title: Twins discordant for schizophrenia: psychopathology of the non-schizophrenic co-twins.
abstract: OBJECTIVE
  Patients with schizophrenia are more likely to suffer from mood and anxiety disorders compared with the general population. We explored the aetiology of this comorbidity using a twin study design.
  
  
  METHODS
  We applied an additive genetic + unique environment (AE) random effects model in the analysis of 35 non-schizophrenic co-twins from pairs discordant for schizophrenia, and 131 control twins.
  
  
  RESULTS
  Non-schizophrenic co-twins had significantly increased rates of depression (P = 0.006) and anxiety disorders (P = 0.021) compared with the control twins.
  
  
  CONCLUSIONS
  Our results provide evidence for a familial association between schizophrenia and anxiety and depression. This could reflect common aetiological factors contributing to each of the disorders. Future studies should attempt to investigate the relative genetic and environmental contribution to the shared risk factors for schizophrenia, mood and anxiety disorders.
authors.affiliation: Division of General Psychiatry and Psychological Medicine, Institute of Psychiatry, London, UK. s.argyropoulos@iop.kcl.ac.uk
authors.forename: S V
authors.initials: SV
authors.lastname: Argyropoulos
authors.forename: S
authors.initials: S
authors.lastname: Landau
authors.forename: S
authors.initials: S
authors.lastname: Kalidindi
authors.forename: T
authors.initials: T
authors.lastname: Toulopoulou
authors.forename: D J
authors.initials: DJ
authors.lastname: Castle
authors.forename: R M
authors.initials: RM
authors.lastname: Murray
authors.forename: M M
authors.initials: MM
authors.lastname: Picchioni
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D015897:Comorbidity; D003866:Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D012565:Schizophrenic Psychology; D011795:Surveys and Questionnaires; D006113:United Kingdom; D055815:Young Adult