Table.

Summary of articles reviewed on plasma oxytocin and depression or depressive symptoms

Plasma oxytocin levels and subclinical depressive symptoms in non-depressed individuals
Authors	Sample	Analyses of Interest	Measures of depression & oxytocin	Confounders controlled	Findings
Eapen et al., 2014	Pregnant women ≥ 18 years old (range 17 – 47) < 38 weeks gestation with singleton pregnancy attending hospital antenatal clinic in Sydney, Australia recruited for larger study on separation anxiety (N = 127)	Cross-sectional and longitudinal relationship between plasma oxytocin level and depressive symptoms in pregnancy and oxytocin level, separation anxiety, and disturbances in maternal infant attachment at 3 months postpartum	Self-report - Edinburgh Postpartum Depression Scale (EPDS)	Regression analysis used, but covariates not reported.	Lower postpartum oxytocin level associated with greater postpartum depressive symptoms
			Enzyme immunoassay (EIA) of extracted plasma samples
Seay et al., 2014	Ethnic minority (African-American or Caribbean) HIV-positive women recruited for a larger study on the influence of a cognitive behavioral stress intervention on health among women living with HIV in Miami, FL, USA (N = 70)	Linear and curvilinear relationships between plasma oxytocin levels and depressive symptoms over a 10-week interval.	Self-report – Beck Depression Inventory (BDI)	Age, ethnicity, employment, income, relationship status	Lower baseline oxytocin levels marginally predicted greater depressive symptoms 10 weeks later (p = .06).
			EIA of extracted plasma samples
Zelkowitz et al., 2014	Community sample of pregnant women 12-14 weeks gestation with singleton pregnancy recruited from prenatal clinics in Montreal, Quebec, Canada (N = 287)	Relationship between plasma oxytocin in pregnancy and 8 weeks postpartum to stress, depressive symptoms, maternal interactive behavior with infant.	Self-report – EPDS	Age, education, marital status	Among women reporting high hpsychosocial stress, higher oxytocin levels were associated with fewer depressive symptoms and more sensitive maternal behavior.
			EIA of unextracted plasma samples

Comparison of plasma oxytocin levels in depressed versus non-depressed individuals
Authors	Sample	Analyses of Interest	Measures of depression and oxytocin	Control for confounders	Findings
Cyranowski et al., 2008	Currently depressed (n = 17) and never depressed (n = 17) women aged 20 – 40 years free of antidepressant medication for 2 or more weeks recruited from a mood disorders clinic in Pittsburgh, PA, United States (N = 34)	Compared repeated plasma oxytocin levels and patterns between currently depressed and never depressed women before, during and after completion of an affiliation- focused imagery task and a stress-focused task	Clinician rated Hamilton Depression Rating Scale and self- reported BDI	Age	Depressed women had higher oxytocin levels during affiliation task compared to controls. Depressed women displayed more variability in pulsatile oxytocin release in general.
			Radioimmunoassay of extracted plasma samples
Ozsoy et al., 2009	Psychiatric inpatients (30 women, 10 men) with major depressive disorder (n = 29) or bipolar depression (n = 11) hospitalized at an academic medical hospital in Kayseri, Turkey and 32 (20 women, 12 men) healthy controls recruited from hospital staff (N = 72)	Comparison of plasma oxytocin levels in (a) depressed versus controls; unipolar vs. bipolar depression; (b) male versus female; (c) pharmacotherapy versus ECT treatment	Clinical interview by two independent psychiatrists based on DSM-IV criteria	Age, body mass index (BMI), number of children	(a)Oxytocin levels lower in depressed men and women versus controls, but difference driven by differences in females only. (b)No difference between male and female controls, male and female depressed. (c)No difference in oxytocin levels based pre/post treatment.
			Radioimmunoassay of unextracted serum samples
Skrundz et al., 2011	Community sample of German-speaking healthy pregnant women 21 to 32 weeks gestation in Basel, Switzerland with singleton pregnancy, pre-pregnancy BMI < 32, without major depressive episode in past 2 years (N = 73)	Relationship between pregnancy plasma oxytocin concentration and risk-for postpartum depression (PPD) group versus no-risk for PPD using EPDS cutoff of 10	Self-report EPDS at 2 weeks postpartum	Prenatal EPDS score, length of gestation	Lower oxytocin level in pregnancy was associated with greater risk of postpartum depression at 2 weeks postpartum
			EIA of unextracted plasma samples
Turan et al., 2013	Sixty-seven (39 male, 28 female) psychiatric outpatients with bipolar disorder (22 with acute mania, 21 with acute depression, 24 in remission) aged 18 – 65 years seen at an academic medical center clinic and 24 healthy controls recruited from hospital staff in Kayseri, Turkey (N = 91)	Compared plasma oxytocin levels among bipolar mania, bipolar depression, and bipolar remission and control groups	Self-report – Hamilton Depression Rating Scale	Age, gender, BMI, cigarettes/day	Oxytocin levels were higher in bipolar patients in any phase compared to controls. No statistically significant difference in oxytocin levels among bipolar groups.
			EIA of unextracted serum samples
Yuen et al., 2014	Adults with major depressive disorder with psychosis (10 female, 4 male) and without psychosis (12 female, 5 male), and 19 healthy controls recruited from a large academic medical center in California, USA participating in a larger study on HPA axis physiology and depressive disorders (N = 50)	Comparison of plasma oxytocin levels among psychotic depressed, non-psychotic depressed, and healthy individuals; gender differences in oxytocin levels in depressed versus non-depressed individuals	Self-report – Hamilton Depression Rating Scale	Gender, cortisol concentration	Oxytocin concentration differed between female and male depressed individuals, and were decreased in depressed females versus controls, while marginally increased in depressed males versus controls.
			EIA of extracted plasma samples