Sufferers of premenstrual dysphoric disorder (PMDD) say they face extreme emotional distress.
PMDD causes a range of mental and physical symptoms in the two weeks leading up to a period, including anger, depressed mood and anxiety - which lift completely during menstruation., 34% of people who have been diagnosed with the condition have attempted suicide.
"There was a lot of screaming and just feeling like my world was over and it didn't really matter what anybody said to me, they couldn't understand how it felt inside of me." She described it as an "evil monster" inside her wanting to break out every month, saying the "black cloud" took its toll on family relations.Ms Williams, a Labour member of the Senedd, said: "It was almost like every single movement, every single part of my life revolved around my period.
An expert on the condition, based at the University of the West of Scotland, she described the problems as "complex".