OBJECTIVE: We sought to compare the probandwise concordance rate (PRC) for affective illness (AI) in monozygotic (MZ) and dizygotic (DZ) twins in samples ascertained through psychiatric hospitalization vs samples from the general population. METHODS: Twins were ascertained through psychiatric hospitalization for AI from the Swedish Psychiatric Twin Registry or as a matched sample from the population-based Swedish Twin Registry. Lifetime diagnoses were based on a mailed questionnaire containing, in self-report format, DSM-III-R criteria for mania and major depression. Returned questionnaires were obtained from 1484 individuals and both members of 486 pairs, of whom 154 were classified as MZ, 326 as DZ, and six of unknown zygosity. RESULTS: No evidence was found for violations of the equal environment assumption. Using either a narrow or broad diagnostic approach, the risk for AI in cotwins of proband twins was independent of the gender, polarity (ie, unipolar vs bipolar) and mode of ascertainment of the affected proband (ie, via hospitalization vs from the general population). Combining both subsamples, PRC for total AI using narrow diagnostic criteria was 48.2% in MZ and 23.4% in DZ twins. Using broad diagnostic criteria, the parallel figures were 69.7% and 34.9%. The risk for bipolar illness was substantially increased in the cotwins of probands with bipolar AI. CONCLUSIONS: Genetic factors play a major role in the etiology of AI in Sweden, as assessed by self-report questionnaire. Heritable factors appear to be equally important in AI as ascertained in clinical and epidemiological samples.
OBJECTIVE: We sought to compare the probandwise concordance rate (PRC) for affective illness (AI) in monozygotic (MZ) and dizygotic (DZ) twins in samples ascertained through psychiatric hospitalization vs samples from the general population. METHODS: Twins were ascertained through psychiatric hospitalization for AI from the Swedish Psychiatric Twin Registry or as a matched sample from the population-based Swedish Twin Registry. Lifetime diagnoses were based on a mailed questionnaire containing, in self-report format, DSM-III-R criteria for mania and major depression. Returned questionnaires were obtained from 1484 individuals and both members of 486 pairs, of whom 154 were classified as MZ, 326 as DZ, and six of unknown zygosity. RESULTS: No evidence was found for violations of the equal environment assumption. Using either a narrow or broad diagnostic approach, the risk for AI in cotwins of proband twins was independent of the gender, polarity (ie, unipolar vs bipolar) and mode of ascertainment of the affected proband (ie, via hospitalization vs from the general population). Combining both subsamples, PRC for total AI using narrow diagnostic criteria was 48.2% in MZ and 23.4% in DZ twins. Using broad diagnostic criteria, the parallel figures were 69.7% and 34.9%. The risk for bipolar illness was substantially increased in the cotwins of probands with bipolar AI. CONCLUSIONS: Genetic factors play a major role in the etiology of AI in Sweden, as assessed by self-report questionnaire. Heritable factors appear to be equally important in AI as ascertained in clinical and epidemiological samples.
Authors: Nathan A Gillespie; Michael C Neale; Donald J Hagler; Lisa T Eyler; Christine Fennema-Notestine; Carol E Franz; Michael J Lyons; Linda K McEvoy; Anders M Dale; Matthew S Panizzon; William S Kremen Journal: Hum Brain Mapp Date: 2017-02-27 Impact factor: 5.038
Authors: Helena Furberg; Megan Olarte; Niloo Afari; Jack Goldberg; Dedra Buchwald; Patrick F Sullivan Journal: J Psychosom Res Date: 2005-11 Impact factor: 3.006
Authors: Michael J McCarthy; Thomas B Barrett; Stephanie Nissen; John R Kelsoe; Eric E Turner Journal: J Psychiatr Res Date: 2009-09-18 Impact factor: 4.791
Authors: Danielle M Dick; Tatiana Foroud; Leah Flury; Elizabeth S Bowman; Marvin J Miller; N Leela Rau; P Ryan Moe; Nalini Samavedy; Rif El-Mallakh; Husseini Manji; Debra A Glitz; Eric T Meyer; Carrie Smiley; Rhoda Hahn; Clifford Widmark; Rebecca McKinney; Laura Sutton; Christos Ballas; Dorothy Grice; Wade Berrettini; William Byerley; William Coryell; Raymond DePaulo; Dean F MacKinnon; Elliot S Gershon; John R Kelsoe; Francis J McMahon; Melvin McInnis; Dennis L Murphy; Theodore Reich; William Scheftner; John I Nurnberger Journal: Am J Hum Genet Date: 2003-05-27 Impact factor: 11.025