Methods and compositions for treating depression using cyclobenzaprine

A method for treating a major depressive disorder in a fibromyalgia patient in need thereof, the method comprising administering to the fibromyalgia patient a pharmaceutical composition comprising cyclobenzaprine or a pharmaceutically acceptable or water-soluble salt thereof and a pharmaceutically acceptable carrier, wherein treatment with the cyclobenzaprine or salt thereof ameliorates or eliminates the major depressive disorder, and wherein the amount of cyclobenzaprine administered is less than 5 mg/day.