A Deficit of Oxytocin – Major Depression
A new study published in the Journal of Psychiatric Research extends the results of two previous studies and provides evidence for a deficit of oxytocin in women with depression, including patients with psychotic major depression (PMD), who typically exhibit greater depressive severity.
The neuropeptide oxytocin (OXT) has been implicated in many aspects of reproductive and social behaviors or mammalian sociality. This includes parental care, recognition and attachment; social bonding and ‘the shift from self to other’, trust, empathy, ‘social selectivity’ and other components of the behavioral spectrum.
The evidence from animal and clinical studies suggests a potential role of the OXT system in the pathophysiology of major depression , as well as a potential therapeutic benefit of OXT in at least some subsets of MDD patients.
Recent evidence has implicated OXT in numerous complex behaviours, particularly anxiolysis. Thus, given that half of the patients diagnosed with major depression meet criteria for co-morbid anxiety disorder, OXT may be of therapeutic benefit in these patients, as well as those with only anxiety.
In the Journal of Psychiatric Research study Kaeli Yuen and colleagues from the Department of Psychiatry, Stanford University, Stanford, CA found that plasma oxytocin levels were decreased in depressed females but increased (non-significantly) in depressed males compared to gender-matched healthy controls.
The study provides further insights into the link between oxytocin and depression, and the role of dysregulated oxytocin pathways in this condition. As depression is much more common in women than men (and 1 in 4 women will require treatment for depression at some time), the study may also help explain, at least in part, the female preponderance of depression.
In addition, the study suggests that oxytocin levels may also be linked to desirability, drug dependence, and compulsivity scores as measured by the Million Clinical Multiaxial Inventory-III.
Source: J Psychiatr Res, 2014, 51:30-6. doi: 10.1016/j.jpsychires.2013.12.012. Epub 2013 Dec 28.
Read more: J Psychiatr Res
A 2018 study reports reduced serum oxytocin levels in depressed female patients. Of note, on comparing both oxytocin level in the female patients and female control groups, it revealed high statistical significance among the two groups. The authors of this study concluded that this is consistent with the hypothesis of dysregulated oxytocin biology may serve as a biomarker for major depression.
A 2020 systematic review entitled: ‘Oxytocin and postpartum depression’ identified twelve studies with the generalized goal of correlating endogenous oxytocin (OT) concentration with depressive symptomatology in the perinatal period. The publications identified were split between those that looked exclusively postpartum (n=5) and those that examined OT measurements both prenatally and postpartum (n=7). Eight found an inverse association between plasma OT and PPD symptoms (i.e. lower OT associated with higher depressive symptoms), two did not find any significant relationships and one found a change of OT trajectory over pregnancy and postpartum (rather than relative value) predictive of depressive symptoms.
A 2021 study found that serum oxytocin levels of patients with depression were significantly lower, and those of patients with generalized anxiety disorder, social anxiety disorder, and panic disorder (PD) with agoraphobia were significantly higher compared to the control group. Of note, in patients with PD with agoraphobia, oxytocin levels were significantly higher than in PD patients without agoraphobia.
A 2022 study aimed to assess the relationship between serum oxytocin, depression and temperament traits and to analyze the effect of serum oxytocin and temperament in depressive symptomatology in a sample of 45 young, healthy university female students.
Figure 1. From ‘Depressive symptomatology, temperament and oxytocin serum levels in a sample of healthy female university students’ by L. Veiga et al. BMC Psychology volume 10, Article number: 36, 2022. Open Access, Public Domain.
The study reports that oxytocin level, rather than personality dimensions, was associated with depressive symptomatology. Oxytocin serum levels were strong and negatively associated with depression scores suggesting that lower levels of oxytocin are associated with higher levels of depression.
These results highlight the relevance of the discussion on the use of oxytocin as a biological marker of emotional and social symptoms that characterize depression.
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