Why do PMS and PMDD happen?
No one is completely sure what causes PMS and PMDD. Scientists think that the mood and physical changes are related to hormone levels that change during your menstrual cycle. Hormones are chemicals that your brain and other parts of your body use to communicate with each other. During your menstrual cycle, the levels of two different types of hormones, estrogen and progesterone, go up and down. When these levels change a lot, they can cause changes in your mood, your behavior, and can cause physical changes too. Other chemicals in the brain may be related to PMDD also. Some chemicals (called neurotransmitters) that play a part when people get depressed seem to be involved with the mood changes that happen right before your period. That’s why some people with really bad PMS actually can get better when they take medicine that is also used for people that get depressed. Some people have found that high levels of stress make PMS and PMDD worse. Diet can also affect PMDD; low levels of vit
