title: Affective disorders in the first-degree relatives of bipolar probands: results from the South Island Bipolar Study.
abstract: The current study was performed to document observed rates of affective disorders in the first degree relatives of probands with bipolar I or II disorder; to determine whether bipolar II probands have an excess of bipolar II relatives; and to determine whether bipolar probands with a history of one or more suicide attempts have more relatives who have also made suicide attempts. Bipolar probands with positive family histories of affective disorder were recruited from a variety of sources for a study on the molecular genetics of bipolar disorder. Probands and relatives were interviewed with the Diagnostic Interview for Genetic Studies (DIGS) and blood was obtained for DNA extraction and genetic analyses. Among 423 first-degree adult relatives of 153 bipolar probands, 7% (29) had bipolar I disorder, 7% had bipolar II disorder, and 7% had bipolar not otherwise specified (NOS) disorder, making 21% of relatives with any bipolar disorder. A further 42% of relatives had a depressive disorder and only 38% had no affective disorder. A suicide attempt by a proband was not associated with any increase in suicide attempts by relatives. We conclude that while unipolar depressive disorders are the most common affective disorders in the first-degree relatives of bipolar probands, extension of the bipolar phenotype to include bipolar spectrum disorders results in 21% of relatives having any bipolar disorder.
authors.affiliation: Department of Psychological Medicine, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Joyce
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Doughty
authors.forename: J Elisabeth
authors.initials: JE
authors.lastname: Wells
authors.forename: Anne E s
authors.initials: AE
authors.lastname: Walsh
authors.forename: Anita
authors.initials: A
authors.lastname: Admiraal
authors.forename: Marianne
authors.initials: M
authors.lastname: Lill
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Olds
mesh_terms: D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D017668:Age of Onset; D001714:Bipolar Disorder / Q000453:epidemiology / Q000235:genetics*; D003863:Depression / Q000453:epidemiology / Q000235:genetics; D005260:Female; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D009520:New Zealand / Q000453:epidemiology; D012042:Registries; D017678:Sex Distribution; D013406:Suicide, Attempted / Q000706:statistics & numerical data