Women are more than twice as likely to develop bipolar disorder in the years leading up to their final period, a study has indicated.
Experts said research like this could help predict individual risk of mental health problems during this time, which could be “life-saving”.
Perimenopause is the time from the start of menopausal symptoms until after a woman has experienced her last period.
The study of 128,294 UK women by Cardiff University academics working with Bipolar UK and the UK Biobank focused on the four years around the last menstrual period.
It found there was a 112% increase in bipolar during perimenopause, while clinical depression increased 30%.
Cardiff University’s Prof Arianna Di Florio said: “During perimenopause approximately 80% of people develop symptoms, but the impact on the onset of severe mental illness was unknown.
“In my clinic, I found that some women, previously living lives without any experience of severe mental health issues, developed severe mental illness around the time of the menopause.”
Bipolar UK ambassador Clare Dolman, who is also patient and public involvement lead on the project, said: “This confirms what we have observed and heard from women with bipolar themselves, that hormonal change is a very important factor in mood disorders and one that deserves to be researched thoroughly.”
The study, she believed, would help predict women’s risk of getting ill.
“That knowledge could be life-saving,” Ms Dolman said.
Prof Di Florio believed the findings, published in Nature Mental Health, could help provide more support for women.
“We have been able to expand our knowledge of the mental health changes associated with perimenopause, which can help provide explanations, diagnoses and support for women who have previously been left in the dark about what is happening to them,” she said.