Premenstrual syndrome is something many women are familiar with. From painful cramps and mood swings to weight gain and breast pain, nearly all women experience PMS – but for some women, the symptoms are debilitating.
Around one in 20 women have symptoms severe enough to stop them living their normal lives, which is often the result of premenstrual dysphoric disorder – or PMDD – a lesser-known condition which can have a hugely detrimental on a woman's wellbeing.
Women with PMDD experience the same symptoms as PMS, but at a much more intense level. Psychological or behavioural symptoms are common when it comes to PMS, such as feeling irritable, angry or upset – but PMDD sufferers can experience intense feelings of depression, hopelessless, anxiety and low self-esteem.
As depression is a common symptom of PMDD, it's possible that a woman suffering from the condition may have thoughts about suicide. It can also affect a sleeping patterns and decrease interest in everyday activities.
For Sarra Sedghi, a US-based writer, PMDD has had a big impact on her life.
"Every so often I feel uncontrollably crazy, even when I'm doing everything I can to feel stable – remembering my medication, eating healthily, exercising," she says.
"And even though I'm used to feeling hopeless at least once a month from this, remembering that my period is to blame still feels like a surprise every time. And it's frustrating because there's only so much you can do to help with that.
"I'm sure I've been lucky with doctors who've listened to me and easy access to birth control. Some people I know have it harder," Sedghi adds.
"I've read that PMDD and depression are different things. And that having depression doesn't mean you'll have it. But the two are connected for me."
Awareness of the condition is still scant, but we are gradually beginning to find out more about PMDD. Research has shown women with the condition have normal hormone levels but for some reason, their bodies are more likely to be sensitive to them.
A recent paper published by the National Institute of Mental Health found the condition appears to be genetic – finally proving once and for all that severe mood-related PMS is very real. The study found that PMDD is linked to a gene cluster called ESC/E(Z), according to a study in the journal Molecular Psychiatry.
"This is a big moment for women's health, because it establishes that women with PMDD have an intrinsic difference in their molecular apparatus for response to sex hormones – not just emotional behaviours they should be able to voluntarily control," said one of the researchers David Goldman, from the US National Institutes of Health.
At the moment, treatments include anti-inflammatory drugs, oral contraceptives, hormone treatment and antidepressants such as selective serotonin reuptake inhibitors. But as more is understood about PMDD and its causes, this opens up possibilities for new ways to treat the condition.
That being said, it is crucial to be cautious about the use of hormonal treatments, which could trigger side effects.
"PMDD can make life extremely difficult. While hormone treatments and antidepressants help some women, you can't use hormone treatments if you're trying to get pregnant, and they have side effects that mean they're not suitable for everyone," the NHS warns.
"Finding out more about the condition is a first step to understanding it, and might lead to better treatments in the long term."