Emerging, controversial research suggests children as young as 3 years of age can meet the clinical criteria for major depressive disorder (MDD).

And researchers are discovering that depressed children demonstrate brain activation patterns very similar to those seen in adults diagnosed with the disorder.

Child psychiatrist Dr. Joan Luby, director of the early emotional development program at Washington University in St. Louis, has been studying preschool depression for almost two decades. Her clinical experience, she said, contradicts the view of many developmental psychologists that young children do not have the emotional or cognitive competence to experience depression.

“When you think about it, most of the core symptoms of depression are developmentally broad,” Luby said.

“Sadness and irritability can occur at any age from infancy to very old age. But symptoms like anhedonia were thought to be adult problems because it’s often talked about as decreased libido. That, obviously, doesn’t occur in young children. But when you developmentally translate it to an absence of joyfulness, especially when joyfulness is the dominant mood state of young children, you have a pretty robust clinical marker.”

According to new research findings, depressed preschoolers do not just show synonymous clinical symptoms to adult depression—they also show similar patterns of brain activity when scanned using functional magnetic resonance imaging (fMRI).

In a study published in the March 2011 issue of the Journal of Affective Disorders, Luby and colleagues scanned 11 depressed children with an average age of 4.5 years while the children viewed faces with different expressions of emotion. The group found that there was a significant correlation between the severity of the depression and increased activity in the right amygdala, the same pattern of activity viewed in adults with depression.

“There is something about the experience of depression in very early childhood that seems to leave an enduring mark on the brain—these kids are more likely to be depressed as adults, too,” she said. “So these results suggest that there may be very early markers of a depressed brain that can be picked up in kids as early as age 4 or 5 and may open the door to much earlier intervention.”

Another researcher, psychologist Daniel Klein, Ph.D., is investigating potential factors in early childhood that may predict later chronic depression.

“When clinicians ask a depressed person when they first started feeling depressed, they’ll often report having been depressed their entire lives,” he said. “It’s not clear when the onset is, so I study preschool age children with the intent of trying to identify behavioral and emotional precursors that will later evolve into chronic depression.”

Klein is currently following more than 600 families from the local community sample in a longitudinal study. Though preliminary, a few factors appear to play a large role in the onset of depression later in life.

“In terms of temperament, a lack of exuberance and joy in situations where most kids get very excited about and then a lot of feelings of fearfulness and sadness stand out,” he said. “These kids tend to have parents who have a history of depression and we’re seeing some abnormalities in electrical activity when we take EEGs. There’s some evidence now that these patterns predict not necessarily clinical depression but more depressive symptoms three or four years later.”

Naturally, parents of depressed preschoolers are concerned about treatment options for their children. While antidepressants have been used with some success in the adult population, there is wide concern about whether they should be used in children, let alone children of such a young age whose brains are going through critical periods of development.

“Certainly, with kids, there are all kinds of concerns particular to their age and level of neurological and physical development when we’re talking about drug treatments,” said clinical psychologist Dr. Michael Yapko. “Despite those concerns, the Food and Drug Administration estimates that 7 percent of antidepressants are still being prescribed to children.”

While Luby does not dismiss the idea of a pharmacological treatment, her lab is currently testing a unique early intervention called dyadic play therapy. The approach is innovative as children work with their primary caregivers, who are coached via an earpiece by a therapist, on emotional regulation and development.

“So far, the treatment appears promising,” she said. “We are just now writing up the results of a small randomized, controlled trial suggesting there may be large effect sizes with this intervention.”

Both Luby and Klein emphasize that our biological understanding of preschool depression is still very preliminary. And while there is no one treatment option for these children at this point, Luby offers this advice to parents.

“Be attentive. If you have a child who is persistently irritable, persistently sad, who does not brighten in play or when fun and exciting things happen, that’s every bit as much of a concern as a child who is disruptive in preschool,” said Luby. “We don’t tend to pay as much attention to it but it is every bit as much of a concern. And treating it early may make all the difference.”

Source: The Dana Foundation