Beneficial effects of aging on mood in healthy postmenopausal women
This study makes a valuable contribution to knowledge about the role of chronological aging versus reproductive state affecting the course of mood changes not only during the menopause transition, but also during the early and late postmenopause stages. Although previous work has focused on mood changes during the menopause transition, this longitudinal investigation helped to fill a gap in the systematic examination of mood changes that occur during the postmenopausal period to help distinguish the effects of hormonal change versus age on the course of mood changes.
The longitudinal nature of the study is one of its greatest strengths. To test their hypotheses regarding the role of reproductive menopausal stage versus chronological age on the course of mood symptoms, the investigators conducted the study over 20 years, a rare feat in this age when more cross-sectional designs are predominant, perhaps because of the limitation of consistent funding opportunities. One could well make a case for the need for consistent long-term funding opportunities to address pertinent questions based on this study. The fact that they had a 53% retention rate after 20 years also underlies this point.
Another strength of the study includes using the updated Stages of Reproductive Aging Workshop +10 criteria to define reproductive stage and menopausal status: after the final menstrual period (FMP), women were categorized as being in the late reproductive stage, early menopause transition, late menopause transition, stage 1, 1b, or 1c of the early postmenopause, or late postmenopause stage 2 depending on menstrual cycle regularity and time elapsed since the FMP. This delineation allowed them to decipher the effects of age versus reproductive stage on the course of mood symptoms more specifically.
The focus of the study was the spectrum of mood symptoms in healthy women. Using the Actometer 2 allowed the investigators to assess a continuum of scores in a healthy population ranging from women who hardly ever experienced negative feelings to those women experiencing them most of the time. In the past 10 years of the study in the postmenopause group, the investigators included the complimentary Centre for Epidemiological Studies Depression Scale, a subjective assessment of depressive symptoms more designed for clinical populations (with a ≥10 cut-off score) for more mild or moderate versus normal symptoms. Thus, rather than focusing on categorical diagnoses, this study yielded important information on the dimension of mood symptoms that occur during the menopause transition and with aging, now more the focus of studies emphasizing research domain criteria. The design of the study using these scales allowed for the comparison of intraindividual changes in mood across two decades.