Women and men appear to respond differently to the same biochemical manipulation. Major depressive disorder (MDD) is one of the most common mental disorders, and it is also one of the most studied. It is already known that reduced serotonin transmission contributes to the pathophysiology, or functional changes, associated with MDD and most of today’s most popular antidepressants block the serotonin “uptake site”, also known as the transporter, in the brain. It is also known that people with MDD are frequently found to have impaired impulse control.