Assessing the relationship between attachment, parental attitude and plasma oxytocin in schizophrenia patients and their unaffected siblings

Nord J Psychiatry. 2019 Jan;73(1):51-57. doi: 10.1080/08039488.2018.1554698. Epub 2019 Jan 14.


Background: It is widely acknowledged that schizophrenia patients tend to have insecure attachment styles and improper parenting. However, the biological processes related to these adversities remain unclear and that the disturbance in oxytocin system is considered as one of the strongest predictors of such adversities.

Methods: Thirty-four patients with schizophrenia and their unaffected thirty-four healthy siblings were recruited for the study and they were compared with thirty-one healthy controls. We examined attachment styles via Experience in Close Relationship-Revised Test and perceived parental attitudes with the My Memories of Upbringing-Short Version Test. In addition, we evaluated plasma oxytocin levels across groups.

Results: The patients with schizophrenia had lower plasma oxytocin levels and obtained higher levels for attachment anxiety and avoidance with more parental rejection and over protection. There was a significantly negative relationship between the levels of plasma oxytocin in blood and parental over protection in the healthy sibling and healthy control groups. In contrast, there was a significantly positive relationship between the levels of plasma oxytocin in blood and parental over protection in the schizophrenia group. Results of the regression analyses revealed that the plasma oxytocin levels and over protection were notable factors in discriminating the groups from each other.

Conclusion: Our findings suggested that disturbance in oxytocin is associated with susceptibility to schizophrenia predisposition. In sum, therapeutic interventions that address oxytocin and over protection may influence the outcomes in this severe mental disorder.

Keywords: Oxytocin; attachment; over protection; parental care; schizophrenia; sibling.

MeSH terms

  • Adult
  • Anxiety
  • Case-Control Studies
  • Female
  • Humans
  • Male
  • Object Attachment*
  • Oxytocin / blood*
  • Parent-Child Relations*
  • Parenting
  • Parents / psychology*
  • Psychological Tests
  • Regression Analysis
  • Schizophrenia / blood*
  • Schizophrenic Psychology*
  • Siblings


  • Oxytocin