[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]

The percentage of Americans using antidepressants doubled between 1996 and 2005. That number’s from a new study in the Archives of General Psychiatry. The reasons aren’t fully clear. But researchers think that a big factor is simple cultural change—it’s more and more acceptable to be on the drugs.

But another paper published in the Journal of Child Psychology and Psychiatry finds predictors, at least, for childhood depression.

Scientists followed more than 1,700 children from infants of five months to preschoolers of five years.

The top predictor for depression later in life, researchers found, is a difficult temperament at five months. And this means, "a child being fussy, being irritable, difficult to soothe. And a child that is particularly challenged by novel situations. So a child that is slow to adapt, or is fearful in new situations." 

That's Sylvanna Cote from the University of Montreal.

And the second leading depression predictor is lifetime maternal depression: "We know from studies that are genetically informative, so twin studies or studies that have measures of the genotype of people, that depression runs in families. But of course genetics is not destiny, even though it's an important factor. So someone who is at risk because of genetic vulnerability may go on to develop depression or not, depending on the quality of care. And the quality of the family environment. So it's very important to realize that environment is a major factor and we can change people's environment."

Some 15 percent of preschoolers suffer from high levels of depression and anxiety.

Cote stresses that treatments like cognitive behavioral therapy and properly prescribed medication have high success rates, so there is no reason mothers need to suffer—and put their children at risk, as well.

—Christie Nicholson