The study’s findings may explain the high rates of first-time depression seen among women in this transitional stage of life, known as perimenopause, according to researchers at the Centre for Addiction and Mental Health (CAMH) in Canada.
“This is the first time that a biological change in the brain has been identified in perimenopause, which is also associated with clinical depression,” said Jeffrey Meyer, M.D., Ph.D., a senior scientist at CAMH’s Campbell Family Mental Health Research Institute.
Rates of first-time clinical depression among this group reach 16 percent to 17 percent, while a similar number of women get milder depressive symptoms, the researchers reported.
According to the study, published in JAMA Psychiatry, Meyer’s research team found elevated levels of the chemical monoamine oxidase-A (MAO-A) among women aged 41-51.
MAO-A is an enzyme that breaks down brain chemicals such as serotonin, norepinephrine, and dopamine, which help to maintain normal mood.
In previous studies, Meyer linked high levels of MAO-A to major depressive disorder, depressed mood related to alcohol dependence and smoking cessation, and the period immediately after childbirth.
To investigate if MAO-A levels could explain mood changes during perimenopause, the research team conducted brain scans of three groups of women using a brain imaging technique called positron emission tomography (PET). Among the three groups of women, 19 were of reproductive age, 27 were in perimenopause, and 12 were in menopause.
The researchers found that, on average, levels of MAO-A were 34 percent higher in women with perimenopause than in the younger women, and 16 percent higher than those in menopause.
The women in perimenopause also reported a higher tendency to cry, based on a questionnaire called the Adult Crying Inventory. This was associated with high MAO-A levels in the front part of the brain, the prefrontal cortex.
The researchers also predicted that MAO-A levels would drop during menopause, once fluctuating levels of estrogen stabilized, and this also proved to be the case.
The results suggest new opportunities for prevention, according to Meyer.
“Using PET imaging, we can test treatments to see if they can prevent this elevation of MAO-A, and potentially prevent clinical depression,” he said.
One approach may be a dietary supplement, which he is currently investigating in another study of women after childbirth, to prevent postpartum depression. Another approach may be to offer hormone replacement therapy (HRT) at an earlier stage to prevent the fluctuation of estrogen levels, which is also linked to higher amounts of MAO-A, he concluded.