Jun 3, 2011 14:39 GMT  ·  By

Children as young as 3 can meet the clinical criteria for being diagnosed with major depressive disorder (MDD), says a part of the international scientific community. The other half opposes this notion, arguing that such a diagnostic cannot be placed on a 3-year-old.

Studies conducted on this issue up to this point have demonstrated that infants suspected of MDD display similar brain activity patterns to adults suffering from the same disorder. This is the main piece of evidence that scientists in the first group has.

But these findings are controversial. One of the reason for that is the fact that we still don't know very much about how the human brain operates, especially at a young age. Only in recent times have experts begun taking an active interest in how the brain changes with age.

Investigations have demonstrated that children perceive words, emotions, shapes, colors, morality, math and a whole host of other factors differently than adults do. Does this imply that diagnostics should be placed differently, or not?

Washington University in St. Louis (WUSL) child psychiatrist Dr. Joan Luby, the director of the early emotional development program at the university, says that she has been studying depression in preschool children for the better part of two decades.

The expert argues that the view holding that young children do not have the emotional or cognitive competence or capabilities to experience MDD is wrong. “When you think about it, most of the core symptoms of depression are developmentally broad,” Luby says, quoted by PsychCentral.

“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,” she adds.

“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,” the investigator adds.

Functional magnetic resonance imaging (fMRI) of the preschool brain has evidence neural activation patterns that are surprisingly consistent across age groups, the researcher concludes. Details of the work appear in a paper published in the March 2011 issue of the Journal of Affective Disorders.