Head Lines; September / October 2010; Scientific American Mind; by Allison Bond; Sandy Fritz; Frank Bures; Ferris Jabr; Mark Lescroart; Emily Anthes; Graciela Flores; David DiSalvo; R. Douglas Fields; Michele Solis; David Jay Brown; Karen Schrock; Melinda Wenner Moyer; Nikhil Swaminathan; 8 Page(s)

Friends and family of people with depression may feel that their loved one has been replaced by a gloomy doppelgänger. According to recent research, however, it may be the treatment of depression that actually causes personality changes in people with the disorder.

Experts have long known that the placebo effect explains much of the mood lift patients report after going on antidepressants. This was the case in the new study, published in the journal Archives of General Psychiatry—patients with major depressive disorder who were given a placebo saw their symptoms im­prove about three quarters as much as those given paroxetine, an antidepressant also known as Paxil. But only the patients who took parox­etine displayed personality changes in two key areas of the widely used five-factor model of personality: they scored lower on neuroti­cism, the tendency to experience negative emotions such as guilt and anxiety, and they scored higher on extroversion, which includes traits such as talkativeness and assertiveness.