RESEARCHERS AT the University of Birmingham believe they have found the cause of premenstrual syndrome (PMS). They have also tested a treatment based on the antidepressant drug Prozac, which cleared PMS symptoms in laboratory rats.
“We are beginning to understand the mechanism that underlies the development of premenstrual syndrome,” said neuroscience researcher Dr Thelma Lovick, who believes symptoms could be reduced or even eliminated.
One of the hormones that naturally fluctuates throughout the menstrual cycle also regulates emotions such as anxiety, irritability and aggression, Dr Lovick explained. This hormone drops suddenly in the week before the period, coinciding with many PMS symptoms.
The specific substance is called allopregnanolone (Allo) and usually inhibits activity in brain circuits involved in controlling emotions. “To put it simply . . . Allo calms your brain,” said Dr Lovick. There is “a sharp fall in brain Allo that I think triggers PMS symptoms”.
To test this theory, the group performed a study using lab rats. It was possible to experiment on rats because they have cycles not unlike those of humans, she explained.
Low doses of Prozac (fluoxetine) were given to rats to stimulate Allo production. These “completely blocked development of their PMS symptoms”, explained Dr Lovick.
The laboratory tests looked at anxiety levels in the rats during their equivalent to the premenstrual period.
At the British Science Festival in Birmingham this week Dr Lovick proposed a treatment regime for PMS using fluoxetine.
The drug would be taken at 10 per cent of the current standard dose for the week before the period, a dose so low that it would not retain any antidepressant effects.
Alison Jones is a British Science Association media fellow on placement with The Irish Times.