Anxiety disorders, the most common mental health problems in children and adolescents, often go untreated while children suffer, even though there are effective treatments available, according to a new report on anxiety in children and adolescents from the Child Mind Institute in New York. Anxiety may be missed because it doesn’t necessarily declare itself with attention-getting disruptive behaviors; in fact, symptoms may keep some children quiet and inhibited, though in other children, alternatively, anxiety may be misunderstood as oppositional behavior.

Adults may also assume that anxiety in a child is just a phase to be outgrown. A certain amount of anxiety is a normal aspect of development for young children — consider separation anxiety, for example — and it can even be protective, since children need to learn to keep themselves safe and anticipate certain kinds of dangers. But when worrying or avoiding possible threats gets in the way of a child’s functioning or a child’s enjoyment, it should be a signal to parents that help is needed, not just watching and waiting, not arranging the child’s life to avoid the occasions of anxiety.

Kathleen Merikangas, the senior investigator and chief of the Genetic Epidemiology Research Branch at the National Institute of Mental Health, said, “To me, anxiety is one of the most underrecognized or under-treated conditions of childhood and adolescence.” These children can get missed, she said, because they may seem to be functioning well; many don’t have the kinds of developmental problems or attention issues that draw attention in school, though they may be suffering.

Consider the child whose anxiety about speaking in public gets in the way of participating in class. The child may be silent out of a fear of being laughed at or otherwise rejected, Dr. Merikangas said, but to the teacher, it may look like the child is just not interested. Environmental modifications can really help these children thrive in school, she said; for example, working in small groups with children they know.