When Tana Amen was suffering from depression, she had no idea it was caused by her thyroid medication. She started taking antidepressant medication, and the effect it had on her was completely unexpected. In the second episode of a series on antidepressants, Dr. Daniel Amen and Tana describe how some antidepressant medications can give your entire personality an overhaul, and how it may not always be a positive change.