5. Age
As we age things in the body start to work differently. Essentially, your body does not work the same way it did when you were younger. One of the things that change dramatically as we age is our hormone levels. Women going through menopause will often experience mood swings. The reason for this is because the hormone levels are changing. When the hormones are not in balance, they can cause many different reactions. Serotonin plays an important role in the body relating to mood. When you age, your body might start producing less serotonin than before. Hormone replacement supplements might be prescribed to help keep things in balance. If you are getting older and notice that you are experiencing mood swings more often and that you are feeling depressed, angry, anxious, or just not yourself, it could be that your hormones are out of balance.