• Parental characteristics;
  • twin study;
  • mood disorders;
  • heritability

ABSTRACT A study of monozygotic (MZ) and dizygotic (DZ) twins was undertaken to assess further the properties of the Parental Bonding Instrument (PBI), a self-report measure of parental care and overprotection, to examine for associations between PBI and mood (trait anxiety and depression) scores, and to assess the genetic contribution to anxiety and depression scores. Mean correlations on the PBI scales were high and strikingly similar for the MZ and DZ twin pairs, supporting the construct validity of the PBI as a measure of parental characteristics. Higher mood scores were linked with less parental care and greater parental protection, the associations being stronger with anxiety than depression. Finally, methodological limitations in estimating heritability are noted.