Women who suffer from mood swings while going through the menopause can no longer blame it on their hormones, according to a new study.
For decades it has been believed the change of life can cause the blues, with tens of millions of women around the world becoming snappy at this time.
But the new American research found changes in the levels of the sex hormone oestrogen, which regulates a woman's periods, were not linked to bad temper.
Women who suffer from mood swings while going through the menopause can no longer blame it on their hormones, according to a new study
The menopause is caused by a change in the balance of the body's sex hormones.
In the lead up to it - perimenopause - oestrogen levels decrease, which causes the ovaries to stop producing an egg each month.
But the new research focusing on a post-menopausal group not using hormone therapy found hormone concentrations were not related to memory, thinking or mood.
The one exception was progesterone, which was connected with verbal memory and overall cognition in early menopause, but still not mood.
The study, published online in Proceedings of the National Academy of Sciences, is the first to investigate associations between sex hormones and cognition in both younger and older post-menopausal women.
It is also the first to determine whether the hormones affect women differently based on their age and how much time has elapsed since they reached menopause.
Professor Victor Henderson, of Stanford University in California, said the findings help clarify the role of hormones in age-related brain disturbances.
After menopause there is a permanent reduction in a woman's levels of estradiol - the predominant oestrogen beforehand - estrone which is the main one after and progesterone, another hormone involved in the menstrual cycle.
The research found hormone concentrations were not related to memory, thinking or mood
Several studies have examined the association between hormone concentrations and cognition but results have been inconsistent.
Some researchers have speculated that the effect of oestrogen on cognitive ageing could differ depending on when exposure occurs.
Professor Henderson said: 'Some effects might be more beneficial for younger post-menopausal women closer to the time of menopause than for older post-menopausal women.' This is known as the 'critical window.'
In a study of 643 middle aged and elderly participants, he sorted his participants - whose ages ranged from 41 to 84 - into those who had gone into menopause less than six years previously and a later group who were beyond ten years.
His researchers then gave the women a series of tests to gauge their memory and overall cognition before assessing them for depression and sampling their blood for the hormones.
Professor Henderson said: 'We viewed the availability of hormone levels as an opportunity to test one aspect of the critical-window hypothesis - especially since we had two fairly large samples of women.'
Based on the critical-window theory - along with past animal studies showing the timing of estradiol replacement affects memory - Prof Henderson had hypothesized higher levels would boost memory in younger menopausal women.
He said: 'Instead we found no significant link - positive or negative - in either group.'
He said the findings don't 'necessarily mean oestrogens are irrelevant to cognition since we have no way of measuring oestrogen directly at the brain level.'
Professor Henderson added: 'But they imply boosting blood levels of estradiol or estrone - even in younger post-menopausal women - may not have a substantial effect on cognitive skills one way or the other.'
Read more: http://www.dailymail.co.uk/health/article-2513341/Dont-blame-bad-moods-menopause-Hormonal-changes-NOT-linked-temper-tantrums-study-finds.html#ixzz2lhQOIYrx
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