Small Child, Big Worries

Be grateful you can't climb inside your baby's brain. The mind of a baby might seem like a fun place to be — a swirl of light and color and constant touch, where primal needs are promptly met. But there's another side, one that's more than just a sensory carnival. All of us come into the world with our own genetic predispositions to psychological ills. Depression, anxiety, the whole panoply of adult woes are woven into our genomes. That may not be surprising to scientists, but new research shows that these conditions can start to express themselves much earlier than we knew — sometimes during the first year of life. Trauma can trigger the onset; so can stress, and so can still unknown variables. No matter the cause, we're increasingly learning that a baby's brain is not only far more fragile than we realized but far more like an adult's too.

Psychologists historically drew bright lines between the mental ills of infancy and those of later years. Babies could suffer from psychological conditions — defiance, aggression, attention deficits — but those problems were particular to their minimally complex states. "There were behavioral checklists," says Dr. Helen Egger of Duke University Medical Center, "but that was it." The existential suffering of adults — depression, fear, dread — was thought to be beyond a baby's scope. Read "Health Checkup: Kids and Mental Health.")

No more. The nonprofit child-advocacy group Zero to Three — which, as its name suggests, studies development in the first three years of life — estimates that about 10% of very young children have some kind of clinical emotional condition, about the same rate as the adult population. And while some of those ills are indeed unique to babies, a growing body of research shows that many others — including posttraumatic stress disorder (PTSD), social-anxiety disorder, major depression, insomnia, even prolonged bereavement — also afflict young children. "Disorders we see in adulthood have antecedents in childhood," says Dr. Robert Emde, an emeritus professor of psychiatry at the University of Colorado School of Medicine. "The psychopathology simply becomes more complex."

Zero to Three publishes a diagnostic-classification handbook, DC: 0-3, which is modeled on the Diagnostic and Statistical Manual (DSM), the guidebook for adult mental disorders. The handbook is rapidly bringing new order to the field. If the idea of a depressed baby seems preposterous at first, it doesn't once you know what to look for: the same fatigue, indifference and appetite change seen in depressed adults. The possibility that a shy baby may actually be socially phobic similarly seems less of a reach when you look at scans of the brain showing irregular activity in regions that process threat or fear.

One obstacle to broad acceptance of the new thinking is that babies can't talk. An adult with social-anxiety disorder can describe in detail the throat-choking panic triggered by a cocktail party. In the case of a baby, it takes careful observation, and even then the signs can be misleading. Crying, tantrums or clinging are among the symptoms DC: 0-3 lists for social anxiety. Is there a parent alive who hasn't contended with them? "We see this with PTSD too," says Egger. "A combat veteran can say, 'I'm having a flashback.' With a traumatized baby, we have to look for how it manifests itself in play." A once calm child might become easily startled; enthusiasm for play may diminish or vanish.

See the top 10 medical breakthroughs of 2010.