Since these symptoms are temporary, somewhat vague and often perceived as psychosomatic by the medical profession, the problem has gone largely unmentioned and untreated. Research has suggested that women with PMS respond abnormally to the normal ovarian hormones oestrogen and progesterone, which are released into the blood as part of the menstrual cycle. This new attribution of the cause of PMS called into question its status as an emotional disorder. Other research favors changes in neurotransmitter levels, including mood-altering endorphins and serotonin, and diet -- especially a lack of calcium. This is in line with an association with lower oestrogen levels during the last part of the menstrual cycle, oestrogen also being a precursor for serotonin. It is also possible that these imbalances are related. Until PMS is understood in medical terms, women who suffer its symptoms manage by self-experimentation or adjusting to several days of under-par health.
2. If 75% of women show symptoms of PMS and PMS is treated as abnormal, it begs the question of how normalcy should be defined.