Habits and Tics
In the course of growing up, most children will display at least one fixed repetitive behavior that is not always under voluntary control, called a “habit” or “tic.” For most children, these behaviors are responses to temporary physical or emotional needs and seem to help them cope with normal everyday stresses. They typically appear and disappear during the normal course of development. Almost all children, for example, are observed sucking their fists within an hour after birth, then primarily after a feeding. By the preschool years, however, most children suck only at bedtime. Similarly, the use of a transitional object (e.g., a blanket, teddy bear, or doll) increases after age 2, at just about the time when separation and individuation issues peak, whereas the need for these objects begins to decrease after the preschool years. Body rocking peaks between 9 and 17 months, when children begin to sleep for longer periods of time, but it is usually gone by 2 to 3 years of age. Similiarly, head banging peaks between 12 and 17 months. Movement tics (e.g., blinking, shoulder shrugs, etc.) become evident between 6 and 8 years of age, when demands to “sit still and learn” increase; however, these tics also diminish rather quickly for most children.
“Old” habits may reappear with new stresses, such as the birth of a sibling, parental divorce, going to a new school, or the prolonged absence of a parent. Some children “hang on” to a particular habit for no apparent reason, and over time it becomes an automatic, involuntary response. These behaviors or habits are not usually symptomatic of underlying pathology, and only become problems under certain circumstances: (1) The behavior continues longer than is typical; (2) the behavior becomes severe or chronic enough to cause physical damage; and/or (3) the behavior is engaged in so frequently that it interferes with ongoing physical, social, and/or cognitive development. This chapter reviews a number of habits that have been known to create problems for children or their families, including oral habits (thumb sucking, nail biting, bruxism, etc.), hair pulling, and other behaviors (such as rituals and breath holding). Motor and vocal tics are most often transient problems; however, they can persist and/or be indicative of a more serious problem, Tourette's disorder (TD), and thus are reviewed in some depth.
Thumb sucking (which can actually include sucking the thumbs, fingers, fists, or a pacifier) is a common behavior among children; there is evidence that some children begin to suck while