How to Stop Kids From Biting Their Nails, Sucking Their Thumbs, and More

You adore your child, but you can’t say the same about some of his annoying habits: The knuckle cracking. The nail nibbling. The way he interrupts your phone calls with emergency pleas for peanut butter. Relax—there are a few wise strategies to restore your sanity.

First, it’s important to understand the impulse behind the actions. If he’s smacking away at the dinner table, he may just need an etiquette adjustment. However, some parental button-pushers—like thumb-sucking, nail biting, knuckle cracking, and hair twirling—are unconscious ways to relieve tension. “They can help alleviate feelings that a child is experiencing in a big way—boredom, anxiety, overexcitement,” says Dawn Huebner, Ph.D., a psychologist in Exeter, New Hampshire, and the author of What to Do When Bad Habits Take Hold ($16, amazon.com).

A gentle approach is best. “Shaming or punishing him may just compound the stress that’s feeding these habits in the first place,” says Jack Maypole, M.D., the director of pediatrics at the South End Community Health Center, in Boston. Instead, he says, try to point out the appeal of giving up the behavior. If he clings to the thumb, for instance, say, “You’re a big kid now, and I don’t think big kids do that anymore.”

Since these activities often fill an important sensory need, says Huebner, help your child find a substitute. Don’t underestimate the power of incentives. If she goes a day without biting her nails, let her choose dinner. And for every success, praise lavishly. “A little ‘whoop-de-do!’ is as much a reward as anything,” says Maypole.

Finally, be patient. “Kids can be trying really hard,” says Huebner, “and have a setback on a tough day.” She notes that it can take 21 days of sustained effort to break a habit.