Narrator: This is Science Today. At the UCLA Center for PharmacoGenomics and Clinical Pharmacology, researchers look into the genetic basis of response to antidepressant treatment. Julio Licinio, co-director of the center, says to understand who responds well and who doesn't, they look at genetics. To do that, patients at the clinic are treated with antidepressants – but when recent reports began linking antidepressant use to suicidal behavior, Licinio launched a new study.

Licinio: I became concerned that I might be putting patients at risk, so I examined all available data from different perspectives and the conclusions that I had were pretty different from what was being said out there.

Narrator: Licinio's search of studies in a national database from 1960 to 2004 on antidepressants and suicide, found that since the introduction of drugs like Prozac in 1988, suicide rates have actually plummeted.

Licinio: The more that the drugs are prescribed, the fewer suicides we have.

Narrator: Licinio's conclusion was that the biggest cause of suicide in the United States is not antidepressants, but rather untreated depression. For Science Today, I'm Larissa Branin.