kendler et al "female mz male mz"

aim

investigate heritability of mdd

method

interview, survey, twin study, genotype

procedure

15493 twin pairs interviewed over the phone on lifetime depression based on DSM-IV

results

8056 twins met criteria for mdd at one point in lifetime. concordance rates of female mz: 0.44 male mz: 0.31 female dz: 0.16 male dz: 0.13

link

females have higher rates of mdd and mz twins (sharing 100% dna) have sig higher concordance rates showing the genetic influence on mdd and the environmental as well because concordance is not 100% in mz twins