Trigeminal Nerve Stimulation for Post Traumatic Stress Disorder (PTSD) and Depression

This is a 20-subject, dose finding study to examine the use of external trigeminal nerve stimulation (TNS) as an adjunctive treatment for adults with major depressive disorder (MDD) co- occurring with posttraumatic stress disorder (PTSD) when added onto antidepressant medications. Our primary objective is the examination of TNS in this patient population. To accomplish our specific aims, the investigators will test the following specific hypotheses: 1. Subjects will show improvement in ratings of mood, PTSD, and other symptoms during the eight-week period. 2. Subjects will show improvement in ratings of life functional capacity and quality of life with TNS. 3. Subjects will report the TNS treatments to be acceptable in terms of side effects and burden of using the device.