Purpose: Quality of life (QoL) is greatly impaired in major depressive disorder (MDD). These impairments are not fully accounted for by symptom severity, may persist beyond depressive episodes, and are a risk factor for poor outcomes. MDD is often associated with prominent neuroendocrine changes and increased risk of chronic disease. However, there is a lack of research examining whether biological factors are related to QoL in MDD. This research examined relationships between cortisol, oxytocin, symptom severity, and QoL in MDD.
Methods: Sixty adults meeting DSM-5 criteria for MDD and 60 healthy controls provided morning plasma samples which were analysed for cortisol and oxytocin levels, and completed measures of QoL and psychopathology.
Results: Participants with MDD had lower QoL than controls. Cortisol correlated negatively with overall QoL and all QoL domains. Oxytocin correlated positively with overall QoL, and Psychological and Social-Relationships domains. Additionally, cortisol levels were inversely related to psychological QoL, and oxytocin was positively related to social QoL, after controlling for symptom severity and demographic variables.
Conclusions: This study provides novel evidence linking neuroendocrine pathways to particular domains of QoL in MDD. The results indicate that activity of the hypothalamic-pituitary-adrenal axis is linked to poor psychological QoL, and that oxytocin is important to social QoL, independently of severity of psychopathology. Biopsychosocial approaches to QoL associated with mental health conditions may lead to greater understanding of the underlying mechanisms and to improved, tailored interventions.