Depression in the perimenopause has been found to be due to swings in estrogen levels and deficiency of progesterone because there are no or few ovulatory cycles at this time of life. We women knew this personally, but it takes years for academic medicine to give affirmation to what we women intuitively knew.
It makes sense to support women with natural progesterone and or estradiol during this transition. One interesting fact is that mood symptoms can be present with or without hot flushes and night sweats.
References: Joffe H. et al. Impact of estradiol variability and progesterone on mood in perimenopausal women with depressive symptoms. Journal of Clinical Endocrinology and Metabolism 101(3):e642-e650, 2020.