Narrator:        This is Science Today. Prozac is one of several drugs used to treat depression that are called selective serotonin reuptake inhibitors, or SSRIs. These work by boosting low levels of serotonin in the brain, which is associated with depression and anxiety. Matt Lieberman, an associate professor of psychology at UCLA, has found that low levels of serotonin may also affect our sense of fairness - and this knowledge may offer more insight into the treatment of depression and anxiety.

Lieberman:     When we think about depression and anxiety, I think we tend to think of it in very broad mood-state kinds of ways. But part of what makes people, individual experiences and individual moments feel depressed or anxiety, has to do with the appraisals we make about whether or not we're being treated fairly, whether or not we're being respected. And so it may be that it's not just that serotonin in a blanket sort of way makes people depressed or anxious, but it predisposes them to see the world in certain ways that would make anyone a bit more depressed or anxious.

Narrator:        For Science Today, I'm Larissa Branin.