From this week, the popular and controversial anti-depressant can be used to treat premenstrual dysphoric disorder (PMDD) which is estimated to affect 1.5 million women in the UK.

The disorder stops them from functioning normally, can cause family and work problems and may be so severe that it pushes women to commit violence against others.

The causes of PMT are unknown, but may be linked to imbalances in levels of serotonin, a chemical messenger in the brain.

Women who are most at risk are thought to have a family history of PMT, a history of post-natal depression or clinical depression and are likely to suffer mood swings as a result of taking oral contraceptives.

Symptoms

There are about 150 symptoms asociated with the condition.

A recent survey shows nearly 70% of women associate PMT with mood swings, depression and irritability.

Forty per cent try to ignore the symptoms and the one in five who do try to tackle the problem say they get little relief from the treatment they receive.

It is hoped that Prozac, which is said to restore serotonin levels, will reduce some of the symptoms of PMDD, although opponents say it does not address what causes the disorder.

And some are worried about the drug's side effects, which include a reduction in sex drive.

A minority of women who take it also report breast pain, early menopause or excess bleeding during periods.

Stephanie Allen, executive officer of the National Association for Premenstrual Syndrome, said PMT was often not treated seriously.

"I know many women who have lost their partners and careers as a result of suffering from premenstrual symptoms.

"I have sat and listened to numerous women describe their 'uncontrollable violence towards their partner' and 'feelings of isolation'," she said.

Professor Shaughn O'Brien from North Staffordshire Hospital in Stoke-on-Trent added: "A woman menstruates every month for more than 30 years.

"This means that she could experience premenstrual symptoms for up to 5,000 days in her lifetime, possibly without any help or advice on how to alleviate these symptoms.

"If you have a persistent toothache - wouldn't you visit your dentist for help and advice?"