March 2000, Volume 3, Issue 1, Pages 28 - 32

Article

Lifetime prevalence of mood and anxiety disorders in twin pairs discordant for schizophrenia Michael J Lyons1,2,3,4, Jonathan Huppert1, Rosemary Toomey2,3,4, Rebecca Harley1, Jack Goldberg5,6, Seth Eisen7,8, William True7,9, Stephen V Faraone2,3 & Ming T Tsuang2,3,4 1Department of Psychology, Boston University     2Harvard Medical School Department of Psychiatry at Massachusetts Mental Health Center, Boston, MA     3Harvard Institute of Psychiatric Epidemiology and Genetics, Boston, MA     4Department of Psychiatry, Brockton VA, Brockton, MA     5Department of Epidemiology, University of Illinois School of Public Health, Chicago, IL     6Hines VA Cooperative Studies Program Coordinating Center, Hines, IL     7Research and Medical Service, St Louis, MO     8Department of Medicine, Washington University, St Louis, MO     9School of Public Health, St Louis University, St Louis, MO, USA     Correspondence to: Michael J Lyons PhD, Psychology Department, Boston University, 64 Cummington Street, Boston, MA 02215, USA. Tel: (617)353 3820; Fax: (508)586 6791; E-mail: mlyons@bu.edu

Keywords

schizophrenia;   twins;   discordant;   mood disorders;   anxiety disorders

Abstract

There have been long questions about the relationship of schizophrenia to other mental disorders. Lifetime DSM-III-R diagnoses of mood and anxiety disorders in twins with clinically diagnosed schizophrenia (n = 24) and their non-affected co-twins (n = 24) were compared with twins from pairs without schizophrenia (n = 3327) using a sample from the Vietnam Era Twin Registry. Schizophrenic probands had significantly elevated rates of all included disorders (bipolar disorder, major depression, dysthymia, generalized anxiety disorder, panic disorder, and PTSD) compared with controls (P < 0.01). The odd ratios comparing co-twins of schizophrenic probands with controls was greater than three for every disorder, but did not attain statistical significance. A similar pattern was observed when analyses were restricted to only monozygotic twins (n = 12). Consistent with other studies, schizophrenics appeared to have higher rates of a range of mental disorders. Our results suggest that schizophrenia per se represents a risk factor for other psychiatric disorders, but the absence of significantly elevated risk among non-schizophrenic co-twins suggested that family environmental and/or genetic factors that contribute to risk of schizophrenia do not increase the risk of mood and anxiety disorders to the same extent that the risk of these other disorders is increased by the presence of schizophrenia. Twin Research (2000) 3, 28-32.

Received 26 March 1999; Revised 28 July 1999; Accepted 17 August 1999

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