The study, published in Psychological Medicine, also examined the effects of hormone replacement therapy (HRT). While HRT did not appear to prevent these brain or mental health changes, it was associated with a slower decline in reaction speed.

Understanding Menopause and Its Symptoms

Menopause marks the stage of life when a woman’s menstrual periods permanently stop due to declining hormone levels. It most commonly occurs between ages 45 and 55 and is often accompanied by symptoms such as hot flushes, low mood, and disrupted sleep. Previous research has also linked menopause to changes in cognitive abilities, including memory, attention, and language.

To help manage menopause related symptoms, particularly depression and sleep problems, many women are prescribed HRT. In England, 15% of women were prescribed HRT in 2023. Despite its widespread use, scientists still have limited insight into how menopause and HRT affect the brain, thinking skills, and mental health.

A Large Study Using UK Biobank Data

To better understand these effects, researchers analyzed data from the UK Biobank involving nearly 125,000 women. Participants were divided into three groups: women who had not yet reached menopause, women who were post-menopause and had never used HRT, and women who were post-menopause and had used HRT.

Participants completed questionnaires about menopause symptoms, mental health, sleep patterns, and overall health. Some also completed cognitive tests measuring memory and reaction time. In addition, around 11,000 women underwent magnetic resonance imaging (MRI) scans, which allowed researchers to examine differences in brain structure.

The average age at menopause among participants was about 49.5 years. Women who were prescribed HRT typically began treatment at around age 49.

Anxiety Depression and Sleep After Menopause

Women who had gone through menopause were more likely than those who had not to seek help from a GP or psychiatrist for anxiety, nervousness, or depression. They also scored higher on depression questionnaires and were more likely to have been prescribed antidepressant medications.

Women in the HRT group showed higher levels of anxiety and depression compared with women who did not use HRT. However, further analysis revealed that these differences were already present before menopause began. According to the researchers, this suggests that some GPs may have prescribed HRT in anticipation that menopause could worsen existing symptoms.

Sleep problems were also more common after menopause. Post-menopausal women were more likely to report insomnia, reduced sleep, and ongoing tiredness. Women using HRT reported feeling the most fatigued of all three groups, even though their total sleep duration did not differ from post-menopausal women who were not taking HRT.

The Importance of Lifestyle and Mental Health Support

Dr. Christelle Langley from the Department of Psychiatry said: “Most women will go through menopause, and it can be a life-changing event, whether they take HRT or not. A healthy lifestyle — exercising, keeping active and eating a healthy diet, for example — is particularly important during this period to help mitigate some of its effects.

“We all need to be more sensitive to not only the physical, but also the mental health of women during menopause, however, and recognize when they are struggling. There should be no embarrassment in letting others know what you’re going through and asking for help.”

Reaction Time Slows While Memory Remains Stable

Menopause was also linked to changes in cognitive performance. Women who were post-menopause and not using HRT showed slower reaction times compared with women who had not yet reached menopause and those who were using HRT. Memory performance did not differ significantly among the three groups.

Dr. Katharina Zühlsdorff from the Department of Psychology at the University of Cambridge, said: “As we age, our reaction times tend to get slower — it’s just a part of the natural ageing process and it happens to both women and men. You can imagine being asked a question at a quiz — while you might still arrive at the correct answer as your younger self, younger people would no doubt get there much faster. Menopause seems to accelerate this process, but HRT appears to put the brakes on, slowing the ageing process slightly.”

Grey Matter Loss in Brain Regions Linked to Memory and Emotion

Brain imaging revealed that women who were post-menopause showed significant reductions in grey matter volume, regardless of whether they had used HRT. Grey matter contains nerve cell bodies and plays a key role in processing information, controlling movement, and supporting memory and emotional regulation.

The most affected areas included the hippocampus (responsible for forming and storing memories), the entorhinal cortex (the ‘gateway’ for passing information between the hippocampus and the rest of the brain), and the anterior cingulate cortex (part of the brain that helps you manage emotions, make decisions, and focus your attention).

Possible Clues to Dementia Risk in Women

Professor Barbara Sahakian, the study’s senior author from the Department of Psychiatry, added: “The brain regions where we saw these differences are ones that tend to be affected by Alzheimer’s disease. Menopause could make these women vulnerable further down the line. While not the whole story, it may help explain why we see almost twice as many cases of dementia in women than in men.”