Table 3 The role of female sex hormones in MDD overall and in MDD circuit function

Rudolph et al. [138]

Postmenopausal women with and without MDD

Treatment: 24 weeks of continuous combined HRT (2 mg estradiol valerate + 2 mg dienogest)

A clinically relevant reduction in depression severity

Marsh et al. [142]

Regularly cycling premenopausal women

Treatment: various durations of OC

A longer use of OC (i.e., a longer exposure to estrogens from menarche to menopause) was associated with reduced risk of postmenopausal depression.

Saletu et al. [140]

Menopausal women with and without MDD

Treatment: 3 months of transdermal estradiol (100 μg/week)

Estradiol treatment increased alpha and theta power and reduced beta power in the temporal region, which reflected improved vigilance. No changes in frontal alpha asymmetry observed.

Zhang et al. [164]

Regularly cycling women with and without MDD

The degree of frontal asymmetry positively correlated to depression severity scores during periovulation only. The level of frontal asymmetry during the premenstrual phase was predictive of postmenstrual depression severity scores. The degree of frontal asymmetry during postmenstrual and periovulation phases predicted depression severity scores during periovulation.

Saletu et al. [162]

Postmenopausal women without previous HRT, with or without MDD

Frontal asymmetry positively correlates with depression severity scores. Postmenopausal women with depression had reduced global total and absolute power in delta, theta, and beta bands, as well as increased global relative delta and theta power, and attenuated alpha power. Both estradiol levels and depression severity scores directly correlated with EEG changes.