Depression is the leading cause of disability worldwide. Because a significant number of people with depression do not respond to medication or therapy, alternative treatment options are greatly needed. Recent research has focused on brain stimulation methods due to their therapeutic utility for treating depression. Yet, current brain stimulation methods have drawbacks, including invasive surgery and limited precision in targeting specific areas. A novel brain stimulation method, transcranial ultrasound (TUS), is noninvasive, has greater spatial precision than most existing methods, and is proven safe for humans. TUS has been found to increase positive mood in chronic pain patients. In a double blind study, TUS increased positive mood in over 140 healthy undergraduates at the University of Arizona.