Women later diagnosed with endometriosis used more antidepressant and anxiety medication than other women, with the pattern emerging years before diagnosis.

The difference was evident up to 10 years before diagnosis and continued for a decade afterwards, according to a large Danish registry-based study involving 136,842 women.

Women with the condition also had substantially more contact with psychiatric hospital departments than those without it.

Researchers at Aarhus University found that women with endometriosis redeemed 29 per cent more prescriptions for antidepressants and 16 per cent more for anxiety medication in the years before diagnosis.

After diagnosis, the differences rose to 40 per cent for antidepressants and 46 per cent for anxiety medication.

Marie Josiasen, PhD student at the department of public health and one of the researchers behind the study, said: “What surprised us was how clear and persistent the pattern was, and that the difference did not diminish over time. On the contrary. Women with endometriosis consistently redeemed more prescriptions for antidepressant medication than women without the disease throughout the entire period, from ten years before to ten years after diagnosis.”

The study does not provide an answer as to what causes the mental strain.

Josiasen said prolonged pain, uncertainty about the cause of symptoms and fertility problems could be among the factors contributing to psychological strain.

She said: “It’s possible that prolonged pain, uncertainty about the cause of the symptoms, and frustration over not being able to live the life one wants may be among the reasons. For some women, fertility problems can also be a major psychological burden.”

Researchers also found that the gap compared with women without endometriosis did not narrow after diagnosis. Instead, it became more pronounced in the years that followed.

Josiasen said: “A diagnosis can be a relief, but it also involves coming to terms with having a chronic illness.”

The study does not indicate whether diagnosing endometriosis earlier could reduce psychological strain.

As part of her PhD project, Josiasen will investigate the role hormonal contraception may play in the mental health of women with endometriosis.

She said: “We can see that many receive medication and are in contact with psychiatric services. But we still lack an understanding of what actually helps these women. That’s what I want to help find out.”

Women using menopausal hormone therapy had a lower dementia risk, with oestrogen-only users showing fewer Alzheimer’s-related brain changes in a recent study.

Researchers stressed that the findings do not show that hormone therapy prevents dementia, but found women using oestrogen-only treatment had fewer biological signs linked to Alzheimer’s disease.

The observational study also found that women using this form of hormone therapy were less likely to receive a clinical dementia diagnosis.

The study combined clinical data with biomarkers and evidence from brain tissue collected after death to build a more detailed picture of the relationship between hormone therapy and Alzheimer’s-related changes.

The findings contrast with several previous studies reporting that menopausal hormone therapy increases dementia risk.

Dr Hadi Hosseini, associate professor of psychiatry and behavioural sciences at Stanford University in the US and senior author, said: “Our study is unique in that we looked at all the standards of Alzheimer’s diagnosis, including the gold-standard outcome: Alzheimer’s-associated hallmarks in autopsied brains.”

Hosseini said many conditions can affect memory and that clinical diagnoses are not always accurate. Examining brain tissue allows researchers to look directly for the defining biological features associated with Alzheimer’s disease.

Researchers examined medical records from 21,462 women taking part in two large US studies.

They looked only at women who used oestrogen-only therapy because previous studies indicated that treatment combining oestrogen and progestin may increase dementia risk.

This group was compared with women who reported no use of menopausal hormone therapy.

The records included data from 258 brain autopsies of women who had reported using oestrogen-only menopausal hormone therapy and 2,701 autopsies from women who had not used hormone therapy.

After adjusting for factors including age, women who took hormone therapy had a 35 per cent lower chance of showing biological signs of Alzheimer’s disease than those who did not use hormone therapy.

Hormone therapy use was also associated with a 39 per cent lower risk of receiving a clinical dementia diagnosis and a reduced risk of memory problems or declining functional abilities.

Dr Tom Blackmore, research programmes manager at Alzheimer’s Research UK, said: “Dementia has been the leading cause of death for women in the UK for over a decade, yet we still don’t fully understand why women are more likely to be affected by the condition than men.

“Understanding how hormones, menopause and ageing influence brain health is an important area of dementia research.

“While these findings are interesting, this study can only show an association and cannot tell us whether hormone therapy itself reduced dementia risk.

“Many factors influence a person’s likelihood of developing dementia, and women who received hormone therapy may differ from those who did not in ways that also affect their long-term brain health.”

In current standard practice, oestrogen-only therapy is prescribed to people who have undergone a hysterectomy because of the increased risk of endometrial cancer.

Blackmore also said the study focused exclusively on women taking oestrogen-only hormone therapy, which “differs substantially from how hormone replacement therapy is typically used today.”

Although early studies suggested menopausal hormone therapy might help protect menopausal women from dementia, later research produced inconclusive results.

A large analysis published in 2003 suggested the opposite, finding that oestrogen-plus-progestin formulations appeared to increase dementia risk, particularly when started at an older age.

Hosseini said: “There have been a lot of conflicting findings about MHT’s [menopausal hormone therapy’s] effects on Alzheimer’s disease outcomes.”

He added: “Different studies may have involved different age ranges of initiating MHT.”

Hosseini said studies may also have examined different clinical outcomes and biomarkers, combined different hormone therapy formulations or looked at different routes of administration and treatment durations.

Blackmore added that the findings “are not a reason for women to start or stop hormone replacement therapy with the aim of reducing dementia risk.”

He added: “Instead, the study provides valuable clues about the biology underlying dementia and highlights the need for more research into women’s brain health.

“Larger and more diverse studies will be needed to determine whether hormone-based treatments could play any role in reducing dementia risk.”

According to Alzheimer’s Research UK, an estimated 982,000 people are living with dementia in the UK, with around 65 per cent of those affected being women.

A third of women surveyed did not know perimenopause could affect mental health, with many experiencing symptoms for months before recognising them.

The survey of 1,000 women found many had been caught off guard by mental health symptoms linked to perimenopause or menopause.

It was conducted by Dynata on behalf of LifeStance Health in June 2026 and included women born between 1960 and 1990 who had, or suspected they had, perimenopause or menopause.

Respondents described anxiety as somewhat or extremely severe in 66 per cent of cases and depression in 54 per cent, with many initially attributing the symptoms to a separate condition rather than a hormonal transition.

Stephanie Eken, chief medical officer at LifeStance Health, said: “Women’s mental health needs change across their life stages, and perimenopause and menopause are among the biggest transitions of all.

“Specialised, life-stage-specific care should be standard practice, and I believe the organisations that build care around this reality, rather than taking a one-size-fits-all approach, will define the next era of women’s health.”

Around 33 per cent of respondents said they did not know perimenopause could cause mental health symptoms.

Almost half, 49 per cent, were surprised that mental health symptoms linked to perimenopause or menopause could last for several years.

A further 22 per cent were surprised that perimenopause could begin shortly after childbirth.

The survey found 74 per cent experienced symptoms for six months or longer before suspecting perimenopause or menopause, while 27 per cent recognised the transition within six months.

Before recognising the symptoms as potentially linked to perimenopause or menopause, 49 per cent believed they were experiencing anxiety as a standalone condition and 39 per cent thought they had depression.

Around 36 per cent were surprised that symptoms linked to perimenopause or menopause could resemble a standalone mental health condition.

Among respondents who tried therapy for perimenopause or menopause-related symptoms, 83 per cent said it was helpful.

Around 82 per cent of those who tried medications such as antidepressants or oestrogen also found them helpful.

Nearly half, 47 per cent, said mental healthcare should be a standard part of perimenopause care, while 59 per cent said they would be more likely to seek mental healthcare if they knew it could meaningfully improve their symptoms.

Around 35 per cent said perimenopause or menopause had a slight to significant negative impact on their overall mental health, while 42 per cent reported a negative impact on mood.

However, 32 per cent reported no impact on their overall mental health and 22 per cent reported no impact on mood.

The survey points to women experiencing mental health symptoms for an extended period before connecting them to perimenopause or menopause, with many initially attributing anxiety or depression to an unrelated cause.

That delay may help explain why nearly half did not realise how long these symptoms can persist and why more than a third were surprised they could resemble a standalone mental health condition.

Despite the awareness gap, most respondents who sought treatment, whether therapy or medication, said it had been helpful.

Separate research published in 2023 estimated that menopause symptoms cost the US economy around US$1.8bn a year in lost work productivity.

The estimated cost rose to US$26.6bn when associated healthcare costs were included.

That research was based on more than 4,400 employed women aged 45 to 60, with its authors saying further studies in larger and more diverse populations were needed to confirm the findings.