title: Genetic studies of affective disorders: should we be starting with childhood onset probands?
abstract: OBJECTIVE
  The objective of this study is to test whether the presence of childhood onset affective disorder identifies families with increased incidence and severity of affective disorders.
  
  
  METHODS
  Family history information was collected on the first and second degree relatives and first cousins age > or = 15 years of 22 children with bipolar affective disorder, 54 children with major depressive disorder, and 31 psychiatrically normal children.
  
  
  RESULTS
  Compared with the relatives of normal children, relatives identified through children with bipolar affective disorder or major depressive disorder had elevated rates of affective disorders and increased severity of affective disorders as judged by earlier age of onset and increased suicide attempts. Segregation analyses could reject purely environmental transmission of illness.
  
  
  CONCLUSIONS
  Ascertaining families through childhood onset affective disorder probands identifies extended pedigrees with high incidence and severity of affective disorders. These families may be more appropriate for genetic analyses than are families of adult probands.
authors.affiliation: Washington University School of Medicine, Department of Psychiatry, St. Louis, MO 63110.
authors.forename: R D
authors.initials: RD
authors.lastname: Todd
authors.forename: R
authors.initials: R
authors.lastname: Neuman
authors.forename: B
authors.initials: B
authors.lastname: Geller
authors.forename: L W
authors.initials: LW
authors.lastname: Fox
authors.forename: J
authors.initials: J
authors.lastname: Hickok
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002648:Child; D003866:Depressive Disorder / Q000175:diagnosis / Q000235:genetics*; D004311:Double-Blind Method; D005190:Family; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D019964:Mood Disorders / Q000175:diagnosis / Q000235:genetics*; D015995:Prevalence; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D012720:Severity of Illness Index