Something my wife tried worked for her, and that is 5-HTP found at most health food stores. It's the precursor to serotonin, so the body does not need so much energy to make the neurotransmitter. If this works, look into better ways to get the nutrition so your body can make the stuff on its own.
This is found in a book we found at the library, so it cost us nothing! The book name is The Guide to Vitamins, Minerals and Supplements by Dr.Helen Pensanti. She has a web site, but the thing is, she only sells stuff there, and doesn't talk about much. The website is askdrhelen.com if you are interested.