Untreated Type II diabetes causes depression and mood swings.
Have you ever tested yourself for a few days - 2 hours after eating?
If your blood sugar is over 100 you're pre diabetic and if it's over 120 your
are diabetic.
Type II can be controlled by eliminating sugar and all carbohydrates as well
as caffeine and sugar substitutes. Try it and you might find that your
depression goes away.