New research looks at how young kids at risk for depression react to rewards.

sad toddler girl
Credit: KateStone/Shutterstock

Believe it or not, kids as young as 3 can show signs of depression.

A new study out of the Washington University School of Medicine, and published in the ournal of the American Academy of Child & Adolescent Psychiatry, finds that depressed little ones don't respond to rewards like other children do.

Using an electroencephalogram machine (EEG), the researchers measured the brain waves of 84 kids, ages 3 to 7, as they played a computer game where they could choose between two doors, which either won them points or caused them to lose points. The goal was to determine if a "blunted response" to rewards, which is noted in depressed adults, would also be evident in preschoolers.

"In fact, the brains of children as young as 4 showed very similar responses," first author Andrew C. Belden, Ph.D., said in a press release, adding, "That's consistent with other findings in that many neurobehavioral aspects of depression remain consistent throughout the lifespan."

"The EEG results showed that their brains did not react as robustly [to] the pleasurable event of choosing the correct door on the screen," Dr. Belden further explained. "It was not that their brains somehow overreacted to making the wrong choice. The brains of both depressed and nondepressed children reacted the same way to making the wrong choice. The differences we observed were specific to the reward response."

It's very sad to think that little kids can experience depression. But the important takeaway here is that if you detect risk factors in your children, they can get the help they need. "Decreased ability to enjoy activities and play is a key sign," says senior investigator Joan L. Luby, M.D. "Kids who feel excessively guilty about wrongdoing and those who experience changes in sleep and appetite also may be at risk. If they're persistently sad, irritable, or less motivated, those are markers that may indicate depression, even in kids as young as 3 or 4, and we would recommend that parents get them evaluated."

Melissa Willets is a writer/blogger and a mom. Find her on Facebook where she chronicles her life momming under the influence. Of coffee.