Depression in kids in preschool is likely to continue throughout adolescence.

Researchers at the Washington University in St. Louis found in a study published in The American Journal of Psychiatry that tracked 246 children from ages 3-5 and 9-12 that depressed preschoolers were 2.5 times more likely to exhibit depressive symptoms into elementary and middle school.

In the study 51 percent of the children who were originally diagnosed with depression still exhibited symptoms of depression while only 25 percent of the children who were not diagnosed with depression earlier on went on to develop depression in adolescence.

"It's the same old bad news about depression; it is a chronic and recurrent disorder," said Dr. Joan Luby, child psychiatrist and lead author of the study. "But the good news is that if we can identify depression early, perhaps we have a window of opportunity to treat it more effectively and potentially change the trajectory of the illness so that it is less likely to be chronic and recurring."

Children and their caregivers were given the Preschool Feelings Checklist in six annual and four semiannual assessments.

The caregivers were asked to indicate their children's levels of sadness, guilt, irritability and other factors. Researchers used a two-way mirror to evaluate the child-caregiver interactions.

At the beginning of the study, 74 children were diagnosed with depression. Six years later, they had 79 children who met the criteria for clinical depression.

Luby and her team found that children were at a higher risk for depression if their mothers had depression and children who were diagnosed with a conduct disorder had an elevated risk of depression later. However, children with significant maternal support had less risk.

"Preschool depression predicted school-age depression over and above any of the other well-established risk factors," Luby said. "Those children appear to be on a trajectory for depression that is independent of other psychosocial variables."

This is contrary to doctors who say younger children cannot be depressed.

"The reason it hasn't yet become a huge call to action is because we don't yet have any proven, effective treatments for depressed preschoolers," she said. "Pediatricians don't usually want to screen for a condition if they can't then refer patients to someone who can help."

These studies may encourage people to be more aware of childhood depression and its effects later in life.