title: Gender differences in heritability of depressive symptoms in the elderly.
abstract: BACKGROUND
  The present study aimed to investigate the relative importance of genetic and environmental influences on depressive symptoms in the elderly.
  
  
  METHODS
  Depressive symptoms were assessed through the Center for Epidemiological Studies-Depression (CES-D) scale. The CES-D scale was administered to 959 twin pairs (123 female MZs, 90 male MZs, 207 same-sex female DZs, 109 same-sex male DZs and 430 opposite-sex DZs) aged 50 years or older (mean age 72 years). A dichotomous depressed state variable was constructed based on CES-D cut-offs and self-reported use of antidepressant medication. Structural equation models were fitted to the data to dissect genetic and environmental variance components.
  
  
  RESULTS
  The sex-specific heritability estimates for depressive symptoms were 14% for males and 29% for females and 23% when constrained to be equal for men and women. The prevalence of clinically significant depressive symptoms was 16% for men and 24% for women. Heritability estimates for the dichotomous depressed state measure were 7% for males and 49% for females in the full model and 33% when constrained to be equal.
  
  
  CONCLUSIONS
  Our results suggest that depressive symptoms in the elderly are moderately heritable, with a higher heritability for women than men, although differences in heritability estimates were not statistically significant.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. martja@ki.se
authors.forename: M
authors.initials: M
authors.lastname: Jansson
authors.forename: M
authors.initials: M
authors.lastname: Gatz
authors.forename: S
authors.initials: S
authors.lastname: Berg
authors.forename: B
authors.initials: B
authors.lastname: Johansson
authors.forename: B
authors.initials: B
authors.lastname: Malmberg
authors.forename: G E
authors.initials: GE
authors.lastname: McClearn
authors.forename: M
authors.initials: M
authors.lastname: Schalling
authors.forename: N L
authors.initials: NL
authors.lastname: Pedersen
mesh_terms: D000368:Aged; D000928:Antidepressive Agents / Q000008:administration & dosage; D003863:Depression / Q000188:drug therapy / Q000453:epidemiology* / Q000235:genetics*; D004200:Diseases in Twins / Q000453:epidemiology / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D012737:Sex Factors
chemical_list: D000928:Antidepressive Agents