risk of psychopathology in offspring in function of the age of onset of the parental disorder.
  
  
  METHODS
  Clinical information was collected on 208 probands (n=81 with BPD, n=64 with MDD, n=63 medical controls) as well as their 202 spouses and 372 children aged 6-17 years at study entry. Parents and children were directly interviewed every 3 years (mean duration of follow-up=10.6 years). Parental age of onset was dichotomized at age 21.
  
  
  RESULTS
  Offspring of parents with early onset BPD entailed a higher risk of BPD HR=7.9(1.8-34.6) and substance use disorders HR=5.0(1.1-21.9) than those with later onset and controls. Depressive disorders were not significantly increased in offspring regardless of parental mood disorder subtype or age of onset.
  
  
  CONCLUSIONS
  Limited sample size, age of onset in probands was obtained retrospectively, age of onset in co-parents was not adequately documented, and a quarter of the children had no direct interview.
  
  
  CONCLUSIONS
  Our results provide support for the independence of familial aggregation of BPD from MDD and the heterogeneity of BPD based on patterns of onset. Future studies should further investigate correlates of early versus later onset BPD.
authors.affiliation: Department of Psychiatry, University Hospital of Lausanne, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Preisig
authors.affiliation: Department of Psychiatry, University Hospital of Lausanne, Switzerland.
authors.forename: Marie-Pierre F
authors.initials: MF
authors.lastname: Strippoli
authors.affiliation: Department of Psychiatry, University Hospital of Lausanne, Switzerland.
authors.forename: Enrique
authors.initials: E
authors.lastname: Castelao
authors.affiliation: Genetic Epidemiology Research Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA.
authors.forename: Kathleen Ries
authors.initials: KR
authors.lastname: Merikangas
authors.affiliation: Department of Psychiatry, University Hospital of Lausanne, Switzerland.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Gholam-Rezaee
authors.affiliation: Department of Psychiatry, University Hospital of Lausanne, Switzerland.
authors.forename: Pierre
authors.initials: P
authors.lastname: Marquet
authors.affiliation: Department of Mental Health and Psychiatry, University Hospital of Geneva, Switzerland.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Aubry
authors.affiliation: Department of Psychiatry, University Hospital of Lausanne, Switzerland. Electronic address: Caroline.Vandeleur@chuv.ch.
authors.forename: Caroline L
authors.initials: CL
authors.lastname: Vandeleur
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001714:Bipolar Disorder / Q000235:genetics*; D002648:Child; D016241:Child of Impaired Parents / Q000523:psychology*; D003865:Major Depressive Disorder / Q000235:genetics*; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors
keywords: Age of onset; Family aggregation; High-risk study; Major depression; Mania; Substance use disorders