I got it the same time I got Rheumatoid Arthritis, 14 years ago. Every single woman in my family has it including my daughter who got it at age 15. I'm on 125 mg of Synthroid. I can't make it through the day without it, and I had terrible exhaustion and mood swings all summer because I needed a 25 mg increase. My daughter was researching papers on mental health, and came across hypothyroidism as a cause of mood swings in people with bipolar disorder. Of course, if you don't have it, it will not be a trigger.